drivers/input/keyboard/qt2160.c - maze/linux - Git at Google

 /*
  *  qt2160.c - Atmel AT42QT2160 Touch Sense Controller
  *
  *  Copyright (C) 2009 Raphael Derosso Pereira <raphaelpereira@gmail.com>
  *
  *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/jiffies.h>
 #include <linux/i2c.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/input.h>

 #define QT2160_VALID_CHIPID  0x11

 #define QT2160_CMD_CHIPID     0
 #define QT2160_CMD_CODEVER    1
 #define QT2160_CMD_GSTAT      2
 #define QT2160_CMD_KEYS3      3
 #define QT2160_CMD_KEYS4      4
 #define QT2160_CMD_SLIDE      5
 #define QT2160_CMD_GPIOS      6
 #define QT2160_CMD_SUBVER     7
 #define QT2160_CMD_CALIBRATE  10
 #define QT2160_CMD_DRIVE_X    70
 #define QT2160_CMD_PWMEN_X    74
 #define QT2160_CMD_PWM_DUTY   76

 #define QT2160_NUM_LEDS_X	8

 #define QT2160_CYCLE_INTERVAL	(2*HZ)

 static unsigned char qt2160_key2code[] = {
 	KEY_0, KEY_1, KEY_2, KEY_3,
 	KEY_4, KEY_5, KEY_6, KEY_7,
 	KEY_8, KEY_9, KEY_A, KEY_B,
 	KEY_C, KEY_D, KEY_E, KEY_F,
 };

 #ifdef CONFIG_LEDS_CLASS
 struct qt2160_led {
 	struct qt2160_data *qt2160;
 	struct led_classdev cdev;
 	struct work_struct work;
 	char name[32];
 	int id;
 	enum led_brightness new_brightness;
 };
 #endif

 struct qt2160_data {
 	struct i2c_client *client;
 	struct input_dev *input;
 	struct delayed_work dwork;
 	spinlock_t lock;        /* Protects canceling/rescheduling of dwork */
 	unsigned short keycodes[ARRAY_SIZE(qt2160_key2code)];
 	u16 key_matrix;
 #ifdef CONFIG_LEDS_CLASS
 	struct qt2160_led leds[QT2160_NUM_LEDS_X];
 	struct mutex led_lock;
 #endif
 };

 static int qt2160_read(struct i2c_client *client, u8 reg);
 static int qt2160_write(struct i2c_client *client, u8 reg, u8 data);

 #ifdef CONFIG_LEDS_CLASS

 static void qt2160_led_work(struct work_struct *work)
 {
 	struct qt2160_led *led = container_of(work, struct qt2160_led, work);
 	struct qt2160_data *qt2160 = led->qt2160;
 	struct i2c_client *client = qt2160->client;
 	int value = led->new_brightness;
 	u32 drive, pwmen;

 	mutex_lock(&qt2160->led_lock);

 	drive = qt2160_read(client, QT2160_CMD_DRIVE_X);
 	pwmen = qt2160_read(client, QT2160_CMD_PWMEN_X);
 	if (value != LED_OFF) {
 		drive |= (1 << led->id);
 		pwmen |= (1 << led->id);

 	} else {
 		drive &= ~(1 << led->id);
 		pwmen &= ~(1 << led->id);
 	}
 	qt2160_write(client, QT2160_CMD_DRIVE_X, drive);
 	qt2160_write(client, QT2160_CMD_PWMEN_X, pwmen);

 	/*
 	 * Changing this register will change the brightness
 	 * of every LED in the qt2160. It's a HW limitation.
 	 */
 	if (value != LED_OFF)
 		qt2160_write(client, QT2160_CMD_PWM_DUTY, value);

 	mutex_unlock(&qt2160->led_lock);
 }

 static void qt2160_led_set(struct led_classdev *cdev,
 			   enum led_brightness value)
 {
 	struct qt2160_led *led = container_of(cdev, struct qt2160_led, cdev);

 	led->new_brightness = value;
 	schedule_work(&led->work);
 }

 #endif /* CONFIG_LEDS_CLASS */

 static int qt2160_read_block(struct i2c_client *client,
 			     u8 inireg, u8 *buffer, unsigned int count)
 {
 	int error, idx = 0;

