drivers/leds/leds-is31fl319x.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2015-16 Golden Delicious Computers
  *
  * Author: Nikolaus Schaller <hns@goldelico.com>
  *
  * LED driver for the IS31FL319{0,1,3,6,9} to drive 1, 3, 6 or 9 light
  * effect LEDs.
  */

 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/leds.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>

 /* register numbers */
 #define IS31FL319X_SHUTDOWN		0x00

 /* registers for 3190, 3191 and 3193 */
 #define IS31FL3190_BREATHING		0x01
 #define IS31FL3190_LEDMODE		0x02
 #define IS31FL3190_CURRENT		0x03
 #define IS31FL3190_PWM(channel)		(0x04 + channel)
 #define IS31FL3190_DATA_UPDATE		0x07
 #define IS31FL3190_T0(channel)		(0x0a + channel)
 #define IS31FL3190_T1T2(channel)	(0x10 + channel)
 #define IS31FL3190_T3T4(channel)	(0x16 + channel)
 #define IS31FL3190_TIME_UPDATE		0x1c
 #define IS31FL3190_LEDCONTROL		0x1d
 #define IS31FL3190_RESET		0x2f

 #define IS31FL3190_CURRENT_uA_MIN	5000
 #define IS31FL3190_CURRENT_uA_DEFAULT	42000
 #define IS31FL3190_CURRENT_uA_MAX	42000
 #define IS31FL3190_CURRENT_SHIFT	2
 #define IS31FL3190_CURRENT_MASK		GENMASK(4, 2)
 #define IS31FL3190_CURRENT_5_mA		0x02
 #define IS31FL3190_CURRENT_10_mA	0x01
 #define IS31FL3190_CURRENT_17dot5_mA	0x04
 #define IS31FL3190_CURRENT_30_mA	0x03
 #define IS31FL3190_CURRENT_42_mA	0x00

 /* registers for 3196 and 3199 */
 #define IS31FL3196_CTRL1		0x01
 #define IS31FL3196_CTRL2		0x02
 #define IS31FL3196_CONFIG1		0x03
 #define IS31FL3196_CONFIG2		0x04
 #define IS31FL3196_RAMP_MODE		0x05
 #define IS31FL3196_BREATH_MARK		0x06
 #define IS31FL3196_PWM(channel)		(0x07 + channel)
 #define IS31FL3196_DATA_UPDATE		0x10
 #define IS31FL3196_T0(channel)		(0x11 + channel)
 #define IS31FL3196_T123_1		0x1a
 #define IS31FL3196_T123_2		0x1b
 #define IS31FL3196_T123_3		0x1c
 #define IS31FL3196_T4(channel)		(0x1d + channel)
 #define IS31FL3196_TIME_UPDATE		0x26
 #define IS31FL3196_RESET		0xff

 #define IS31FL3196_REG_CNT		(IS31FL3196_RESET + 1)

 #define IS31FL319X_MAX_LEDS		9

 /* CS (Current Setting) in CONFIG2 register */
 #define IS31FL3196_CONFIG2_CS_SHIFT	4
 #define IS31FL3196_CONFIG2_CS_MASK	GENMASK(2, 0)
 #define IS31FL3196_CONFIG2_CS_STEP_REF	12

 #define IS31FL3196_CURRENT_uA_MIN	5000
 #define IS31FL3196_CURRENT_uA_MAX	40000
 #define IS31FL3196_CURRENT_uA_STEP	5000
 #define IS31FL3196_CURRENT_uA_DEFAULT	20000

 /* Audio gain in CONFIG2 register */
 #define IS31FL3196_AUDIO_GAIN_DB_MAX	((u32)21)
 #define IS31FL3196_AUDIO_GAIN_DB_STEP	3

 /*
  * regmap is used as a cache of chip's register space,
  * to avoid reading back brightness values from chip,
  * which is known to hang.
  */
 struct is31fl319x_chip {
 	const struct is31fl319x_chipdef *cdef;
 	struct i2c_client               *client;
 	struct gpio_desc		*shutdown_gpio;
 	struct regmap                   *regmap;
 	struct mutex                    lock;
 	u32                             audio_gain_db;

 	struct is31fl319x_led {
 		struct is31fl319x_chip  *chip;
 		struct led_classdev     cdev;
 		u32                     max_microamp;
 		bool                    configured;
 	} leds[IS31FL319X_MAX_LEDS];
 };

 struct is31fl319x_chipdef {
 	int num_leds;
 	u8 reset_reg;
 	const struct regmap_config *is31fl319x_regmap_config;
 	int (*brightness_set)(struct led_classdev *cdev, enum led_brightness brightness);
 	u32 current_default;
 	u32 current_min;
 	u32 current_max;
 	bool is_3196or3199;
 };

 static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
 {
 	/* we have no readable registers */
 	return false;
 }

 static bool is31fl3190_volatile_reg(struct device *dev, unsigned int reg)
 {
 	/* volatile registers are not cached */
 	switch (reg) {
 	case IS31FL3190_DATA_UPDATE:
 	case IS31FL3190_TIME_UPDATE:
 	case IS31FL3190_RESET:
 		return true; /* always write-through */
 	default:
 		return false;
 	}
 }

 static const struct reg_default is31fl3190_reg_defaults[] = {
 	{ IS31FL3190_LEDMODE, 0x00 },
 	{ IS31FL3190_CURRENT, 0x00 },
 	{ IS31FL3190_PWM(0), 0x00 },
 	{ IS31FL3190_PWM(1), 0x00 },
 	{ IS31FL3190_PWM(2), 0x00 },
 };

