drivers/input/keyboard/cap11xx.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Input driver for Microchip CAP11xx based capacitive touch sensors
  *
  * (c) 2014 Daniel Mack <linux@zonque.org>
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/input.h>
 #include <linux/leds.h>
 #include <linux/of_irq.h>
 #include <linux/regmap.h>
 #include <linux/i2c.h>
 #include <linux/gpio/consumer.h>

 #define CAP11XX_REG_MAIN_CONTROL	0x00
 #define CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT	(6)
 #define CAP11XX_REG_MAIN_CONTROL_GAIN_MASK	(0xc0)
 #define CAP11XX_REG_MAIN_CONTROL_DLSEEP		BIT(4)
 #define CAP11XX_REG_GENERAL_STATUS	0x02
 #define CAP11XX_REG_SENSOR_INPUT	0x03
 #define CAP11XX_REG_NOISE_FLAG_STATUS	0x0a
 #define CAP11XX_REG_SENOR_DELTA(X)	(0x10 + (X))
 #define CAP11XX_REG_SENSITIVITY_CONTROL	0x1f
 #define CAP11XX_REG_CONFIG		0x20
 #define CAP11XX_REG_SENSOR_ENABLE	0x21
 #define CAP11XX_REG_SENSOR_CONFIG	0x22
 #define CAP11XX_REG_SENSOR_CONFIG2	0x23
 #define CAP11XX_REG_SAMPLING_CONFIG	0x24
 #define CAP11XX_REG_CALIBRATION		0x26
 #define CAP11XX_REG_INT_ENABLE		0x27
 #define CAP11XX_REG_REPEAT_RATE		0x28
 #define CAP11XX_REG_MT_CONFIG		0x2a
 #define CAP11XX_REG_MT_PATTERN_CONFIG	0x2b
 #define CAP11XX_REG_MT_PATTERN		0x2d
 #define CAP11XX_REG_RECALIB_CONFIG	0x2f
 #define CAP11XX_REG_SENSOR_THRESH(X)	(0x30 + (X))
 #define CAP11XX_REG_SENSOR_NOISE_THRESH	0x38
 #define CAP11XX_REG_STANDBY_CHANNEL	0x40
 #define CAP11XX_REG_STANDBY_CONFIG	0x41
 #define CAP11XX_REG_STANDBY_SENSITIVITY	0x42
 #define CAP11XX_REG_STANDBY_THRESH	0x43
 #define CAP11XX_REG_CONFIG2		0x44
 #define CAP11XX_REG_CONFIG2_ALT_POL	BIT(6)
 #define CAP11XX_REG_SENSOR_BASE_CNT(X)	(0x50 + (X))
 #define CAP11XX_REG_LED_POLARITY	0x73
 #define CAP11XX_REG_LED_OUTPUT_CONTROL	0x74

 #define CAP11XX_REG_LED_DUTY_CYCLE_1	0x90
 #define CAP11XX_REG_LED_DUTY_CYCLE_2	0x91
 #define CAP11XX_REG_LED_DUTY_CYCLE_3	0x92
 #define CAP11XX_REG_LED_DUTY_CYCLE_4	0x93

 #define CAP11XX_REG_LED_DUTY_MIN_MASK	(0x0f)
 #define CAP11XX_REG_LED_DUTY_MIN_MASK_SHIFT	(0)
 #define CAP11XX_REG_LED_DUTY_MAX_MASK	(0xf0)
 #define CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT	(4)
 #define CAP11XX_REG_LED_DUTY_MAX_VALUE	(15)

 #define CAP11XX_REG_SENSOR_CALIB	(0xb1 + (X))
 #define CAP11XX_REG_SENSOR_CALIB_LSB1	0xb9
 #define CAP11XX_REG_SENSOR_CALIB_LSB2	0xba
 #define CAP11XX_REG_PRODUCT_ID		0xfd
 #define CAP11XX_REG_MANUFACTURER_ID	0xfe
 #define CAP11XX_REG_REVISION		0xff

 #define CAP11XX_MANUFACTURER_ID	0x5d

 #ifdef CONFIG_LEDS_CLASS
 struct cap11xx_led {
 	struct cap11xx_priv *priv;
 	struct led_classdev cdev;
 	u32 reg;
 };
 #endif

 struct cap11xx_priv {
 	struct regmap *regmap;
 	struct input_dev *idev;

 	struct cap11xx_led *leds;
 	int num_leds;

