// SPDX-License-Identifier: GPL-2.0
  // TI LM3532 LED driver

  // Copyright (C) 2019 Texas Instruments Incorporated - https://www.ti.com/
  // https://www.ti.com/lit/ds/symlink/lm3532.pdf

  
  #include <linux/i2c.h>
  #include <linux/leds.h>
  #include <linux/slab.h>
  #include <linux/regmap.h>
  #include <linux/types.h>
  #include <linux/regulator/consumer.h>
  #include <linux/module.h>
  #include <uapi/linux/uleds.h>
  #include <linux/gpio/consumer.h>
  
  #define LM3532_NAME "lm3532-led"
  #define LM3532_BL_MODE_MANUAL	0x00
  #define LM3532_BL_MODE_ALS	0x01
  
  #define LM3532_REG_OUTPUT_CFG	0x10
  #define LM3532_REG_STARTSHUT_RAMP	0x11
  #define LM3532_REG_RT_RAMP	0x12
  #define LM3532_REG_PWM_A_CFG	0x13
  #define LM3532_REG_PWM_B_CFG	0x14
  #define LM3532_REG_PWM_C_CFG	0x15
  #define LM3532_REG_ZONE_CFG_A	0x16

  #define LM3532_REG_CTRL_A_FS_CURR	0x17

  #define LM3532_REG_ZONE_CFG_B	0x18

  #define LM3532_REG_CTRL_B_FS_CURR	0x19

  #define LM3532_REG_ZONE_CFG_C	0x1a

  #define LM3532_REG_CTRL_C_FS_CURR	0x1b

  #define LM3532_REG_ENABLE	0x1d
  #define LM3532_ALS_CONFIG	0x23
  #define LM3532_REG_ZN_0_HI	0x60
  #define LM3532_REG_ZN_0_LO	0x61
  #define LM3532_REG_ZN_1_HI	0x62
  #define LM3532_REG_ZN_1_LO	0x63
  #define LM3532_REG_ZN_2_HI	0x64
  #define LM3532_REG_ZN_2_LO	0x65
  #define LM3532_REG_ZN_3_HI	0x66
  #define LM3532_REG_ZN_3_LO	0x67

  #define LM3532_REG_ZONE_TRGT_A	0x70
  #define LM3532_REG_ZONE_TRGT_B	0x75
  #define LM3532_REG_ZONE_TRGT_C	0x7a

  #define LM3532_REG_MAX		0x7e

  /* Control Enable */

  #define LM3532_CTRL_A_ENABLE	BIT(0)
  #define LM3532_CTRL_B_ENABLE	BIT(1)
  #define LM3532_CTRL_C_ENABLE	BIT(2)
  
  /* PWM Zone Control */
  #define LM3532_PWM_ZONE_MASK	0x7c
  #define LM3532_PWM_ZONE_0_EN	BIT(2)
  #define LM3532_PWM_ZONE_1_EN	BIT(3)
  #define LM3532_PWM_ZONE_2_EN	BIT(4)
  #define LM3532_PWM_ZONE_3_EN	BIT(5)
  #define LM3532_PWM_ZONE_4_EN	BIT(6)
  
  /* Brightness Configuration */
  #define LM3532_I2C_CTRL		BIT(0)
  #define LM3532_ALS_CTRL		0
  #define LM3532_LINEAR_MAP	BIT(1)
  #define LM3532_ZONE_MASK	(BIT(2) | BIT(3) | BIT(4))
  #define LM3532_ZONE_0		0
  #define LM3532_ZONE_1		BIT(2)
  #define LM3532_ZONE_2		BIT(3)
  #define LM3532_ZONE_3		(BIT(2) | BIT(3))
  #define LM3532_ZONE_4		BIT(4)
  
  #define LM3532_ENABLE_ALS	BIT(3)
  #define LM3532_ALS_SEL_SHIFT	6
  
  /* Zone Boundary Register */
  #define LM3532_ALS_WINDOW_mV	2000
  #define LM3532_ALS_ZB_MAX	4
  #define LM3532_ALS_OFFSET_mV	2
  