 static const struct regmap_config is31fl3190_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = IS31FL3190_RESET,
 	.cache_type = REGCACHE_FLAT,
 	.readable_reg = is31fl319x_readable_reg,
 	.volatile_reg = is31fl3190_volatile_reg,
 	.reg_defaults = is31fl3190_reg_defaults,
 	.num_reg_defaults = ARRAY_SIZE(is31fl3190_reg_defaults),
 };

 static bool is31fl3196_volatile_reg(struct device *dev, unsigned int reg)
 {
 	/* volatile registers are not cached */
 	switch (reg) {
 	case IS31FL3196_DATA_UPDATE:
 	case IS31FL3196_TIME_UPDATE:
 	case IS31FL3196_RESET:
 		return true; /* always write-through */
 	default:
 		return false;
 	}
 }

 static const struct reg_default is31fl3196_reg_defaults[] = {
 	{ IS31FL3196_CONFIG1, 0x00 },
 	{ IS31FL3196_CONFIG2, 0x00 },
 	{ IS31FL3196_PWM(0), 0x00 },
 	{ IS31FL3196_PWM(1), 0x00 },
 	{ IS31FL3196_PWM(2), 0x00 },
 	{ IS31FL3196_PWM(3), 0x00 },
 	{ IS31FL3196_PWM(4), 0x00 },
 	{ IS31FL3196_PWM(5), 0x00 },
 	{ IS31FL3196_PWM(6), 0x00 },
 	{ IS31FL3196_PWM(7), 0x00 },
 	{ IS31FL3196_PWM(8), 0x00 },
 };

 static const struct regmap_config is31fl3196_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = IS31FL3196_REG_CNT,
 	.cache_type = REGCACHE_FLAT,
 	.readable_reg = is31fl319x_readable_reg,
 	.volatile_reg = is31fl3196_volatile_reg,
 	.reg_defaults = is31fl3196_reg_defaults,
 	.num_reg_defaults = ARRAY_SIZE(is31fl3196_reg_defaults),
 };

 static int is31fl3190_brightness_set(struct led_classdev *cdev,
 				     enum led_brightness brightness)
 {
 	struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led, cdev);
 	struct is31fl319x_chip *is31 = led->chip;
 	int chan = led - is31->leds;
 	int ret;
 	int i;
 	u8 ctrl = 0;

 	dev_dbg(&is31->client->dev, "channel %d: %d\n", chan, brightness);

 	mutex_lock(&is31->lock);

 	/* update PWM register */
 	ret = regmap_write(is31->regmap, IS31FL3190_PWM(chan), brightness);
 	if (ret < 0)
 		goto out;

 	/* read current brightness of all PWM channels */
 	for (i = 0; i < is31->cdef->num_leds; i++) {
 		unsigned int pwm_value;
 		bool on;

 		/*
 		 * since neither cdev nor the chip can provide
 		 * the current setting, we read from the regmap cache
 		 */

 		ret = regmap_read(is31->regmap, IS31FL3190_PWM(i), &pwm_value);
 		on = ret >= 0 && pwm_value > LED_OFF;

 		ctrl |= on << i;
 	}

 	if (ctrl > 0) {
 		dev_dbg(&is31->client->dev, "power up %02x\n", ctrl);
 		regmap_write(is31->regmap, IS31FL3190_LEDCONTROL, ctrl);
 		/* update PWMs */
 		regmap_write(is31->regmap, IS31FL3190_DATA_UPDATE, 0x00);
 		/* enable chip from shut down and enable all channels */
 		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x20);
 	} else {
 		dev_dbg(&is31->client->dev, "power down\n");
 		/* shut down (no need to clear LEDCONTROL) */
 		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
 	}

 out:
 	mutex_unlock(&is31->lock);

 	return ret;
 }

 static int is31fl3196_brightness_set(struct led_classdev *cdev,
 				     enum led_brightness brightness)
 {
 	struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led, cdev);
 	struct is31fl319x_chip *is31 = led->chip;
 	int chan = led - is31->leds;
 	int ret;
 	int i;
 	u8 ctrl1 = 0, ctrl2 = 0;

 	dev_dbg(&is31->client->dev, "channel %d: %d\n", chan, brightness);

 	mutex_lock(&is31->lock);

 	/* update PWM register */
 	ret = regmap_write(is31->regmap, IS31FL3196_PWM(chan), brightness);
 	if (ret < 0)
 		goto out;

 	/* read current brightness of all PWM channels */
 	for (i = 0; i < is31->cdef->num_leds; i++) {
 		unsigned int pwm_value;
 		bool on;

 		/*
 		 * since neither cdev nor the chip can provide
 		 * the current setting, we read from the regmap cache
 		 */

 		ret = regmap_read(is31->regmap, IS31FL3196_PWM(i), &pwm_value);
 		on = ret >= 0 && pwm_value > LED_OFF;

 		if (i < 3)
 			ctrl1 |= on << i;       /* 0..2 => bit 0..2 */
 		else if (i < 6)
 			ctrl1 |= on << (i + 1); /* 3..5 => bit 4..6 */
 		else
 			ctrl2 |= on << (i - 6); /* 6..8 => bit 0..2 */
 	}

 	if (ctrl1 > 0 || ctrl2 > 0) {
 		dev_dbg(&is31->client->dev, "power up %02x %02x\n",
 			ctrl1, ctrl2);
 		regmap_write(is31->regmap, IS31FL3196_CTRL1, ctrl1);
 		regmap_write(is31->regmap, IS31FL3196_CTRL2, ctrl2);
 		/* update PWMs */
 		regmap_write(is31->regmap, IS31FL3196_DATA_UPDATE, 0x00);
 		/* enable chip from shut down */
 		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
 	} else {
 		dev_dbg(&is31->client->dev, "power down\n");
 		/* shut down (no need to clear CTRL1/2) */
 		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
 	}

 out:
 	mutex_unlock(&is31->lock);

