4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
44 static void spidev_release(struct device *dev)
46 struct spi_device *spi = to_spi_device(dev);
48 /* spi masters may cleanup for released devices */
49 if (spi->master->cleanup)
50 spi->master->cleanup(spi);
52 spi_master_put(spi->master);
57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 const struct spi_device *spi = to_spi_device(dev);
62 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 static DEVICE_ATTR_RO(modalias);
70 #define SPI_STATISTICS_ATTRS(field, file) \
71 static ssize_t spi_master_##field##_show(struct device *dev, \
72 struct device_attribute *attr, \
75 struct spi_master *master = container_of(dev, \
76 struct spi_master, dev); \
77 return spi_statistics_##field##_show(&master->statistics, buf); \
79 static struct device_attribute dev_attr_spi_master_##field = { \
80 .attr = { .name = file, .mode = S_IRUGO }, \
81 .show = spi_master_##field##_show, \
83 static ssize_t spi_device_##field##_show(struct device *dev, \
84 struct device_attribute *attr, \
87 struct spi_device *spi = to_spi_device(dev); \
88 return spi_statistics_##field##_show(&spi->statistics, buf); \
90 static struct device_attribute dev_attr_spi_device_##field = { \
91 .attr = { .name = file, .mode = S_IRUGO }, \
92 .show = spi_device_##field##_show, \
95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
99 unsigned long flags; \
101 spin_lock_irqsave(&stat->lock, flags); \
102 len = sprintf(buf, format_string, stat->field); \
103 spin_unlock_irqrestore(&stat->lock, flags); \
106 SPI_STATISTICS_ATTRS(name, file)
108 #define SPI_STATISTICS_SHOW(field, format_string) \
109 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
110 field, format_string)
112 SPI_STATISTICS_SHOW(messages, "%lu");
113 SPI_STATISTICS_SHOW(transfers, "%lu");
114 SPI_STATISTICS_SHOW(errors, "%lu");
115 SPI_STATISTICS_SHOW(timedout, "%lu");
117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
119 SPI_STATISTICS_SHOW(spi_async, "%lu");
121 SPI_STATISTICS_SHOW(bytes, "%llu");
122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
126 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
127 "transfer_bytes_histo_" number, \
128 transfer_bytes_histo[index], "%lu")
129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
147 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
149 static struct attribute *spi_dev_attrs[] = {
150 &dev_attr_modalias.attr,
154 static const struct attribute_group spi_dev_group = {
155 .attrs = spi_dev_attrs,
158 static struct attribute *spi_device_statistics_attrs[] = {
159 &dev_attr_spi_device_messages.attr,
160 &dev_attr_spi_device_transfers.attr,
161 &dev_attr_spi_device_errors.attr,
162 &dev_attr_spi_device_timedout.attr,
163 &dev_attr_spi_device_spi_sync.attr,
164 &dev_attr_spi_device_spi_sync_immediate.attr,
165 &dev_attr_spi_device_spi_async.attr,
166 &dev_attr_spi_device_bytes.attr,
167 &dev_attr_spi_device_bytes_rx.attr,
168 &dev_attr_spi_device_bytes_tx.attr,
169 &dev_attr_spi_device_transfer_bytes_histo0.attr,
170 &dev_attr_spi_device_transfer_bytes_histo1.attr,
171 &dev_attr_spi_device_transfer_bytes_histo2.attr,
172 &dev_attr_spi_device_transfer_bytes_histo3.attr,
173 &dev_attr_spi_device_transfer_bytes_histo4.attr,
174 &dev_attr_spi_device_transfer_bytes_histo5.attr,
175 &dev_attr_spi_device_transfer_bytes_histo6.attr,
176 &dev_attr_spi_device_transfer_bytes_histo7.attr,
177 &dev_attr_spi_device_transfer_bytes_histo8.attr,
178 &dev_attr_spi_device_transfer_bytes_histo9.attr,
179 &dev_attr_spi_device_transfer_bytes_histo10.attr,
180 &dev_attr_spi_device_transfer_bytes_histo11.attr,
181 &dev_attr_spi_device_transfer_bytes_histo12.attr,
182 &dev_attr_spi_device_transfer_bytes_histo13.attr,
183 &dev_attr_spi_device_transfer_bytes_histo14.attr,
184 &dev_attr_spi_device_transfer_bytes_histo15.attr,
185 &dev_attr_spi_device_transfer_bytes_histo16.attr,
186 &dev_attr_spi_device_transfers_split_maxsize.attr,
190 static const struct attribute_group spi_device_statistics_group = {
191 .name = "statistics",
192 .attrs = spi_device_statistics_attrs,
195 static const struct attribute_group *spi_dev_groups[] = {
197 &spi_device_statistics_group,
201 static struct attribute *spi_master_statistics_attrs[] = {
202 &dev_attr_spi_master_messages.attr,
203 &dev_attr_spi_master_transfers.attr,
204 &dev_attr_spi_master_errors.attr,
205 &dev_attr_spi_master_timedout.attr,
206 &dev_attr_spi_master_spi_sync.attr,
207 &dev_attr_spi_master_spi_sync_immediate.attr,
208 &dev_attr_spi_master_spi_async.attr,
209 &dev_attr_spi_master_bytes.attr,
210 &dev_attr_spi_master_bytes_rx.attr,
211 &dev_attr_spi_master_bytes_tx.attr,
212 &dev_attr_spi_master_transfer_bytes_histo0.attr,
213 &dev_attr_spi_master_transfer_bytes_histo1.attr,
214 &dev_attr_spi_master_transfer_bytes_histo2.attr,
215 &dev_attr_spi_master_transfer_bytes_histo3.attr,
216 &dev_attr_spi_master_transfer_bytes_histo4.attr,
217 &dev_attr_spi_master_transfer_bytes_histo5.attr,
218 &dev_attr_spi_master_transfer_bytes_histo6.attr,
219 &dev_attr_spi_master_transfer_bytes_histo7.attr,
220 &dev_attr_spi_master_transfer_bytes_histo8.attr,
221 &dev_attr_spi_master_transfer_bytes_histo9.attr,
222 &dev_attr_spi_master_transfer_bytes_histo10.attr,
223 &dev_attr_spi_master_transfer_bytes_histo11.attr,
224 &dev_attr_spi_master_transfer_bytes_histo12.attr,
225 &dev_attr_spi_master_transfer_bytes_histo13.attr,
226 &dev_attr_spi_master_transfer_bytes_histo14.attr,
227 &dev_attr_spi_master_transfer_bytes_histo15.attr,
228 &dev_attr_spi_master_transfer_bytes_histo16.attr,
229 &dev_attr_spi_master_transfers_split_maxsize.attr,
233 static const struct attribute_group spi_master_statistics_group = {
234 .name = "statistics",
235 .attrs = spi_master_statistics_attrs,
238 static const struct attribute_group *spi_master_groups[] = {
239 &spi_master_statistics_group,
243 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
244 struct spi_transfer *xfer,
245 struct spi_master *master)
248 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
253 spin_lock_irqsave(&stats->lock, flags);
256 stats->transfer_bytes_histo[l2len]++;
258 stats->bytes += xfer->len;
259 if ((xfer->tx_buf) &&
260 (xfer->tx_buf != master->dummy_tx))
261 stats->bytes_tx += xfer->len;
262 if ((xfer->rx_buf) &&
263 (xfer->rx_buf != master->dummy_rx))
264 stats->bytes_rx += xfer->len;
266 spin_unlock_irqrestore(&stats->lock, flags);
268 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
270 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
271 * and the sysfs version makes coldplug work too.
274 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
275 const struct spi_device *sdev)
277 while (id->name[0]) {
278 if (!strcmp(sdev->modalias, id->name))
285 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
287 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
289 return spi_match_id(sdrv->id_table, sdev);
291 EXPORT_SYMBOL_GPL(spi_get_device_id);
293 static int spi_match_device(struct device *dev, struct device_driver *drv)
295 const struct spi_device *spi = to_spi_device(dev);
296 const struct spi_driver *sdrv = to_spi_driver(drv);
298 /* Attempt an OF style match */
299 if (of_driver_match_device(dev, drv))
303 if (acpi_driver_match_device(dev, drv))
307 return !!spi_match_id(sdrv->id_table, spi);
309 return strcmp(spi->modalias, drv->name) == 0;
312 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
314 const struct spi_device *spi = to_spi_device(dev);
317 rc = acpi_device_uevent_modalias(dev, env);
321 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
325 struct bus_type spi_bus_type = {
327 .dev_groups = spi_dev_groups,
328 .match = spi_match_device,
329 .uevent = spi_uevent,
331 EXPORT_SYMBOL_GPL(spi_bus_type);
334 static int spi_drv_probe(struct device *dev)
336 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
337 struct spi_device *spi = to_spi_device(dev);
340 ret = of_clk_set_defaults(dev->of_node, false);
345 spi->irq = of_irq_get(dev->of_node, 0);
346 if (spi->irq == -EPROBE_DEFER)
347 return -EPROBE_DEFER;
352 ret = dev_pm_domain_attach(dev, true);
353 if (ret != -EPROBE_DEFER) {
354 ret = sdrv->probe(spi);
356 dev_pm_domain_detach(dev, true);
362 static int spi_drv_remove(struct device *dev)
364 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
367 ret = sdrv->remove(to_spi_device(dev));
368 dev_pm_domain_detach(dev, true);
373 static void spi_drv_shutdown(struct device *dev)
375 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
377 sdrv->shutdown(to_spi_device(dev));
381 * __spi_register_driver - register a SPI driver
382 * @owner: owner module of the driver to register
383 * @sdrv: the driver to register
386 * Return: zero on success, else a negative error code.