 	/* config */
 	u32 keycodes[];
 };

 struct cap11xx_hw_model {
 	u8 product_id;
 	unsigned int num_channels;
 	unsigned int num_leds;
 	bool no_gain;
 };

 enum {
 	CAP1106,
 	CAP1126,
 	CAP1188,
 	CAP1206,
 };

 static const struct cap11xx_hw_model cap11xx_devices[] = {
 	[CAP1106] = { .product_id = 0x55, .num_channels = 6, .num_leds = 0, .no_gain = false },
 	[CAP1126] = { .product_id = 0x53, .num_channels = 6, .num_leds = 2, .no_gain = false },
 	[CAP1188] = { .product_id = 0x50, .num_channels = 8, .num_leds = 8, .no_gain = false },
 	[CAP1206] = { .product_id = 0x67, .num_channels = 6, .num_leds = 0, .no_gain = true },
 };

 static const struct reg_default cap11xx_reg_defaults[] = {
 	{ CAP11XX_REG_MAIN_CONTROL,		0x00 },
 	{ CAP11XX_REG_GENERAL_STATUS,		0x00 },
 	{ CAP11XX_REG_SENSOR_INPUT,		0x00 },
 	{ CAP11XX_REG_NOISE_FLAG_STATUS,	0x00 },
 	{ CAP11XX_REG_SENSITIVITY_CONTROL,	0x2f },
 	{ CAP11XX_REG_CONFIG,			0x20 },
 	{ CAP11XX_REG_SENSOR_ENABLE,		0x3f },
 	{ CAP11XX_REG_SENSOR_CONFIG,		0xa4 },
 	{ CAP11XX_REG_SENSOR_CONFIG2,		0x07 },
 	{ CAP11XX_REG_SAMPLING_CONFIG,		0x39 },
 	{ CAP11XX_REG_CALIBRATION,		0x00 },
 	{ CAP11XX_REG_INT_ENABLE,		0x3f },
 	{ CAP11XX_REG_REPEAT_RATE,		0x3f },
 	{ CAP11XX_REG_MT_CONFIG,		0x80 },
 	{ CAP11XX_REG_MT_PATTERN_CONFIG,	0x00 },
 	{ CAP11XX_REG_MT_PATTERN,		0x3f },
 	{ CAP11XX_REG_RECALIB_CONFIG,		0x8a },
 	{ CAP11XX_REG_SENSOR_THRESH(0),		0x40 },
 	{ CAP11XX_REG_SENSOR_THRESH(1),		0x40 },
 	{ CAP11XX_REG_SENSOR_THRESH(2),		0x40 },
 	{ CAP11XX_REG_SENSOR_THRESH(3),		0x40 },
 	{ CAP11XX_REG_SENSOR_THRESH(4),		0x40 },
 	{ CAP11XX_REG_SENSOR_THRESH(5),		0x40 },
 	{ CAP11XX_REG_SENSOR_NOISE_THRESH,	0x01 },
 	{ CAP11XX_REG_STANDBY_CHANNEL,		0x00 },
 	{ CAP11XX_REG_STANDBY_CONFIG,		0x39 },
 	{ CAP11XX_REG_STANDBY_SENSITIVITY,	0x02 },
 	{ CAP11XX_REG_STANDBY_THRESH,		0x40 },
 	{ CAP11XX_REG_CONFIG2,			0x40 },
 	{ CAP11XX_REG_LED_POLARITY,		0x00 },
 	{ CAP11XX_REG_SENSOR_CALIB_LSB1,	0x00 },
 	{ CAP11XX_REG_SENSOR_CALIB_LSB2,	0x00 },
 };

 static bool cap11xx_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case CAP11XX_REG_MAIN_CONTROL:
 	case CAP11XX_REG_SENSOR_INPUT:
 	case CAP11XX_REG_SENOR_DELTA(0):
 	case CAP11XX_REG_SENOR_DELTA(1):
 	case CAP11XX_REG_SENOR_DELTA(2):
 	case CAP11XX_REG_SENOR_DELTA(3):
 	case CAP11XX_REG_SENOR_DELTA(4):
 	case CAP11XX_REG_SENOR_DELTA(5):
 	case CAP11XX_REG_PRODUCT_ID:
 	case CAP11XX_REG_MANUFACTURER_ID:
 	case CAP11XX_REG_REVISION:
 		return true;
 	}

 	return false;
 }

 static const struct regmap_config cap11xx_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,

 	.max_register = CAP11XX_REG_REVISION,
 	.reg_defaults = cap11xx_reg_defaults,

 	.num_reg_defaults = ARRAY_SIZE(cap11xx_reg_defaults),
 	.cache_type = REGCACHE_RBTREE,
 	.volatile_reg = cap11xx_volatile_reg,
 };

 static irqreturn_t cap11xx_thread_func(int irq_num, void *data)
 {
 	struct cap11xx_priv *priv = data;
 	unsigned int status;
 	int ret, i;