 	/*
 	 * Can't use SMBus block data read. Check for I2C functionality to speed
 	 * things up whenever possible. Otherwise we will be forced to read
 	 * sequentially.
 	 */
 	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))	{

 		error = i2c_smbus_write_byte(client, inireg + idx);
 		if (error) {
 			dev_err(&client->dev,
 				"couldn't send request. Returned %d\n", error);
 			return error;
 		}

 		error = i2c_master_recv(client, buffer, count);
 		if (error != count) {
 			dev_err(&client->dev,
 				"couldn't read registers. Returned %d bytes\n", error);
 			return error;
 		}
 	} else {

 		while (count--) {
 			int data;

 			error = i2c_smbus_write_byte(client, inireg + idx);
 			if (error) {
 				dev_err(&client->dev,
 					"couldn't send request. Returned %d\n", error);
 				return error;
 			}

 			data = i2c_smbus_read_byte(client);
 			if (data < 0) {
 				dev_err(&client->dev,
 					"couldn't read register. Returned %d\n", data);
 				return data;
 			}

 			buffer[idx++] = data;
 		}
 	}

 	return 0;
 }

 static int qt2160_get_key_matrix(struct qt2160_data *qt2160)
 {
 	struct i2c_client *client = qt2160->client;
 	struct input_dev *input = qt2160->input;
 	u8 regs[6];
 	u16 old_matrix, new_matrix;
 	int ret, i, mask;

 	dev_dbg(&client->dev, "requesting keys...\n");

 	/*
 	 * Read all registers from General Status Register
 	 * to GPIOs register
 	 */
 	ret = qt2160_read_block(client, QT2160_CMD_GSTAT, regs, 6);
 	if (ret) {
 		dev_err(&client->dev,
 			"could not perform chip read.\n");
 		return ret;
 	}

 	old_matrix = qt2160->key_matrix;
 	qt2160->key_matrix = new_matrix = (regs[2] << 8) | regs[1];

 	mask = 0x01;
 	for (i = 0; i < 16; ++i, mask <<= 1) {
 		int keyval = new_matrix & mask;

 		if ((old_matrix & mask) != keyval) {
 			input_report_key(input, qt2160->keycodes[i], keyval);
 			dev_dbg(&client->dev, "key %d %s\n",
 				i, keyval ? "pressed" : "released");
 		}
 	}

 	input_sync(input);

 	return 0;
 }

 static irqreturn_t qt2160_irq(int irq, void *_qt2160)
 {
 	struct qt2160_data *qt2160 = _qt2160;
 	unsigned long flags;

 	spin_lock_irqsave(&qt2160->lock, flags);

 	mod_delayed_work(system_wq, &qt2160->dwork, 0);

 	spin_unlock_irqrestore(&qt2160->lock, flags);

 	return IRQ_HANDLED;
 }

 static void qt2160_schedule_read(struct qt2160_data *qt2160)
 {
 	spin_lock_irq(&qt2160->lock);
 	schedule_delayed_work(&qt2160->dwork, QT2160_CYCLE_INTERVAL);
 	spin_unlock_irq(&qt2160->lock);
 }

 static void qt2160_worker(struct work_struct *work)
 {
 	struct qt2160_data *qt2160 =
 		container_of(work, struct qt2160_data, dwork.work);

 	dev_dbg(&qt2160->client->dev, "worker\n");

 	qt2160_get_key_matrix(qt2160);

 	/* Avoid device lock up by checking every so often */
 	qt2160_schedule_read(qt2160);
 }

 static int qt2160_read(struct i2c_client *client, u8 reg)
 {
 	int ret;

 	ret = i2c_smbus_write_byte(client, reg);
 	if (ret) {
 		dev_err(&client->dev,
 			"couldn't send request. Returned %d\n", ret);
 		return ret;
 	}

 	ret = i2c_smbus_read_byte(client);
 	if (ret < 0) {
 		dev_err(&client->dev,
 			"couldn't read register. Returned %d\n", ret);
 		return ret;
 	}

 	return ret;
 }

 static int qt2160_write(struct i2c_client *client, u8 reg, u8 data)
 {
 	int ret;

 	ret = i2c_smbus_write_byte_data(client, reg, data);
 	if (ret < 0)
 		dev_err(&client->dev,
 			"couldn't write data. Returned %d\n", ret);

 	return ret;
 }

 #ifdef CONFIG_LEDS_CLASS

 static int qt2160_register_leds(struct qt2160_data *qt2160)
 {
 	struct i2c_client *client = qt2160->client;
 	int ret;
 	int i;

 	mutex_init(&qt2160->led_lock);

 	for (i = 0; i < QT2160_NUM_LEDS_X; i++) {
 		struct qt2160_led *led = &qt2160->leds[i];

 		snprintf(led->name, sizeof(led->name), "qt2160:x%d", i);
 		led->cdev.name = led->name;
 		led->cdev.brightness_set = qt2160_led_set;
 		led->cdev.brightness = LED_OFF;
 		led->id = i;
 		led->qt2160 = qt2160;

