drivers/input/keyboard/mpr121_touchkey.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Touchkey driver for Freescale MPR121 Controllor
  *
  * Copyright (C) 2011 Freescale Semiconductor, Inc.
  * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
  *
  * Based on mcs_touchkey.c
  */

 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/property.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>

 /* Register definitions */
 #define ELE_TOUCH_STATUS_0_ADDR	0x0
 #define ELE_TOUCH_STATUS_1_ADDR	0X1
 #define MHD_RISING_ADDR		0x2b
 #define NHD_RISING_ADDR		0x2c
 #define NCL_RISING_ADDR		0x2d
 #define FDL_RISING_ADDR		0x2e
 #define MHD_FALLING_ADDR	0x2f
 #define NHD_FALLING_ADDR	0x30
 #define NCL_FALLING_ADDR	0x31
 #define FDL_FALLING_ADDR	0x32
 #define ELE0_TOUCH_THRESHOLD_ADDR	0x41
 #define ELE0_RELEASE_THRESHOLD_ADDR	0x42
 #define AFE_CONF_ADDR			0x5c
 #define FILTER_CONF_ADDR		0x5d

 /*
  * ELECTRODE_CONF_ADDR: This register configures the number of
  * enabled capacitance sensing inputs and its run/suspend mode.
  */
 #define ELECTRODE_CONF_ADDR		0x5e
 #define ELECTRODE_CONF_QUICK_CHARGE	0x80
 #define AUTO_CONFIG_CTRL_ADDR		0x7b
 #define AUTO_CONFIG_USL_ADDR		0x7d
 #define AUTO_CONFIG_LSL_ADDR		0x7e
 #define AUTO_CONFIG_TL_ADDR		0x7f

 /* Threshold of touch/release trigger */
 #define TOUCH_THRESHOLD			0x08
 #define RELEASE_THRESHOLD		0x05
 /* Masks for touch and release triggers */
 #define TOUCH_STATUS_MASK		0xfff
 /* MPR121 has 12 keys */
 #define MPR121_MAX_KEY_COUNT		12

 #define MPR121_MIN_POLL_INTERVAL	10
 #define MPR121_MAX_POLL_INTERVAL	200

 struct mpr121_touchkey {
 	struct i2c_client	*client;
 	struct input_dev	*input_dev;
 	unsigned int		statusbits;
 	unsigned int		keycount;
 	u32			keycodes[MPR121_MAX_KEY_COUNT];
 };

 struct mpr121_init_register {
 	int addr;
 	u8 val;
 };

 static const struct mpr121_init_register init_reg_table[] = {
 	{ MHD_RISING_ADDR,	0x1 },
 	{ NHD_RISING_ADDR,	0x1 },
 	{ MHD_FALLING_ADDR,	0x1 },
 	{ NHD_FALLING_ADDR,	0x1 },
 	{ NCL_FALLING_ADDR,	0xff },
 	{ FDL_FALLING_ADDR,	0x02 },
 	{ FILTER_CONF_ADDR,	0x04 },
 	{ AFE_CONF_ADDR,	0x0b },
 	{ AUTO_CONFIG_CTRL_ADDR, 0x0b },
 };

 static void mpr121_vdd_supply_disable(void *data)
 {
 	struct regulator *vdd_supply = data;

 	regulator_disable(vdd_supply);
 }

 static struct regulator *mpr121_vdd_supply_init(struct device *dev)
 {
 	struct regulator *vdd_supply;
 	int err;

 	vdd_supply = devm_regulator_get(dev, "vdd");
 	if (IS_ERR(vdd_supply)) {
 		dev_err(dev, "failed to get vdd regulator: %ld\n",
 			PTR_ERR(vdd_supply));
 		return vdd_supply;
 	}

 	err = regulator_enable(vdd_supply);
 	if (err) {
 		dev_err(dev, "failed to enable vdd regulator: %d\n", err);
 		return ERR_PTR(err);
 	}

 	err = devm_add_action_or_reset(dev, mpr121_vdd_supply_disable,
 				       vdd_supply);
 	if (err) {
 		dev_err(dev, "failed to add disable regulator action: %d\n",
 			err);
 		return ERR_PTR(err);
 	}

 	return vdd_supply;
 }

 static void mpr_touchkey_report(struct input_dev *dev)
 {
 	struct mpr121_touchkey *mpr121 = input_get_drvdata(dev);
 	struct input_dev *input = mpr121->input_dev;
 	struct i2c_client *client = mpr121->client;
 	unsigned long bit_changed;
 	unsigned int key_num;
 	int reg;