  #define LM3532_CONTROL_A	0
  #define LM3532_CONTROL_B	1
  #define LM3532_CONTROL_C	2
  #define LM3532_MAX_CONTROL_BANKS 3
  #define LM3532_MAX_LED_STRINGS	3
  
  #define LM3532_OUTPUT_CFG_MASK	0x3
  #define LM3532_BRT_VAL_ADJUST	8
  #define LM3532_RAMP_DOWN_SHIFT	3
  
  #define LM3532_NUM_RAMP_VALS	8
  #define LM3532_NUM_AVG_VALS	8
  #define LM3532_NUM_IMP_VALS	32

  #define LM3532_FS_CURR_MIN	5000
  #define LM3532_FS_CURR_MAX	29800
  #define LM3532_FS_CURR_STEP	800

  /*
   * struct lm3532_als_data

   * @config: value of ALS configuration register
   * @als1_imp_sel: value of ALS1 resistor select register
   * @als2_imp_sel: value of ALS2 resistor select register
   * @als_avrg_time: ALS averaging time
   * @als_input_mode: ALS input mode for brightness control
   * @als_vmin: Minimum ALS voltage
   * @als_vmax: Maximum ALS voltage
   * @zone_lo: values of ALS lo ZB(Zone Boundary) registers
   * @zone_hi: values of ALS hi ZB(Zone Boundary) registers

   */
  struct lm3532_als_data {
  	u8 config;
  	u8 als1_imp_sel;
  	u8 als2_imp_sel;
  	u8 als_avrg_time;
  	u8 als_input_mode;
  	u32 als_vmin;
  	u32 als_vmax;
  	u8 zones_lo[LM3532_ALS_ZB_MAX];
  	u8 zones_hi[LM3532_ALS_ZB_MAX];
  };
  
  /**
   * struct lm3532_led
   * @led_dev: led class device

   * @priv: Pointer the device data structure
   * @control_bank: Control bank the LED is associated to
   * @mode: Mode of the LED string
   * @ctrl_brt_pointer: Zone target register that controls the sink
   * @num_leds: Number of LED strings are supported in this array
   * @full_scale_current: The full-scale current setting for the current sink.
   * @led_strings: The LED strings supported in this array
   * @enabled: Enabled status

   */
  struct lm3532_led {
  	struct led_classdev led_dev;
  	struct lm3532_data *priv;
  
  	int control_bank;
  	int mode;

  	int ctrl_brt_pointer;

  	int num_leds;

  	int full_scale_current;

  	unsigned int enabled:1;

  	u32 led_strings[LM3532_MAX_CONTROL_BANKS];

  };
  
  /**
   * struct lm3532_data

   * @enable_gpio: Hardware enable gpio

   * @regulator: regulator
   * @client: i2c client

   * @regmap: Devices register map
   * @dev: Pointer to the devices device struct
   * @lock: Lock for reading/writing the device
   * @als_data: Pointer to the als data struct
   * @runtime_ramp_up: Runtime ramp up setting
   * @runtime_ramp_down: Runtime ramp down setting
   * @leds: Array of LED strings

   */
  struct lm3532_data {
  	struct gpio_desc *enable_gpio;
  	struct regulator *regulator;
  	struct i2c_client *client;
  	struct regmap *regmap;
  	struct device *dev;
  	struct mutex lock;
  
  	struct lm3532_als_data *als_data;
  
  	u32 runtime_ramp_up;
  	u32 runtime_ramp_down;
  
  	struct lm3532_led leds[];
  };
  
  static const struct reg_default lm3532_reg_defs[] = {
  	{LM3532_REG_OUTPUT_CFG, 0xe4},
  	{LM3532_REG_STARTSHUT_RAMP, 0xc0},
  	{LM3532_REG_RT_RAMP, 0xc0},
  	{LM3532_REG_PWM_A_CFG, 0x82},
  	{LM3532_REG_PWM_B_CFG, 0x82},
  	{LM3532_REG_PWM_C_CFG, 0x82},
  	{LM3532_REG_ZONE_CFG_A, 0xf1},