 	/*
 	 * Deassert interrupt. This needs to be done before reading the status
 	 * registers, which will not carry valid values otherwise.
 	 */
 	ret = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL, 1, 0);
 	if (ret < 0)
 		goto out;

 	ret = regmap_read(priv->regmap, CAP11XX_REG_SENSOR_INPUT, &status);
 	if (ret < 0)
 		goto out;

 	for (i = 0; i < priv->idev->keycodemax; i++)
 		input_report_key(priv->idev, priv->keycodes[i],
 				 status & (1 << i));

 	input_sync(priv->idev);

 out:
 	return IRQ_HANDLED;
 }

 static int cap11xx_set_sleep(struct cap11xx_priv *priv, bool sleep)
 {
 	/*
 	 * DLSEEP mode will turn off all LEDS, prevent this
 	 */
 	if (IS_ENABLED(CONFIG_LEDS_CLASS) && priv->num_leds)
 		return 0;

 	return regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
 				  CAP11XX_REG_MAIN_CONTROL_DLSEEP,
 				  sleep ? CAP11XX_REG_MAIN_CONTROL_DLSEEP : 0);
 }

 static int cap11xx_input_open(struct input_dev *idev)
 {
 	struct cap11xx_priv *priv = input_get_drvdata(idev);

 	return cap11xx_set_sleep(priv, false);
 }

 static void cap11xx_input_close(struct input_dev *idev)
 {
 	struct cap11xx_priv *priv = input_get_drvdata(idev);

 	cap11xx_set_sleep(priv, true);
 }

 #ifdef CONFIG_LEDS_CLASS
 static int cap11xx_led_set(struct led_classdev *cdev,
 			    enum led_brightness value)
 {
 	struct cap11xx_led *led = container_of(cdev, struct cap11xx_led, cdev);
 	struct cap11xx_priv *priv = led->priv;

 	/*
 	 * All LEDs share the same duty cycle as this is a HW
 	 * limitation. Brightness levels per LED are either
 	 * 0 (OFF) and 1 (ON).
 	 */
 	return regmap_update_bits(priv->regmap,
 				  CAP11XX_REG_LED_OUTPUT_CONTROL,
 				  BIT(led->reg),
 				  value ? BIT(led->reg) : 0);
 }

 static int cap11xx_init_leds(struct device *dev,
 			     struct cap11xx_priv *priv, int num_leds)
 {
 	struct device_node *node = dev->of_node, *child;
 	struct cap11xx_led *led;
 	int cnt = of_get_child_count(node);
 	int error;

 	if (!num_leds || !cnt)
 		return 0;

 	if (cnt > num_leds)
 		return -EINVAL;

 	led = devm_kcalloc(dev, cnt, sizeof(struct cap11xx_led), GFP_KERNEL);
 	if (!led)
 		return -ENOMEM;

 	priv->leds = led;

 	error = regmap_update_bits(priv->regmap,
 				CAP11XX_REG_LED_OUTPUT_CONTROL, 0xff, 0);
 	if (error)
 		return error;

 	error = regmap_update_bits(priv->regmap, CAP11XX_REG_LED_DUTY_CYCLE_4,
 				CAP11XX_REG_LED_DUTY_MAX_MASK,
 				CAP11XX_REG_LED_DUTY_MAX_VALUE <<
 				CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT);
 	if (error)
 		return error;

 	for_each_child_of_node(node, child) {
 		u32 reg;

 		led->cdev.name =
 			of_get_property(child, "label", NULL) ? : child->name;
 		led->cdev.default_trigger =
 			of_get_property(child, "linux,default-trigger", NULL);
 		led->cdev.flags = 0;
 		led->cdev.brightness_set_blocking = cap11xx_led_set;
 		led->cdev.max_brightness = 1;
 		led->cdev.brightness = LED_OFF;

 		error = of_property_read_u32(child, "reg", &reg);
 		if (error != 0 || reg >= num_leds) {
 			of_node_put(child);
 			return -EINVAL;
 		}

 		led->reg = reg;
 		led->priv = priv;

 		error = devm_led_classdev_register(dev, &led->cdev);
 		if (error) {
 			of_node_put(child);
 			return error;
 		}

 		priv->num_leds++;
 		led++;
 	}

 	return 0;
 }
 #else
 static int cap11xx_init_leds(struct device *dev,
 			     struct cap11xx_priv *priv, int num_leds)
 {
 	return 0;
 }
 #endif

 static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
 			     const struct i2c_device_id *id)
 {
 	struct device *dev = &i2c_client->dev;
 	struct cap11xx_priv *priv;
 	struct device_node *node;
 	const struct cap11xx_hw_model *cap;
 	int i, error, irq, gain = 0;
 	unsigned int val, rev;
 	u32 gain32;

 	if (id->driver_data >= ARRAY_SIZE(cap11xx_devices)) {
 		dev_err(dev, "Invalid device ID %lu\n", id->driver_data);
 		return -EINVAL;
 	}

 	cap = &cap11xx_devices[id->driver_data];
 	if (!cap || !cap->num_channels) {
 		dev_err(dev, "Invalid device configuration\n");
 		return -EINVAL;
 	}

 	priv = devm_kzalloc(dev,
 			    struct_size(priv, keycodes, cap->num_channels),
 			    GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	priv->regmap = devm_regmap_init_i2c(i2c_client, &cap11xx_regmap_config);
 	if (IS_ERR(priv->regmap))
 		return PTR_ERR(priv->regmap);

 	error = regmap_read(priv->regmap, CAP11XX_REG_PRODUCT_ID, &val);
 	if (error)
 		return error;