 	return ret;
 }

 static const struct is31fl319x_chipdef is31fl3190_cdef = {
 	.num_leds = 1,
 	.reset_reg = IS31FL3190_RESET,
 	.is31fl319x_regmap_config = &is31fl3190_regmap_config,
 	.brightness_set = is31fl3190_brightness_set,
 	.current_default = IS31FL3190_CURRENT_uA_DEFAULT,
 	.current_min = IS31FL3190_CURRENT_uA_MIN,
 	.current_max = IS31FL3190_CURRENT_uA_MAX,
 	.is_3196or3199 = false,
 };

 static const struct is31fl319x_chipdef is31fl3193_cdef = {
 	.num_leds = 3,
 	.reset_reg = IS31FL3190_RESET,
 	.is31fl319x_regmap_config = &is31fl3190_regmap_config,
 	.brightness_set = is31fl3190_brightness_set,
 	.current_default = IS31FL3190_CURRENT_uA_DEFAULT,
 	.current_min = IS31FL3190_CURRENT_uA_MIN,
 	.current_max = IS31FL3190_CURRENT_uA_MAX,
 	.is_3196or3199 = false,
 };

 static const struct is31fl319x_chipdef is31fl3196_cdef = {
 	.num_leds = 6,
 	.reset_reg = IS31FL3196_RESET,
 	.is31fl319x_regmap_config = &is31fl3196_regmap_config,
 	.brightness_set = is31fl3196_brightness_set,
 	.current_default = IS31FL3196_CURRENT_uA_DEFAULT,
 	.current_min = IS31FL3196_CURRENT_uA_MIN,
 	.current_max = IS31FL3196_CURRENT_uA_MAX,
 	.is_3196or3199 = true,
 };

 static const struct is31fl319x_chipdef is31fl3199_cdef = {
 	.num_leds = 9,
 	.reset_reg = IS31FL3196_RESET,
 	.is31fl319x_regmap_config = &is31fl3196_regmap_config,
 	.brightness_set = is31fl3196_brightness_set,
 	.current_default = IS31FL3196_CURRENT_uA_DEFAULT,
 	.current_min = IS31FL3196_CURRENT_uA_MIN,
 	.current_max = IS31FL3196_CURRENT_uA_MAX,
 	.is_3196or3199 = true,
 };

 static const struct of_device_id of_is31fl319x_match[] = {
 	{ .compatible = "issi,is31fl3190", .data = &is31fl3190_cdef, },
 	{ .compatible = "issi,is31fl3191", .data = &is31fl3190_cdef, },
 	{ .compatible = "issi,is31fl3193", .data = &is31fl3193_cdef, },
 	{ .compatible = "issi,is31fl3196", .data = &is31fl3196_cdef, },
 	{ .compatible = "issi,is31fl3199", .data = &is31fl3199_cdef, },
 	{ .compatible = "si-en,sn3190",    .data = &is31fl3190_cdef, },
 	{ .compatible = "si-en,sn3191",    .data = &is31fl3190_cdef, },
 	{ .compatible = "si-en,sn3193",    .data = &is31fl3193_cdef, },
 	{ .compatible = "si-en,sn3196",    .data = &is31fl3196_cdef, },
 	{ .compatible = "si-en,sn3199",    .data = &is31fl3199_cdef, },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, of_is31fl319x_match);

 static int is31fl319x_parse_child_fw(const struct device *dev,
 				     const struct fwnode_handle *child,
 				     struct is31fl319x_led *led,
 				     struct is31fl319x_chip *is31)
 {
 	struct led_classdev *cdev = &led->cdev;
 	int ret;

 	if (fwnode_property_read_string(child, "label", &cdev->name))
 		cdev->name = fwnode_get_name(child);

 	ret = fwnode_property_read_string(child, "linux,default-trigger", &cdev->default_trigger);
 	if (ret < 0 && ret != -EINVAL) /* is optional */
 		return ret;

 	led->max_microamp = is31->cdef->current_default;
 	ret = fwnode_property_read_u32(child, "led-max-microamp", &led->max_microamp);
 	if (!ret) {
 		if (led->max_microamp < is31->cdef->current_min)
 			return -EINVAL;	/* not supported */
 		led->max_microamp = min(led->max_microamp,
 					is31->cdef->current_max);
 	}

 	return 0;
 }

 static int is31fl319x_parse_fw(struct device *dev, struct is31fl319x_chip *is31)
 {
 	struct fwnode_handle *fwnode = dev_fwnode(dev);
 	int count;
 	int ret;

 	is31->shutdown_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
 	if (IS_ERR(is31->shutdown_gpio))
 		return dev_err_probe(dev, PTR_ERR(is31->shutdown_gpio),
 				     "Failed to get shutdown gpio\n");

 	is31->cdef = device_get_match_data(dev);

 	count = 0;
 	device_for_each_child_node_scoped(dev, child)
 		count++;

 	dev_dbg(dev, "probing with %d leds defined in DT\n", count);

 	if (!count || count > is31->cdef->num_leds)
 		return dev_err_probe(dev, -ENODEV,
 				     "Number of leds defined must be between 1 and %u\n",
 				     is31->cdef->num_leds);

 	device_for_each_child_node_scoped(dev, child) {
 		struct is31fl319x_led *led;
 		u32 reg;

 		ret = fwnode_property_read_u32(child, "reg", &reg);
 		if (ret)
 			return dev_err_probe(dev, ret, "Failed to read led 'reg' property\n");

 		if (reg < 1 || reg > is31->cdef->num_leds)
 			return dev_err_probe(dev, -EINVAL, "invalid led reg %u\n", reg);

 		led = &is31->leds[reg - 1];

 		if (led->configured)
 			return dev_err_probe(dev, -EINVAL, "led %u is already configured\n", reg);