  	{LM3532_REG_CTRL_A_FS_CURR, 0xf3},

  	{LM3532_REG_ZONE_CFG_B, 0xf1},

  	{LM3532_REG_CTRL_B_FS_CURR, 0xf3},

  	{LM3532_REG_ZONE_CFG_C, 0xf1},

  	{LM3532_REG_CTRL_C_FS_CURR, 0xf3},

  	{LM3532_REG_ENABLE, 0xf8},
  	{LM3532_ALS_CONFIG, 0x44},
  	{LM3532_REG_ZN_0_HI, 0x35},
  	{LM3532_REG_ZN_0_LO, 0x33},
  	{LM3532_REG_ZN_1_HI, 0x6a},
  	{LM3532_REG_ZN_1_LO, 0x66},
  	{LM3532_REG_ZN_2_HI, 0xa1},
  	{LM3532_REG_ZN_2_LO, 0x99},
  	{LM3532_REG_ZN_3_HI, 0xdc},
  	{LM3532_REG_ZN_3_LO, 0xcc},
  };
  
  static const struct regmap_config lm3532_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 8,
  
  	.max_register = LM3532_REG_MAX,
  	.reg_defaults = lm3532_reg_defs,
  	.num_reg_defaults = ARRAY_SIZE(lm3532_reg_defs),
  	.cache_type = REGCACHE_FLAT,
  };

  static const int als_imp_table[LM3532_NUM_IMP_VALS] = {37000, 18500, 12330,

  						       92500, 7400, 6170, 5290,
  						       4630, 4110, 3700, 3360,
  						       3080, 2850, 2640, 2440,
  						       2310, 2180, 2060, 1950,
  						       1850, 1760, 1680, 1610,
  						       1540, 1480, 1420, 1370,
  						       1320, 1280, 1230, 1190};
  static int lm3532_get_als_imp_index(int als_imped)
  {
  	int i;
  
  	if (als_imped > als_imp_table[1])
  		return 0;
  
  	if (als_imped < als_imp_table[LM3532_NUM_IMP_VALS - 1])
  		return LM3532_NUM_IMP_VALS - 1;
  
  	for (i = 1; i < LM3532_NUM_IMP_VALS; i++) {
  		if (als_imped == als_imp_table[i])
  			return i;
  
  		/* Find an approximate index by looking up the table */
  		if (als_imped < als_imp_table[i - 1] &&
  		    als_imped > als_imp_table[i]) {
  			if (als_imped - als_imp_table[i - 1] <
  			    als_imp_table[i] - als_imped)
  				return i + 1;
  			else
  				return i;
  		}
  	}
  
  	return -EINVAL;
  }
  
  static int lm3532_get_index(const int table[], int size, int value)
  {
  	int i;
  
  	for (i = 1; i < size; i++) {
  		if (value == table[i])
  			return i;
  
  		/* Find an approximate index by looking up the table */
  		if (value > table[i - 1] &&
  		    value < table[i]) {
  			if (value - table[i - 1] < table[i] - value)
  				return i - 1;
  			else
  				return i;
  		}
  	}
  
  	return -EINVAL;
  }

  static const int als_avrg_table[LM3532_NUM_AVG_VALS] = {17920, 35840, 71680,

  							1433360, 286720, 573440,
  							1146880, 2293760};
  static int lm3532_get_als_avg_index(int avg_time)
  {
  	if (avg_time <= als_avrg_table[0])
  		return 0;
  
  	if (avg_time > als_avrg_table[LM3532_NUM_AVG_VALS - 1])
  		return LM3532_NUM_AVG_VALS - 1;
  
  	return lm3532_get_index(&als_avrg_table[0], LM3532_NUM_AVG_VALS,
  				avg_time);
  }

  static const int ramp_table[LM3532_NUM_RAMP_VALS] = { 8, 1024, 2048, 4096, 8192,

  						     16384, 32768, 65536};
  static int lm3532_get_ramp_index(int ramp_time)
  {
  	if (ramp_time <= ramp_table[0])
  		return 0;
  
  	if (ramp_time > ramp_table[LM3532_NUM_RAMP_VALS - 1])
  		return LM3532_NUM_RAMP_VALS - 1;
  
  	return lm3532_get_index(&ramp_table[0], LM3532_NUM_RAMP_VALS,
  				ramp_time);
  }

