drivers/input/keyboard/tca8418_keypad.c - kernel/bruno - Git at Google

 /*
  * Driver for TCA8418 I2C keyboard
  *
  * Copyright (C) 2011 Fuel7, Inc.  All rights reserved.
  *
  * Author: Kyle Manna <kyle.manna@fuel7.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public
  * License v2 as published by the Free Software Foundation.
  *
  * 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 021110-1307, USA.
  *
  * If you can't comply with GPLv2, alternative licensing terms may be
  * arranged. Please contact Fuel7, Inc. (http://fuel7.com/) for proprietary
  * alternative licensing inquiries.
  */

 #include <linux/types.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/workqueue.h>
 #include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
 #include <linux/input/tca8418_keypad.h>
 #include <linux/of.h>

 /* TCA8418 hardware limits */
 #define TCA8418_MAX_ROWS	8
 #define TCA8418_MAX_COLS	10

 /* TCA8418 register offsets */
 #define REG_CFG			0x01
 #define REG_INT_STAT		0x02
 #define REG_KEY_LCK_EC		0x03
 #define REG_KEY_EVENT_A		0x04
 #define REG_KEY_EVENT_B		0x05
 #define REG_KEY_EVENT_C		0x06
 #define REG_KEY_EVENT_D		0x07
 #define REG_KEY_EVENT_E		0x08
 #define REG_KEY_EVENT_F		0x09
 #define REG_KEY_EVENT_G		0x0A
 #define REG_KEY_EVENT_H		0x0B
 #define REG_KEY_EVENT_I		0x0C
 #define REG_KEY_EVENT_J		0x0D
 #define REG_KP_LCK_TIMER	0x0E
 #define REG_UNLOCK1		0x0F
 #define REG_UNLOCK2		0x10
 #define REG_GPIO_INT_STAT1	0x11
 #define REG_GPIO_INT_STAT2	0x12
 #define REG_GPIO_INT_STAT3	0x13
 #define REG_GPIO_DAT_STAT1	0x14
 #define REG_GPIO_DAT_STAT2	0x15
 #define REG_GPIO_DAT_STAT3	0x16
 #define REG_GPIO_DAT_OUT1	0x17
 #define REG_GPIO_DAT_OUT2	0x18
 #define REG_GPIO_DAT_OUT3	0x19
 #define REG_GPIO_INT_EN1	0x1A
 #define REG_GPIO_INT_EN2	0x1B
 #define REG_GPIO_INT_EN3	0x1C
 #define REG_KP_GPIO1		0x1D
 #define REG_KP_GPIO2		0x1E
 #define REG_KP_GPIO3		0x1F
 #define REG_GPI_EM1		0x20
 #define REG_GPI_EM2		0x21
 #define REG_GPI_EM3		0x22
 #define REG_GPIO_DIR1		0x23
 #define REG_GPIO_DIR2		0x24
 #define REG_GPIO_DIR3		0x25
 #define REG_GPIO_INT_LVL1	0x26
 #define REG_GPIO_INT_LVL2	0x27
 #define REG_GPIO_INT_LVL3	0x28
 #define REG_DEBOUNCE_DIS1	0x29
 #define REG_DEBOUNCE_DIS2	0x2A
 #define REG_DEBOUNCE_DIS3	0x2B
 #define REG_GPIO_PULL1		0x2C
 #define REG_GPIO_PULL2		0x2D
 #define REG_GPIO_PULL3		0x2E

 /* TCA8418 bit definitions */
 #define CFG_AI			BIT(7)
 #define CFG_GPI_E_CFG		BIT(6)
 #define CFG_OVR_FLOW_M		BIT(5)
 #define CFG_INT_CFG		BIT(4)
 #define CFG_OVR_FLOW_IEN	BIT(3)
 #define CFG_K_LCK_IEN		BIT(2)
 #define CFG_GPI_IEN		BIT(1)
 #define CFG_KE_IEN		BIT(0)

 #define INT_STAT_CAD_INT	BIT(4)
 #define INT_STAT_OVR_FLOW_INT	BIT(3)
 #define INT_STAT_K_LCK_INT	BIT(2)
 #define INT_STAT_GPI_INT	BIT(1)
 #define INT_STAT_K_INT		BIT(0)

 /* TCA8418 register masks */
 #define KEY_LCK_EC_KEC		0x7
 #define KEY_EVENT_CODE		0x7f
 #define KEY_EVENT_VALUE		0x80

 struct tca8418_keypad {
 	struct i2c_client *client;
 	struct input_dev *input;

 	unsigned int row_shift;
 };