 		ret = is31fl319x_parse_child_fw(dev, child, led, is31);
 		if (ret)
 			return dev_err_probe(dev, ret, "led %u DT parsing failed\n", reg);

 		led->configured = true;
 	}

 	is31->audio_gain_db = 0;
 	if (is31->cdef->is_3196or3199) {
 		ret = fwnode_property_read_u32(fwnode, "audio-gain-db", &is31->audio_gain_db);
 		if (!ret)
 			is31->audio_gain_db = min(is31->audio_gain_db,
 						  IS31FL3196_AUDIO_GAIN_DB_MAX);
 	}

 	return 0;
 }

 static inline int is31fl3190_microamp_to_cs(struct device *dev, u32 microamp)
 {
 	switch (microamp) {
 	case 5000:
 		return IS31FL3190_CURRENT_5_mA;
 	case 10000:
 		return IS31FL3190_CURRENT_10_mA;
 	case 17500:
 		return IS31FL3190_CURRENT_17dot5_mA;
 	case 30000:
 		return IS31FL3190_CURRENT_30_mA;
 	case 42000:
 		return IS31FL3190_CURRENT_42_mA;
 	default:
 		dev_warn(dev, "Unsupported current value: %d, using 5000 µA!\n", microamp);
 		return IS31FL3190_CURRENT_5_mA;
 	}
 }

 static inline int is31fl3196_microamp_to_cs(struct device *dev, u32 microamp)
 {
 	/* round down to nearest supported value (range check done by caller) */
 	u32 step = microamp / IS31FL3196_CURRENT_uA_STEP;

 	return ((IS31FL3196_CONFIG2_CS_STEP_REF - step) &
 		IS31FL3196_CONFIG2_CS_MASK) <<
 		IS31FL3196_CONFIG2_CS_SHIFT; /* CS encoding */
 }

 static inline int is31fl3196_db_to_gain(u32 dezibel)
 {
 	/* round down to nearest supported value (range check done by caller) */
 	return dezibel / IS31FL3196_AUDIO_GAIN_DB_STEP;
 }

 static void is31f1319x_mutex_destroy(void *lock)
 {
 	mutex_destroy(lock);
 }

 static int is31fl319x_probe(struct i2c_client *client)
 {
 	struct is31fl319x_chip *is31;
 	struct device *dev = &client->dev;
 	int err;
 	int i = 0;
 	u32 aggregated_led_microamp;

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 		return -EIO;

 	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
 	if (!is31)
 		return -ENOMEM;

 	mutex_init(&is31->lock);
 	err = devm_add_action_or_reset(dev, is31f1319x_mutex_destroy, &is31->lock);
 	if (err)
 		return err;

 	err = is31fl319x_parse_fw(&client->dev, is31);
 	if (err)
 		return err;

 	if (is31->shutdown_gpio) {
 		gpiod_direction_output(is31->shutdown_gpio, 0);
 		mdelay(5);
 		gpiod_direction_output(is31->shutdown_gpio, 1);
 	}

 	is31->client = client;
 	is31->regmap = devm_regmap_init_i2c(client, is31->cdef->is31fl319x_regmap_config);
 	if (IS_ERR(is31->regmap))
 		return dev_err_probe(dev, PTR_ERR(is31->regmap), "failed to allocate register map\n");

 	i2c_set_clientdata(client, is31);

 	/* check for write-reply from chip (we can't read any registers) */
 	err = regmap_write(is31->regmap, is31->cdef->reset_reg, 0x00);
 	if (err < 0)
 		return dev_err_probe(dev, err, "no response from chip write\n");

 	/*
 	 * Kernel conventions require per-LED led-max-microamp property.
 	 * But the chip does not allow to limit individual LEDs.
 	 * So we take minimum from all subnodes for safety of hardware.
 	 */
 	aggregated_led_microamp = is31->cdef->current_max;
 	for (i = 0; i < is31->cdef->num_leds; i++)
 		if (is31->leds[i].configured &&
 		    is31->leds[i].max_microamp < aggregated_led_microamp)
 			aggregated_led_microamp = is31->leds[i].max_microamp;

 	if (is31->cdef->is_3196or3199)
 		regmap_write(is31->regmap, IS31FL3196_CONFIG2,
 			     is31fl3196_microamp_to_cs(dev, aggregated_led_microamp) |
 			     is31fl3196_db_to_gain(is31->audio_gain_db));
 	else
 		regmap_update_bits(is31->regmap, IS31FL3190_CURRENT, IS31FL3190_CURRENT_MASK,
 				   is31fl3190_microamp_to_cs(dev, aggregated_led_microamp) << IS31FL3190_CURRENT_SHIFT);

 	for (i = 0; i < is31->cdef->num_leds; i++) {
 		struct is31fl319x_led *led = &is31->leds[i];

 		if (!led->configured)
 			continue;

 		led->chip = is31;
 		led->cdev.brightness_set_blocking = is31->cdef->brightness_set;

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

 	return 0;
 }

 /*
  * i2c-core (and modalias) requires that id_table be properly filled,
  * even though it is not used for DeviceTree based instantiation.
  */
 static const struct i2c_device_id is31fl319x_id[] = {
 	{ "is31fl3190" },
 	{ "is31fl3191" },
 	{ "is31fl3193" },
 	{ "is31fl3196" },
 	{ "is31fl3199" },
 	{ "sn3190" },
 	{ "sn3191" },
 	{ "sn3193" },
 	{ "sn3196" },
 	{ "sn3199" },
 	{},
 };
 MODULE_DEVICE_TABLE(i2c, is31fl319x_id);

 static struct i2c_driver is31fl319x_driver = {
 	.driver   = {
 		.name           = "leds-is31fl319x",
 		.of_match_table = of_is31fl319x_match,
 	},
 	.probe = is31fl319x_probe,
 	.id_table = is31fl319x_id,
 };

 module_i2c_driver(is31fl319x_driver);

 MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
 MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
 MODULE_DESCRIPTION("IS31FL319X LED driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright 2015-16 Golden Delicious Computers
	*
	* Author: Nikolaus Schaller <hns@goldelico.com>
	*
	* LED driver for the IS31FL319{0,1,3,6,9} to drive 1, 3, 6 or 9 light
	* effect LEDs.
	*/

	#include <linux/err.h>
	#include <linux/i2c.h>
	#include <linux/leds.h>
	#include <linux/mod_devicetable.h>
	#include <linux/module.h>
	#include <linux/property.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>
	#include <linux/delay.h>
	#include <linux/gpio/consumer.h>

	/* register numbers */
	#define IS31FL319X_SHUTDOWN 0x00

	/* registers for 3190, 3191 and 3193 */
	#define IS31FL3190_BREATHING 0x01
	#define IS31FL3190_LEDMODE 0x02
	#define IS31FL3190_CURRENT 0x03
	#define IS31FL3190_PWM(channel) (0x04 + channel)
	#define IS31FL3190_DATA_UPDATE 0x07
	#define IS31FL3190_T0(channel) (0x0a + channel)
	#define IS31FL3190_T1T2(channel) (0x10 + channel)
	#define IS31FL3190_T3T4(channel) (0x16 + channel)
	#define IS31FL3190_TIME_UPDATE 0x1c
	#define IS31FL3190_LEDCONTROL 0x1d
	#define IS31FL3190_RESET 0x2f

	#define IS31FL3190_CURRENT_uA_MIN 5000
	#define IS31FL3190_CURRENT_uA_DEFAULT 42000
	#define IS31FL3190_CURRENT_uA_MAX 42000
	#define IS31FL3190_CURRENT_SHIFT 2
	#define IS31FL3190_CURRENT_MASK GENMASK(4, 2)
	#define IS31FL3190_CURRENT_5_mA 0x02
	#define IS31FL3190_CURRENT_10_mA 0x01
	#define IS31FL3190_CURRENT_17dot5_mA 0x04
	#define IS31FL3190_CURRENT_30_mA 0x03
	#define IS31FL3190_CURRENT_42_mA 0x00

	/* registers for 3196 and 3199 */
	#define IS31FL3196_CTRL1 0x01
	#define IS31FL3196_CTRL2 0x02
	#define IS31FL3196_CONFIG1 0x03
	#define IS31FL3196_CONFIG2 0x04
	#define IS31FL3196_RAMP_MODE 0x05
	#define IS31FL3196_BREATH_MARK 0x06
	#define IS31FL3196_PWM(channel) (0x07 + channel)
	#define IS31FL3196_DATA_UPDATE 0x10
	#define IS31FL3196_T0(channel) (0x11 + channel)
	#define IS31FL3196_T123_1 0x1a
	#define IS31FL3196_T123_2 0x1b
	#define IS31FL3196_T123_3 0x1c
	#define IS31FL3196_T4(channel) (0x1d + channel)
	#define IS31FL3196_TIME_UPDATE 0x26
	#define IS31FL3196_RESET 0xff

	#define IS31FL3196_REG_CNT (IS31FL3196_RESET + 1)

	#define IS31FL319X_MAX_LEDS 9

	/* CS (Current Setting) in CONFIG2 register */
	#define IS31FL3196_CONFIG2_CS_SHIFT 4
	#define IS31FL3196_CONFIG2_CS_MASK GENMASK(2, 0)
	#define IS31FL3196_CONFIG2_CS_STEP_REF 12

	#define IS31FL3196_CURRENT_uA_MIN 5000
	#define IS31FL3196_CURRENT_uA_MAX 40000
	#define IS31FL3196_CURRENT_uA_STEP 5000
	#define IS31FL3196_CURRENT_uA_DEFAULT 20000

	/* Audio gain in CONFIG2 register */
	#define IS31FL3196_AUDIO_GAIN_DB_MAX ((u32)21)
	#define IS31FL3196_AUDIO_GAIN_DB_STEP 3

	/*
	* regmap is used as a cache of chip's register space,
	* to avoid reading back brightness values from chip,
	* which is known to hang.
	*/
	struct is31fl319x_chip {
	const struct is31fl319x_chipdef *cdef;
	struct i2c_client *client;
	struct gpio_desc *shutdown_gpio;
	struct regmap *regmap;
	struct mutex lock;
	u32 audio_gain_db;

	struct is31fl319x_led {
	struct is31fl319x_chip *chip;
	struct led_classdev cdev;
	u32 max_microamp;
	bool configured;
	} leds[IS31FL319X_MAX_LEDS];
	};

	struct is31fl319x_chipdef {
	int num_leds;
	u8 reset_reg;
	const struct regmap_config *is31fl319x_regmap_config;
	int (brightness_set)(struct led_classdev cdev, enum led_brightness brightness);
	u32 current_default;
	u32 current_min;
	u32 current_max;
	bool is_3196or3199;
	};

	static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
	{
	/* we have no readable registers */
	return false;
	}

	static bool is31fl3190_volatile_reg(struct device *dev, unsigned int reg)
	{
	/* volatile registers are not cached */
	switch (reg) {
	case IS31FL3190_DATA_UPDATE:
	case IS31FL3190_TIME_UPDATE:
	case IS31FL3190_RESET:
	return true; /* always write-through */
	default:
	return false;
	}
	}