 		INIT_WORK(&led->work, qt2160_led_work);

 		ret = led_classdev_register(&client->dev, &led->cdev);
 		if (ret < 0)
 			return ret;
 	}

 	/* Tur off LEDs */
 	qt2160_write(client, QT2160_CMD_DRIVE_X, 0);
 	qt2160_write(client, QT2160_CMD_PWMEN_X, 0);
 	qt2160_write(client, QT2160_CMD_PWM_DUTY, 0);

 	return 0;
 }

 static void qt2160_unregister_leds(struct qt2160_data *qt2160)
 {
 	int i;

 	for (i = 0; i < QT2160_NUM_LEDS_X; i++) {
 		led_classdev_unregister(&qt2160->leds[i].cdev);
 		cancel_work_sync(&qt2160->leds[i].work);
 	}
 }

 #else

 static inline int qt2160_register_leds(struct qt2160_data *qt2160)
 {
 	return 0;
 }

 static inline void qt2160_unregister_leds(struct qt2160_data *qt2160)
 {
 }

 #endif

 static bool qt2160_identify(struct i2c_client *client)
 {
 	int id, ver, rev;

 	/* Read Chid ID to check if chip is valid */
 	id = qt2160_read(client, QT2160_CMD_CHIPID);
 	if (id != QT2160_VALID_CHIPID) {
 		dev_err(&client->dev, "ID %d not supported\n", id);
 		return false;
 	}

 	/* Read chip firmware version */
 	ver = qt2160_read(client, QT2160_CMD_CODEVER);
 	if (ver < 0) {
 		dev_err(&client->dev, "could not get firmware version\n");
 		return false;
 	}

 	/* Read chip firmware revision */
 	rev = qt2160_read(client, QT2160_CMD_SUBVER);
 	if (rev < 0) {
 		dev_err(&client->dev, "could not get firmware revision\n");
 		return false;
 	}

 	dev_info(&client->dev, "AT42QT2160 firmware version %d.%d.%d\n",
 			ver >> 4, ver & 0xf, rev);

 	return true;
 }

 static int qt2160_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct qt2160_data *qt2160;
 	struct input_dev *input;
 	int i;
 	int error;

 	/* Check functionality */
 	error = i2c_check_functionality(client->adapter,
 			I2C_FUNC_SMBUS_BYTE);
 	if (!error) {
 		dev_err(&client->dev, "%s adapter not supported\n",
 				dev_driver_string(&client->adapter->dev));
 		return -ENODEV;
 	}

 	if (!qt2160_identify(client))
 		return -ENODEV;

 	/* Chip is valid and active. Allocate structure */
 	qt2160 = kzalloc(sizeof(struct qt2160_data), GFP_KERNEL);
 	input = input_allocate_device();
 	if (!qt2160 || !input) {
 		dev_err(&client->dev, "insufficient memory\n");
 		error = -ENOMEM;
 		goto err_free_mem;
 	}

 	qt2160->client = client;
 	qt2160->input = input;
 	INIT_DELAYED_WORK(&qt2160->dwork, qt2160_worker);
 	spin_lock_init(&qt2160->lock);

 	input->name = "AT42QT2160 Touch Sense Keyboard";
 	input->id.bustype = BUS_I2C;

 	input->keycode = qt2160->keycodes;
 	input->keycodesize = sizeof(qt2160->keycodes[0]);
 	input->keycodemax = ARRAY_SIZE(qt2160_key2code);

 	__set_bit(EV_KEY, input->evbit);
 	__clear_bit(EV_REP, input->evbit);
 	for (i = 0; i < ARRAY_SIZE(qt2160_key2code); i++) {
 		qt2160->keycodes[i] = qt2160_key2code[i];
 		__set_bit(qt2160_key2code[i], input->keybit);
 	}
 	__clear_bit(KEY_RESERVED, input->keybit);