 	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
 	if (reg < 0) {
 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
 		return;
 	}

 	reg <<= 8;
 	reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
 	if (reg < 0) {
 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
 		return;
 	}

 	reg &= TOUCH_STATUS_MASK;
 	/* use old press bit to figure out which bit changed */
 	bit_changed = reg ^ mpr121->statusbits;
 	mpr121->statusbits = reg;
 	for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
 		unsigned int key_val, pressed;

 		pressed = reg & BIT(key_num);
 		key_val = mpr121->keycodes[key_num];

 		input_event(input, EV_MSC, MSC_SCAN, key_num);
 		input_report_key(input, key_val, pressed);

 		dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
 			pressed ? "pressed" : "released");

 	}
 	input_sync(input);
 }

 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
 {
 	struct mpr121_touchkey *mpr121 = dev_id;

 	mpr_touchkey_report(mpr121->input_dev);

 	return IRQ_HANDLED;
 }

 static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
 			    struct i2c_client *client, int vdd_uv)
 {
 	const struct mpr121_init_register *reg;
 	unsigned char usl, lsl, tl, eleconf;
 	int i, t, vdd, ret;

 	/* Set up touch/release threshold for ele0-ele11 */
 	for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
 		t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
 		ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
 		if (ret < 0)
 			goto err_i2c_write;
 		ret = i2c_smbus_write_byte_data(client, t + 1,
 						RELEASE_THRESHOLD);
 		if (ret < 0)
 			goto err_i2c_write;
 	}

 	/* Set up init register */
 	for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
 		reg = &init_reg_table[i];
 		ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
 		if (ret < 0)
 			goto err_i2c_write;
 	}


 	/*
 	 * Capacitance on sensing input varies and needs to be compensated.
 	 * The internal MPR121-auto-configuration can do this if it's
 	 * registers are set properly (based on vdd_uv).
 	 */
 	vdd = vdd_uv / 1000;
 	usl = ((vdd - 700) * 256) / vdd;
 	lsl = (usl * 65) / 100;
 	tl = (usl * 90) / 100;
 	ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
 	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
 	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);

 	/*
 	 * Quick charge bit will let the capacitive charge to ready
 	 * state quickly, or the buttons may not function after system
 	 * boot.
 	 */
 	eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
 	ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 					 eleconf);
 	if (ret != 0)
 		goto err_i2c_write;

 	dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);

 	return 0;

 err_i2c_write:
 	dev_err(&client->dev, "i2c write error: %d\n", ret);
 	return ret;
 }

 static int mpr_touchkey_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct regulator *vdd_supply;
 	int vdd_uv;
 	struct mpr121_touchkey *mpr121;
 	struct input_dev *input_dev;
 	u32 poll_interval = 0;
 	int error;
 	int i;

 	vdd_supply = mpr121_vdd_supply_init(dev);
 	if (IS_ERR(vdd_supply))
 		return PTR_ERR(vdd_supply);

 	vdd_uv = regulator_get_voltage(vdd_supply);

 	mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
 	if (!mpr121)
 		return -ENOMEM;

 	input_dev = devm_input_allocate_device(dev);
 	if (!input_dev)
 		return -ENOMEM;

 	mpr121->client = client;
 	mpr121->input_dev = input_dev;
 	mpr121->keycount = device_property_count_u32(dev, "linux,keycodes");
 	if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
 		dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
 		return -EINVAL;
 	}

 	error = device_property_read_u32_array(dev, "linux,keycodes",
 					       mpr121->keycodes,
 					       mpr121->keycount);
 	if (error) {
 		dev_err(dev,
 			"failed to read linux,keycode property: %d\n", error);
 		return error;
 	}

 	input_dev->name = "Freescale MPR121 Touchkey";
 	input_dev->id.bustype = BUS_I2C;
 	input_dev->dev.parent = dev;
 	if (device_property_read_bool(dev, "autorepeat"))
 		__set_bit(EV_REP, input_dev->evbit);
 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
 	input_set_drvdata(input_dev, mpr121);

 	input_dev->keycode = mpr121->keycodes;
 	input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
 	input_dev->keycodemax = mpr121->keycount;

 	for (i = 0; i < mpr121->keycount; i++)
 		input_set_capability(input_dev, EV_KEY, mpr121->keycodes[i]);

 	error = mpr121_phys_init(mpr121, client, vdd_uv);
 	if (error) {
 		dev_err(dev, "Failed to init register\n");
 		return error;
 	}

 	device_property_read_u32(dev, "poll-interval", &poll_interval);