 	if (val != cap->product_id) {
 		dev_err(dev, "Product ID: Got 0x%02x, expected 0x%02x\n",
 			val, cap->product_id);
 		return -ENXIO;
 	}

 	error = regmap_read(priv->regmap, CAP11XX_REG_MANUFACTURER_ID, &val);
 	if (error)
 		return error;

 	if (val != CAP11XX_MANUFACTURER_ID) {
 		dev_err(dev, "Manufacturer ID: Got 0x%02x, expected 0x%02x\n",
 			val, CAP11XX_MANUFACTURER_ID);
 		return -ENXIO;
 	}

 	error = regmap_read(priv->regmap, CAP11XX_REG_REVISION, &rev);
 	if (error < 0)
 		return error;

 	dev_info(dev, "CAP11XX detected, revision 0x%02x\n", rev);
 	node = dev->of_node;

 	if (!of_property_read_u32(node, "microchip,sensor-gain", &gain32)) {
 		if (cap->no_gain)
 			dev_warn(dev,
 				 "This version doesn't support sensor gain\n");
 		else if (is_power_of_2(gain32) && gain32 <= 8)
 			gain = ilog2(gain32);
 		else
 			dev_err(dev, "Invalid sensor-gain value %d\n", gain32);
 	}

 	if (id->driver_data != CAP1206) {
 		if (of_property_read_bool(node, "microchip,irq-active-high")) {
 			error = regmap_update_bits(priv->regmap,
 						   CAP11XX_REG_CONFIG2,
 						   CAP11XX_REG_CONFIG2_ALT_POL,
 						   0);
 			if (error)
 				return error;
 		}
 	}

 	/* Provide some useful defaults */
 	for (i = 0; i < cap->num_channels; i++)
 		priv->keycodes[i] = KEY_A + i;

 	of_property_read_u32_array(node, "linux,keycodes",
 				   priv->keycodes, cap->num_channels);

 	if (!cap->no_gain) {
 		error = regmap_update_bits(priv->regmap,
 				CAP11XX_REG_MAIN_CONTROL,
 				CAP11XX_REG_MAIN_CONTROL_GAIN_MASK,
 				gain << CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT);
 		if (error)
 			return error;
 	}

 	/* Disable autorepeat. The Linux input system has its own handling. */
 	error = regmap_write(priv->regmap, CAP11XX_REG_REPEAT_RATE, 0);
 	if (error)
 		return error;

 	priv->idev = devm_input_allocate_device(dev);
 	if (!priv->idev)
 		return -ENOMEM;

 	priv->idev->name = "CAP11XX capacitive touch sensor";
 	priv->idev->id.bustype = BUS_I2C;
 	priv->idev->evbit[0] = BIT_MASK(EV_KEY);

 	if (of_property_read_bool(node, "autorepeat"))
 		__set_bit(EV_REP, priv->idev->evbit);

 	for (i = 0; i < cap->num_channels; i++)
 		__set_bit(priv->keycodes[i], priv->idev->keybit);

 	__clear_bit(KEY_RESERVED, priv->idev->keybit);

 	priv->idev->keycode = priv->keycodes;
 	priv->idev->keycodesize = sizeof(priv->keycodes[0]);
 	priv->idev->keycodemax = cap->num_channels;

 	priv->idev->id.vendor = CAP11XX_MANUFACTURER_ID;
 	priv->idev->id.product = cap->product_id;
 	priv->idev->id.version = rev;

 	priv->idev->open = cap11xx_input_open;
 	priv->idev->close = cap11xx_input_close;

 	error = cap11xx_init_leds(dev, priv, cap->num_leds);
 	if (error)
 		return error;

 	input_set_drvdata(priv->idev, priv);

 	/*
 	 * Put the device in deep sleep mode for now.
 	 * ->open() will bring it back once the it is actually needed.
 	 */
 	cap11xx_set_sleep(priv, true);

 	error = input_register_device(priv->idev);
 	if (error)
 		return error;

 	irq = irq_of_parse_and_map(node, 0);
 	if (!irq) {
 		dev_err(dev, "Unable to parse or map IRQ\n");
 		return -ENXIO;
 	}

 	error = devm_request_threaded_irq(dev, irq, NULL, cap11xx_thread_func,
 					  IRQF_ONESHOT, dev_name(dev), priv);
 	if (error)
 		return error;

 	return 0;
 }

 static const struct of_device_id cap11xx_dt_ids[] = {
 	{ .compatible = "microchip,cap1106", },
 	{ .compatible = "microchip,cap1126", },
 	{ .compatible = "microchip,cap1188", },
 	{ .compatible = "microchip,cap1206", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, cap11xx_dt_ids);

 static const struct i2c_device_id cap11xx_i2c_ids[] = {
 	{ "cap1106", CAP1106 },
 	{ "cap1126", CAP1126 },
 	{ "cap1188", CAP1188 },
 	{ "cap1206", CAP1206 },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, cap11xx_i2c_ids);

 static struct i2c_driver cap11xx_i2c_driver = {
 	.driver = {
 		.name	= "cap11xx",
 		.of_match_table = cap11xx_dt_ids,
 	},
 	.id_table	= cap11xx_i2c_ids,
 	.probe		= cap11xx_i2c_probe,
 };

 module_i2c_driver(cap11xx_i2c_driver);