 	/* Calibrate device */
 	error = qt2160_write(client, QT2160_CMD_CALIBRATE, 1);
 	if (error) {
 		dev_err(&client->dev, "failed to calibrate device\n");
 		goto err_free_mem;
 	}

 	if (client->irq) {
 		error = request_irq(client->irq, qt2160_irq,
 				    IRQF_TRIGGER_FALLING, "qt2160", qt2160);
 		if (error) {
 			dev_err(&client->dev,
 				"failed to allocate irq %d\n", client->irq);
 			goto err_free_mem;
 		}
 	}

 	error = qt2160_register_leds(qt2160);
 	if (error) {
 		dev_err(&client->dev, "Failed to register leds\n");
 		goto err_free_irq;
 	}

 	error = input_register_device(qt2160->input);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to register input device\n");
 		goto err_unregister_leds;
 	}

 	i2c_set_clientdata(client, qt2160);
 	qt2160_schedule_read(qt2160);

 	return 0;

 err_unregister_leds:
 	qt2160_unregister_leds(qt2160);
 err_free_irq:
 	if (client->irq)
 		free_irq(client->irq, qt2160);
 err_free_mem:
 	input_free_device(input);
 	kfree(qt2160);
 	return error;
 }

 static int qt2160_remove(struct i2c_client *client)
 {
 	struct qt2160_data *qt2160 = i2c_get_clientdata(client);

 	qt2160_unregister_leds(qt2160);

 	/* Release IRQ so no queue will be scheduled */
 	if (client->irq)
 		free_irq(client->irq, qt2160);

 	cancel_delayed_work_sync(&qt2160->dwork);

 	input_unregister_device(qt2160->input);
 	kfree(qt2160);

 	return 0;
 }

 static const struct i2c_device_id qt2160_idtable[] = {
 	{ "qt2160", 0, },
 	{ }
 };

 MODULE_DEVICE_TABLE(i2c, qt2160_idtable);

 static struct i2c_driver qt2160_driver = {
 	.driver = {
 		.name	= "qt2160",
 		.owner  = THIS_MODULE,
 	},

 	.id_table	= qt2160_idtable,
 	.probe		= qt2160_probe,
 	.remove		= qt2160_remove,
 };

 module_i2c_driver(qt2160_driver);

 MODULE_AUTHOR("Raphael Derosso Pereira <raphaelpereira@gmail.com>");
 MODULE_DESCRIPTION("Driver for AT42QT2160 Touch Sensor");
 MODULE_LICENSE("GPL");
	/*
	* qt2160.c - Atmel AT42QT2160 Touch Sense Controller
	*
	* Copyright (C) 2009 Raphael Derosso Pereira <raphaelpereira@gmail.com>
	*
	* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/leds.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/jiffies.h>
	#include <linux/i2c.h>
	#include <linux/irq.h>
	#include <linux/interrupt.h>
	#include <linux/input.h>

	#define QT2160_VALID_CHIPID 0x11

	#define QT2160_CMD_CHIPID 0
	#define QT2160_CMD_CODEVER 1
	#define QT2160_CMD_GSTAT 2
	#define QT2160_CMD_KEYS3 3
	#define QT2160_CMD_KEYS4 4
	#define QT2160_CMD_SLIDE 5
	#define QT2160_CMD_GPIOS 6
	#define QT2160_CMD_SUBVER 7
	#define QT2160_CMD_CALIBRATE 10
	#define QT2160_CMD_DRIVE_X 70
	#define QT2160_CMD_PWMEN_X 74
	#define QT2160_CMD_PWM_DUTY 76

	#define QT2160_NUM_LEDS_X 8

	#define QT2160_CYCLE_INTERVAL (2*HZ)

	static unsigned char qt2160_key2code[] = {
	KEY_0, KEY_1, KEY_2, KEY_3,
	KEY_4, KEY_5, KEY_6, KEY_7,
	KEY_8, KEY_9, KEY_A, KEY_B,
	KEY_C, KEY_D, KEY_E, KEY_F,
	};

