Input: add EETI eGalax I2C capacitive multi touch driver

This patch adds the EETI eGalax serial multi touch controller driver.

EETI eGalax serial touch screen controller is a I2C based multiple
capacitive touch screen controller, it can support 5 touch events maximum.

Signed-off-by: Zhang Jiejing <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called eeti_ts.
 
+config TOUCHSCREEN_EGALAX
+	tristate "EETI eGalax multi-touch panel support"
+	depends on I2C
+	help
+	  Say Y here to enable support for I2C connected EETI
+	  eGalax multi-touch panels.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called egalax_ts.
+
 config TOUCHSCREEN_FUJITSU
 	tristate "Fujitsu serial touchscreen"
 	select SERIO

drivers/input/touchscreen/Makefile

···
 obj-$(CONFIG_TOUCHSCREEN_GUNZE)		+= gunze.o
 obj-$(CONFIG_TOUCHSCREEN_EETI)		+= eeti_ts.o
 obj-$(CONFIG_TOUCHSCREEN_ELO)		+= elo.o
+obj-$(CONFIG_TOUCHSCREEN_EGALAX)	+= egalax_ts.o
 obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o
 obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
 obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o

drivers/input/touchscreen/egalax_ts.c

···
+/*
+ * Driver for EETI eGalax Multiple Touch Controller
+ *
+ * Copyright (C) 2011 Freescale Semiconductor, Inc.
+ *
+ * based on max11801_ts.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/* EETI eGalax serial touch screen controller is a I2C based multiple
+ * touch screen controller, it supports 5 point multiple touch. */
+
+/* TODO:
+  - auto idle mode support
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/input/mt.h>
+
+/*
+ * Mouse Mode: some panel may configure the controller to mouse mode,
+ * which can only report one point at a given time.
+ * This driver will ignore events in this mode.
+ */
+#define REPORT_MODE_MOUSE		0x1
+/*
+ * Vendor Mode: this mode is used to transfer some vendor specific
+ * messages.
+ * This driver will ignore events in this mode.
+ */
+#define REPORT_MODE_VENDOR		0x3
+/* Multiple Touch Mode */
+#define REPORT_MODE_MTTOUCH		0x4
+
+#define MAX_SUPPORT_POINTS		5
+
+#define EVENT_VALID_OFFSET	7
+#define EVENT_VALID_MASK	(0x1 << EVENT_VALID_OFFSET)
+#define EVENT_ID_OFFSET		2
+#define EVENT_ID_MASK		(0xf << EVENT_ID_OFFSET)
+#define EVENT_IN_RANGE		(0x1 << 1)
+#define EVENT_DOWN_UP		(0X1 << 0)
+
+#define MAX_I2C_DATA_LEN	10
+
+#define EGALAX_MAX_X	32760
+#define EGALAX_MAX_Y	32760
+#define EGALAX_MAX_TRIES 100
+
+struct egalax_ts {
+	struct i2c_client		*client;
+	struct input_dev		*input_dev;
+};
+
+static irqreturn_t egalax_ts_interrupt(int irq, void *dev_id)
+{
+	struct egalax_ts *ts = dev_id;
+	struct input_dev *input_dev = ts->input_dev;
+	struct i2c_client *client = ts->client;
+	u8 buf[MAX_I2C_DATA_LEN];
+	int id, ret, x, y, z;
+	int tries = 0;
+	bool down, valid;
+	u8 state;
+
+	do {
+		ret = i2c_master_recv(client, buf, MAX_I2C_DATA_LEN);
+	} while (ret == -EAGAIN && tries++ < EGALAX_MAX_TRIES);
+
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	if (buf[0] != REPORT_MODE_MTTOUCH) {
+		/* ignore mouse events and vendor events */
+		return IRQ_HANDLED;
+	}
+
+	state = buf[1];
+	x = (buf[3] << 8) | buf[2];
+	y = (buf[5] << 8) | buf[4];
+	z = (buf[7] << 8) | buf[6];
+
+	valid = state & EVENT_VALID_MASK;
+	id = (state & EVENT_ID_MASK) >> EVENT_ID_OFFSET;
+	down = state & EVENT_DOWN_UP;
+
+	if (!valid || id > MAX_SUPPORT_POINTS) {
+		dev_dbg(&client->dev, "point invalid\n");
+		return IRQ_HANDLED;
+	}
+
+	input_mt_slot(input_dev, id);
+	input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, down);
+
+	dev_dbg(&client->dev, "%s id:%d x:%d y:%d z:%d",
+		down ? "down" : "up", id, x, y, z);
+
+	if (down) {
+		input_report_abs(input_dev, ABS_MT_POSITION_X, x);
+		input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
+		input_report_abs(input_dev, ABS_MT_PRESSURE, z);
+	}
+
+	input_mt_report_pointer_emulation(input_dev, true);
+	input_sync(input_dev);
+
+	return IRQ_HANDLED;
+}
+
+/* wake up controller by an falling edge of interrupt gpio.  */
+static int egalax_wake_up_device(struct i2c_client *client)
+{
+	int gpio = irq_to_gpio(client->irq);
+	int ret;
+
+	ret = gpio_request(gpio, "egalax_irq");