  /* Caller must take care of locking */

  static int lm3532_led_enable(struct lm3532_led *led_data)
  {
  	int ctrl_en_val = BIT(led_data->control_bank);
  	int ret;

  	if (led_data->enabled)
  		return 0;

  	ret = regmap_update_bits(led_data->priv->regmap, LM3532_REG_ENABLE,
  					 ctrl_en_val, ctrl_en_val);
  	if (ret) {
  		dev_err(led_data->priv->dev, "Failed to set ctrl:%d
  ", ret);
  		return ret;
  	}

  	ret = regulator_enable(led_data->priv->regulator);
  	if (ret < 0)
  		return ret;
  
  	led_data->enabled = 1;
  
  	return 0;

  }

  /* Caller must take care of locking */

  static int lm3532_led_disable(struct lm3532_led *led_data)
  {
  	int ctrl_en_val = BIT(led_data->control_bank);
  	int ret;

  	if (!led_data->enabled)
  		return 0;

  	ret = regmap_update_bits(led_data->priv->regmap, LM3532_REG_ENABLE,

  					 ctrl_en_val, 0);

  	if (ret) {
  		dev_err(led_data->priv->dev, "Failed to set ctrl:%d
  ", ret);
  		return ret;
  	}

  	ret = regulator_disable(led_data->priv->regulator);
  	if (ret < 0)
  		return ret;
  
  	led_data->enabled = 0;
  
  	return 0;

  }
  
  static int lm3532_brightness_set(struct led_classdev *led_cdev,
  				 enum led_brightness brt_val)
  {
  	struct lm3532_led *led =
  			container_of(led_cdev, struct lm3532_led, led_dev);
  	u8 brightness_reg;
  	int ret;
  
  	mutex_lock(&led->priv->lock);

  	if (led->mode == LM3532_ALS_CTRL) {

  		if (brt_val > LED_OFF)
  			ret = lm3532_led_enable(led);
  		else
  			ret = lm3532_led_disable(led);
  
  		goto unlock;
  	}
  
  	if (brt_val == LED_OFF) {
  		ret = lm3532_led_disable(led);
  		goto unlock;
  	}
  
  	ret = lm3532_led_enable(led);
  	if (ret)
  		goto unlock;

  	brightness_reg = LM3532_REG_ZONE_TRGT_A + led->control_bank * 5 +
  			 (led->ctrl_brt_pointer >> 2);

  
  	ret = regmap_write(led->priv->regmap, brightness_reg, brt_val);
  
  unlock:
  	mutex_unlock(&led->priv->lock);
  	return ret;
  }
  
  static int lm3532_init_registers(struct lm3532_led *led)
  {
  	struct lm3532_data *drvdata = led->priv;
  	unsigned int runtime_ramp_val;
  	unsigned int output_cfg_val = 0;
  	unsigned int output_cfg_shift = 0;
  	unsigned int output_cfg_mask = 0;

  	unsigned int brightness_config_reg;
  	unsigned int brightness_config_val;

  	int fs_current_reg;
  	int fs_current_val;

  	int ret, i;

  	if (drvdata->enable_gpio)
  		gpiod_direction_output(drvdata->enable_gpio, 1);
  
  	brightness_config_reg = LM3532_REG_ZONE_CFG_A + led->control_bank * 2;
  	/*
  	 * This could be hard coded to the default value but the control
  	 * brightness register may have changed during boot.
  	 */
  	ret = regmap_read(drvdata->regmap, brightness_config_reg,
  			  &led->ctrl_brt_pointer);
  	if (ret)
  		return ret;
  