	#ifdef CONFIG_LEDS_CLASS
	struct qt2160_led {
	struct qt2160_data *qt2160;
	struct led_classdev cdev;
	struct work_struct work;
	char name[32];
	int id;
	enum led_brightness new_brightness;
	};
	#endif

	struct qt2160_data {
	struct i2c_client *client;
	struct input_dev *input;
	struct delayed_work dwork;
	spinlock_t lock; /* Protects canceling/rescheduling of dwork */
	unsigned short keycodes[ARRAY_SIZE(qt2160_key2code)];
	u16 key_matrix;
	#ifdef CONFIG_LEDS_CLASS
	struct qt2160_led leds[QT2160_NUM_LEDS_X];
	struct mutex led_lock;
	#endif
	};

	static int qt2160_read(struct i2c_client *client, u8 reg);
	static int qt2160_write(struct i2c_client *client, u8 reg, u8 data);

	#ifdef CONFIG_LEDS_CLASS

	static void qt2160_led_work(struct work_struct *work)
	{
	struct qt2160_led *led = container_of(work, struct qt2160_led, work);
	struct qt2160_data *qt2160 = led->qt2160;
	struct i2c_client *client = qt2160->client;
	int value = led->new_brightness;
	u32 drive, pwmen;

	mutex_lock(&qt2160->led_lock);

	drive = qt2160_read(client, QT2160_CMD_DRIVE_X);
	pwmen = qt2160_read(client, QT2160_CMD_PWMEN_X);
	if (value != LED_OFF) {
	drive \|= (1 << led->id);
	pwmen \|= (1 << led->id);

	} else {
	drive &= ~(1 << led->id);
	pwmen &= ~(1 << led->id);
	}
	qt2160_write(client, QT2160_CMD_DRIVE_X, drive);
	qt2160_write(client, QT2160_CMD_PWMEN_X, pwmen);

	/*
	* Changing this register will change the brightness
	* of every LED in the qt2160. It's a HW limitation.
	*/
	if (value != LED_OFF)
	qt2160_write(client, QT2160_CMD_PWM_DUTY, value);

	mutex_unlock(&qt2160->led_lock);
	}

	static void qt2160_led_set(struct led_classdev *cdev,
	enum led_brightness value)
	{
	struct qt2160_led *led = container_of(cdev, struct qt2160_led, cdev);

	led->new_brightness = value;
	schedule_work(&led->work);
	}

	#endif /* CONFIG_LEDS_CLASS */

	static int qt2160_read_block(struct i2c_client *client,
	u8 inireg, u8 *buffer, unsigned int count)
	{
	int error, idx = 0;

	/*
	* Can't use SMBus block data read. Check for I2C functionality to speed
	* things up whenever possible. Otherwise we will be forced to read
	* sequentially.
	*/
	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {

	error = i2c_smbus_write_byte(client, inireg + idx);
	if (error) {
	dev_err(&client->dev,
	"couldn't send request. Returned %d\n", error);
	return error;
	}

	error = i2c_master_recv(client, buffer, count);
	if (error != count) {
	dev_err(&client->dev,
	"couldn't read registers. Returned %d bytes\n", error);
	return error;
	}
	} else {

	while (count--) {
	int data;

	error = i2c_smbus_write_byte(client, inireg + idx);
	if (error) {
	dev_err(&client->dev,
	"couldn't send request. Returned %d\n", error);
	return error;
	}

	data = i2c_smbus_read_byte(client);
	if (data < 0) {
	dev_err(&client->dev,
	"couldn't read register. Returned %d\n", data);
	return data;
	}

	buffer[idx++] = data;
	}
	}

	return 0;
	}

	static int qt2160_get_key_matrix(struct qt2160_data *qt2160)
	{
	struct i2c_client *client = qt2160->client;
	struct input_dev *input = qt2160->input;
	u8 regs[6];
	u16 old_matrix, new_matrix;
	int ret, i, mask;

	dev_dbg(&client->dev, "requesting keys...\n");

	/*
	* Read all registers from General Status Register
	* to GPIOs register
	*/
	ret = qt2160_read_block(client, QT2160_CMD_GSTAT, regs, 6);
	if (ret) {
	dev_err(&client->dev,
	"could not perform chip read.\n");
	return ret;
	}

	old_matrix = qt2160->key_matrix;
	qt2160->key_matrix = new_matrix = (regs[2] << 8) \| regs[1];

	mask = 0x01;
	for (i = 0; i < 16; ++i, mask <<= 1) {
	int keyval = new_matrix & mask;

	if ((old_matrix & mask) != keyval) {
	input_report_key(input, qt2160->keycodes[i], keyval);
	dev_dbg(&client->dev, "key %d %s\n",
	i, keyval ? "pressed" : "released");
	}
	}