388 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
390 sdrv->driver.owner = owner;
391 sdrv->driver.bus = &spi_bus_type;
393 sdrv->driver.probe = spi_drv_probe;
395 sdrv->driver.remove = spi_drv_remove;
397 sdrv->driver.shutdown = spi_drv_shutdown;
398 return driver_register(&sdrv->driver);
400 EXPORT_SYMBOL_GPL(__spi_register_driver);
402 /*-------------------------------------------------------------------------*/
404 /* SPI devices should normally not be created by SPI device drivers; that
405 * would make them board-specific. Similarly with SPI master drivers.
406 * Device registration normally goes into like arch/.../mach.../board-YYY.c
407 * with other readonly (flashable) information about mainboard devices.
411 struct list_head list;
412 struct spi_board_info board_info;
415 static LIST_HEAD(board_list);
416 static LIST_HEAD(spi_master_list);
419 * Used to protect add/del opertion for board_info list and
420 * spi_master list, and their matching process
422 static DEFINE_MUTEX(board_lock);
425 * spi_alloc_device - Allocate a new SPI device
426 * @master: Controller to which device is connected
429 * Allows a driver to allocate and initialize a spi_device without
430 * registering it immediately. This allows a driver to directly
431 * fill the spi_device with device parameters before calling
432 * spi_add_device() on it.
434 * Caller is responsible to call spi_add_device() on the returned
435 * spi_device structure to add it to the SPI master. If the caller
436 * needs to discard the spi_device without adding it, then it should
437 * call spi_dev_put() on it.
439 * Return: a pointer to the new device, or NULL.
441 struct spi_device *spi_alloc_device(struct spi_master *master)
443 struct spi_device *spi;
445 if (!spi_master_get(master))
448 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
450 spi_master_put(master);
454 spi->master = master;
455 spi->dev.parent = &master->dev;
456 spi->dev.bus = &spi_bus_type;
457 spi->dev.release = spidev_release;
458 spi->cs_gpio = -ENOENT;
460 spin_lock_init(&spi->statistics.lock);
462 device_initialize(&spi->dev);
465 EXPORT_SYMBOL_GPL(spi_alloc_device);
467 static void spi_dev_set_name(struct spi_device *spi)
469 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
472 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
476 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
480 static int spi_dev_check(struct device *dev, void *data)
482 struct spi_device *spi = to_spi_device(dev);
483 struct spi_device *new_spi = data;
485 if (spi->master == new_spi->master &&
486 spi->chip_select == new_spi->chip_select)
492 * spi_add_device - Add spi_device allocated with spi_alloc_device
493 * @spi: spi_device to register
495 * Companion function to spi_alloc_device. Devices allocated with
496 * spi_alloc_device can be added onto the spi bus with this function.
498 * Return: 0 on success; negative errno on failure
500 int spi_add_device(struct spi_device *spi)
502 static DEFINE_MUTEX(spi_add_lock);
503 struct spi_master *master = spi->master;
504 struct device *dev = master->dev.parent;
507 /* Chipselects are numbered 0..max; validate. */
508 if (spi->chip_select >= master->num_chipselect) {
509 dev_err(dev, "cs%d >= max %d\n",
511 master->num_chipselect);
515 /* Set the bus ID string */
516 spi_dev_set_name(spi);
518 /* We need to make sure there's no other device with this
519 * chipselect **BEFORE** we call setup(), else we'll trash
520 * its configuration. Lock against concurrent add() calls.
522 mutex_lock(&spi_add_lock);
524 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
526 dev_err(dev, "chipselect %d already in use\n",
531 if (master->cs_gpios)
532 spi->cs_gpio = master->cs_gpios[spi->chip_select];
534 /* Drivers may modify this initial i/o setup, but will
535 * normally rely on the device being setup. Devices
536 * using SPI_CS_HIGH can't coexist well otherwise...
538 status = spi_setup(spi);
540 dev_err(dev, "can't setup %s, status %d\n",
541 dev_name(&spi->dev), status);
545 /* Device may be bound to an active driver when this returns */
546 status = device_add(&spi->dev);
548 dev_err(dev, "can't add %s, status %d\n",
549 dev_name(&spi->dev), status);
551 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
554 mutex_unlock(&spi_add_lock);
557 EXPORT_SYMBOL_GPL(spi_add_device);
560 * spi_new_device - instantiate one new SPI device
561 * @master: Controller to which device is connected
562 * @chip: Describes the SPI device
565 * On typical mainboards, this is purely internal; and it's not needed
566 * after board init creates the hard-wired devices. Some development
567 * platforms may not be able to use spi_register_board_info though, and
568 * this is exported so that for example a USB or parport based adapter
569 * driver could add devices (which it would learn about out-of-band).
571 * Return: the new device, or NULL.
573 struct spi_device *spi_new_device(struct spi_master *master,
574 struct spi_board_info *chip)
576 struct spi_device *proxy;
579 /* NOTE: caller did any chip->bus_num checks necessary.
581 * Also, unless we change the return value convention to use
582 * error-or-pointer (not NULL-or-pointer), troubleshootability
583 * suggests syslogged diagnostics are best here (ugh).
586 proxy = spi_alloc_device(master);
590 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
592 proxy->chip_select = chip->chip_select;
593 proxy->max_speed_hz = chip->max_speed_hz;
594 proxy->mode = chip->mode;
595 proxy->irq = chip->irq;
596 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
597 proxy->dev.platform_data = (void *) chip->platform_data;
598 proxy->controller_data = chip->controller_data;
599 proxy->controller_state = NULL;
601 status = spi_add_device(proxy);
609 EXPORT_SYMBOL_GPL(spi_new_device);
612 * spi_unregister_device - unregister a single SPI device
613 * @spi: spi_device to unregister
615 * Start making the passed SPI device vanish. Normally this would be handled
616 * by spi_unregister_master().
618 void spi_unregister_device(struct spi_device *spi)
623 if (spi->dev.of_node)
624 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
625 device_unregister(&spi->dev);
627 EXPORT_SYMBOL_GPL(spi_unregister_device);
629 static void spi_match_master_to_boardinfo(struct spi_master *master,
630 struct spi_board_info *bi)
632 struct spi_device *dev;
634 if (master->bus_num != bi->bus_num)
637 dev = spi_new_device(master, bi);
639 dev_err(master->dev.parent, "can't create new device for %s\n",
644 * spi_register_board_info - register SPI devices for a given board
645 * @info: array of chip descriptors
646 * @n: how many descriptors are provided
649 * Board-specific early init code calls this (probably during arch_initcall)
650 * with segments of the SPI device table. Any device nodes are created later,
651 * after the relevant parent SPI controller (bus_num) is defined. We keep
652 * this table of devices forever, so that reloading a controller driver will
653 * not make Linux forget about these hard-wired devices.
655 * Other code can also call this, e.g. a particular add-on board might provide
656 * SPI devices through its expansion connector, so code initializing that board
657 * would naturally declare its SPI devices.
659 * The board info passed can safely be __initdata ... but be careful of
660 * any embedded pointers (platform_data, etc), they're copied as-is.
662 * Return: zero on success, else a negative error code.
