--- /dev/null
+/*
+ * Copyright (C) 2012 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ *
+ * The ChromeOS EC multi function device is used to mux all the requests
+ * to the EC device for its multiple features : keyboard controller,
+ * battery charging and regulator control, firmware update.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/chromeos_ec.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+
+#define MKBP_MAX_TRIES 3
+
+/* Send a one-byte command to the keyboard and receive a response of length
+ * BUF_LEN. Return BUF_LEN, or a negative error code.
+ */
+static int mkbp_command_noretry(struct chromeos_ec_device *ec_dev,
+ char cmd, uint8_t *buf, int buf_len)
+{
+ int ret;
+ int i;
+ int packet_len;
+ uint8_t *packet;
+ uint8_t sum;
+
+ /* allocate larger packet (one extra byte for checksum) */
+ packet_len = buf_len + MKBP_MSG_PROTO_BYTES;
+ packet = kzalloc(packet_len, GFP_KERNEL);
+ if (!packet)
+ return -ENOMEM;
+
+ /* send command to EC */
+ ret = i2c_master_send(ec_dev->client, &cmd, 1);
+ if (ret < 0) {
+ dev_err(ec_dev->dev, "i2c send failed: %d\n", ret);
+ goto done;
+ }
+ /* receive response */
+ ret = i2c_master_recv(ec_dev->client, packet, packet_len);
+ if (ret < 0) {
+ dev_err(ec_dev->dev, "i2c receive failed: %d\n", ret);
+ goto done;
+ } else if (ret != packet_len) {
+ dev_err(ec_dev->dev, "expected %d bytes, got %d\n",
+ packet_len, ret);
+ ret = -EIO;
+ goto done;
+ }
+ /* copy response packet payload and compute checksum */
+ for (i = 0, sum = 0; i < buf_len; i++) {
+ buf[i] = packet[i];
+ sum += buf[i];
+ }
+#ifdef DEBUG
+ dev_dbg(ec_dev->dev, "packet: ");
+ for (i = 0; i < packet_len; i++) {
+ printk(" %02x", packet[i]);
+ }
+ printk(", sum = %02x\n", sum);
+#endif
+ if (sum != packet[packet_len - 1]) {
+ dev_err(ec_dev->dev, "bad keyboard packet checksum\n");
+ ret = -EIO;
+ goto done;
+ }
+ ret = buf_len;
+ done:
+ kfree(packet);
+ return ret;
+}
+
+static int mkbp_command(struct chromeos_ec_device *ec_dev,
+ char cmd, uint8_t *buf, int buf_len)
+{
+ int try;
+ int ret;
+ /*
+ * Try the command a few times in case there are transmission errors.
+ * It is possible that this is overkill, but we don't completely trust
+ * i2c.
+ */
+ for (try = 0; try < MKBP_MAX_TRIES; try++) {
+ ret = mkbp_command_noretry(ec_dev, cmd, buf, buf_len);
+ if (ret >= 0)
+ return ret;
+ }
+ dev_err(ec_dev->dev, "mkbp_command failed with %d (%d tries)\n",
+ ret, try);
+ return ret;
+}
+
+static irqreturn_t mkbp_isr(int irq, void *data)
+{
+ struct chromeos_ec_device *ec = data;
+
+ atomic_notifier_call_chain(&ec->event_notifier, 1, ec);
+
+ return IRQ_HANDLED;
+}
+
+static int __devinit mkbp_check_protocol_version(struct chromeos_ec_device *ec)
+{
+ int ret;
+ char buf[4];
+ static char expected_version[4] = {1, 0, 0, 0};
+ int i;
+
+ ret = mkbp_command(ec, MKBP_CMDC_PROTO_VER, buf, sizeof(buf));
+ if (ret < 0)
+ return ret;
+ for (i = 0; i < sizeof(expected_version); i++) {
+ if (buf[i] != expected_version[i])
+ return -EPROTONOSUPPORT;
+ }
+ return 0;
+}