  	led->ctrl_brt_pointer &= LM3532_ZONE_MASK;
  	brightness_config_val = led->ctrl_brt_pointer | led->mode;
  	ret = regmap_write(drvdata->regmap, brightness_config_reg,
  			   brightness_config_val);
  	if (ret)
  		return ret;

  	if (led->full_scale_current) {
  		fs_current_reg = LM3532_REG_CTRL_A_FS_CURR + led->control_bank * 2;
  		fs_current_val = (led->full_scale_current - LM3532_FS_CURR_MIN) /
  				 LM3532_FS_CURR_STEP;
  
  		ret = regmap_write(drvdata->regmap, fs_current_reg,
  				   fs_current_val);
  		if (ret)
  			return ret;
  	}

  	for (i = 0; i < led->num_leds; i++) {
  		output_cfg_shift = led->led_strings[i] * 2;
  		output_cfg_val |= (led->control_bank << output_cfg_shift);
  		output_cfg_mask |= LM3532_OUTPUT_CFG_MASK << output_cfg_shift;
  	}
  
  	ret = regmap_update_bits(drvdata->regmap, LM3532_REG_OUTPUT_CFG,
  				 output_cfg_mask, output_cfg_val);
  	if (ret)
  		return ret;
  
  	runtime_ramp_val = drvdata->runtime_ramp_up |
  			 (drvdata->runtime_ramp_down << LM3532_RAMP_DOWN_SHIFT);
  
  	return regmap_write(drvdata->regmap, LM3532_REG_RT_RAMP,
  			    runtime_ramp_val);
  }
  
  static int lm3532_als_configure(struct lm3532_data *priv,
  				struct lm3532_led *led)
  {
  	struct lm3532_als_data *als = priv->als_data;
  	u32 als_vmin, als_vmax, als_vstep;
  	int zone_reg = LM3532_REG_ZN_0_HI;

  	int ret;
  	int i;
  
  	als_vmin = als->als_vmin;
  	als_vmax = als->als_vmax;
  
  	als_vstep = (als_vmax - als_vmin) / ((LM3532_ALS_ZB_MAX + 1) * 2);
  
  	for (i = 0; i < LM3532_ALS_ZB_MAX; i++) {
  		als->zones_lo[i] = ((als_vmin + als_vstep + (i * als_vstep)) *
  				LED_FULL) / 1000;
  		als->zones_hi[i] = ((als_vmin + LM3532_ALS_OFFSET_mV +
  				als_vstep + (i * als_vstep)) * LED_FULL) / 1000;
  
  		zone_reg = LM3532_REG_ZN_0_HI + i * 2;
  		ret = regmap_write(priv->regmap, zone_reg, als->zones_lo[i]);
  		if (ret)
  			return ret;
  
  		zone_reg += 1;
  		ret = regmap_write(priv->regmap, zone_reg, als->zones_hi[i]);
  		if (ret)
  			return ret;
  	}
  
  	als->config = (als->als_avrg_time | (LM3532_ENABLE_ALS) |
  		(als->als_input_mode << LM3532_ALS_SEL_SHIFT));

  	return regmap_write(priv->regmap, LM3532_ALS_CONFIG, als->config);

  }
  
  static int lm3532_parse_als(struct lm3532_data *priv)
  {
  	struct lm3532_als_data *als;
  	int als_avg_time;
  	int als_impedance;
  	int ret;
  
  	als = devm_kzalloc(priv->dev, sizeof(*als), GFP_KERNEL);
  	if (als == NULL)
  		return -ENOMEM;
  
  	ret = device_property_read_u32(&priv->client->dev, "ti,als-vmin",
  				       &als->als_vmin);
  	if (ret)
  		als->als_vmin = 0;
  
  	ret = device_property_read_u32(&priv->client->dev, "ti,als-vmax",
  				       &als->als_vmax);
  	if (ret)
  		als->als_vmax = LM3532_ALS_WINDOW_mV;
  
  	if (als->als_vmax > LM3532_ALS_WINDOW_mV) {
  		ret = -EINVAL;
  		return ret;
  	}
  