	input_sync(input);

	return 0;
	}

	static irqreturn_t qt2160_irq(int irq, void *_qt2160)
	{
	struct qt2160_data *qt2160 = _qt2160;
	unsigned long flags;

	spin_lock_irqsave(&qt2160->lock, flags);

	mod_delayed_work(system_wq, &qt2160->dwork, 0);

	spin_unlock_irqrestore(&qt2160->lock, flags);

	return IRQ_HANDLED;
	}

	static void qt2160_schedule_read(struct qt2160_data *qt2160)
	{
	spin_lock_irq(&qt2160->lock);
	schedule_delayed_work(&qt2160->dwork, QT2160_CYCLE_INTERVAL);
	spin_unlock_irq(&qt2160->lock);
	}

	static void qt2160_worker(struct work_struct *work)
	{
	struct qt2160_data *qt2160 =
	container_of(work, struct qt2160_data, dwork.work);

	dev_dbg(&qt2160->client->dev, "worker\n");

	qt2160_get_key_matrix(qt2160);

	/* Avoid device lock up by checking every so often */
	qt2160_schedule_read(qt2160);
	}

	static int qt2160_read(struct i2c_client *client, u8 reg)
	{
	int ret;

	ret = i2c_smbus_write_byte(client, reg);
	if (ret) {
	dev_err(&client->dev,
	"couldn't send request. Returned %d\n", ret);
	return ret;
	}

	ret = i2c_smbus_read_byte(client);
	if (ret < 0) {
	dev_err(&client->dev,
	"couldn't read register. Returned %d\n", ret);
	return ret;
	}

	return ret;
	}

	static int qt2160_write(struct i2c_client *client, u8 reg, u8 data)
	{
	int ret;

	ret = i2c_smbus_write_byte_data(client, reg, data);
	if (ret < 0)
	dev_err(&client->dev,
	"couldn't write data. Returned %d\n", ret);

	return ret;
	}

	#ifdef CONFIG_LEDS_CLASS

	static int qt2160_register_leds(struct qt2160_data *qt2160)
	{
	struct i2c_client *client = qt2160->client;
	int ret;
	int i;

	mutex_init(&qt2160->led_lock);

	for (i = 0; i < QT2160_NUM_LEDS_X; i++) {
	struct qt2160_led *led = &qt2160->leds[i];

	snprintf(led->name, sizeof(led->name), "qt2160:x%d", i);
	led->cdev.name = led->name;
	led->cdev.brightness_set = qt2160_led_set;
	led->cdev.brightness = LED_OFF;
	led->id = i;
	led->qt2160 = qt2160;

	INIT_WORK(&led->work, qt2160_led_work);

	ret = led_classdev_register(&client->dev, &led->cdev);
	if (ret < 0)
	return ret;
	}

	/* Tur off LEDs */
	qt2160_write(client, QT2160_CMD_DRIVE_X, 0);
	qt2160_write(client, QT2160_CMD_PWMEN_X, 0);
	qt2160_write(client, QT2160_CMD_PWM_DUTY, 0);

	return 0;
	}

	static void qt2160_unregister_leds(struct qt2160_data *qt2160)
	{
	int i;

	for (i = 0; i < QT2160_NUM_LEDS_X; i++) {
	led_classdev_unregister(&qt2160->leds[i].cdev);
	cancel_work_sync(&qt2160->leds[i].work);
	}
	}

	#else

	static inline int qt2160_register_leds(struct qt2160_data *qt2160)
	{
	return 0;
	}

	static inline void qt2160_unregister_leds(struct qt2160_data *qt2160)
	{
	}

	#endif

	static bool qt2160_identify(struct i2c_client *client)
	{
	int id, ver, rev;

	/* Read Chid ID to check if chip is valid */
	id = qt2160_read(client, QT2160_CMD_CHIPID);
	if (id != QT2160_VALID_CHIPID) {
	dev_err(&client->dev, "ID %d not supported\n", id);
	return false;
	}

	/* Read chip firmware version */
	ver = qt2160_read(client, QT2160_CMD_CODEVER);
	if (ver < 0) {
	dev_err(&client->dev, "could not get firmware version\n");
	return false;
	}