 MODULE_DESCRIPTION("Microchip CAP11XX driver");
 MODULE_AUTHOR("Daniel Mack <linux@zonque.org>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Input driver for Microchip CAP11xx based capacitive touch sensors
	*
	* (c) 2014 Daniel Mack <linux@zonque.org>
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/input.h>
	#include <linux/leds.h>
	#include <linux/of_irq.h>
	#include <linux/regmap.h>
	#include <linux/i2c.h>
	#include <linux/gpio/consumer.h>

	#define CAP11XX_REG_MAIN_CONTROL 0x00
	#define CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT (6)
	#define CAP11XX_REG_MAIN_CONTROL_GAIN_MASK (0xc0)
	#define CAP11XX_REG_MAIN_CONTROL_DLSEEP BIT(4)
	#define CAP11XX_REG_GENERAL_STATUS 0x02
	#define CAP11XX_REG_SENSOR_INPUT 0x03
	#define CAP11XX_REG_NOISE_FLAG_STATUS 0x0a
	#define CAP11XX_REG_SENOR_DELTA(X) (0x10 + (X))
	#define CAP11XX_REG_SENSITIVITY_CONTROL 0x1f
	#define CAP11XX_REG_CONFIG 0x20
	#define CAP11XX_REG_SENSOR_ENABLE 0x21
	#define CAP11XX_REG_SENSOR_CONFIG 0x22
	#define CAP11XX_REG_SENSOR_CONFIG2 0x23
	#define CAP11XX_REG_SAMPLING_CONFIG 0x24
	#define CAP11XX_REG_CALIBRATION 0x26
	#define CAP11XX_REG_INT_ENABLE 0x27
	#define CAP11XX_REG_REPEAT_RATE 0x28
	#define CAP11XX_REG_MT_CONFIG 0x2a
	#define CAP11XX_REG_MT_PATTERN_CONFIG 0x2b
	#define CAP11XX_REG_MT_PATTERN 0x2d
	#define CAP11XX_REG_RECALIB_CONFIG 0x2f
	#define CAP11XX_REG_SENSOR_THRESH(X) (0x30 + (X))
	#define CAP11XX_REG_SENSOR_NOISE_THRESH 0x38
	#define CAP11XX_REG_STANDBY_CHANNEL 0x40
	#define CAP11XX_REG_STANDBY_CONFIG 0x41
	#define CAP11XX_REG_STANDBY_SENSITIVITY 0x42
	#define CAP11XX_REG_STANDBY_THRESH 0x43
	#define CAP11XX_REG_CONFIG2 0x44
	#define CAP11XX_REG_CONFIG2_ALT_POL BIT(6)
	#define CAP11XX_REG_SENSOR_BASE_CNT(X) (0x50 + (X))
	#define CAP11XX_REG_LED_POLARITY 0x73
	#define CAP11XX_REG_LED_OUTPUT_CONTROL 0x74

	#define CAP11XX_REG_LED_DUTY_CYCLE_1 0x90
	#define CAP11XX_REG_LED_DUTY_CYCLE_2 0x91
	#define CAP11XX_REG_LED_DUTY_CYCLE_3 0x92
	#define CAP11XX_REG_LED_DUTY_CYCLE_4 0x93

	#define CAP11XX_REG_LED_DUTY_MIN_MASK (0x0f)
	#define CAP11XX_REG_LED_DUTY_MIN_MASK_SHIFT (0)
	#define CAP11XX_REG_LED_DUTY_MAX_MASK (0xf0)
	#define CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT (4)
	#define CAP11XX_REG_LED_DUTY_MAX_VALUE (15)

	#define CAP11XX_REG_SENSOR_CALIB (0xb1 + (X))
	#define CAP11XX_REG_SENSOR_CALIB_LSB1 0xb9
	#define CAP11XX_REG_SENSOR_CALIB_LSB2 0xba
	#define CAP11XX_REG_PRODUCT_ID 0xfd
	#define CAP11XX_REG_MANUFACTURER_ID 0xfe
	#define CAP11XX_REG_REVISION 0xff

	#define CAP11XX_MANUFACTURER_ID 0x5d

	#ifdef CONFIG_LEDS_CLASS
	struct cap11xx_led {
	struct cap11xx_priv *priv;
	struct led_classdev cdev;
	u32 reg;
	};
	#endif

	struct cap11xx_priv {
	struct regmap *regmap;
	struct input_dev *idev;

	struct cap11xx_led *leds;
	int num_leds;