	static const struct reg_default is31fl3190_reg_defaults[] = {
	{ IS31FL3190_LEDMODE, 0x00 },
	{ IS31FL3190_CURRENT, 0x00 },
	{ IS31FL3190_PWM(0), 0x00 },
	{ IS31FL3190_PWM(1), 0x00 },
	{ IS31FL3190_PWM(2), 0x00 },
	};

	static const struct regmap_config is31fl3190_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = IS31FL3190_RESET,
	.cache_type = REGCACHE_FLAT,
	.readable_reg = is31fl319x_readable_reg,
	.volatile_reg = is31fl3190_volatile_reg,
	.reg_defaults = is31fl3190_reg_defaults,
	.num_reg_defaults = ARRAY_SIZE(is31fl3190_reg_defaults),
	};

	static bool is31fl3196_volatile_reg(struct device *dev, unsigned int reg)
	{
	/* volatile registers are not cached */
	switch (reg) {
	case IS31FL3196_DATA_UPDATE:
	case IS31FL3196_TIME_UPDATE:
	case IS31FL3196_RESET:
	return true; /* always write-through */
	default:
	return false;
	}
	}

	static const struct reg_default is31fl3196_reg_defaults[] = {
	{ IS31FL3196_CONFIG1, 0x00 },
	{ IS31FL3196_CONFIG2, 0x00 },
	{ IS31FL3196_PWM(0), 0x00 },
	{ IS31FL3196_PWM(1), 0x00 },
	{ IS31FL3196_PWM(2), 0x00 },
	{ IS31FL3196_PWM(3), 0x00 },
	{ IS31FL3196_PWM(4), 0x00 },
	{ IS31FL3196_PWM(5), 0x00 },
	{ IS31FL3196_PWM(6), 0x00 },
	{ IS31FL3196_PWM(7), 0x00 },
	{ IS31FL3196_PWM(8), 0x00 },
	};

	static const struct regmap_config is31fl3196_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = IS31FL3196_REG_CNT,
	.cache_type = REGCACHE_FLAT,
	.readable_reg = is31fl319x_readable_reg,
	.volatile_reg = is31fl3196_volatile_reg,
	.reg_defaults = is31fl3196_reg_defaults,
	.num_reg_defaults = ARRAY_SIZE(is31fl3196_reg_defaults),
	};

	static int is31fl3190_brightness_set(struct led_classdev *cdev,
	enum led_brightness brightness)
	{
	struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led, cdev);
	struct is31fl319x_chip *is31 = led->chip;
	int chan = led - is31->leds;
	int ret;
	int i;
	u8 ctrl = 0;

	dev_dbg(&is31->client->dev, "channel %d: %d\n", chan, brightness);

	mutex_lock(&is31->lock);

	/* update PWM register */
	ret = regmap_write(is31->regmap, IS31FL3190_PWM(chan), brightness);
	if (ret < 0)
	goto out;

	/* read current brightness of all PWM channels */
	for (i = 0; i < is31->cdef->num_leds; i++) {
	unsigned int pwm_value;
	bool on;

	/*
	* since neither cdev nor the chip can provide
	* the current setting, we read from the regmap cache
	*/

	ret = regmap_read(is31->regmap, IS31FL3190_PWM(i), &pwm_value);
	on = ret >= 0 && pwm_value > LED_OFF;

	ctrl \|= on << i;
	}

	if (ctrl > 0) {
	dev_dbg(&is31->client->dev, "power up %02x\n", ctrl);
	regmap_write(is31->regmap, IS31FL3190_LEDCONTROL, ctrl);
	/* update PWMs */
	regmap_write(is31->regmap, IS31FL3190_DATA_UPDATE, 0x00);
	/* enable chip from shut down and enable all channels */
	ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x20);
	} else {
	dev_dbg(&is31->client->dev, "power down\n");
	/* shut down (no need to clear LEDCONTROL) */
	ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
	}

	out:
	mutex_unlock(&is31->lock);

	return ret;
	}

	static int is31fl3196_brightness_set(struct led_classdev *cdev,
	enum led_brightness brightness)
	{
	struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led, cdev);
	struct is31fl319x_chip *is31 = led->chip;
	int chan = led - is31->leds;
	int ret;
	int i;
	u8 ctrl1 = 0, ctrl2 = 0;

	dev_dbg(&is31->client->dev, "channel %d: %d\n", chan, brightness);

	mutex_lock(&is31->lock);

	/* update PWM register */
	ret = regmap_write(is31->regmap, IS31FL3196_PWM(chan), brightness);
	if (ret < 0)
	goto out;

	/* read current brightness of all PWM channels */
	for (i = 0; i < is31->cdef->num_leds; i++) {
	unsigned int pwm_value;
	bool on;

	/*
	* since neither cdev nor the chip can provide
	* the current setting, we read from the regmap cache
	*/

	ret = regmap_read(is31->regmap, IS31FL3196_PWM(i), &pwm_value);
	on = ret >= 0 && pwm_value > LED_OFF;

	if (i < 3)
	ctrl1 \|= on << i; /* 0..2 => bit 0..2 */
	else if (i < 6)
	ctrl1 \|= on << (i + 1); /* 3..5 => bit 4..6 */
	else
	ctrl2 \|= on << (i - 6); /* 6..8 => bit 0..2 */
	}

	if (ctrl1 > 0 \|\| ctrl2 > 0) {
	dev_dbg(&is31->client->dev, "power up %02x %02x\n",
	ctrl1, ctrl2);
	regmap_write(is31->regmap, IS31FL3196_CTRL1, ctrl1);
	regmap_write(is31->regmap, IS31FL3196_CTRL2, ctrl2);
	/* update PWMs */
	regmap_write(is31->regmap, IS31FL3196_DATA_UPDATE, 0x00);
	/* enable chip from shut down */
	ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
	} else {
	dev_dbg(&is31->client->dev, "power down\n");
	/* shut down (no need to clear CTRL1/2) */
	ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
	}