664 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
666 struct boardinfo *bi;
672 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
676 for (i = 0; i < n; i++, bi++, info++) {
677 struct spi_master *master;
679 memcpy(&bi->board_info, info, sizeof(*info));
680 mutex_lock(&board_lock);
681 list_add_tail(&bi->list, &board_list);
682 list_for_each_entry(master, &spi_master_list, list)
683 spi_match_master_to_boardinfo(master, &bi->board_info);
684 mutex_unlock(&board_lock);
690 /*-------------------------------------------------------------------------*/
692 static void spi_set_cs(struct spi_device *spi, bool enable)
694 if (spi->mode & SPI_CS_HIGH)
697 if (gpio_is_valid(spi->cs_gpio))
698 gpio_set_value(spi->cs_gpio, !enable);
699 else if (spi->master->set_cs)
700 spi->master->set_cs(spi, !enable);
703 #ifdef CONFIG_HAS_DMA
704 static int spi_map_buf(struct spi_master *master, struct device *dev,
705 struct sg_table *sgt, void *buf, size_t len,
706 enum dma_data_direction dir)
708 const bool vmalloced_buf = is_vmalloc_addr(buf);
711 struct page *vm_page;
717 desc_len = PAGE_SIZE;
718 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
720 desc_len = master->max_dma_len;
721 sgs = DIV_ROUND_UP(len, desc_len);
724 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
728 for (i = 0; i < sgs; i++) {
732 len, desc_len - offset_in_page(buf));
733 vm_page = vmalloc_to_page(buf);
738 sg_set_page(&sgt->sgl[i], vm_page,
739 min, offset_in_page(buf));
741 min = min_t(size_t, len, desc_len);
743 sg_set_buf(&sgt->sgl[i], sg_buf, min);
751 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
764 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
765 struct sg_table *sgt, enum dma_data_direction dir)
767 if (sgt->orig_nents) {
768 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
773 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
775 struct device *tx_dev, *rx_dev;
776 struct spi_transfer *xfer;
779 if (!master->can_dma)
783 tx_dev = master->dma_tx->device->dev;
785 tx_dev = &master->dev;
788 rx_dev = master->dma_rx->device->dev;
790 rx_dev = &master->dev;
792 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
793 if (!master->can_dma(master, msg->spi, xfer))
796 if (xfer->tx_buf != NULL) {
797 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
798 (void *)xfer->tx_buf, xfer->len,
804 if (xfer->rx_buf != NULL) {
805 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
806 xfer->rx_buf, xfer->len,
809 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
816 master->cur_msg_mapped = true;
821 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
823 struct spi_transfer *xfer;
824 struct device *tx_dev, *rx_dev;
826 if (!master->cur_msg_mapped || !master->can_dma)
830 tx_dev = master->dma_tx->device->dev;
832 tx_dev = &master->dev;
835 rx_dev = master->dma_rx->device->dev;
837 rx_dev = &master->dev;
839 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
840 if (!master->can_dma(master, msg->spi, xfer))
843 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
844 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
849 #else /* !CONFIG_HAS_DMA */
850 static inline int __spi_map_msg(struct spi_master *master,
851 struct spi_message *msg)
856 static inline int __spi_unmap_msg(struct spi_master *master,
857 struct spi_message *msg)
861 #endif /* !CONFIG_HAS_DMA */
863 static inline int spi_unmap_msg(struct spi_master *master,
864 struct spi_message *msg)
866 struct spi_transfer *xfer;
868 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
870 * Restore the original value of tx_buf or rx_buf if they are
873 if (xfer->tx_buf == master->dummy_tx)
875 if (xfer->rx_buf == master->dummy_rx)
879 return __spi_unmap_msg(master, msg);
882 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
884 struct spi_transfer *xfer;
886 unsigned int max_tx, max_rx;
888 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
892 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
893 if ((master->flags & SPI_MASTER_MUST_TX) &&
895 max_tx = max(xfer->len, max_tx);
896 if ((master->flags & SPI_MASTER_MUST_RX) &&
898 max_rx = max(xfer->len, max_rx);
902 tmp = krealloc(master->dummy_tx, max_tx,
903 GFP_KERNEL | GFP_DMA);
906 master->dummy_tx = tmp;
907 memset(tmp, 0, max_tx);
911 tmp = krealloc(master->dummy_rx, max_rx,
912 GFP_KERNEL | GFP_DMA);
915 master->dummy_rx = tmp;
918 if (max_tx || max_rx) {
919 list_for_each_entry(xfer, &msg->transfers,
922 xfer->tx_buf = master->dummy_tx;
924 xfer->rx_buf = master->dummy_rx;
929 return __spi_map_msg(master, msg);
933 * spi_transfer_one_message - Default implementation of transfer_one_message()
935 * This is a standard implementation of transfer_one_message() for
936 * drivers which impelment a transfer_one() operation. It provides
937 * standard handling of delays and chip select management.
939 static int spi_transfer_one_message(struct spi_master *master,
940 struct spi_message *msg)
942 struct spi_transfer *xfer;
943 bool keep_cs = false;
945 unsigned long ms = 1;
946 struct spi_statistics *statm = &master->statistics;
947 struct spi_statistics *stats = &msg->spi->statistics;
949 spi_set_cs(msg->spi, true);
951 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
952 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
954 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
955 trace_spi_transfer_start(msg, xfer);
957 spi_statistics_add_transfer_stats(statm, xfer, master);
958 spi_statistics_add_transfer_stats(stats, xfer, master);
960 if (xfer->tx_buf || xfer->rx_buf) {
961 reinit_completion(&master->xfer_completion);
963 ret = master->transfer_one(master, msg->spi, xfer);
965 SPI_STATISTICS_INCREMENT_FIELD(statm,
967 SPI_STATISTICS_INCREMENT_FIELD(stats,
969 dev_err(&msg->spi->dev,
970 "SPI transfer failed: %d\n", ret);
976 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
977 ms += ms + 100; /* some tolerance */
979 ms = wait_for_completion_timeout(&master->xfer_completion,
980 msecs_to_jiffies(ms));
984 SPI_STATISTICS_INCREMENT_FIELD(statm,
986 SPI_STATISTICS_INCREMENT_FIELD(stats,
988 dev_err(&msg->spi->dev,
989 "SPI transfer timed out\n");
990 msg->status = -ETIMEDOUT;
994 dev_err(&msg->spi->dev,
995 "Bufferless transfer has length %u\n",
999 trace_spi_transfer_stop(msg, xfer);
1001 if (msg->status != -EINPROGRESS)
1004 if (xfer->delay_usecs)
1005 udelay(xfer->delay_usecs);
1007 if (xfer->cs_change) {
1008 if (list_is_last(&xfer->transfer_list,
1012 spi_set_cs(msg->spi, false);
1014 spi_set_cs(msg->spi, true);
1018 msg->actual_length += xfer->len;
1022 if (ret != 0 || !keep_cs)
1023 spi_set_cs(msg->spi, false);
1025 if (msg->status == -EINPROGRESS)
1028 if (msg->status && master->handle_err)
1029 master->handle_err(master, msg);
1031 spi_res_release(master, msg);
1033 spi_finalize_current_message(master);
1039 * spi_finalize_current_transfer - report completion of a transfer
1040 * @master: the master reporting completion
1042 * Called by SPI drivers using the core transfer_one_message()
1043 * implementation to notify it that the current interrupt driven
1044 * transfer has finished and the next one may be scheduled.
1046 void spi_finalize_current_transfer(struct spi_master *master)
1048 complete(&master->xfer_completion);
1050 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1053 * __spi_pump_messages - function which processes spi message queue
1054 * @master: master to process queue for
1055 * @in_kthread: true if we are in the context of the message pump thread
1057 * This function checks if there is any spi message in the queue that
1058 * needs processing and if so call out to the driver to initialize hardware
1059 * and transfer each message.
1061 * Note that it is called both from the kthread itself and also from
1062 * inside spi_sync(); the queue extraction handling at the top of the
1063 * function should deal with this safely.
1065 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1067 unsigned long flags;
1068 bool was_busy = false;
1072 spin_lock_irqsave(&master->queue_lock, flags);
1074 /* Make sure we are not already running a message */
1075 if (master->cur_msg) {
1076 spin_unlock_irqrestore(&master->queue_lock, flags);
1080 /* If another context is idling the device then defer */
1081 if (master->idling) {
1082 queue_kthread_work(&master->kworker, &master->pump_messages);
1083 spin_unlock_irqrestore(&master->queue_lock, flags);
1087 /* Check if the queue is idle */
1088 if (list_empty(&master->queue) || !master->running) {
1089 if (!master->busy) {
1090 spin_unlock_irqrestore(&master->queue_lock, flags);
1094 /* Only do teardown in the thread */
1096 queue_kthread_work(&master->kworker,
1097 &master->pump_messages);
1098 spin_unlock_irqrestore(&master->queue_lock, flags);
1102 master->busy = false;
1103 master->idling = true;
1104 spin_unlock_irqrestore(&master->queue_lock, flags);
1106 kfree(master->dummy_rx);
1107 master->dummy_rx = NULL;
1108 kfree(master->dummy_tx);
1109 master->dummy_tx = NULL;
1110 if (master->unprepare_transfer_hardware &&
1111 master->unprepare_transfer_hardware(master))
1112 dev_err(&master->dev,
1113 "failed to unprepare transfer hardware\n");
1114 if (master->auto_runtime_pm) {
1115 pm_runtime_mark_last_busy(master->dev.parent);
1116 pm_runtime_put_autosuspend(master->dev.parent);
1118 trace_spi_master_idle(master);
1120 spin_lock_irqsave(&master->queue_lock, flags);
1121 master->idling = false;
1122 spin_unlock_irqrestore(&master->queue_lock, flags);
1126 /* Extract head of queue */
1128 list_first_entry(&master->queue, struct spi_message, queue);
1130 list_del_init(&master->cur_msg->queue);
1134 master->busy = true;
1135 spin_unlock_irqrestore(&master->queue_lock, flags);
1137 if (!was_busy && master->auto_runtime_pm) {
1138 ret = pm_runtime_get_sync(master->dev.parent);
1140 dev_err(&master->dev, "Failed to power device: %d\n",
1147 trace_spi_master_busy(master);
1149 if (!was_busy && master->prepare_transfer_hardware) {
1150 ret = master->prepare_transfer_hardware(master);
1152 dev_err(&master->dev,
1153 "failed to prepare transfer hardware\n");
1155 if (master->auto_runtime_pm)
1156 pm_runtime_put(master->dev.parent);
1161 trace_spi_message_start(master->cur_msg);
1163 if (master->prepare_message) {
1164 ret = master->prepare_message(master, master->cur_msg);
1166 dev_err(&master->dev,
1167 "failed to prepare message: %d\n", ret);
1168 master->cur_msg->status = ret;
1169 spi_finalize_current_message(master);
1172 master->cur_msg_prepared = true;
1175 ret = spi_map_msg(master, master->cur_msg);
1177 master->cur_msg->status = ret;
1178 spi_finalize_current_message(master);
1182 ret = master->transfer_one_message(master, master->cur_msg);
1184 dev_err(&master->dev,
1185 "failed to transfer one message from queue\n");
1191 * spi_pump_messages - kthread work function which processes spi message queue
1192 * @work: pointer to kthread work struct contained in the master struct
1194 static void spi_pump_messages(struct kthread_work *work)
1196 struct spi_master *master =
1197 container_of(work, struct spi_master, pump_messages);
1199 __spi_pump_messages(master, true);
1202 static int spi_init_queue(struct spi_master *master)
1204 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1206 master->running = false;
1207 master->busy = false;
1209 init_kthread_worker(&master->kworker);
1210 master->kworker_task = kthread_run(kthread_worker_fn,
1211 &master->kworker, "%s",
1212 dev_name(&master->dev));
1213 if (IS_ERR(master->kworker_task)) {
1214 dev_err(&master->dev, "failed to create message pump task\n");
1215 return PTR_ERR(master->kworker_task);
1217 init_kthread_work(&master->pump_messages, spi_pump_messages);
1220 * Master config will indicate if this controller should run the
1221 * message pump with high (realtime) priority to reduce the transfer
1222 * latency on the bus by minimising the delay between a transfer
1223 * request and the scheduling of the message pump thread. Without this
1224 * setting the message pump thread will remain at default priority.