	/* config */
	u32 keycodes[];
	};

	struct cap11xx_hw_model {
	u8 product_id;
	unsigned int num_channels;
	unsigned int num_leds;
	bool no_gain;
	};

	enum {
	CAP1106,
	CAP1126,
	CAP1188,
	CAP1206,
	};

	static const struct cap11xx_hw_model cap11xx_devices[] = {
	[CAP1106] = { .product_id = 0x55, .num_channels = 6, .num_leds = 0, .no_gain = false },
	[CAP1126] = { .product_id = 0x53, .num_channels = 6, .num_leds = 2, .no_gain = false },
	[CAP1188] = { .product_id = 0x50, .num_channels = 8, .num_leds = 8, .no_gain = false },
	[CAP1206] = { .product_id = 0x67, .num_channels = 6, .num_leds = 0, .no_gain = true },
	};

	static const struct reg_default cap11xx_reg_defaults[] = {
	{ CAP11XX_REG_MAIN_CONTROL, 0x00 },
	{ CAP11XX_REG_GENERAL_STATUS, 0x00 },
	{ CAP11XX_REG_SENSOR_INPUT, 0x00 },
	{ CAP11XX_REG_NOISE_FLAG_STATUS, 0x00 },
	{ CAP11XX_REG_SENSITIVITY_CONTROL, 0x2f },
	{ CAP11XX_REG_CONFIG, 0x20 },
	{ CAP11XX_REG_SENSOR_ENABLE, 0x3f },
	{ CAP11XX_REG_SENSOR_CONFIG, 0xa4 },
	{ CAP11XX_REG_SENSOR_CONFIG2, 0x07 },
	{ CAP11XX_REG_SAMPLING_CONFIG, 0x39 },
	{ CAP11XX_REG_CALIBRATION, 0x00 },
	{ CAP11XX_REG_INT_ENABLE, 0x3f },
	{ CAP11XX_REG_REPEAT_RATE, 0x3f },
	{ CAP11XX_REG_MT_CONFIG, 0x80 },
	{ CAP11XX_REG_MT_PATTERN_CONFIG, 0x00 },
	{ CAP11XX_REG_MT_PATTERN, 0x3f },
	{ CAP11XX_REG_RECALIB_CONFIG, 0x8a },
	{ CAP11XX_REG_SENSOR_THRESH(0), 0x40 },
	{ CAP11XX_REG_SENSOR_THRESH(1), 0x40 },
	{ CAP11XX_REG_SENSOR_THRESH(2), 0x40 },
	{ CAP11XX_REG_SENSOR_THRESH(3), 0x40 },
	{ CAP11XX_REG_SENSOR_THRESH(4), 0x40 },
	{ CAP11XX_REG_SENSOR_THRESH(5), 0x40 },
	{ CAP11XX_REG_SENSOR_NOISE_THRESH, 0x01 },
	{ CAP11XX_REG_STANDBY_CHANNEL, 0x00 },
	{ CAP11XX_REG_STANDBY_CONFIG, 0x39 },
	{ CAP11XX_REG_STANDBY_SENSITIVITY, 0x02 },
	{ CAP11XX_REG_STANDBY_THRESH, 0x40 },
	{ CAP11XX_REG_CONFIG2, 0x40 },
	{ CAP11XX_REG_LED_POLARITY, 0x00 },
	{ CAP11XX_REG_SENSOR_CALIB_LSB1, 0x00 },
	{ CAP11XX_REG_SENSOR_CALIB_LSB2, 0x00 },
	};

	static bool cap11xx_volatile_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case CAP11XX_REG_MAIN_CONTROL:
	case CAP11XX_REG_SENSOR_INPUT:
	case CAP11XX_REG_SENOR_DELTA(0):
	case CAP11XX_REG_SENOR_DELTA(1):
	case CAP11XX_REG_SENOR_DELTA(2):
	case CAP11XX_REG_SENOR_DELTA(3):
	case CAP11XX_REG_SENOR_DELTA(4):
	case CAP11XX_REG_SENOR_DELTA(5):
	case CAP11XX_REG_PRODUCT_ID:
	case CAP11XX_REG_MANUFACTURER_ID:
	case CAP11XX_REG_REVISION:
	return true;
	}

	return false;
	}

	static const struct regmap_config cap11xx_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,

	.max_register = CAP11XX_REG_REVISION,
	.reg_defaults = cap11xx_reg_defaults,

	.num_reg_defaults = ARRAY_SIZE(cap11xx_reg_defaults),
	.cache_type = REGCACHE_RBTREE,
	.volatile_reg = cap11xx_volatile_reg,
	};

	static irqreturn_t cap11xx_thread_func(int irq_num, void *data)
	{
	struct cap11xx_priv *priv = data;
	unsigned int status;
	int ret, i;