 	if (client->irq) {
 		error = devm_request_threaded_irq(dev, client->irq, NULL,
 						  mpr_touchkey_interrupt,
 						  IRQF_TRIGGER_FALLING |
 						  IRQF_ONESHOT,
 						  dev->driver->name, mpr121);
 		if (error) {
 			dev_err(dev, "Failed to register interrupt\n");
 			return error;
 		}
 	} else if (poll_interval) {
 		if (poll_interval < MPR121_MIN_POLL_INTERVAL)
 			return -EINVAL;

 		if (poll_interval > MPR121_MAX_POLL_INTERVAL)
 			return -EINVAL;

 		error = input_setup_polling(input_dev, mpr_touchkey_report);
 		if (error) {
 			dev_err(dev, "Failed to setup polling\n");
 			return error;
 		}

 		input_set_poll_interval(input_dev, poll_interval);
 		input_set_min_poll_interval(input_dev,
 					    MPR121_MIN_POLL_INTERVAL);
 		input_set_max_poll_interval(input_dev,
 					    MPR121_MAX_POLL_INTERVAL);
 	} else {
 		dev_err(dev,
 			"invalid IRQ number and polling not configured\n");
 		return -EINVAL;
 	}

 	error = input_register_device(input_dev);
 	if (error)
 		return error;

 	i2c_set_clientdata(client, mpr121);
 	device_init_wakeup(dev,
 			device_property_read_bool(dev, "wakeup-source"));

 	return 0;
 }

 static int mpr_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);

 	if (device_may_wakeup(&client->dev))
 		enable_irq_wake(client->irq);

 	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);

 	return 0;
 }

 static int mpr_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);

 	if (device_may_wakeup(&client->dev))
 		disable_irq_wake(client->irq);

 	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 				  mpr121->keycount);

 	return 0;
 }

 static DEFINE_SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);

 static const struct i2c_device_id mpr121_id[] = {
 	{ "mpr121_touchkey", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, mpr121_id);

 #ifdef CONFIG_OF
 static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
 	{ .compatible = "fsl,mpr121-touchkey" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
 #endif

 static struct i2c_driver mpr_touchkey_driver = {
 	.driver = {
 		.name	= "mpr121",
 		.pm	= pm_sleep_ptr(&mpr121_touchkey_pm_ops),
 		.of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
 	},
 	.id_table	= mpr121_id,
 	.probe		= mpr_touchkey_probe,
 };

 module_i2c_driver(mpr_touchkey_driver);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Touchkey driver for Freescale MPR121 Controllor
	*
	* Copyright (C) 2011 Freescale Semiconductor, Inc.
	* Author: Zhang Jiejing <jiejing.zhang@freescale.com>
	*
	* Based on mcs_touchkey.c
	*/

	#include <linux/bitops.h>
	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/input.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/property.h>
	#include <linux/regulator/consumer.h>
	#include <linux/slab.h>

	/* Register definitions */
	#define ELE_TOUCH_STATUS_0_ADDR 0x0
	#define ELE_TOUCH_STATUS_1_ADDR 0X1
	#define MHD_RISING_ADDR 0x2b
	#define NHD_RISING_ADDR 0x2c
	#define NCL_RISING_ADDR 0x2d
	#define FDL_RISING_ADDR 0x2e
	#define MHD_FALLING_ADDR 0x2f
	#define NHD_FALLING_ADDR 0x30
	#define NCL_FALLING_ADDR 0x31
	#define FDL_FALLING_ADDR 0x32
	#define ELE0_TOUCH_THRESHOLD_ADDR 0x41
	#define ELE0_RELEASE_THRESHOLD_ADDR 0x42
	#define AFE_CONF_ADDR 0x5c
	#define FILTER_CONF_ADDR 0x5d

	/*
	* ELECTRODE_CONF_ADDR: This register configures the number of
	* enabled capacitance sensing inputs and its run/suspend mode.
	*/
	#define ELECTRODE_CONF_ADDR 0x5e
	#define ELECTRODE_CONF_QUICK_CHARGE 0x80
	#define AUTO_CONFIG_CTRL_ADDR 0x7b
	#define AUTO_CONFIG_USL_ADDR 0x7d
	#define AUTO_CONFIG_LSL_ADDR 0x7e
	#define AUTO_CONFIG_TL_ADDR 0x7f

	/* Threshold of touch/release trigger */
	#define TOUCH_THRESHOLD 0x08
	#define RELEASE_THRESHOLD 0x05
	/* Masks for touch and release triggers */
	#define TOUCH_STATUS_MASK 0xfff
	/* MPR121 has 12 keys */
	#define MPR121_MAX_KEY_COUNT 12