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"request gpio failed, cannot wake up controller: %d\n",
+			ret);
+		return ret;
+	}
+
+	/* wake up controller via an falling edge on IRQ gpio. */
+	gpio_direction_output(gpio, 0);
+	gpio_set_value(gpio, 1);
+
+	/* controller should be waken up, return irq.  */
+	gpio_direction_input(gpio);
+	gpio_free(gpio);
+
+	return 0;
+}
+
+static int __devinit egalax_firmware_version(struct i2c_client *client)
+{
+	static const u8 cmd[MAX_I2C_DATA_LEN] = { 0x03, 0x03, 0xa, 0x01, 0x41 };
+	int ret;
+
+	ret = i2c_master_send(client, cmd, MAX_I2C_DATA_LEN);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int __devinit egalax_ts_probe(struct i2c_client *client,
+				       const struct i2c_device_id *id)
+{
+	struct egalax_ts *ts;
+	struct input_dev *input_dev;
+	int ret;
+	int error;
+
+	ts = kzalloc(sizeof(struct egalax_ts), GFP_KERNEL);
+	if (!ts) {
+		dev_err(&client->dev, "Failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	input_dev = input_allocate_device();
+	if (!input_dev) {
+		dev_err(&client->dev, "Failed to allocate memory\n");
+		error = -ENOMEM;
+		goto err_free_ts;
+	}
+
+	ts->client = client;
+	ts->input_dev = input_dev;
+
+	/* controller may be in sleep, wake it up. */
+	egalax_wake_up_device(client);
+
+	ret = egalax_firmware_version(client);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read firmware version\n");
+		error = -EIO;
+		goto err_free_dev;
+	}
+
+	input_dev->name = "EETI eGalax Touch Screen";
+	input_dev->id.bustype = BUS_I2C;
+	input_dev->dev.parent = &client->dev;
+
+	__set_bit(EV_ABS, input_dev->evbit);
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(BTN_TOUCH, input_dev->keybit);
+
+	input_set_abs_params(input_dev, ABS_X, 0, EGALAX_MAX_X, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, EGALAX_MAX_Y, 0, 0);
+	input_set_abs_params(input_dev,
+			     ABS_MT_POSITION_X, 0, EGALAX_MAX_X, 0, 0);
+	input_set_abs_params(input_dev,
+			     ABS_MT_POSITION_X, 0, EGALAX_MAX_Y, 0, 0);
+	input_mt_init_slots(input_dev, MAX_SUPPORT_POINTS);
+
+	input_set_drvdata(input_dev, ts);
+
+	error = request_threaded_irq(client->irq, NULL, egalax_ts_interrupt,
+				     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+				     "egalax_ts", ts);
+	if (error < 0) {
+		dev_err(&client->dev, "Failed to register interrupt\n");
+		goto err_free_dev;
+	}
+
+	error = input_register_device(ts->input_dev);
+	if (error)
+		goto err_free_irq;
+
+	i2c_set_clientdata(client, ts);
+	return 0;
+
+err_free_irq:
+	free_irq(client->irq, ts);
+err_free_dev:
+	input_free_device(input_dev);
+err_free_ts:
+	kfree(ts);
+
+	return error;
+}
+
+static __devexit int egalax_ts_remove(struct i2c_client *client)
+{
+	struct egalax_ts *ts = i2c_get_clientdata(client);
+
+	free_irq(client->irq, ts);
+
+	input_unregister_device(ts->input_dev);
+	kfree(ts);
+
+	return 0;
+}
+
+static const struct i2c_device_id egalax_ts_id[] = {
+	{ "egalax_ts", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, egalax_ts_id);
+
+#ifdef CONFIG_PM_SLEEP
+static int egalax_ts_suspend(struct device *dev)
+{
+	static const u8 suspend_cmd[MAX_I2C_DATA_LEN] = {
+		0x3, 0x6, 0xa, 0x3, 0x36, 0x3f, 0x2, 0, 0, 0
+	};
+	struct i2c_client *client = to_i2c_client(dev);
+	int ret;
+
+	ret = i2c_master_send(client, suspend_cmd, MAX_I2C_DATA_LEN);
+	return ret > 0 ? 0 : ret;
+}
+
+static int egalax_ts_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	return egalax_wake_up_device(client);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);
+
+static struct i2c_driver egalax_ts_driver = {
+	.driver = {
+		.name	= "egalax_ts",
+		.owner	= THIS_MODULE,
+		.pm	= &egalax_ts_pm_ops,
+	},
+	.id_table	= egalax_ts_id,
+	.probe		= egalax_ts_probe,
+	.remove		= __devexit_p(egalax_ts_remove),
+};
+
+static int __init egalax_ts_init(void)
+{
+	return i2c_add_driver(&egalax_ts_driver);
+}
+
+static void __exit egalax_ts_exit(void)
+{
+	i2c_del_driver(&egalax_ts_driver);
+}
+
+module_init(egalax_ts_init);
+module_exit(egalax_ts_exit);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("Touchscreen driver for EETI eGalax touch controller");
+MODULE_LICENSE("GPL");