	out:
	mutex_unlock(&is31->lock);

	return ret;
	}

	static const struct is31fl319x_chipdef is31fl3190_cdef = {
	.num_leds = 1,
	.reset_reg = IS31FL3190_RESET,
	.is31fl319x_regmap_config = &is31fl3190_regmap_config,
	.brightness_set = is31fl3190_brightness_set,
	.current_default = IS31FL3190_CURRENT_uA_DEFAULT,
	.current_min = IS31FL3190_CURRENT_uA_MIN,
	.current_max = IS31FL3190_CURRENT_uA_MAX,
	.is_3196or3199 = false,
	};

	static const struct is31fl319x_chipdef is31fl3193_cdef = {
	.num_leds = 3,
	.reset_reg = IS31FL3190_RESET,
	.is31fl319x_regmap_config = &is31fl3190_regmap_config,
	.brightness_set = is31fl3190_brightness_set,
	.current_default = IS31FL3190_CURRENT_uA_DEFAULT,
	.current_min = IS31FL3190_CURRENT_uA_MIN,
	.current_max = IS31FL3190_CURRENT_uA_MAX,
	.is_3196or3199 = false,
	};

	static const struct is31fl319x_chipdef is31fl3196_cdef = {
	.num_leds = 6,
	.reset_reg = IS31FL3196_RESET,
	.is31fl319x_regmap_config = &is31fl3196_regmap_config,
	.brightness_set = is31fl3196_brightness_set,
	.current_default = IS31FL3196_CURRENT_uA_DEFAULT,
	.current_min = IS31FL3196_CURRENT_uA_MIN,
	.current_max = IS31FL3196_CURRENT_uA_MAX,
	.is_3196or3199 = true,
	};

	static const struct is31fl319x_chipdef is31fl3199_cdef = {
	.num_leds = 9,
	.reset_reg = IS31FL3196_RESET,
	.is31fl319x_regmap_config = &is31fl3196_regmap_config,
	.brightness_set = is31fl3196_brightness_set,
	.current_default = IS31FL3196_CURRENT_uA_DEFAULT,
	.current_min = IS31FL3196_CURRENT_uA_MIN,
	.current_max = IS31FL3196_CURRENT_uA_MAX,
	.is_3196or3199 = true,
	};

	static const struct of_device_id of_is31fl319x_match[] = {
	{ .compatible = "issi,is31fl3190", .data = &is31fl3190_cdef, },
	{ .compatible = "issi,is31fl3191", .data = &is31fl3190_cdef, },
	{ .compatible = "issi,is31fl3193", .data = &is31fl3193_cdef, },
	{ .compatible = "issi,is31fl3196", .data = &is31fl3196_cdef, },
	{ .compatible = "issi,is31fl3199", .data = &is31fl3199_cdef, },
	{ .compatible = "si-en,sn3190", .data = &is31fl3190_cdef, },
	{ .compatible = "si-en,sn3191", .data = &is31fl3190_cdef, },
	{ .compatible = "si-en,sn3193", .data = &is31fl3193_cdef, },
	{ .compatible = "si-en,sn3196", .data = &is31fl3196_cdef, },
	{ .compatible = "si-en,sn3199", .data = &is31fl3199_cdef, },
	{ }
	};
	MODULE_DEVICE_TABLE(of, of_is31fl319x_match);

	static int is31fl319x_parse_child_fw(const struct device *dev,
	const struct fwnode_handle *child,
	struct is31fl319x_led *led,
	struct is31fl319x_chip *is31)
	{
	struct led_classdev *cdev = &led->cdev;
	int ret;

	if (fwnode_property_read_string(child, "label", &cdev->name))
	cdev->name = fwnode_get_name(child);

	ret = fwnode_property_read_string(child, "linux,default-trigger", &cdev->default_trigger);
	if (ret < 0 && ret != -EINVAL) /* is optional */
	return ret;

	led->max_microamp = is31->cdef->current_default;
	ret = fwnode_property_read_u32(child, "led-max-microamp", &led->max_microamp);
	if (!ret) {
	if (led->max_microamp < is31->cdef->current_min)
	return -EINVAL; /* not supported */
	led->max_microamp = min(led->max_microamp,
	is31->cdef->current_max);
	}

	return 0;
	}

	static int is31fl319x_parse_fw(struct device dev, struct is31fl319x_chip is31)
	{
	struct fwnode_handle *fwnode = dev_fwnode(dev);
	int count;
	int ret;

	is31->shutdown_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
	if (IS_ERR(is31->shutdown_gpio))
	return dev_err_probe(dev, PTR_ERR(is31->shutdown_gpio),
	"Failed to get shutdown gpio\n");

	is31->cdef = device_get_match_data(dev);

	count = 0;
	device_for_each_child_node_scoped(dev, child)
	count++;

	dev_dbg(dev, "probing with %d leds defined in DT\n", count);

	if (!count \|\| count > is31->cdef->num_leds)
	return dev_err_probe(dev, -ENODEV,
	"Number of leds defined must be between 1 and %u\n",
	is31->cdef->num_leds);

	device_for_each_child_node_scoped(dev, child) {
	struct is31fl319x_led *led;
	u32 reg;

	ret = fwnode_property_read_u32(child, "reg", &reg);
	if (ret)
	return dev_err_probe(dev, ret, "Failed to read led 'reg' property\n");

	if (reg < 1 \|\| reg > is31->cdef->num_leds)
	return dev_err_probe(dev, -EINVAL, "invalid led reg %u\n", reg);

	led = &is31->leds[reg - 1];

	if (led->configured)
	return dev_err_probe(dev, -EINVAL, "led %u is already configured\n", reg);