	#define MPR121_MIN_POLL_INTERVAL 10
	#define MPR121_MAX_POLL_INTERVAL 200

	struct mpr121_touchkey {
	struct i2c_client *client;
	struct input_dev *input_dev;
	unsigned int statusbits;
	unsigned int keycount;
	u32 keycodes[MPR121_MAX_KEY_COUNT];
	};

	struct mpr121_init_register {
	int addr;
	u8 val;
	};

	static const struct mpr121_init_register init_reg_table[] = {
	{ MHD_RISING_ADDR, 0x1 },
	{ NHD_RISING_ADDR, 0x1 },
	{ MHD_FALLING_ADDR, 0x1 },
	{ NHD_FALLING_ADDR, 0x1 },
	{ NCL_FALLING_ADDR, 0xff },
	{ FDL_FALLING_ADDR, 0x02 },
	{ FILTER_CONF_ADDR, 0x04 },
	{ AFE_CONF_ADDR, 0x0b },
	{ AUTO_CONFIG_CTRL_ADDR, 0x0b },
	};

	static void mpr121_vdd_supply_disable(void *data)
	{
	struct regulator *vdd_supply = data;

	regulator_disable(vdd_supply);
	}

	static struct regulator mpr121_vdd_supply_init(struct device dev)
	{
	struct regulator *vdd_supply;
	int err;

	vdd_supply = devm_regulator_get(dev, "vdd");
	if (IS_ERR(vdd_supply)) {
	dev_err(dev, "failed to get vdd regulator: %ld\n",
	PTR_ERR(vdd_supply));
	return vdd_supply;
	}

	err = regulator_enable(vdd_supply);
	if (err) {
	dev_err(dev, "failed to enable vdd regulator: %d\n", err);
	return ERR_PTR(err);
	}

	err = devm_add_action_or_reset(dev, mpr121_vdd_supply_disable,
	vdd_supply);
	if (err) {
	dev_err(dev, "failed to add disable regulator action: %d\n",
	err);
	return ERR_PTR(err);
	}

	return vdd_supply;
	}

	static void mpr_touchkey_report(struct input_dev *dev)
	{
	struct mpr121_touchkey *mpr121 = input_get_drvdata(dev);
	struct input_dev *input = mpr121->input_dev;
	struct i2c_client *client = mpr121->client;
	unsigned long bit_changed;
	unsigned int key_num;
	int reg;

	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
	if (reg < 0) {
	dev_err(&client->dev, "i2c read error [%d]\n", reg);
	return;
	}

	reg <<= 8;
	reg \|= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
	if (reg < 0) {
	dev_err(&client->dev, "i2c read error [%d]\n", reg);
	return;
	}

	reg &= TOUCH_STATUS_MASK;
	/* use old press bit to figure out which bit changed */
	bit_changed = reg ^ mpr121->statusbits;
	mpr121->statusbits = reg;
	for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
	unsigned int key_val, pressed;

	pressed = reg & BIT(key_num);
	key_val = mpr121->keycodes[key_num];

	input_event(input, EV_MSC, MSC_SCAN, key_num);
	input_report_key(input, key_val, pressed);

	dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
	pressed ? "pressed" : "released");

	}
	input_sync(input);
	}

	static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
	{
	struct mpr121_touchkey *mpr121 = dev_id;

	mpr_touchkey_report(mpr121->input_dev);

	return IRQ_HANDLED;
	}

	static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
	struct i2c_client *client, int vdd_uv)
	{
	const struct mpr121_init_register *reg;
	unsigned char usl, lsl, tl, eleconf;
	int i, t, vdd, ret;

	/* Set up touch/release threshold for ele0-ele11 */
	for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
	t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
	ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
	if (ret < 0)
	goto err_i2c_write;
	ret = i2c_smbus_write_byte_data(client, t + 1,
	RELEASE_THRESHOLD);
	if (ret < 0)
	goto err_i2c_write;
	}

	/* Set up init register */
	for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
	reg = &init_reg_table[i];
	ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
	if (ret < 0)
	goto err_i2c_write;
	}


	/*
	* Capacitance on sensing input varies and needs to be compensated.
	* The internal MPR121-auto-configuration can do this if it's
	* registers are set properly (based on vdd_uv).
	*/
	vdd = vdd_uv / 1000;
	usl = ((vdd - 700) * 256) / vdd;
	lsl = (usl * 65) / 100;
	tl = (usl * 90) / 100;
	ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
	ret \|= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
	ret \|= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);