1227 dev_info(&master->dev,
1228 "will run message pump with realtime priority\n");
1229 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1236 * spi_get_next_queued_message() - called by driver to check for queued
1238 * @master: the master to check for queued messages
1240 * If there are more messages in the queue, the next message is returned from
1243 * Return: the next message in the queue, else NULL if the queue is empty.
1245 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1247 struct spi_message *next;
1248 unsigned long flags;
1250 /* get a pointer to the next message, if any */
1251 spin_lock_irqsave(&master->queue_lock, flags);
1252 next = list_first_entry_or_null(&master->queue, struct spi_message,
1254 spin_unlock_irqrestore(&master->queue_lock, flags);
1258 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1261 * spi_finalize_current_message() - the current message is complete
1262 * @master: the master to return the message to
1264 * Called by the driver to notify the core that the message in the front of the
1265 * queue is complete and can be removed from the queue.
1267 void spi_finalize_current_message(struct spi_master *master)
1269 struct spi_message *mesg;
1270 unsigned long flags;
1273 spin_lock_irqsave(&master->queue_lock, flags);
1274 mesg = master->cur_msg;
1275 spin_unlock_irqrestore(&master->queue_lock, flags);
1277 spi_unmap_msg(master, mesg);
1279 if (master->cur_msg_prepared && master->unprepare_message) {
1280 ret = master->unprepare_message(master, mesg);
1282 dev_err(&master->dev,
1283 "failed to unprepare message: %d\n", ret);
1287 spin_lock_irqsave(&master->queue_lock, flags);
1288 master->cur_msg = NULL;
1289 master->cur_msg_prepared = false;
1290 queue_kthread_work(&master->kworker, &master->pump_messages);
1291 spin_unlock_irqrestore(&master->queue_lock, flags);
1293 trace_spi_message_done(mesg);
1297 mesg->complete(mesg->context);
1299 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1301 static int spi_start_queue(struct spi_master *master)
1303 unsigned long flags;
1305 spin_lock_irqsave(&master->queue_lock, flags);
1307 if (master->running || master->busy) {
1308 spin_unlock_irqrestore(&master->queue_lock, flags);
1312 master->running = true;
1313 master->cur_msg = NULL;
1314 spin_unlock_irqrestore(&master->queue_lock, flags);
1316 queue_kthread_work(&master->kworker, &master->pump_messages);
1321 static int spi_stop_queue(struct spi_master *master)
1323 unsigned long flags;
1324 unsigned limit = 500;
1327 spin_lock_irqsave(&master->queue_lock, flags);
1330 * This is a bit lame, but is optimized for the common execution path.
1331 * A wait_queue on the master->busy could be used, but then the common
1332 * execution path (pump_messages) would be required to call wake_up or
1333 * friends on every SPI message. Do this instead.
1335 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1336 spin_unlock_irqrestore(&master->queue_lock, flags);
1337 usleep_range(10000, 11000);
1338 spin_lock_irqsave(&master->queue_lock, flags);
1341 if (!list_empty(&master->queue) || master->busy)
1344 master->running = false;
1346 spin_unlock_irqrestore(&master->queue_lock, flags);
1349 dev_warn(&master->dev,
1350 "could not stop message queue\n");
1356 static int spi_destroy_queue(struct spi_master *master)
1360 ret = spi_stop_queue(master);
1363 * flush_kthread_worker will block until all work is done.
1364 * If the reason that stop_queue timed out is that the work will never
1365 * finish, then it does no good to call flush/stop thread, so
1369 dev_err(&master->dev, "problem destroying queue\n");
1373 flush_kthread_worker(&master->kworker);
1374 kthread_stop(master->kworker_task);
1379 static int __spi_queued_transfer(struct spi_device *spi,
1380 struct spi_message *msg,
1383 struct spi_master *master = spi->master;
1384 unsigned long flags;
1386 spin_lock_irqsave(&master->queue_lock, flags);
1388 if (!master->running) {
1389 spin_unlock_irqrestore(&master->queue_lock, flags);
1392 msg->actual_length = 0;
1393 msg->status = -EINPROGRESS;
1395 list_add_tail(&msg->queue, &master->queue);
1396 if (!master->busy && need_pump)
1397 queue_kthread_work(&master->kworker, &master->pump_messages);
1399 spin_unlock_irqrestore(&master->queue_lock, flags);
1404 * spi_queued_transfer - transfer function for queued transfers
1405 * @spi: spi device which is requesting transfer
1406 * @msg: spi message which is to handled is queued to driver queue
1408 * Return: zero on success, else a negative error code.
1410 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1412 return __spi_queued_transfer(spi, msg, true);
1415 static int spi_master_initialize_queue(struct spi_master *master)
1419 master->transfer = spi_queued_transfer;
1420 if (!master->transfer_one_message)
1421 master->transfer_one_message = spi_transfer_one_message;
1423 /* Initialize and start queue */
1424 ret = spi_init_queue(master);
1426 dev_err(&master->dev, "problem initializing queue\n");
1427 goto err_init_queue;
1429 master->queued = true;
1430 ret = spi_start_queue(master);
1432 dev_err(&master->dev, "problem starting queue\n");
1433 goto err_start_queue;
1439 spi_destroy_queue(master);
1444 /*-------------------------------------------------------------------------*/
1446 #if defined(CONFIG_OF)
1447 static struct spi_device *
1448 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1450 struct spi_device *spi;
1454 /* Alloc an spi_device */
1455 spi = spi_alloc_device(master);
1457 dev_err(&master->dev, "spi_device alloc error for %s\n",
1463 /* Select device driver */
1464 rc = of_modalias_node(nc, spi->modalias,
1465 sizeof(spi->modalias));
1467 dev_err(&master->dev, "cannot find modalias for %s\n",
1472 /* Device address */
1473 rc = of_property_read_u32(nc, "reg", &value);
1475 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1479 spi->chip_select = value;
1481 /* Mode (clock phase/polarity/etc.) */
1482 if (of_find_property(nc, "spi-cpha", NULL))
1483 spi->mode |= SPI_CPHA;
1484 if (of_find_property(nc, "spi-cpol", NULL))
1485 spi->mode |= SPI_CPOL;
1486 if (of_find_property(nc, "spi-cs-high", NULL))
1487 spi->mode |= SPI_CS_HIGH;
1488 if (of_find_property(nc, "spi-3wire", NULL))
1489 spi->mode |= SPI_3WIRE;
1490 if (of_find_property(nc, "spi-lsb-first", NULL))
1491 spi->mode |= SPI_LSB_FIRST;
1493 /* Device DUAL/QUAD mode */
1494 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1499 spi->mode |= SPI_TX_DUAL;
1502 spi->mode |= SPI_TX_QUAD;
1505 dev_warn(&master->dev,
1506 "spi-tx-bus-width %d not supported\n",
1512 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1517 spi->mode |= SPI_RX_DUAL;
1520 spi->mode |= SPI_RX_QUAD;
1523 dev_warn(&master->dev,
1524 "spi-rx-bus-width %d not supported\n",
1531 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1533 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1537 spi->max_speed_hz = value;
1539 /* Store a pointer to the node in the device structure */
1541 spi->dev.of_node = nc;
1543 /* Register the new device */
1544 rc = spi_add_device(spi);
1546 dev_err(&master->dev, "spi_device register error %s\n",
1559 * of_register_spi_devices() - Register child devices onto the SPI bus
1560 * @master: Pointer to spi_master device
1562 * Registers an spi_device for each child node of master node which has a 'reg'
1565 static void of_register_spi_devices(struct spi_master *master)
1567 struct spi_device *spi;
1568 struct device_node *nc;
1570 if (!master->dev.of_node)
1573 for_each_available_child_of_node(master->dev.of_node, nc) {
1574 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1576 spi = of_register_spi_device(master, nc);
1578 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1583 static void of_register_spi_devices(struct spi_master *master) { }
1587 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1589 struct spi_device *spi = data;
1591 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1592 struct acpi_resource_spi_serialbus *sb;
1594 sb = &ares->data.spi_serial_bus;
1595 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1596 spi->chip_select = sb->device_selection;
1597 spi->max_speed_hz = sb->connection_speed;
1599 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1600 spi->mode |= SPI_CPHA;
1601 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1602 spi->mode |= SPI_CPOL;