	ret = is31fl319x_parse_child_fw(dev, child, led, is31);
	if (ret)
	return dev_err_probe(dev, ret, "led %u DT parsing failed\n", reg);

	led->configured = true;
	}

	is31->audio_gain_db = 0;
	if (is31->cdef->is_3196or3199) {
	ret = fwnode_property_read_u32(fwnode, "audio-gain-db", &is31->audio_gain_db);
	if (!ret)
	is31->audio_gain_db = min(is31->audio_gain_db,
	IS31FL3196_AUDIO_GAIN_DB_MAX);
	}

	return 0;
	}

	static inline int is31fl3190_microamp_to_cs(struct device *dev, u32 microamp)
	{
	switch (microamp) {
	case 5000:
	return IS31FL3190_CURRENT_5_mA;
	case 10000:
	return IS31FL3190_CURRENT_10_mA;
	case 17500:
	return IS31FL3190_CURRENT_17dot5_mA;
	case 30000:
	return IS31FL3190_CURRENT_30_mA;
	case 42000:
	return IS31FL3190_CURRENT_42_mA;
	default:
	dev_warn(dev, "Unsupported current value: %d, using 5000 µA!\n", microamp);
	return IS31FL3190_CURRENT_5_mA;
	}
	}

	static inline int is31fl3196_microamp_to_cs(struct device *dev, u32 microamp)
	{
	/* round down to nearest supported value (range check done by caller) */
	u32 step = microamp / IS31FL3196_CURRENT_uA_STEP;

	return ((IS31FL3196_CONFIG2_CS_STEP_REF - step) &
	IS31FL3196_CONFIG2_CS_MASK) <<
	IS31FL3196_CONFIG2_CS_SHIFT; /* CS encoding */
	}

	static inline int is31fl3196_db_to_gain(u32 dezibel)
	{
	/* round down to nearest supported value (range check done by caller) */
	return dezibel / IS31FL3196_AUDIO_GAIN_DB_STEP;
	}

	static void is31f1319x_mutex_destroy(void *lock)
	{
	mutex_destroy(lock);
	}

	static int is31fl319x_probe(struct i2c_client *client)
	{
	struct is31fl319x_chip *is31;
	struct device *dev = &client->dev;
	int err;
	int i = 0;
	u32 aggregated_led_microamp;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	return -EIO;

	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
	if (!is31)
	return -ENOMEM;

	mutex_init(&is31->lock);
	err = devm_add_action_or_reset(dev, is31f1319x_mutex_destroy, &is31->lock);
	if (err)
	return err;

	err = is31fl319x_parse_fw(&client->dev, is31);
	if (err)
	return err;

	if (is31->shutdown_gpio) {
	gpiod_direction_output(is31->shutdown_gpio, 0);
	mdelay(5);
	gpiod_direction_output(is31->shutdown_gpio, 1);
	}

	is31->client = client;
	is31->regmap = devm_regmap_init_i2c(client, is31->cdef->is31fl319x_regmap_config);
	if (IS_ERR(is31->regmap))
	return dev_err_probe(dev, PTR_ERR(is31->regmap), "failed to allocate register map\n");

	i2c_set_clientdata(client, is31);

	/* check for write-reply from chip (we can't read any registers) */
	err = regmap_write(is31->regmap, is31->cdef->reset_reg, 0x00);
	if (err < 0)
	return dev_err_probe(dev, err, "no response from chip write\n");

	/*
	* Kernel conventions require per-LED led-max-microamp property.
	* But the chip does not allow to limit individual LEDs.
	* So we take minimum from all subnodes for safety of hardware.
	*/
	aggregated_led_microamp = is31->cdef->current_max;
	for (i = 0; i < is31->cdef->num_leds; i++)
	if (is31->leds[i].configured &&
	is31->leds[i].max_microamp < aggregated_led_microamp)
	aggregated_led_microamp = is31->leds[i].max_microamp;

	if (is31->cdef->is_3196or3199)
	regmap_write(is31->regmap, IS31FL3196_CONFIG2,
	is31fl3196_microamp_to_cs(dev, aggregated_led_microamp) \|
	is31fl3196_db_to_gain(is31->audio_gain_db));
	else
	regmap_update_bits(is31->regmap, IS31FL3190_CURRENT, IS31FL3190_CURRENT_MASK,
	is31fl3190_microamp_to_cs(dev, aggregated_led_microamp) << IS31FL3190_CURRENT_SHIFT);

	for (i = 0; i < is31->cdef->num_leds; i++) {
	struct is31fl319x_led *led = &is31->leds[i];

	if (!led->configured)
	continue;

	led->chip = is31;
	led->cdev.brightness_set_blocking = is31->cdef->brightness_set;

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

	return 0;
	}

	/*
	* i2c-core (and modalias) requires that id_table be properly filled,
	* even though it is not used for DeviceTree based instantiation.
	*/
	static const struct i2c_device_id is31fl319x_id[] = {
	{ "is31fl3190" },
	{ "is31fl3191" },
	{ "is31fl3193" },
	{ "is31fl3196" },
	{ "is31fl3199" },
	{ "sn3190" },
	{ "sn3191" },
	{ "sn3193" },
	{ "sn3196" },
	{ "sn3199" },
	{},
	};
	MODULE_DEVICE_TABLE(i2c, is31fl319x_id);

	static struct i2c_driver is31fl319x_driver = {
	.driver = {
	.name = "leds-is31fl319x",
	.of_match_table = of_is31fl319x_match,
	},
	.probe = is31fl319x_probe,
	.id_table = is31fl319x_id,
	};

	module_i2c_driver(is31fl319x_driver);

	MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
	MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
	MODULE_DESCRIPTION("IS31FL319X LED driver");
	MODULE_LICENSE("GPL v2");