 /*
  * Write a byte to the TCA8418
  */
 static int tca8418_write_byte(struct tca8418_keypad *keypad_data,
 			      int reg, u8 val)
 {
 	int error;

 	error = i2c_smbus_write_byte_data(keypad_data->client, reg, val);
 	if (error < 0) {
 		dev_err(&keypad_data->client->dev,
 			"%s failed, reg: %d, val: %d, error: %d\n",
 			__func__, reg, val, error);
 		return error;
 	}

 	return 0;
 }

 /*
  * Read a byte from the TCA8418
  */
 static int tca8418_read_byte(struct tca8418_keypad *keypad_data,
 			     int reg, u8 *val)
 {
 	int error;

 	error = i2c_smbus_read_byte_data(keypad_data->client, reg);
 	if (error < 0) {
 		dev_err(&keypad_data->client->dev,
 				"%s failed, reg: %d, error: %d\n",
 				__func__, reg, error);
 		return error;
 	}

 	*val = (u8)error;

 	return 0;
 }

 static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
 {
 	struct input_dev *input = keypad_data->input;
 	unsigned short *keymap = input->keycode;
 	int error, col, row;
 	u8 reg, state, code;

 	/* Initial read of the key event FIFO */
 	error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);

 	/* Assume that key code 0 signifies empty FIFO */
 	while (error >= 0 && reg > 0) {
 		state = reg & KEY_EVENT_VALUE;
 		code  = reg & KEY_EVENT_CODE;

 		row = code / TCA8418_MAX_COLS;
 		col = code % TCA8418_MAX_COLS;

 		row = (col) ? row : row - 1;
 		col = (col) ? col - 1 : TCA8418_MAX_COLS - 1;

 		code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
 		input_event(input, EV_MSC, MSC_SCAN, code);
 		input_report_key(input, keymap[code], state);

 		/* Read for next loop */
 		error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
 	}

 	if (error < 0)
 		dev_err(&keypad_data->client->dev,
 			"unable to read REG_KEY_EVENT_A\n");

 	input_sync(input);
 }

 /*
  * Threaded IRQ handler and this can (and will) sleep.
  */
 static irqreturn_t tca8418_irq_handler(int irq, void *dev_id)
 {
 	struct tca8418_keypad *keypad_data = dev_id;
 	u8 reg;
 	int error;

 	error = tca8418_read_byte(keypad_data, REG_INT_STAT, &reg);
 	if (error) {
 		dev_err(&keypad_data->client->dev,
 			"unable to read REG_INT_STAT\n");
 		return IRQ_NONE;
 	}

 	if (!reg)
 		return IRQ_NONE;

 	if (reg & INT_STAT_OVR_FLOW_INT)
 		dev_warn(&keypad_data->client->dev, "overflow occurred\n");

 	if (reg & INT_STAT_K_INT)
 		tca8418_read_keypad(keypad_data);

 	/* Clear all interrupts, even IRQs we didn't check (GPI, CAD, LCK) */
 	reg = 0xff;
 	error = tca8418_write_byte(keypad_data, REG_INT_STAT, reg);
 	if (error)
 		dev_err(&keypad_data->client->dev,
 			"unable to clear REG_INT_STAT\n");

 	return IRQ_HANDLED;
 }

 /*
  * Configure the TCA8418 for keypad operation
  */
 static int tca8418_configure(struct tca8418_keypad *keypad_data,
 			     u32 rows, u32 cols)
 {
 	int reg, error;

 	/* Write config register, if this fails assume device not present */
 	error = tca8418_write_byte(keypad_data, REG_CFG,
 				CFG_INT_CFG | CFG_OVR_FLOW_IEN | CFG_KE_IEN);
 	if (error < 0)
 		return -ENODEV;


 	/* Assemble a mask for row and column registers */
 	reg  =  ~(~0 << rows);
 	reg += (~(~0 << cols)) << 8;

 	/* Set registers to keypad mode */
 	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
 	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
 	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);

 	/* Enable column debouncing */
 	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
 	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
 	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);

 	return error;
 }

 static int tca8418_keypad_probe(struct i2c_client *client,
 					  const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	const struct tca8418_keypad_platform_data *pdata =
 						dev_get_platdata(dev);
 	struct tca8418_keypad *keypad_data;
 	struct input_dev *input;
 	const struct matrix_keymap_data *keymap_data = NULL;
 	u32 rows = 0, cols = 0;
 	bool rep = false;
 	bool irq_is_gpio = false;
 	int irq;
 	int error, row_shift, max_keys;