1603 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1604 spi->mode |= SPI_CS_HIGH;
1606 } else if (spi->irq < 0) {
1609 if (acpi_dev_resource_interrupt(ares, 0, &r))
1613 /* Always tell the ACPI core to skip this resource */
1617 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1618 void *data, void **return_value)
1620 struct spi_master *master = data;
1621 struct list_head resource_list;
1622 struct acpi_device *adev;
1623 struct spi_device *spi;
1626 if (acpi_bus_get_device(handle, &adev))
1628 if (acpi_bus_get_status(adev) || !adev->status.present)
1631 spi = spi_alloc_device(master);
1633 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1634 dev_name(&adev->dev));
1635 return AE_NO_MEMORY;
1638 ACPI_COMPANION_SET(&spi->dev, adev);
1641 INIT_LIST_HEAD(&resource_list);
1642 ret = acpi_dev_get_resources(adev, &resource_list,
1643 acpi_spi_add_resource, spi);
1644 acpi_dev_free_resource_list(&resource_list);
1646 if (ret < 0 || !spi->max_speed_hz) {
1652 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1654 adev->power.flags.ignore_parent = true;
1655 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1656 if (spi_add_device(spi)) {
1657 adev->power.flags.ignore_parent = false;
1658 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1659 dev_name(&adev->dev));
1666 static void acpi_register_spi_devices(struct spi_master *master)
1671 handle = ACPI_HANDLE(master->dev.parent);
1675 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1676 acpi_spi_add_device, NULL,
1678 if (ACPI_FAILURE(status))
1679 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1682 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1683 #endif /* CONFIG_ACPI */
1685 static void spi_master_release(struct device *dev)
1687 struct spi_master *master;
1689 master = container_of(dev, struct spi_master, dev);
1693 static struct class spi_master_class = {
1694 .name = "spi_master",
1695 .owner = THIS_MODULE,
1696 .dev_release = spi_master_release,
1697 .dev_groups = spi_master_groups,
1702 * spi_alloc_master - allocate SPI master controller
1703 * @dev: the controller, possibly using the platform_bus
1704 * @size: how much zeroed driver-private data to allocate; the pointer to this
1705 * memory is in the driver_data field of the returned device,
1706 * accessible with spi_master_get_devdata().
1707 * Context: can sleep
1709 * This call is used only by SPI master controller drivers, which are the
1710 * only ones directly touching chip registers. It's how they allocate
1711 * an spi_master structure, prior to calling spi_register_master().
1713 * This must be called from context that can sleep.
1715 * The caller is responsible for assigning the bus number and initializing
1716 * the master's methods before calling spi_register_master(); and (after errors
1717 * adding the device) calling spi_master_put() to prevent a memory leak.
1719 * Return: the SPI master structure on success, else NULL.
1721 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1723 struct spi_master *master;
1728 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1732 device_initialize(&master->dev);
1733 master->bus_num = -1;
1734 master->num_chipselect = 1;
1735 master->dev.class = &spi_master_class;
1736 master->dev.parent = dev;
1737 spi_master_set_devdata(master, &master[1]);
1741 EXPORT_SYMBOL_GPL(spi_alloc_master);
1744 static int of_spi_register_master(struct spi_master *master)
1747 struct device_node *np = master->dev.of_node;
1752 nb = of_gpio_named_count(np, "cs-gpios");
1753 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1755 /* Return error only for an incorrectly formed cs-gpios property */
1756 if (nb == 0 || nb == -ENOENT)
1761 cs = devm_kzalloc(&master->dev,
1762 sizeof(int) * master->num_chipselect,
1764 master->cs_gpios = cs;
1766 if (!master->cs_gpios)
1769 for (i = 0; i < master->num_chipselect; i++)
1772 for (i = 0; i < nb; i++)
1773 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1778 static int of_spi_register_master(struct spi_master *master)
1785 * spi_register_master - register SPI master controller
1786 * @master: initialized master, originally from spi_alloc_master()
1787 * Context: can sleep
1789 * SPI master controllers connect to their drivers using some non-SPI bus,
1790 * such as the platform bus. The final stage of probe() in that code
1791 * includes calling spi_register_master() to hook up to this SPI bus glue.
1793 * SPI controllers use board specific (often SOC specific) bus numbers,
1794 * and board-specific addressing for SPI devices combines those numbers
1795 * with chip select numbers. Since SPI does not directly support dynamic
1796 * device identification, boards need configuration tables telling which
1797 * chip is at which address.
1799 * This must be called from context that can sleep. It returns zero on
1800 * success, else a negative error code (dropping the master's refcount).
1801 * After a successful return, the caller is responsible for calling
1802 * spi_unregister_master().
1804 * Return: zero on success, else a negative error code.
1806 int spi_register_master(struct spi_master *master)
1808 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1809 struct device *dev = master->dev.parent;
1810 struct boardinfo *bi;
1811 int status = -ENODEV;
1817 status = of_spi_register_master(master);
1821 /* even if it's just one always-selected device, there must
1822 * be at least one chipselect
1824 if (master->num_chipselect == 0)
1827 if ((master->bus_num < 0) && master->dev.of_node)
1828 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1830 /* convention: dynamically assigned bus IDs count down from the max */
1831 if (master->bus_num < 0) {
1832 /* FIXME switch to an IDR based scheme, something like
1833 * I2C now uses, so we can't run out of "dynamic" IDs
1835 master->bus_num = atomic_dec_return(&dyn_bus_id);
1839 INIT_LIST_HEAD(&master->queue);
1840 spin_lock_init(&master->queue_lock);
1841 spin_lock_init(&master->bus_lock_spinlock);
1842 mutex_init(&master->bus_lock_mutex);
1843 master->bus_lock_flag = 0;
1844 init_completion(&master->xfer_completion);
1845 if (!master->max_dma_len)
1846 master->max_dma_len = INT_MAX;
1848 /* register the device, then userspace will see it.
1849 * registration fails if the bus ID is in use.
1851 dev_set_name(&master->dev, "spi%u", master->bus_num);
1852 status = device_add(&master->dev);
1855 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1856 dynamic ? " (dynamic)" : "");
1858 /* If we're using a queued driver, start the queue */
1859 if (master->transfer)
1860 dev_info(dev, "master is unqueued, this is deprecated\n");
1862 status = spi_master_initialize_queue(master);
1864 device_del(&master->dev);
1868 /* add statistics */
1869 spin_lock_init(&master->statistics.lock);
1871 mutex_lock(&board_lock);
1872 list_add_tail(&master->list, &spi_master_list);
1873 list_for_each_entry(bi, &board_list, list)
1874 spi_match_master_to_boardinfo(master, &bi->board_info);
1875 mutex_unlock(&board_lock);
1877 /* Register devices from the device tree and ACPI */
1878 of_register_spi_devices(master);
1879 acpi_register_spi_devices(master);
1883 EXPORT_SYMBOL_GPL(spi_register_master);
1885 static void devm_spi_unregister(struct device *dev, void *res)
1887 spi_unregister_master(*(struct spi_master **)res);
1891 * dev_spi_register_master - register managed SPI master controller
1892 * @dev: device managing SPI master
1893 * @master: initialized master, originally from spi_alloc_master()
1894 * Context: can sleep
1896 * Register a SPI device as with spi_register_master() which will
1897 * automatically be unregister
1899 * Return: zero on success, else a negative error code.
1901 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1903 struct spi_master **ptr;
1906 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1910 ret = spi_register_master(master);
1913 devres_add(dev, ptr);
1920 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1922 static int __unregister(struct device *dev, void *null)
1924 spi_unregister_device(to_spi_device(dev));
1929 * spi_unregister_master - unregister SPI master controller
1930 * @master: the master being unregistered
1931 * Context: can sleep
1933 * This call is used only by SPI master controller drivers, which are the
1934 * only ones directly touching chip registers.
1936 * This must be called from context that can sleep.