	/*
	* Deassert interrupt. This needs to be done before reading the status
	* registers, which will not carry valid values otherwise.
	*/
	ret = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL, 1, 0);
	if (ret < 0)
	goto out;

	ret = regmap_read(priv->regmap, CAP11XX_REG_SENSOR_INPUT, &status);
	if (ret < 0)
	goto out;

	for (i = 0; i < priv->idev->keycodemax; i++)
	input_report_key(priv->idev, priv->keycodes[i],
	status & (1 << i));

	input_sync(priv->idev);

	out:
	return IRQ_HANDLED;
	}

	static int cap11xx_set_sleep(struct cap11xx_priv *priv, bool sleep)
	{
	/*
	* DLSEEP mode will turn off all LEDS, prevent this
	*/
	if (IS_ENABLED(CONFIG_LEDS_CLASS) && priv->num_leds)
	return 0;

	return regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
	CAP11XX_REG_MAIN_CONTROL_DLSEEP,
	sleep ? CAP11XX_REG_MAIN_CONTROL_DLSEEP : 0);
	}

	static int cap11xx_input_open(struct input_dev *idev)
	{
	struct cap11xx_priv *priv = input_get_drvdata(idev);

	return cap11xx_set_sleep(priv, false);
	}

	static void cap11xx_input_close(struct input_dev *idev)
	{
	struct cap11xx_priv *priv = input_get_drvdata(idev);

	cap11xx_set_sleep(priv, true);
	}

	#ifdef CONFIG_LEDS_CLASS
	static int cap11xx_led_set(struct led_classdev *cdev,
	enum led_brightness value)
	{
	struct cap11xx_led *led = container_of(cdev, struct cap11xx_led, cdev);
	struct cap11xx_priv *priv = led->priv;

	/*
	* All LEDs share the same duty cycle as this is a HW
	* limitation. Brightness levels per LED are either
	* 0 (OFF) and 1 (ON).
	*/
	return regmap_update_bits(priv->regmap,
	CAP11XX_REG_LED_OUTPUT_CONTROL,
	BIT(led->reg),
	value ? BIT(led->reg) : 0);
	}

	static int cap11xx_init_leds(struct device *dev,
	struct cap11xx_priv *priv, int num_leds)
	{
	struct device_node node = dev->of_node, child;
	struct cap11xx_led *led;
	int cnt = of_get_child_count(node);
	int error;

	if (!num_leds \|\| !cnt)
	return 0;

	if (cnt > num_leds)
	return -EINVAL;

	led = devm_kcalloc(dev, cnt, sizeof(struct cap11xx_led), GFP_KERNEL);
	if (!led)
	return -ENOMEM;

	priv->leds = led;

	error = regmap_update_bits(priv->regmap,
	CAP11XX_REG_LED_OUTPUT_CONTROL, 0xff, 0);
	if (error)
	return error;

	error = regmap_update_bits(priv->regmap, CAP11XX_REG_LED_DUTY_CYCLE_4,
	CAP11XX_REG_LED_DUTY_MAX_MASK,
	CAP11XX_REG_LED_DUTY_MAX_VALUE <<
	CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT);
	if (error)
	return error;

	for_each_child_of_node(node, child) {
	u32 reg;

	led->cdev.name =
	of_get_property(child, "label", NULL) ? : child->name;
	led->cdev.default_trigger =
	of_get_property(child, "linux,default-trigger", NULL);
	led->cdev.flags = 0;
	led->cdev.brightness_set_blocking = cap11xx_led_set;
	led->cdev.max_brightness = 1;
	led->cdev.brightness = LED_OFF;

	error = of_property_read_u32(child, "reg", &reg);
	if (error != 0 \|\| reg >= num_leds) {
	of_node_put(child);
	return -EINVAL;
	}

	led->reg = reg;
	led->priv = priv;

	error = devm_led_classdev_register(dev, &led->cdev);
	if (error) {
	of_node_put(child);
	return error;
	}

	priv->num_leds++;
	led++;
	}

	return 0;
	}
	#else
	static int cap11xx_init_leds(struct device *dev,
	struct cap11xx_priv *priv, int num_leds)
	{
	return 0;
	}
	#endif

	static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &i2c_client->dev;
	struct cap11xx_priv *priv;
	struct device_node *node;
	const struct cap11xx_hw_model *cap;
	int i, error, irq, gain = 0;
	unsigned int val, rev;
	u32 gain32;

	if (id->driver_data >= ARRAY_SIZE(cap11xx_devices)) {
	dev_err(dev, "Invalid device ID %lu\n", id->driver_data);
	return -EINVAL;
	}

	cap = &cap11xx_devices[id->driver_data];
	if (!cap \|\| !cap->num_channels) {
	dev_err(dev, "Invalid device configuration\n");
	return -EINVAL;
	}

	priv = devm_kzalloc(dev,
	struct_size(priv, keycodes, cap->num_channels),
	GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	priv->regmap = devm_regmap_init_i2c(i2c_client, &cap11xx_regmap_config);
	if (IS_ERR(priv->regmap))
	return PTR_ERR(priv->regmap);

	error = regmap_read(priv->regmap, CAP11XX_REG_PRODUCT_ID, &val);
	if (error)
	return error;

	if (val != cap->product_id) {
	dev_err(dev, "Product ID: Got 0x%02x, expected 0x%02x\n",
	val, cap->product_id);
	return -ENXIO;
	}

	error = regmap_read(priv->regmap, CAP11XX_REG_MANUFACTURER_ID, &val);
	if (error)
	return error;