 	/* Copy the platform data */
 	if (pdata) {
 		if (!pdata->keymap_data) {
 			dev_err(dev, "no keymap data defined\n");
 			return -EINVAL;
 		}
 		keymap_data = pdata->keymap_data;
 		rows = pdata->rows;
 		cols = pdata->cols;
 		rep  = pdata->rep;
 		irq_is_gpio = pdata->irq_is_gpio;
 	} else {
 		struct device_node *np = dev->of_node;
 		int err;

 		err = matrix_keypad_parse_of_params(dev, &rows, &cols);
 		if (err)
 			return err;
 		rep = of_property_read_bool(np, "keypad,autorepeat");
 	}

 	if (!rows || rows > TCA8418_MAX_ROWS) {
 		dev_err(dev, "invalid rows\n");
 		return -EINVAL;
 	}

 	if (!cols || cols > TCA8418_MAX_COLS) {
 		dev_err(dev, "invalid columns\n");
 		return -EINVAL;
 	}

 	/* Check i2c driver capabilities */
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
 		dev_err(dev, "%s adapter not supported\n",
 			dev_driver_string(&client->adapter->dev));
 		return -ENODEV;
 	}

 	row_shift = get_count_order(cols);
 	max_keys = rows << row_shift;

 	/* Allocate memory for keypad_data and input device */
 	keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), GFP_KERNEL);
 	if (!keypad_data)
 		return -ENOMEM;

 	keypad_data->client = client;
 	keypad_data->row_shift = row_shift;

 	/* Initialize the chip or fail if chip isn't present */
 	error = tca8418_configure(keypad_data, rows, cols);
 	if (error < 0)
 		return error;

 	/* Configure input device */
 	input = devm_input_allocate_device(dev);
 	if (!input)
 		return -ENOMEM;

 	keypad_data->input = input;

 	input->name = client->name;
 	input->id.bustype = BUS_I2C;
 	input->id.vendor  = 0x0001;
 	input->id.product = 0x001;
 	input->id.version = 0x0001;

 	error = matrix_keypad_build_keymap(keymap_data, NULL, rows, cols,
 					   NULL, input);
 	if (error) {
 		dev_err(dev, "Failed to build keymap\n");
 		return error;
 	}

 	if (rep)
 		__set_bit(EV_REP, input->evbit);
 	input_set_capability(input, EV_MSC, MSC_SCAN);

 	input_set_drvdata(input, keypad_data);

 	irq = client->irq;
 	if (irq_is_gpio)
 		irq = gpio_to_irq(irq);

 	error = devm_request_threaded_irq(dev, irq, NULL, tca8418_irq_handler,
 					  IRQF_TRIGGER_FALLING |
 						IRQF_SHARED |
 						IRQF_ONESHOT,
 					  client->name, keypad_data);
 	if (error) {
 		dev_err(dev, "Unable to claim irq %d; error %d\n",
 			client->irq, error);
 		return error;
 	}

 	error = input_register_device(input);
 	if (error) {
 		dev_err(dev, "Unable to register input device, error: %d\n",
 			error);
 		return error;
 	}

 	return 0;
 }

 static const struct i2c_device_id tca8418_id[] = {
 	{ TCA8418_NAME, 8418, },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, tca8418_id);

 #ifdef CONFIG_OF
 static const struct of_device_id tca8418_dt_ids[] = {
 	{ .compatible = "ti,tca8418", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, tca8418_dt_ids);

 /*
  * The device tree based i2c loader looks for
  * "i2c:" + second_component_of(property("compatible"))
  * and therefore we need an alias to be found.
  */
 MODULE_ALIAS("i2c:tca8418");
 #endif

 static struct i2c_driver tca8418_keypad_driver = {
 	.driver = {
 		.name	= TCA8418_NAME,
 		.of_match_table = of_match_ptr(tca8418_dt_ids),
 	},
 	.probe		= tca8418_keypad_probe,
 	.id_table	= tca8418_id,
 };

 static int __init tca8418_keypad_init(void)
 {
 	return i2c_add_driver(&tca8418_keypad_driver);
 }
 subsys_initcall(tca8418_keypad_init);

 static void __exit tca8418_keypad_exit(void)
 {
 	i2c_del_driver(&tca8418_keypad_driver);
 }
 module_exit(tca8418_keypad_exit);

 MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
 MODULE_DESCRIPTION("Keypad driver for TCA8418");
 MODULE_LICENSE("GPL");
	/*
	* Driver for TCA8418 I2C keyboard
	*
	* Copyright (C) 2011 Fuel7, Inc. All rights reserved.
	*
	* Author: Kyle Manna <kyle.manna@fuel7.com>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public
	* License v2 as published by the Free Software Foundation.
	*
	* 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 021110-1307, USA.
	*
	* If you can't comply with GPLv2, alternative licensing terms may be
	* arranged. Please contact Fuel7, Inc. (http://fuel7.com/) for proprietary
	* alternative licensing inquiries.
	*/

	#include <linux/types.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/delay.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/workqueue.h>
	#include <linux/gpio.h>
	#include <linux/i2c.h>
	#include <linux/input.h>
	#include <linux/input/tca8418_keypad.h>
	#include <linux/of.h>

	/* TCA8418 hardware limits */
	#define TCA8418_MAX_ROWS 8
	#define TCA8418_MAX_COLS 10

	/* TCA8418 register offsets */
	#define REG_CFG 0x01
	#define REG_INT_STAT 0x02
	#define REG_KEY_LCK_EC 0x03
	#define REG_KEY_EVENT_A 0x04
	#define REG_KEY_EVENT_B 0x05
	#define REG_KEY_EVENT_C 0x06
	#define REG_KEY_EVENT_D 0x07
	#define REG_KEY_EVENT_E 0x08
	#define REG_KEY_EVENT_F 0x09
	#define REG_KEY_EVENT_G 0x0A
	#define REG_KEY_EVENT_H 0x0B
	#define REG_KEY_EVENT_I 0x0C
	#define REG_KEY_EVENT_J 0x0D
	#define REG_KP_LCK_TIMER 0x0E
	#define REG_UNLOCK1 0x0F
	#define REG_UNLOCK2 0x10
	#define REG_GPIO_INT_STAT1 0x11
	#define REG_GPIO_INT_STAT2 0x12
	#define REG_GPIO_INT_STAT3 0x13
	#define REG_GPIO_DAT_STAT1 0x14
	#define REG_GPIO_DAT_STAT2 0x15
	#define REG_GPIO_DAT_STAT3 0x16
	#define REG_GPIO_DAT_OUT1 0x17
	#define REG_GPIO_DAT_OUT2 0x18
	#define REG_GPIO_DAT_OUT3 0x19
	#define REG_GPIO_INT_EN1 0x1A
	#define REG_GPIO_INT_EN2 0x1B
	#define REG_GPIO_INT_EN3 0x1C
	#define REG_KP_GPIO1 0x1D
	#define REG_KP_GPIO2 0x1E
	#define REG_KP_GPIO3 0x1F
	#define REG_GPI_EM1 0x20
	#define REG_GPI_EM2 0x21
	#define REG_GPI_EM3 0x22
	#define REG_GPIO_DIR1 0x23
	#define REG_GPIO_DIR2 0x24
	#define REG_GPIO_DIR3 0x25
	#define REG_GPIO_INT_LVL1 0x26
	#define REG_GPIO_INT_LVL2 0x27
	#define REG_GPIO_INT_LVL3 0x28
	#define REG_DEBOUNCE_DIS1 0x29
	#define REG_DEBOUNCE_DIS2 0x2A
	#define REG_DEBOUNCE_DIS3 0x2B
	#define REG_GPIO_PULL1 0x2C
	#define REG_GPIO_PULL2 0x2D
	#define REG_GPIO_PULL3 0x2E

	/* TCA8418 bit definitions */
	#define CFG_AI BIT(7)
	#define CFG_GPI_E_CFG BIT(6)
	#define CFG_OVR_FLOW_M BIT(5)
	#define CFG_INT_CFG BIT(4)
	#define CFG_OVR_FLOW_IEN BIT(3)
	#define CFG_K_LCK_IEN BIT(2)
	#define CFG_GPI_IEN BIT(1)
	#define CFG_KE_IEN BIT(0)

	#define INT_STAT_CAD_INT BIT(4)
	#define INT_STAT_OVR_FLOW_INT BIT(3)
	#define INT_STAT_K_LCK_INT BIT(2)
	#define INT_STAT_GPI_INT BIT(1)
	#define INT_STAT_K_INT BIT(0)