+
+static struct mfd_cell cros_devs[] = {
+ {
+ .name = "mkbp",
+ .id = 1,
+ },
+};
+
+static int __devinit cros_ec_probe(struct i2c_client *client,
+ const struct i2c_device_id *dev_id)
+{
+ struct device *dev = &client->dev;
+ struct chromeos_ec_device *ec_dev = NULL;
+ int err;
+
+ dev_dbg(dev, "probing\n");
+
+ ec_dev = kzalloc(sizeof(*ec_dev), GFP_KERNEL);
+ if (ec_dev == NULL) {
+ err = -ENOMEM;
+ dev_err(dev, "cannot allocate\n");
+ goto fail;
+ }
+
+ ec_dev->client = client;
+ ec_dev->dev = dev;
+ i2c_set_clientdata(client, ec_dev);
+ ec_dev->irq = client->irq;
+ ec_dev->send_command = mkbp_command;
+
+ ATOMIC_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
+
+ err = request_irq(ec_dev->irq, mkbp_isr,
+ IRQF_TRIGGER_FALLING, "chromeos-ec", ec_dev);
+ if (err) {
+ dev_err(dev, "request irq %d: error %d\n", ec_dev->irq, err);
+ goto fail;
+ }
+
+ err = mkbp_check_protocol_version(ec_dev);
+ if (err < 0) {
+ dev_err(dev, "protocol version check failed: %d\n", err);
+ goto fail_irq;
+ }
+
+ err = mfd_add_devices(dev, 0, cros_devs, ARRAY_SIZE(cros_devs),
+ NULL, ec_dev->irq);
+ if (err)
+ goto fail_irq;
+
+ return 0;
+fail_irq:
+ free_irq(ec_dev->irq, ec_dev);
+fail:
+ kfree(ec_dev);
+ return err;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int cros_ec_suspend(struct device *dev)
+{
+ return 0;
+}
+
+static int cros_ec_resume(struct device *dev)
+{
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(cros_ec_pm_ops, cros_ec_suspend, cros_ec_resume);
+
+static const struct i2c_device_id cros_ec_i2c_id[] = {
+ { "chromeos-ec", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mkbp_i2c_id);
+
+static struct i2c_driver cros_ec_driver = {
+ .driver = {
+ .name = "chromeos-ec",
+ .owner = THIS_MODULE,
+ .pm = &cros_ec_pm_ops,
+ },
+ .probe = cros_ec_probe,
+ .id_table = cros_ec_i2c_id,
+};
+
+module_i2c_driver(cros_ec_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ChromeOS EC multi function device");
--- /dev/null
+/*
+ * Copyright (C) 2012 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ *
+ * ChromeOS EC multi function device
+ * and MKBP (matrix keyboard protocol) message-based protocol definitions.
+ */
+
+#ifndef __LINUX_MFD_CHROMEOS_EC_H
+#define __LINUX_MFD_CHROMEOS_EC_H
+
+enum {
+ /* Mask to convert a command byte into a command */
+ MKBP_MSG_TRAILER_BYTES = 1,
+ MKBP_MSG_PROTO_BYTES = MKBP_MSG_TRAILER_BYTES,
+};
+
+/* The EC command codes */
+
+enum message_cmd_t {
+ /* EC control/status messages */
+ MKBP_CMDC_PROTO_VER = 0x00, /* Read protocol version */
+ MKBP_CMDC_NOP = 0x01, /* No operation / ping */
+ MKBP_CMDC_ID = 0x02, /* Read EC ID */
+
+ /* Functional messages */
+ MKBP_CMDC_KEY_STATE = 0x20, /* Read key state */
+};
+
+
+struct chromeos_ec_device {
+ struct device *dev;
+ struct i2c_client *client;
+ int irq;
+ struct atomic_notifier_head event_notifier;
+ int (*send_command)(struct chromeos_ec_device *ec,
+ char cmd, uint8_t *buf, int buf_len);
+};
+
+#endif /* __LINUX_MFD_CHROMEOS_EC_H */
projects / cascardo / linux.git / commitdiff