1938 void spi_unregister_master(struct spi_master *master)
1942 if (master->queued) {
1943 if (spi_destroy_queue(master))
1944 dev_err(&master->dev, "queue remove failed\n");
1947 mutex_lock(&board_lock);
1948 list_del(&master->list);
1949 mutex_unlock(&board_lock);
1951 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1952 device_unregister(&master->dev);
1954 EXPORT_SYMBOL_GPL(spi_unregister_master);
1956 int spi_master_suspend(struct spi_master *master)
1960 /* Basically no-ops for non-queued masters */
1961 if (!master->queued)
1964 ret = spi_stop_queue(master);
1966 dev_err(&master->dev, "queue stop failed\n");
1970 EXPORT_SYMBOL_GPL(spi_master_suspend);
1972 int spi_master_resume(struct spi_master *master)
1976 if (!master->queued)
1979 ret = spi_start_queue(master);
1981 dev_err(&master->dev, "queue restart failed\n");
1985 EXPORT_SYMBOL_GPL(spi_master_resume);
1987 static int __spi_master_match(struct device *dev, const void *data)
1989 struct spi_master *m;
1990 const u16 *bus_num = data;
1992 m = container_of(dev, struct spi_master, dev);
1993 return m->bus_num == *bus_num;
1997 * spi_busnum_to_master - look up master associated with bus_num
1998 * @bus_num: the master's bus number
1999 * Context: can sleep
2001 * This call may be used with devices that are registered after
2002 * arch init time. It returns a refcounted pointer to the relevant
2003 * spi_master (which the caller must release), or NULL if there is
2004 * no such master registered.
2006 * Return: the SPI master structure on success, else NULL.
2008 struct spi_master *spi_busnum_to_master(u16 bus_num)
2011 struct spi_master *master = NULL;
2013 dev = class_find_device(&spi_master_class, NULL, &bus_num,
2014 __spi_master_match);
2016 master = container_of(dev, struct spi_master, dev);
2017 /* reference got in class_find_device */
2020 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2022 /*-------------------------------------------------------------------------*/
2024 /* Core methods for SPI resource management */
2027 * spi_res_alloc - allocate a spi resource that is life-cycle managed
2028 * during the processing of a spi_message while using
2030 * @spi: the spi device for which we allocate memory
2031 * @release: the release code to execute for this resource
2032 * @size: size to alloc and return
2033 * @gfp: GFP allocation flags
2035 * Return: the pointer to the allocated data
2037 * This may get enhanced in the future to allocate from a memory pool
2038 * of the @spi_device or @spi_master to avoid repeated allocations.
2040 void *spi_res_alloc(struct spi_device *spi,
2041 spi_res_release_t release,
2042 size_t size, gfp_t gfp)
2044 struct spi_res *sres;
2046 sres = kzalloc(sizeof(*sres) + size, gfp);
2050 INIT_LIST_HEAD(&sres->entry);
2051 sres->release = release;
2055 EXPORT_SYMBOL_GPL(spi_res_alloc);
2058 * spi_res_free - free an spi resource
2059 * @res: pointer to the custom data of a resource
2062 void spi_res_free(void *res)
2064 struct spi_res *sres = container_of(res, struct spi_res, data);
2069 WARN_ON(!list_empty(&sres->entry));
2072 EXPORT_SYMBOL_GPL(spi_res_free);
2075 * spi_res_add - add a spi_res to the spi_message
2076 * @message: the spi message
2077 * @res: the spi_resource
2079 void spi_res_add(struct spi_message *message, void *res)
2081 struct spi_res *sres = container_of(res, struct spi_res, data);
2083 WARN_ON(!list_empty(&sres->entry));
2084 list_add_tail(&sres->entry, &message->resources);
2086 EXPORT_SYMBOL_GPL(spi_res_add);
2089 * spi_res_release - release all spi resources for this message
2090 * @master: the @spi_master
2091 * @message: the @spi_message
2093 void spi_res_release(struct spi_master *master,
2094 struct spi_message *message)
2096 struct spi_res *res;
2098 while (!list_empty(&message->resources)) {
2099 res = list_last_entry(&message->resources,
2100 struct spi_res, entry);
2103 res->release(master, message, res->data);
2105 list_del(&res->entry);
2110 EXPORT_SYMBOL_GPL(spi_res_release);
2112 /*-------------------------------------------------------------------------*/
2114 /* Core methods for spi_message alterations */
2116 static void __spi_replace_transfers_release(struct spi_master *master,
2117 struct spi_message *msg,
2120 struct spi_replaced_transfers *rxfer = res;
2123 /* call extra callback if requested */
2125 rxfer->release(master, msg, res);
2127 /* insert replaced transfers back into the message */
2128 list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2130 /* remove the formerly inserted entries */
2131 for (i = 0; i < rxfer->inserted; i++)
2132 list_del(&rxfer->inserted_transfers[i].transfer_list);
2136 * spi_replace_transfers - replace transfers with several transfers
2137 * and register change with spi_message.resources
2138 * @msg: the spi_message we work upon
2139 * @xfer_first: the first spi_transfer we want to replace
2140 * @remove: number of transfers to remove
2141 * @insert: the number of transfers we want to insert instead
2142 * @release: extra release code necessary in some circumstances
2143 * @extradatasize: extra data to allocate (with alignment guarantees
2144 * of struct @spi_transfer)
2146 * Returns: pointer to @spi_replaced_transfers,
2147 * PTR_ERR(...) in case of errors.
2149 struct spi_replaced_transfers *spi_replace_transfers(
2150 struct spi_message *msg,
2151 struct spi_transfer *xfer_first,
2154 spi_replaced_release_t release,
2155 size_t extradatasize,
2158 struct spi_replaced_transfers *rxfer;
2159 struct spi_transfer *xfer;
2162 /* allocate the structure using spi_res */
2163 rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2164 insert * sizeof(struct spi_transfer)
2165 + sizeof(struct spi_replaced_transfers)
2169 return ERR_PTR(-ENOMEM);
2171 /* the release code to invoke before running the generic release */
2172 rxfer->release = release;
2174 /* assign extradata */
2177 &rxfer->inserted_transfers[insert];
2179 /* init the replaced_transfers list */
2180 INIT_LIST_HEAD(&rxfer->replaced_transfers);
2182 /* assign the list_entry after which we should reinsert
2183 * the @replaced_transfers - it may be spi_message.messages!
2185 rxfer->replaced_after = xfer_first->transfer_list.prev;
2187 /* remove the requested number of transfers */
2188 for (i = 0; i < remove; i++) {
2189 /* if the entry after replaced_after it is msg->transfers
2190 * then we have been requested to remove more transfers
2191 * than are in the list
2193 if (rxfer->replaced_after->next == &msg->transfers) {
2194 dev_err(&msg->spi->dev,
2195 "requested to remove more spi_transfers than are available\n");
2196 /* insert replaced transfers back into the message */
2197 list_splice(&rxfer->replaced_transfers,
2198 rxfer->replaced_after);
2200 /* free the spi_replace_transfer structure */
2201 spi_res_free(rxfer);
2203 /* and return with an error */
2204 return ERR_PTR(-EINVAL);
2207 /* remove the entry after replaced_after from list of
2208 * transfers and add it to list of replaced_transfers
2210 list_move_tail(rxfer->replaced_after->next,
2211 &rxfer->replaced_transfers);
2214 /* create copy of the given xfer with identical settings
2215 * based on the first transfer to get removed
2217 for (i = 0; i < insert; i++) {
2218 /* we need to run in reverse order */
2219 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2221 /* copy all spi_transfer data */
2222 memcpy(xfer, xfer_first, sizeof(*xfer));
2225 list_add(&xfer->transfer_list, rxfer->replaced_after);
2227 /* clear cs_change and delay_usecs for all but the last */
2229 xfer->cs_change = false;
2230 xfer->delay_usecs = 0;
2234 /* set up inserted */
2235 rxfer->inserted = insert;
2237 /* and register it with spi_res/spi_message */
2238 spi_res_add(msg, rxfer);
2242 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2244 static int __spi_split_transfer_maxsize(struct spi_master *master,
2245 struct spi_message *msg,
2246 struct spi_transfer **xferp,
2250 struct spi_transfer *xfer = *xferp, *xfers;
2251 struct spi_replaced_transfers *srt;
2255 /* warn once about this fact that we are splitting a transfer */
2256 dev_warn_once(&msg->spi->dev,
2257 "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2258 xfer->len, maxsize);
2260 /* calculate how many we have to replace */
2261 count = DIV_ROUND_UP(xfer->len, maxsize);
2263 /* create replacement */
2264 srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2266 return PTR_ERR(srt);
2267 xfers = srt->inserted_transfers;
2269 /* now handle each of those newly inserted spi_transfers
2270 * note that the replacements spi_transfers all are preset
2271 * to the same values as *xferp, so tx_buf, rx_buf and len
2272 * are all identical (as well as most others)
2273 * so we just have to fix up len and the pointers.
2275 * this also includes support for the depreciated
2276 * spi_message.is_dma_mapped interface
2279 /* the first transfer just needs the length modified, so we
2280 * run it outside the loop
2282 xfers[0].len = min(maxsize, xfer[0].len);
2284 /* all the others need rx_buf/tx_buf also set */
2285 for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2286 /* update rx_buf, tx_buf and dma */
2287 if (xfers[i].rx_buf)
2288 xfers[i].rx_buf += offset;
2289 if (xfers[i].rx_dma)
2290 xfers[i].rx_dma += offset;
2291 if (xfers[i].tx_buf)
2292 xfers[i].tx_buf += offset;
2293 if (xfers[i].tx_dma)
2294 xfers[i].tx_dma += offset;
2297 xfers[i].len = min(maxsize, xfers[i].len - offset);
2300 /* we set up xferp to the last entry we have inserted,
2301 * so that we skip those already split transfers
2303 *xferp = &xfers[count - 1];
2305 /* increment statistics counters */
2306 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2307 transfers_split_maxsize);
2308 SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2309 transfers_split_maxsize);
2315 * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2316 * when an individual transfer exceeds a
2318 * @master: the @spi_master for this transfer
2319 * @message: the @spi_message to transform
2320 * @max_size: the maximum when to apply this
2322 * Return: status of transformation
2324 int spi_split_transfers_maxsize(struct spi_master *master,
2325 struct spi_message *msg,
2329 struct spi_transfer *xfer;
2332 /* iterate over the transfer_list,
2333 * but note that xfer is advanced to the last transfer inserted
2334 * to avoid checking sizes again unnecessarily (also xfer does
2335 * potentiall belong to a different list by the time the
2336 * replacement has happened
2338 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2339 if (xfer->len > maxsize) {
2340 ret = __spi_split_transfer_maxsize(
2341 master, msg, &xfer, maxsize, gfp);
2349 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2351 /*-------------------------------------------------------------------------*/
2353 /* Core methods for SPI master protocol drivers. Some of the
2354 * other core methods are currently defined as inline functions.
