[PATCH v4 4/4] leds: lm3532: Introduce the lm3532 LED driver

[Dan Murphy <dmurphy@ti.com>]

Introduce the Texas Instruments LM3532 White LED driver.
The driver supports ALS configurability or manual brightness
control.

The driver also supports associating LED strings with specific
control banks in a group or as individually controlled strings.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
---

v4 - Updated code to DT doc changes appending "ti," to TI specific properties -
https://lore.kernel.org/patchwork/patch/1050124/

v3 - Removed switch case for register setting in favor of an algorithim (v1 comment),
https://lore.kernel.org/patchwork/patch/1049024/
v2 - Added look up tables for als_avg, als_imp and ramp times, fixed brightness
control when ALS is in control, added property value checks to ensure the values
are not out of bounds - https://lore.kernel.org/patchwork/patch/1048807/

 drivers/leds/Kconfig       |  10 +
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-lm3532.c | 681 +++++++++++++++++++++++++++++++++++++
 3 files changed, 692 insertions(+)
 create mode 100644 drivers/leds/leds-lm3532.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a72f97fca57b..da00b9ed5a5c 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -138,6 +138,16 @@ config LEDS_LM3530
 	  controlled manually or using PWM input or using ambient
 	  light automatically.
 
+config LEDS_LM3532
+	tristate "LCD Backlight driver for LM3532"
+	depends on LEDS_CLASS
+	depends on I2C
+	help
+	  This option enables support for the LCD backlight using
+	  LM3532 ambient light sensor chip. This ALS chip can be
+	  controlled manually or using PWM input or using ambient
+	  light automatically.
+
 config LEDS_LM3533
 	tristate "LED support for LM3533"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 4c1b0054f379..7a8b1f55d459 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_LEDS_BD2802)		+= leds-bd2802.o
 obj-$(CONFIG_LEDS_CPCAP)		+= leds-cpcap.o
 obj-$(CONFIG_LEDS_LOCOMO)		+= leds-locomo.o
 obj-$(CONFIG_LEDS_LM3530)		+= leds-lm3530.o
+obj-$(CONFIG_LEDS_LM3532)		+= leds-lm3532.o
 obj-$(CONFIG_LEDS_LM3533)		+= leds-lm3533.o
 obj-$(CONFIG_LEDS_LM3642)		+= leds-lm3642.o
 obj-$(CONFIG_LEDS_MIKROTIK_RB532)	+= leds-rb532.o
diff --git a/drivers/leds/leds-lm3532.c b/drivers/leds/leds-lm3532.c
new file mode 100644
index 000000000000..e8a614d71469
--- /dev/null
+++ b/drivers/leds/leds-lm3532.c
@@ -0,0 +1,681 @@
+// SPDX-License-Identifier: GPL-2.0
+// TI LM3532 LED driver
+// Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+
+#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_BRT	0x17
+#define LM3532_REG_ZONE_CFG_B	0x18
+#define LM3532_REG_CTRL_B_BRT	0x19
+#define LM3532_REG_ZONE_CFG_C	0x1a
+#define LM3532_REG_CTRL_C_BRT	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_MAX		0x7e
+
+/* Contorl 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
+
+/*
+ * 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
+ * @num_leds - Number of LED strings are supported in this array
+ * @led_strings - The LED strings supported in this array
+ * @label - LED label
+ */
+struct lm3532_led {
+	struct led_classdev led_dev;
+	struct lm3532_data *priv;
+
+	int control_bank;
+	int mode;
+	int num_leds;
+	u32 led_strings[LM3532_MAX_CONTROL_BANKS];
+	char label[LED_MAX_NAME_SIZE];
+};
+
+/**
+ * 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_BRT, 0xf3},
+	{LM3532_REG_ZONE_CFG_B, 0xf1},
+	{LM3532_REG_CTRL_B_BRT, 0xf3},
+	{LM3532_REG_ZONE_CFG_C, 0xf1},
+	{LM3532_REG_CTRL_C_BRT, 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,
+};
+
+const static 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;
+}
+
+const static 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);
+}
+
+const static 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);
+}
+
+static int lm3532_led_enable(struct lm3532_led *led_data)
+{
+	int ctrl_en_val = BIT(led_data->control_bank);
+	int ret;
+
+	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\n", ret);
+		return ret;
+	}
+
+	return regulator_enable(led_data->priv->regulator);
+}
+
+static int lm3532_led_disable(struct lm3532_led *led_data)
+{
+	int ctrl_en_val = BIT(led_data->control_bank);
+	int ret;
+
+	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\n", ret);
+		return ret;
+	}
+
+	return regulator_disable(led_data->priv->regulator);
+}
+
+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_BL_MODE_ALS) {
+		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_CTRL_A_BRT + led->control_bank * 2;
+	brt_val = brt_val / LM3532_BRT_VAL_ADJUST;
+
+	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;
+	int ret, i;
+
+	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 brightnes_config_reg;
+	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));
+
+	ret = regmap_write(priv->regmap, LM3532_ALS_CONFIG, als->config);
+	if (ret)
+		return ret;
+
+	brightnes_config_reg = LM3532_REG_ZONE_CFG_A + led->control_bank * 2;
+
+	return regmap_update_bits(priv->regmap, brightnes_config_reg,
+				  LM3532_I2C_CTRL, LM3532_ALS_CTRL);
+}
+
+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;
+	const char *name;
+	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\n");
+	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\n");
+	else
+		priv->runtime_ramp_down = lm3532_get_ramp_index(ramp_time);
+
+	device_for_each_child_node(priv->dev, child) {
+		led = &priv->leds[i];
+
+		ret = fwnode_property_read_u32(child, "reg", &control_bank);
+		if (ret) {
+			dev_err(&priv->client->dev, "reg property missing\n");
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		if (control_bank > LM3532_CONTROL_C) {
+			dev_err(&priv->client->dev, "Control bank invalid\n");
+			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\n");
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		if (led->mode == LM3532_BL_MODE_ALS) {
+			ret = lm3532_parse_als(priv);
+			if (ret)
+				dev_err(&priv->client->dev, "Failed to parse als\n");
+			else
+				lm3532_als_configure(priv, led);
+		}
+
+		led->num_leds = fwnode_property_read_u32_array(child,
+							       "led-sources",
+							       NULL, 0);
+
+		if (led->num_leds > LM3532_MAX_LED_STRINGS) {
+			dev_err(&priv->client->dev, "To many LED string defined\n");
+			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\n");
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		fwnode_property_read_string(child, "linux,default-trigger",
+					    &led->led_dev.default_trigger);
+
+		ret = fwnode_property_read_string(child, "label", &name);
+		if (ret)
+			snprintf(led->label, sizeof(led->label),
+				"%s::", priv->client->name);
+		else
+			snprintf(led->label, sizeof(led->label),
+				 "%s:%s", priv->client->name, name);
+
+		led->priv = priv;
+		led->led_dev.name = led->label;
+		led->led_dev.brightness_set_blocking = lm3532_brightness_set;
+
+		ret = devm_led_classdev_register(priv->dev, &led->led_dev);
+		if (ret) {
+			dev_err(&priv->client->dev, "led register err: %d\n",
+				ret);
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		lm3532_init_registers(led);
+
+		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\n",
+			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\n");
+		return ret;
+	}
+
+	if (drvdata->enable_gpio)
+		gpiod_direction_output(drvdata->enable_gpio, 1);
+
+	return ret;
+}
+
+static int lm3532_remove(struct i2c_client *client)
+{
+	struct lm3532_data *drvdata = i2c_get_clientdata(client);
+
+	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>");
-- 
2.20.1.390.gb5101f9297