2 * GPIO driver for the ACCES 104-IDI-48 family
3 * Copyright (C) 2015 William Breathitt Gray
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2, as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 #include <linux/bitops.h>
15 #include <linux/device.h>
16 #include <linux/errno.h>
17 #include <linux/gpio/driver.h>
19 #include <linux/ioport.h>
20 #include <linux/interrupt.h>
21 #include <linux/irqdesc.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/platform_device.h>
26 #include <linux/spinlock.h>
28 static unsigned idi_48_base;
29 module_param(idi_48_base, uint, 0);
30 MODULE_PARM_DESC(idi_48_base, "ACCES 104-IDI-48 base address");
31 static unsigned idi_48_irq;
32 module_param(idi_48_irq, uint, 0);
33 MODULE_PARM_DESC(idi_48_irq, "ACCES 104-IDI-48 interrupt line number");
36 * struct idi_48_gpio - GPIO device private data structure
37 * @chip: instance of the gpio_chip
38 * @lock: synchronization lock to prevent I/O race conditions
39 * @ack_lock: synchronization lock to prevent IRQ handler race conditions
40 * @irq_mask: input bits affected by interrupts
41 * @base: base port address of the GPIO device
42 * @extent: extent of port address region of the GPIO device
43 * @irq: Interrupt line number
44 * @cos_enb: Change-Of-State IRQ enable boundaries mask
47 struct gpio_chip chip;
50 unsigned char irq_mask[6];
54 unsigned char cos_enb;
57 static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
62 static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
67 static struct idi_48_gpio *to_idi48gpio(struct gpio_chip *gc)
69 return container_of(gc, struct idi_48_gpio, chip);
72 static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
74 struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
76 const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
80 for (i = 0; i < 48; i += 8)
82 base_offset = register_offset[i / 8];
83 mask = BIT(offset - i);
85 return !!(inb(idi48gpio->base + base_offset) & mask);
88 /* The following line should never execute since offset < 48 */
92 static void idi_48_irq_ack(struct irq_data *data)
96 static void idi_48_irq_mask(struct irq_data *data)
98 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
99 struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
100 const unsigned offset = irqd_to_hwirq(data);
106 for (i = 0; i < 48; i += 8)
107 if (offset < i + 8) {
108 mask = BIT(offset - i);
111 idi48gpio->irq_mask[boundary] &= ~mask;
113 if (!idi48gpio->irq_mask[boundary]) {
114 idi48gpio->cos_enb &= ~BIT(boundary);
116 spin_lock_irqsave(&idi48gpio->lock, flags);
118 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
120 spin_unlock_irqrestore(&idi48gpio->lock, flags);
127 static void idi_48_irq_unmask(struct irq_data *data)
129 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
130 struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
131 const unsigned offset = irqd_to_hwirq(data);
135 unsigned prev_irq_mask;
138 for (i = 0; i < 48; i += 8)
139 if (offset < i + 8) {
140 mask = BIT(offset - i);
142 prev_irq_mask = idi48gpio->irq_mask[boundary];
144 idi48gpio->irq_mask[boundary] |= mask;
146 if (!prev_irq_mask) {
147 idi48gpio->cos_enb |= BIT(boundary);
149 spin_lock_irqsave(&idi48gpio->lock, flags);
151 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
153 spin_unlock_irqrestore(&idi48gpio->lock, flags);
160 static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type)
162 /* The only valid irq types are none and both-edges */
163 if (flow_type != IRQ_TYPE_NONE &&
164 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
170 static struct irq_chip idi_48_irqchip = {
171 .name = "104-idi-48",
172 .irq_ack = idi_48_irq_ack,
173 .irq_mask = idi_48_irq_mask,
174 .irq_unmask = idi_48_irq_unmask,
175 .irq_set_type = idi_48_irq_set_type
178 static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
180 struct idi_48_gpio *const idi48gpio = dev_id;
181 unsigned long cos_status;
182 unsigned long boundary;
183 unsigned long irq_mask;
184 unsigned long bit_num;
186 struct gpio_chip *const chip = &idi48gpio->chip;
188 spin_lock(&idi48gpio->ack_lock);
190 spin_lock(&idi48gpio->lock);
192 cos_status = inb(idi48gpio->base + 7);
194 spin_unlock(&idi48gpio->lock);
196 /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
197 if (cos_status & BIT(6)) {
198 spin_unlock(&idi48gpio->ack_lock);
202 /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
205 for_each_set_bit(boundary, &cos_status, 6) {
206 irq_mask = idi48gpio->irq_mask[boundary];
208 for_each_set_bit(bit_num, &irq_mask, 8) {
209 gpio = bit_num + boundary * 8;
211 generic_handle_irq(irq_find_mapping(chip->irqdomain,
216 spin_unlock(&idi48gpio->ack_lock);
221 static int __init idi_48_probe(struct platform_device *pdev)
223 struct device *dev = &pdev->dev;
224 struct idi_48_gpio *idi48gpio;
225 const unsigned base = idi_48_base;
226 const unsigned extent = 8;
227 const char *const name = dev_name(dev);
229 const unsigned irq = idi_48_irq;
231 idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
235 if (!request_region(base, extent, name)) {
236 dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n",
237 name, base, base + extent);
239 goto err_lock_io_port;
242 idi48gpio->chip.label = name;
243 idi48gpio->chip.parent = dev;
244 idi48gpio->chip.owner = THIS_MODULE;
245 idi48gpio->chip.base = -1;
246 idi48gpio->chip.ngpio = 48;
247 idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
248 idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
249 idi48gpio->chip.get = idi_48_gpio_get;
250 idi48gpio->base = base;
251 idi48gpio->extent = extent;
252 idi48gpio->irq = irq;
254 spin_lock_init(&idi48gpio->lock);
256 dev_set_drvdata(dev, idi48gpio);
258 err = gpiochip_add(&idi48gpio->chip);
260 dev_err(dev, "GPIO registering failed (%d)\n", err);
261 goto err_gpio_register;
264 /* Disable IRQ by default */
268 err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
269 handle_edge_irq, IRQ_TYPE_NONE);
271 dev_err(dev, "Could not add irqchip (%d)\n", err);
272 goto err_gpiochip_irqchip_add;
275 err = request_irq(irq, idi_48_irq_handler, 0, name, idi48gpio);
277 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
278 goto err_request_irq;
284 err_gpiochip_irqchip_add:
285 gpiochip_remove(&idi48gpio->chip);
287 release_region(base, extent);
292 static int idi_48_remove(struct platform_device *pdev)
294 struct idi_48_gpio *const idi48gpio = platform_get_drvdata(pdev);
296 free_irq(idi48gpio->irq, idi48gpio);
297 gpiochip_remove(&idi48gpio->chip);
298 release_region(idi48gpio->base, idi48gpio->extent);
303 static struct platform_device *idi_48_device;
305 static struct platform_driver idi_48_driver = {
309 .remove = idi_48_remove
312 static void __exit idi_48_exit(void)
314 platform_device_unregister(idi_48_device);
315 platform_driver_unregister(&idi_48_driver);
318 static int __init idi_48_init(void)
322 idi_48_device = platform_device_alloc(idi_48_driver.driver.name, -1);
326 err = platform_device_add(idi_48_device);
328 goto err_platform_device;
330 err = platform_driver_probe(&idi_48_driver, idi_48_probe);
332 goto err_platform_driver;
337 platform_device_del(idi_48_device);
339 platform_device_put(idi_48_device);
343 module_init(idi_48_init);
344 module_exit(idi_48_exit);
346 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
347 MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
348 MODULE_LICENSE("GPL");