  	ret = device_property_read_u32(&priv->client->dev, "ti,als1-imp-sel",
  				      &als_impedance);
  	if (ret)
  		als->als1_imp_sel = 0;
  	else
  		als->als1_imp_sel = lm3532_get_als_imp_index(als_impedance);
  
  	ret = device_property_read_u32(&priv->client->dev, "ti,als2-imp-sel",
  				      &als_impedance);
  	if (ret)
  		als->als2_imp_sel = 0;
  	else
  		als->als2_imp_sel = lm3532_get_als_imp_index(als_impedance);
  
  	ret = device_property_read_u32(&priv->client->dev, "ti,als-avrg-time-us",
  				      &als_avg_time);
  	if (ret)
  		als->als_avrg_time = 0;
  	else
  		als->als_avrg_time = lm3532_get_als_avg_index(als_avg_time);
  
  	ret = device_property_read_u8(&priv->client->dev, "ti,als-input-mode",
  				      &als->als_input_mode);
  	if (ret)
  		als->als_input_mode = 0;
  
  	if (als->als_input_mode > LM3532_BL_MODE_ALS) {
  		ret = -EINVAL;
  		return ret;
  	}
  
  	priv->als_data = als;
  
  	return ret;
  }
  
  static int lm3532_parse_node(struct lm3532_data *priv)
  {
  	struct fwnode_handle *child = NULL;
  	struct lm3532_led *led;

  	int control_bank;
  	u32 ramp_time;
  	size_t i = 0;
  	int ret;
  
  	priv->enable_gpio = devm_gpiod_get_optional(&priv->client->dev,
  						   "enable", GPIOD_OUT_LOW);
  	if (IS_ERR(priv->enable_gpio))
  		priv->enable_gpio = NULL;
  
  	priv->regulator = devm_regulator_get(&priv->client->dev, "vin");
  	if (IS_ERR(priv->regulator))
  		priv->regulator = NULL;
  
  	ret = device_property_read_u32(&priv->client->dev, "ramp-up-us",
  				       &ramp_time);
  	if (ret)
  		dev_info(&priv->client->dev, "ramp-up-ms property missing
  ");
  	else
  		priv->runtime_ramp_up = lm3532_get_ramp_index(ramp_time);
  
  	ret = device_property_read_u32(&priv->client->dev, "ramp-down-us",
  				       &ramp_time);
  	if (ret)
  		dev_info(&priv->client->dev, "ramp-down-ms property missing
  ");
  	else
  		priv->runtime_ramp_down = lm3532_get_ramp_index(ramp_time);
  
  	device_for_each_child_node(priv->dev, child) {

  		struct led_init_data idata = {
  			.fwnode = child,
  			.default_label = ":",
  			.devicename = priv->client->name,
  		};

  		led = &priv->leds[i];
  
  		ret = fwnode_property_read_u32(child, "reg", &control_bank);
  		if (ret) {
  			dev_err(&priv->client->dev, "reg property missing
  ");
  			fwnode_handle_put(child);
  			goto child_out;
  		}
  
  		if (control_bank > LM3532_CONTROL_C) {
  			dev_err(&priv->client->dev, "Control bank invalid
  ");
  			continue;
  		}
  
  		led->control_bank = control_bank;
  
  		ret = fwnode_property_read_u32(child, "ti,led-mode",
  					       &led->mode);
  		if (ret) {
  			dev_err(&priv->client->dev, "ti,led-mode property missing
  ");
  			fwnode_handle_put(child);
  			goto child_out;
  		}

  		if (fwnode_property_present(child, "led-max-microamp") &&
  		    fwnode_property_read_u32(child, "led-max-microamp",
  					     &led->full_scale_current))
  			dev_err(&priv->client->dev,
  				"Failed getting led-max-microamp
  ");
  		else
  			led->full_scale_current = min(led->full_scale_current,
  						      LM3532_FS_CURR_MAX);

  		if (led->mode == LM3532_BL_MODE_ALS) {

  			led->mode = LM3532_ALS_CTRL;

  			ret = lm3532_parse_als(priv);
  			if (ret)
  				dev_err(&priv->client->dev, "Failed to parse als
  ");
  			else
  				lm3532_als_configure(priv, led);