	/* Read chip firmware revision */
	rev = qt2160_read(client, QT2160_CMD_SUBVER);
	if (rev < 0) {
	dev_err(&client->dev, "could not get firmware revision\n");
	return false;
	}

	dev_info(&client->dev, "AT42QT2160 firmware version %d.%d.%d\n",
	ver >> 4, ver & 0xf, rev);

	return true;
	}

	static int qt2160_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct qt2160_data *qt2160;
	struct input_dev *input;
	int i;
	int error;

	/* Check functionality */
	error = i2c_check_functionality(client->adapter,
	I2C_FUNC_SMBUS_BYTE);
	if (!error) {
	dev_err(&client->dev, "%s adapter not supported\n",
	dev_driver_string(&client->adapter->dev));
	return -ENODEV;
	}

	if (!qt2160_identify(client))
	return -ENODEV;

	/* Chip is valid and active. Allocate structure */
	qt2160 = kzalloc(sizeof(struct qt2160_data), GFP_KERNEL);
	input = input_allocate_device();
	if (!qt2160 \|\| !input) {
	dev_err(&client->dev, "insufficient memory\n");
	error = -ENOMEM;
	goto err_free_mem;
	}

	qt2160->client = client;
	qt2160->input = input;
	INIT_DELAYED_WORK(&qt2160->dwork, qt2160_worker);
	spin_lock_init(&qt2160->lock);

	input->name = "AT42QT2160 Touch Sense Keyboard";
	input->id.bustype = BUS_I2C;

	input->keycode = qt2160->keycodes;
	input->keycodesize = sizeof(qt2160->keycodes[0]);
	input->keycodemax = ARRAY_SIZE(qt2160_key2code);

	__set_bit(EV_KEY, input->evbit);
	__clear_bit(EV_REP, input->evbit);
	for (i = 0; i < ARRAY_SIZE(qt2160_key2code); i++) {
	qt2160->keycodes[i] = qt2160_key2code[i];
	__set_bit(qt2160_key2code[i], input->keybit);
	}
	__clear_bit(KEY_RESERVED, input->keybit);

	/* Calibrate device */
	error = qt2160_write(client, QT2160_CMD_CALIBRATE, 1);
	if (error) {
	dev_err(&client->dev, "failed to calibrate device\n");
	goto err_free_mem;
	}

	if (client->irq) {
	error = request_irq(client->irq, qt2160_irq,
	IRQF_TRIGGER_FALLING, "qt2160", qt2160);
	if (error) {
	dev_err(&client->dev,
	"failed to allocate irq %d\n", client->irq);
	goto err_free_mem;
	}
	}

	error = qt2160_register_leds(qt2160);
	if (error) {
	dev_err(&client->dev, "Failed to register leds\n");
	goto err_free_irq;
	}

	error = input_register_device(qt2160->input);
	if (error) {
	dev_err(&client->dev,
	"Failed to register input device\n");
	goto err_unregister_leds;
	}

	i2c_set_clientdata(client, qt2160);
	qt2160_schedule_read(qt2160);

	return 0;

	err_unregister_leds:
	qt2160_unregister_leds(qt2160);
	err_free_irq:
	if (client->irq)
	free_irq(client->irq, qt2160);
	err_free_mem:
	input_free_device(input);
	kfree(qt2160);
	return error;
	}

	static int qt2160_remove(struct i2c_client *client)
	{
	struct qt2160_data *qt2160 = i2c_get_clientdata(client);

	qt2160_unregister_leds(qt2160);

	/* Release IRQ so no queue will be scheduled */
	if (client->irq)
	free_irq(client->irq, qt2160);

	cancel_delayed_work_sync(&qt2160->dwork);

	input_unregister_device(qt2160->input);
	kfree(qt2160);

	return 0;
	}

	static const struct i2c_device_id qt2160_idtable[] = {
	{ "qt2160", 0, },
	{ }
	};

	MODULE_DEVICE_TABLE(i2c, qt2160_idtable);

	static struct i2c_driver qt2160_driver = {
	.driver = {
	.name = "qt2160",
	.owner = THIS_MODULE,
	},

	.id_table = qt2160_idtable,
	.probe = qt2160_probe,
	.remove = qt2160_remove,
	};

	module_i2c_driver(qt2160_driver);

	MODULE_AUTHOR("Raphael Derosso Pereira <raphaelpereira@gmail.com>");
	MODULE_DESCRIPTION("Driver for AT42QT2160 Touch Sensor");
	MODULE_LICENSE("GPL");