	/*
	* Quick charge bit will let the capacitive charge to ready
	* state quickly, or the buttons may not function after system
	* boot.
	*/
	eleconf = mpr121->keycount \| ELECTRODE_CONF_QUICK_CHARGE;
	ret \|= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
	eleconf);
	if (ret != 0)
	goto err_i2c_write;

	dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);

	return 0;

	err_i2c_write:
	dev_err(&client->dev, "i2c write error: %d\n", ret);
	return ret;
	}

	static int mpr_touchkey_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct regulator *vdd_supply;
	int vdd_uv;
	struct mpr121_touchkey *mpr121;
	struct input_dev *input_dev;
	u32 poll_interval = 0;
	int error;
	int i;

	vdd_supply = mpr121_vdd_supply_init(dev);
	if (IS_ERR(vdd_supply))
	return PTR_ERR(vdd_supply);

	vdd_uv = regulator_get_voltage(vdd_supply);

	mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
	if (!mpr121)
	return -ENOMEM;

	input_dev = devm_input_allocate_device(dev);
	if (!input_dev)
	return -ENOMEM;

	mpr121->client = client;
	mpr121->input_dev = input_dev;
	mpr121->keycount = device_property_count_u32(dev, "linux,keycodes");
	if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
	dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
	return -EINVAL;
	}

	error = device_property_read_u32_array(dev, "linux,keycodes",
	mpr121->keycodes,
	mpr121->keycount);
	if (error) {
	dev_err(dev,
	"failed to read linux,keycode property: %d\n", error);
	return error;
	}

	input_dev->name = "Freescale MPR121 Touchkey";
	input_dev->id.bustype = BUS_I2C;
	input_dev->dev.parent = dev;
	if (device_property_read_bool(dev, "autorepeat"))
	__set_bit(EV_REP, input_dev->evbit);
	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
	input_set_drvdata(input_dev, mpr121);

	input_dev->keycode = mpr121->keycodes;
	input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
	input_dev->keycodemax = mpr121->keycount;

	for (i = 0; i < mpr121->keycount; i++)
	input_set_capability(input_dev, EV_KEY, mpr121->keycodes[i]);

	error = mpr121_phys_init(mpr121, client, vdd_uv);
	if (error) {
	dev_err(dev, "Failed to init register\n");
	return error;
	}

	device_property_read_u32(dev, "poll-interval", &poll_interval);

	if (client->irq) {
	error = devm_request_threaded_irq(dev, client->irq, NULL,
	mpr_touchkey_interrupt,
	IRQF_TRIGGER_FALLING \|
	IRQF_ONESHOT,
	dev->driver->name, mpr121);
	if (error) {
	dev_err(dev, "Failed to register interrupt\n");
	return error;
	}
	} else if (poll_interval) {
	if (poll_interval < MPR121_MIN_POLL_INTERVAL)
	return -EINVAL;

	if (poll_interval > MPR121_MAX_POLL_INTERVAL)
	return -EINVAL;

	error = input_setup_polling(input_dev, mpr_touchkey_report);
	if (error) {
	dev_err(dev, "Failed to setup polling\n");
	return error;
	}

	input_set_poll_interval(input_dev, poll_interval);
	input_set_min_poll_interval(input_dev,
	MPR121_MIN_POLL_INTERVAL);
	input_set_max_poll_interval(input_dev,
	MPR121_MAX_POLL_INTERVAL);
	} else {
	dev_err(dev,
	"invalid IRQ number and polling not configured\n");
	return -EINVAL;
	}

	error = input_register_device(input_dev);
	if (error)
	return error;

	i2c_set_clientdata(client, mpr121);
	device_init_wakeup(dev,
	device_property_read_bool(dev, "wakeup-source"));

	return 0;
	}

	static int mpr_suspend(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);

	if (device_may_wakeup(&client->dev))
	enable_irq_wake(client->irq);

	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);

	return 0;
	}

	static int mpr_resume(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);

	if (device_may_wakeup(&client->dev))
	disable_irq_wake(client->irq);

	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
	mpr121->keycount);

	return 0;
	}

	static DEFINE_SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);

	static const struct i2c_device_id mpr121_id[] = {
	{ "mpr121_touchkey", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, mpr121_id);

	#ifdef CONFIG_OF
	static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
	{ .compatible = "fsl,mpr121-touchkey" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
	#endif

	static struct i2c_driver mpr_touchkey_driver = {
	.driver = {
	.name = "mpr121",
	.pm = pm_sleep_ptr(&mpr121_touchkey_pm_ops),
	.of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
	},
	.id_table = mpr121_id,
	.probe = mpr_touchkey_probe,
	};

	module_i2c_driver(mpr_touchkey_driver);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
	MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");