	/* TCA8418 register masks */
	#define KEY_LCK_EC_KEC 0x7
	#define KEY_EVENT_CODE 0x7f
	#define KEY_EVENT_VALUE 0x80

	struct tca8418_keypad {
	struct i2c_client *client;
	struct input_dev *input;

	unsigned int row_shift;
	};

	/*
	* Write a byte to the TCA8418
	*/
	static int tca8418_write_byte(struct tca8418_keypad *keypad_data,
	int reg, u8 val)
	{
	int error;

	error = i2c_smbus_write_byte_data(keypad_data->client, reg, val);
	if (error < 0) {
	dev_err(&keypad_data->client->dev,
	"%s failed, reg: %d, val: %d, error: %d\n",
	__func__, reg, val, error);
	return error;
	}

	return 0;
	}

	/*
	* Read a byte from the TCA8418
	*/
	static int tca8418_read_byte(struct tca8418_keypad *keypad_data,
	int reg, u8 *val)
	{
	int error;

	error = i2c_smbus_read_byte_data(keypad_data->client, reg);
	if (error < 0) {
	dev_err(&keypad_data->client->dev,
	"%s failed, reg: %d, error: %d\n",
	__func__, reg, error);
	return error;
	}

	*val = (u8)error;

	return 0;
	}

	static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
	{
	struct input_dev *input = keypad_data->input;
	unsigned short *keymap = input->keycode;
	int error, col, row;
	u8 reg, state, code;

	/* Initial read of the key event FIFO */
	error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);

	/* Assume that key code 0 signifies empty FIFO */
	while (error >= 0 && reg > 0) {
	state = reg & KEY_EVENT_VALUE;
	code = reg & KEY_EVENT_CODE;

	row = code / TCA8418_MAX_COLS;
	col = code % TCA8418_MAX_COLS;

	row = (col) ? row : row - 1;
	col = (col) ? col - 1 : TCA8418_MAX_COLS - 1;

	code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
	input_event(input, EV_MSC, MSC_SCAN, code);
	input_report_key(input, keymap[code], state);

	/* Read for next loop */
	error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
	}

	if (error < 0)
	dev_err(&keypad_data->client->dev,
	"unable to read REG_KEY_EVENT_A\n");

	input_sync(input);
	}

	/*
	* Threaded IRQ handler and this can (and will) sleep.
	*/
	static irqreturn_t tca8418_irq_handler(int irq, void *dev_id)
	{
	struct tca8418_keypad *keypad_data = dev_id;
	u8 reg;
	int error;

	error = tca8418_read_byte(keypad_data, REG_INT_STAT, &reg);
	if (error) {
	dev_err(&keypad_data->client->dev,
	"unable to read REG_INT_STAT\n");
	return IRQ_NONE;
	}

	if (!reg)
	return IRQ_NONE;

	if (reg & INT_STAT_OVR_FLOW_INT)
	dev_warn(&keypad_data->client->dev, "overflow occurred\n");

	if (reg & INT_STAT_K_INT)
	tca8418_read_keypad(keypad_data);

	/* Clear all interrupts, even IRQs we didn't check (GPI, CAD, LCK) */
	reg = 0xff;
	error = tca8418_write_byte(keypad_data, REG_INT_STAT, reg);
	if (error)
	dev_err(&keypad_data->client->dev,
	"unable to clear REG_INT_STAT\n");

	return IRQ_HANDLED;
	}

	/*
	* Configure the TCA8418 for keypad operation
	*/
	static int tca8418_configure(struct tca8418_keypad *keypad_data,
	u32 rows, u32 cols)
	{
	int reg, error;

	/* Write config register, if this fails assume device not present */
	error = tca8418_write_byte(keypad_data, REG_CFG,
	CFG_INT_CFG \| CFG_OVR_FLOW_IEN \| CFG_KE_IEN);
	if (error < 0)
	return -ENODEV;


	/* Assemble a mask for row and column registers */
	reg = ~(~0 << rows);
	reg += (~(~0 << cols)) << 8;

	/* Set registers to keypad mode */
	error \|= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
	error \|= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
	error \|= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);

	/* Enable column debouncing */
	error \|= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
	error \|= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
	error \|= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);

	return error;
	}

	static int tca8418_keypad_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &client->dev;
	const struct tca8418_keypad_platform_data *pdata =
	dev_get_platdata(dev);
	struct tca8418_keypad *keypad_data;
	struct input_dev *input;
	const struct matrix_keymap_data *keymap_data = NULL;
	u32 rows = 0, cols = 0;
	bool rep = false;
	bool irq_is_gpio = false;
	int irq;
	int error, row_shift, max_keys;