	if (val != CAP11XX_MANUFACTURER_ID) {
	dev_err(dev, "Manufacturer ID: Got 0x%02x, expected 0x%02x\n",
	val, CAP11XX_MANUFACTURER_ID);
	return -ENXIO;
	}

	error = regmap_read(priv->regmap, CAP11XX_REG_REVISION, &rev);
	if (error < 0)
	return error;

	dev_info(dev, "CAP11XX detected, revision 0x%02x\n", rev);
	node = dev->of_node;

	if (!of_property_read_u32(node, "microchip,sensor-gain", &gain32)) {
	if (cap->no_gain)
	dev_warn(dev,
	"This version doesn't support sensor gain\n");
	else if (is_power_of_2(gain32) && gain32 <= 8)
	gain = ilog2(gain32);
	else
	dev_err(dev, "Invalid sensor-gain value %d\n", gain32);
	}

	if (id->driver_data != CAP1206) {
	if (of_property_read_bool(node, "microchip,irq-active-high")) {
	error = regmap_update_bits(priv->regmap,
	CAP11XX_REG_CONFIG2,
	CAP11XX_REG_CONFIG2_ALT_POL,
	0);
	if (error)
	return error;
	}
	}

	/* Provide some useful defaults */
	for (i = 0; i < cap->num_channels; i++)
	priv->keycodes[i] = KEY_A + i;

	of_property_read_u32_array(node, "linux,keycodes",
	priv->keycodes, cap->num_channels);

	if (!cap->no_gain) {
	error = regmap_update_bits(priv->regmap,
	CAP11XX_REG_MAIN_CONTROL,
	CAP11XX_REG_MAIN_CONTROL_GAIN_MASK,
	gain << CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT);
	if (error)
	return error;
	}

	/* Disable autorepeat. The Linux input system has its own handling. */
	error = regmap_write(priv->regmap, CAP11XX_REG_REPEAT_RATE, 0);
	if (error)
	return error;

	priv->idev = devm_input_allocate_device(dev);
	if (!priv->idev)
	return -ENOMEM;

	priv->idev->name = "CAP11XX capacitive touch sensor";
	priv->idev->id.bustype = BUS_I2C;
	priv->idev->evbit[0] = BIT_MASK(EV_KEY);

	if (of_property_read_bool(node, "autorepeat"))
	__set_bit(EV_REP, priv->idev->evbit);

	for (i = 0; i < cap->num_channels; i++)
	__set_bit(priv->keycodes[i], priv->idev->keybit);

	__clear_bit(KEY_RESERVED, priv->idev->keybit);

	priv->idev->keycode = priv->keycodes;
	priv->idev->keycodesize = sizeof(priv->keycodes[0]);
	priv->idev->keycodemax = cap->num_channels;

	priv->idev->id.vendor = CAP11XX_MANUFACTURER_ID;
	priv->idev->id.product = cap->product_id;
	priv->idev->id.version = rev;

	priv->idev->open = cap11xx_input_open;
	priv->idev->close = cap11xx_input_close;

	error = cap11xx_init_leds(dev, priv, cap->num_leds);
	if (error)
	return error;

	input_set_drvdata(priv->idev, priv);

	/*
	* Put the device in deep sleep mode for now.
	* ->open() will bring it back once the it is actually needed.
	*/
	cap11xx_set_sleep(priv, true);

	error = input_register_device(priv->idev);
	if (error)
	return error;

	irq = irq_of_parse_and_map(node, 0);
	if (!irq) {
	dev_err(dev, "Unable to parse or map IRQ\n");
	return -ENXIO;
	}

	error = devm_request_threaded_irq(dev, irq, NULL, cap11xx_thread_func,
	IRQF_ONESHOT, dev_name(dev), priv);
	if (error)
	return error;

	return 0;
	}

	static const struct of_device_id cap11xx_dt_ids[] = {
	{ .compatible = "microchip,cap1106", },
	{ .compatible = "microchip,cap1126", },
	{ .compatible = "microchip,cap1188", },
	{ .compatible = "microchip,cap1206", },
	{}
	};
	MODULE_DEVICE_TABLE(of, cap11xx_dt_ids);

	static const struct i2c_device_id cap11xx_i2c_ids[] = {
	{ "cap1106", CAP1106 },
	{ "cap1126", CAP1126 },
	{ "cap1188", CAP1188 },
	{ "cap1206", CAP1206 },
	{}
	};
	MODULE_DEVICE_TABLE(i2c, cap11xx_i2c_ids);

	static struct i2c_driver cap11xx_i2c_driver = {
	.driver = {
	.name = "cap11xx",
	.of_match_table = cap11xx_dt_ids,
	},
	.id_table = cap11xx_i2c_ids,
	.probe = cap11xx_i2c_probe,
	};

	module_i2c_driver(cap11xx_i2c_driver);

	MODULE_DESCRIPTION("Microchip CAP11XX driver");
	MODULE_AUTHOR("Daniel Mack <linux@zonque.org>");
	MODULE_LICENSE("GPL v2");