2357 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2359 if (master->bits_per_word_mask) {
2360 /* Only 32 bits fit in the mask */
2361 if (bits_per_word > 32)
2363 if (!(master->bits_per_word_mask &
2364 SPI_BPW_MASK(bits_per_word)))
2372 * spi_setup - setup SPI mode and clock rate
2373 * @spi: the device whose settings are being modified
2374 * Context: can sleep, and no requests are queued to the device
2376 * SPI protocol drivers may need to update the transfer mode if the
2377 * device doesn't work with its default. They may likewise need
2378 * to update clock rates or word sizes from initial values. This function
2379 * changes those settings, and must be called from a context that can sleep.
2380 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2381 * effect the next time the device is selected and data is transferred to
2382 * or from it. When this function returns, the spi device is deselected.
2384 * Note that this call will fail if the protocol driver specifies an option
2385 * that the underlying controller or its driver does not support. For
2386 * example, not all hardware supports wire transfers using nine bit words,
2387 * LSB-first wire encoding, or active-high chipselects.
2389 * Return: zero on success, else a negative error code.
2391 int spi_setup(struct spi_device *spi)
2393 unsigned bad_bits, ugly_bits;
2396 /* check mode to prevent that DUAL and QUAD set at the same time
2398 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2399 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2401 "setup: can not select dual and quad at the same time\n");
2404 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2406 if ((spi->mode & SPI_3WIRE) && (spi->mode &
2407 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2409 /* help drivers fail *cleanly* when they need options
2410 * that aren't supported with their current master
2412 bad_bits = spi->mode & ~spi->master->mode_bits;
2413 ugly_bits = bad_bits &
2414 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2417 "setup: ignoring unsupported mode bits %x\n",
2419 spi->mode &= ~ugly_bits;
2420 bad_bits &= ~ugly_bits;
2423 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2428 if (!spi->bits_per_word)
2429 spi->bits_per_word = 8;
2431 status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2435 if (!spi->max_speed_hz)
2436 spi->max_speed_hz = spi->master->max_speed_hz;
2438 if (spi->master->setup)
2439 status = spi->master->setup(spi);
2441 spi_set_cs(spi, false);
2443 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2444 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2445 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2446 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2447 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2448 (spi->mode & SPI_LOOP) ? "loopback, " : "",
2449 spi->bits_per_word, spi->max_speed_hz,
2454 EXPORT_SYMBOL_GPL(spi_setup);
2456 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2458 struct spi_master *master = spi->master;
2459 struct spi_transfer *xfer;
2462 if (list_empty(&message->transfers))
2465 /* Half-duplex links include original MicroWire, and ones with
2466 * only one data pin like SPI_3WIRE (switches direction) or where
2467 * either MOSI or MISO is missing. They can also be caused by
2468 * software limitations.
2470 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2471 || (spi->mode & SPI_3WIRE)) {
2472 unsigned flags = master->flags;
2474 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2475 if (xfer->rx_buf && xfer->tx_buf)
2477 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2479 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2485 * Set transfer bits_per_word and max speed as spi device default if
2486 * it is not set for this transfer.
2487 * Set transfer tx_nbits and rx_nbits as single transfer default
2488 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2490 message->frame_length = 0;
2491 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2492 message->frame_length += xfer->len;
2493 if (!xfer->bits_per_word)
2494 xfer->bits_per_word = spi->bits_per_word;
2496 if (!xfer->speed_hz)
2497 xfer->speed_hz = spi->max_speed_hz;
2498 if (!xfer->speed_hz)
2499 xfer->speed_hz = master->max_speed_hz;
2501 if (master->max_speed_hz &&
2502 xfer->speed_hz > master->max_speed_hz)
2503 xfer->speed_hz = master->max_speed_hz;
2505 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2509 * SPI transfer length should be multiple of SPI word size
2510 * where SPI word size should be power-of-two multiple
2512 if (xfer->bits_per_word <= 8)
2514 else if (xfer->bits_per_word <= 16)
2519 /* No partial transfers accepted */
2520 if (xfer->len % w_size)
2523 if (xfer->speed_hz && master->min_speed_hz &&
2524 xfer->speed_hz < master->min_speed_hz)
2527 if (xfer->tx_buf && !xfer->tx_nbits)
2528 xfer->tx_nbits = SPI_NBITS_SINGLE;
2529 if (xfer->rx_buf && !xfer->rx_nbits)
2530 xfer->rx_nbits = SPI_NBITS_SINGLE;
2531 /* check transfer tx/rx_nbits:
2532 * 1. check the value matches one of single, dual and quad
2533 * 2. check tx/rx_nbits match the mode in spi_device
2536 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2537 xfer->tx_nbits != SPI_NBITS_DUAL &&
2538 xfer->tx_nbits != SPI_NBITS_QUAD)
2540 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2541 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2543 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2544 !(spi->mode & SPI_TX_QUAD))
2547 /* check transfer rx_nbits */
2549 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2550 xfer->rx_nbits != SPI_NBITS_DUAL &&
2551 xfer->rx_nbits != SPI_NBITS_QUAD)
2553 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2554 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2556 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2557 !(spi->mode & SPI_RX_QUAD))
2562 message->status = -EINPROGRESS;
2567 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2569 struct spi_master *master = spi->master;
2573 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2574 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2576 trace_spi_message_submit(message);
2578 return master->transfer(spi, message);
2582 * spi_async - asynchronous SPI transfer
2583 * @spi: device with which data will be exchanged
2584 * @message: describes the data transfers, including completion callback
2585 * Context: any (irqs may be blocked, etc)
2587 * This call may be used in_irq and other contexts which can't sleep,
2588 * as well as from task contexts which can sleep.
2590 * The completion callback is invoked in a context which can't sleep.
2591 * Before that invocation, the value of message->status is undefined.
2592 * When the callback is issued, message->status holds either zero (to
2593 * indicate complete success) or a negative error code. After that
2594 * callback returns, the driver which issued the transfer request may
2595 * deallocate the associated memory; it's no longer in use by any SPI
2596 * core or controller driver code.
2598 * Note that although all messages to a spi_device are handled in
2599 * FIFO order, messages may go to different devices in other orders.
2600 * Some device might be higher priority, or have various "hard" access
2601 * time requirements, for example.
2603 * On detection of any fault during the transfer, processing of
2604 * the entire message is aborted, and the device is deselected.
2605 * Until returning from the associated message completion callback,
2606 * no other spi_message queued to that device will be processed.
2607 * (This rule applies equally to all the synchronous transfer calls,
2608 * which are wrappers around this core asynchronous primitive.)
2610 * Return: zero on success, else a negative error code.
2612 int spi_async(struct spi_device *spi, struct spi_message *message)
2614 struct spi_master *master = spi->master;
2616 unsigned long flags;
2618 ret = __spi_validate(spi, message);
2622 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2624 if (master->bus_lock_flag)
2627 ret = __spi_async(spi, message);
2629 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2633 EXPORT_SYMBOL_GPL(spi_async);
2636 * spi_async_locked - version of spi_async with exclusive bus usage
2637 * @spi: device with which data will be exchanged
2638 * @message: describes the data transfers, including completion callback
2639 * Context: any (irqs may be blocked, etc)
2641 * This call may be used in_irq and other contexts which can't sleep,
2642 * as well as from task contexts which can sleep.
2644 * The completion callback is invoked in a context which can't sleep.
2645 * Before that invocation, the value of message->status is undefined.
2646 * When the callback is issued, message->status holds either zero (to
2647 * indicate complete success) or a negative error code. After that
2648 * callback returns, the driver which issued the transfer request may
2649 * deallocate the associated memory; it's no longer in use by any SPI
2650 * core or controller driver code.
2652 * Note that although all messages to a spi_device are handled in
2653 * FIFO order, messages may go to different devices in other orders.
2654 * Some device might be higher priority, or have various "hard" access
2655 * time requirements, for example.
2657 * On detection of any fault during the transfer, processing of
2658 * the entire message is aborted, and the device is deselected.
2659 * Until returning from the associated message completion callback,
2660 * no other spi_message queued to that device will be processed.
2661 * (This rule applies equally to all the synchronous transfer calls,
2662 * which are wrappers around this core asynchronous primitive.)