  		} else {
  			led->mode = LM3532_I2C_CTRL;

  		}

  		led->num_leds = fwnode_property_count_u32(child, "led-sources");

  		if (led->num_leds > LM3532_MAX_LED_STRINGS) {

  			dev_err(&priv->client->dev, "Too many LED string defined
  ");

  			continue;
  		}
  
  		ret = fwnode_property_read_u32_array(child, "led-sources",
  						    led->led_strings,
  						    led->num_leds);
  		if (ret) {
  			dev_err(&priv->client->dev, "led-sources property missing
  ");
  			fwnode_handle_put(child);
  			goto child_out;
  		}

  		led->priv = priv;

  		led->led_dev.brightness_set_blocking = lm3532_brightness_set;

  		ret = devm_led_classdev_register_ext(priv->dev, &led->led_dev, &idata);

  		if (ret) {
  			dev_err(&priv->client->dev, "led register err: %d
  ",
  				ret);
  			fwnode_handle_put(child);
  			goto child_out;
  		}

  		ret = lm3532_init_registers(led);
  		if (ret) {
  			dev_err(&priv->client->dev, "register init err: %d
  ",
  				ret);
  			fwnode_handle_put(child);
  			goto child_out;
  		}

  
  		i++;
  	}
  
  child_out:
  	return ret;
  }
  
  static int lm3532_probe(struct i2c_client *client,
  			   const struct i2c_device_id *id)
  {
  	struct lm3532_data *drvdata;
  	int ret = 0;
  	int count;
  
  	count = device_get_child_node_count(&client->dev);
  	if (!count) {
  		dev_err(&client->dev, "LEDs are not defined in device tree!");
  		return -ENODEV;
  	}
  
  	drvdata = devm_kzalloc(&client->dev, struct_size(drvdata, leds, count),
  			   GFP_KERNEL);
  	if (drvdata == NULL)
  		return -ENOMEM;
  
  	drvdata->client = client;
  	drvdata->dev = &client->dev;
  
  	drvdata->regmap = devm_regmap_init_i2c(client, &lm3532_regmap_config);
  	if (IS_ERR(drvdata->regmap)) {
  		ret = PTR_ERR(drvdata->regmap);
  		dev_err(&client->dev, "Failed to allocate register map: %d
  ",
  			ret);
  		return ret;
  	}
  
  	mutex_init(&drvdata->lock);
  	i2c_set_clientdata(client, drvdata);
  
  	ret = lm3532_parse_node(drvdata);
  	if (ret) {
  		dev_err(&client->dev, "Failed to parse node
  ");
  		return ret;
  	}

  	return ret;
  }
  
  static int lm3532_remove(struct i2c_client *client)
  {
  	struct lm3532_data *drvdata = i2c_get_clientdata(client);
  
  	mutex_destroy(&drvdata->lock);
  
  	if (drvdata->enable_gpio)
  		gpiod_direction_output(drvdata->enable_gpio, 0);
  
  	return 0;
  }
  
  static const struct of_device_id of_lm3532_leds_match[] = {
  	{ .compatible = "ti,lm3532", },
  	{},
  };
  MODULE_DEVICE_TABLE(of, of_lm3532_leds_match);
  
  static const struct i2c_device_id lm3532_id[] = {
  	{LM3532_NAME, 0},
  	{}
  };
  MODULE_DEVICE_TABLE(i2c, lm3532_id);
  
  static struct i2c_driver lm3532_i2c_driver = {
  	.probe = lm3532_probe,
  	.remove = lm3532_remove,
  	.id_table = lm3532_id,
  	.driver = {
  		.name = LM3532_NAME,
  		.of_match_table = of_lm3532_leds_match,
  	},
  };
  module_i2c_driver(lm3532_i2c_driver);
  
  MODULE_DESCRIPTION("Back Light driver for LM3532");
  MODULE_LICENSE("GPL v2");
  MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");