	/* Copy the platform data */
	if (pdata) {
	if (!pdata->keymap_data) {
	dev_err(dev, "no keymap data defined\n");
	return -EINVAL;
	}
	keymap_data = pdata->keymap_data;
	rows = pdata->rows;
	cols = pdata->cols;
	rep = pdata->rep;
	irq_is_gpio = pdata->irq_is_gpio;
	} else {
	struct device_node *np = dev->of_node;
	int err;

	err = matrix_keypad_parse_of_params(dev, &rows, &cols);
	if (err)
	return err;
	rep = of_property_read_bool(np, "keypad,autorepeat");
	}

	if (!rows \|\| rows > TCA8418_MAX_ROWS) {
	dev_err(dev, "invalid rows\n");
	return -EINVAL;
	}

	if (!cols \|\| cols > TCA8418_MAX_COLS) {
	dev_err(dev, "invalid columns\n");
	return -EINVAL;
	}

	/* Check i2c driver capabilities */
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
	dev_err(dev, "%s adapter not supported\n",
	dev_driver_string(&client->adapter->dev));
	return -ENODEV;
	}

	row_shift = get_count_order(cols);
	max_keys = rows << row_shift;

	/* Allocate memory for keypad_data and input device */
	keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), GFP_KERNEL);
	if (!keypad_data)
	return -ENOMEM;

	keypad_data->client = client;
	keypad_data->row_shift = row_shift;

	/* Initialize the chip or fail if chip isn't present */
	error = tca8418_configure(keypad_data, rows, cols);
	if (error < 0)
	return error;

	/* Configure input device */
	input = devm_input_allocate_device(dev);
	if (!input)
	return -ENOMEM;

	keypad_data->input = input;

	input->name = client->name;
	input->id.bustype = BUS_I2C;
	input->id.vendor = 0x0001;
	input->id.product = 0x001;
	input->id.version = 0x0001;

	error = matrix_keypad_build_keymap(keymap_data, NULL, rows, cols,
	NULL, input);
	if (error) {
	dev_err(dev, "Failed to build keymap\n");
	return error;
	}

	if (rep)
	__set_bit(EV_REP, input->evbit);
	input_set_capability(input, EV_MSC, MSC_SCAN);

	input_set_drvdata(input, keypad_data);

	irq = client->irq;
	if (irq_is_gpio)
	irq = gpio_to_irq(irq);

	error = devm_request_threaded_irq(dev, irq, NULL, tca8418_irq_handler,
	IRQF_TRIGGER_FALLING \|
	IRQF_SHARED \|
	IRQF_ONESHOT,
	client->name, keypad_data);
	if (error) {
	dev_err(dev, "Unable to claim irq %d; error %d\n",
	client->irq, error);
	return error;
	}

	error = input_register_device(input);
	if (error) {
	dev_err(dev, "Unable to register input device, error: %d\n",
	error);
	return error;
	}

	return 0;
	}

	static const struct i2c_device_id tca8418_id[] = {
	{ TCA8418_NAME, 8418, },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, tca8418_id);

	#ifdef CONFIG_OF
	static const struct of_device_id tca8418_dt_ids[] = {
	{ .compatible = "ti,tca8418", },
	{ }
	};
	MODULE_DEVICE_TABLE(of, tca8418_dt_ids);

	/*
	* The device tree based i2c loader looks for
	* "i2c:" + second_component_of(property("compatible"))
	* and therefore we need an alias to be found.
	*/
	MODULE_ALIAS("i2c:tca8418");
	#endif

	static struct i2c_driver tca8418_keypad_driver = {
	.driver = {
	.name = TCA8418_NAME,
	.of_match_table = of_match_ptr(tca8418_dt_ids),
	},
	.probe = tca8418_keypad_probe,
	.id_table = tca8418_id,
	};

	static int __init tca8418_keypad_init(void)
	{
	return i2c_add_driver(&tca8418_keypad_driver);
	}
	subsys_initcall(tca8418_keypad_init);

	static void __exit tca8418_keypad_exit(void)
	{
	i2c_del_driver(&tca8418_keypad_driver);
	}
	module_exit(tca8418_keypad_exit);

	MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
	MODULE_DESCRIPTION("Keypad driver for TCA8418");
	MODULE_LICENSE("GPL");