2664 * Return: zero on success, else a negative error code.
2666 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2668 struct spi_master *master = spi->master;
2670 unsigned long flags;
2672 ret = __spi_validate(spi, message);
2676 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2678 ret = __spi_async(spi, message);
2680 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2685 EXPORT_SYMBOL_GPL(spi_async_locked);
2688 /*-------------------------------------------------------------------------*/
2690 /* Utility methods for SPI master protocol drivers, layered on
2691 * top of the core. Some other utility methods are defined as
2695 static void spi_complete(void *arg)
2700 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2703 DECLARE_COMPLETION_ONSTACK(done);
2705 struct spi_master *master = spi->master;
2706 unsigned long flags;
2708 status = __spi_validate(spi, message);
2712 message->complete = spi_complete;
2713 message->context = &done;
2716 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2717 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2720 mutex_lock(&master->bus_lock_mutex);
2722 /* If we're not using the legacy transfer method then we will
2723 * try to transfer in the calling context so special case.
2724 * This code would be less tricky if we could remove the
2725 * support for driver implemented message queues.
2727 if (master->transfer == spi_queued_transfer) {
2728 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2730 trace_spi_message_submit(message);
2732 status = __spi_queued_transfer(spi, message, false);
2734 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2736 status = spi_async_locked(spi, message);
2740 mutex_unlock(&master->bus_lock_mutex);
2743 /* Push out the messages in the calling context if we
2746 if (master->transfer == spi_queued_transfer) {
2747 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2748 spi_sync_immediate);
2749 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2750 spi_sync_immediate);
2751 __spi_pump_messages(master, false);
2754 wait_for_completion(&done);
2755 status = message->status;
2757 message->context = NULL;
2762 * spi_sync - blocking/synchronous SPI data transfers
2763 * @spi: device with which data will be exchanged
2764 * @message: describes the data transfers
2765 * Context: can sleep
2767 * This call may only be used from a context that may sleep. The sleep
2768 * is non-interruptible, and has no timeout. Low-overhead controller
2769 * drivers may DMA directly into and out of the message buffers.
2771 * Note that the SPI device's chip select is active during the message,
2772 * and then is normally disabled between messages. Drivers for some
2773 * frequently-used devices may want to minimize costs of selecting a chip,
2774 * by leaving it selected in anticipation that the next message will go
2775 * to the same chip. (That may increase power usage.)
2777 * Also, the caller is guaranteeing that the memory associated with the
2778 * message will not be freed before this call returns.
2780 * Return: zero on success, else a negative error code.
2782 int spi_sync(struct spi_device *spi, struct spi_message *message)
2784 return __spi_sync(spi, message, 0);
2786 EXPORT_SYMBOL_GPL(spi_sync);
2789 * spi_sync_locked - version of spi_sync with exclusive bus usage
2790 * @spi: device with which data will be exchanged
2791 * @message: describes the data transfers
2792 * Context: can sleep
2794 * This call may only be used from a context that may sleep. The sleep
2795 * is non-interruptible, and has no timeout. Low-overhead controller
2796 * drivers may DMA directly into and out of the message buffers.
2798 * This call should be used by drivers that require exclusive access to the
2799 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2800 * be released by a spi_bus_unlock call when the exclusive access is over.
2802 * Return: zero on success, else a negative error code.
2804 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2806 return __spi_sync(spi, message, 1);
2808 EXPORT_SYMBOL_GPL(spi_sync_locked);
2811 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2812 * @master: SPI bus master that should be locked for exclusive bus access
2813 * Context: can sleep
2815 * This call may only be used from a context that may sleep. The sleep
2816 * is non-interruptible, and has no timeout.
2818 * This call should be used by drivers that require exclusive access to the
2819 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2820 * exclusive access is over. Data transfer must be done by spi_sync_locked
2821 * and spi_async_locked calls when the SPI bus lock is held.
2823 * Return: always zero.
2825 int spi_bus_lock(struct spi_master *master)
2827 unsigned long flags;
2829 mutex_lock(&master->bus_lock_mutex);
2831 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2832 master->bus_lock_flag = 1;
2833 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2835 /* mutex remains locked until spi_bus_unlock is called */
2839 EXPORT_SYMBOL_GPL(spi_bus_lock);
2842 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2843 * @master: SPI bus master that was locked for exclusive bus access
2844 * Context: can sleep
2846 * This call may only be used from a context that may sleep. The sleep
2847 * is non-interruptible, and has no timeout.
2849 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2852 * Return: always zero.
2854 int spi_bus_unlock(struct spi_master *master)
2856 master->bus_lock_flag = 0;
2858 mutex_unlock(&master->bus_lock_mutex);
2862 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2864 /* portable code must never pass more than 32 bytes */
2865 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2870 * spi_write_then_read - SPI synchronous write followed by read
2871 * @spi: device with which data will be exchanged
2872 * @txbuf: data to be written (need not be dma-safe)
2873 * @n_tx: size of txbuf, in bytes
2874 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2875 * @n_rx: size of rxbuf, in bytes
2876 * Context: can sleep
2878 * This performs a half duplex MicroWire style transaction with the
2879 * device, sending txbuf and then reading rxbuf. The return value
2880 * is zero for success, else a negative errno status code.
2881 * This call may only be used from a context that may sleep.
2883 * Parameters to this routine are always copied using a small buffer;
2884 * portable code should never use this for more than 32 bytes.
2885 * Performance-sensitive or bulk transfer code should instead use
2886 * spi_{async,sync}() calls with dma-safe buffers.
2888 * Return: zero on success, else a negative error code.
2890 int spi_write_then_read(struct spi_device *spi,
2891 const void *txbuf, unsigned n_tx,
2892 void *rxbuf, unsigned n_rx)
2894 static DEFINE_MUTEX(lock);
2897 struct spi_message message;
2898 struct spi_transfer x[2];
2901 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2902 * copying here, (as a pure convenience thing), but we can
2903 * keep heap costs out of the hot path unless someone else is
2904 * using the pre-allocated buffer or the transfer is too large.
2906 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2907 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2908 GFP_KERNEL | GFP_DMA);
2915 spi_message_init(&message);
2916 memset(x, 0, sizeof(x));
2919 spi_message_add_tail(&x[0], &message);
2923 spi_message_add_tail(&x[1], &message);
2926 memcpy(local_buf, txbuf, n_tx);
2927 x[0].tx_buf = local_buf;
2928 x[1].rx_buf = local_buf + n_tx;
2931 status = spi_sync(spi, &message);
2933 memcpy(rxbuf, x[1].rx_buf, n_rx);
2935 if (x[0].tx_buf == buf)
2936 mutex_unlock(&lock);
2942 EXPORT_SYMBOL_GPL(spi_write_then_read);
2944 /*-------------------------------------------------------------------------*/
2946 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2947 static int __spi_of_device_match(struct device *dev, void *data)
2949 return dev->of_node == data;
2952 /* must call put_device() when done with returned spi_device device */
2953 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2955 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2956 __spi_of_device_match);
2957 return dev ? to_spi_device(dev) : NULL;
2960 static int __spi_of_master_match(struct device *dev, const void *data)
2962 return dev->of_node == data;
2965 /* the spi masters are not using spi_bus, so we find it with another way */
2966 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2970 dev = class_find_device(&spi_master_class, NULL, node,
2971 __spi_of_master_match);
2975 /* reference got in class_find_device */
2976 return container_of(dev, struct spi_master, dev);
2979 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2982 struct of_reconfig_data *rd = arg;
2983 struct spi_master *master;
2984 struct spi_device *spi;
2986 switch (of_reconfig_get_state_change(action, arg)) {
2987 case OF_RECONFIG_CHANGE_ADD:
2988 master = of_find_spi_master_by_node(rd->dn->parent);
2990 return NOTIFY_OK; /* not for us */
2992 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
2993 put_device(&master->dev);
2997 spi = of_register_spi_device(master, rd->dn);
2998 put_device(&master->dev);
3001 pr_err("%s: failed to create for '%s'\n",
3002 __func__, rd->dn->full_name);
3003 return notifier_from_errno(PTR_ERR(spi));
3007 case OF_RECONFIG_CHANGE_REMOVE:
3008 /* already depopulated? */
3009 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3012 /* find our device by node */
3013 spi = of_find_spi_device_by_node(rd->dn);
3015 return NOTIFY_OK; /* no? not meant for us */
3017 /* unregister takes one ref away */
3018 spi_unregister_device(spi);
3020 /* and put the reference of the find */
3021 put_device(&spi->dev);
3028 static struct notifier_block spi_of_notifier = {
3029 .notifier_call = of_spi_notify,
3031 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3032 extern struct notifier_block spi_of_notifier;
3033 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3035 static int __init spi_init(void)
3039 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3045 status = bus_register(&spi_bus_type);
3049 status = class_register(&spi_master_class);
3053 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3054 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3059 bus_unregister(&spi_bus_type);
3067 /* board_info is normally registered in arch_initcall(),
3068 * but even essential drivers wait till later
3070 * REVISIT only boardinfo really needs static linking. the rest (device and
3071 * driver registration) _could_ be dynamically linked (modular) ... costs
3072 * include needing to have boardinfo data structures be much more public.
3074 postcore_initcall(spi_init);