drivers/leds/leds-sc27xx-bltc.c - linux/kernel/git/viro/vfs - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 // Copyright (C) 2018 Spreadtrum Communications Inc.

 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <uapi/linux/uleds.h>

 /* PMIC global control register definition */
 #define SC27XX_MODULE_EN0	0xc08
 #define SC27XX_CLK_EN0		0xc18
 #define SC27XX_RGB_CTRL		0xebc

 #define SC27XX_BLTC_EN		BIT(9)
 #define SC27XX_RTC_EN		BIT(7)
 #define SC27XX_RGB_PD		BIT(0)

 /* Breathing light controller register definition */
 #define SC27XX_LEDS_CTRL	0x00
 #define SC27XX_LEDS_PRESCALE	0x04
 #define SC27XX_LEDS_DUTY	0x08
 #define SC27XX_LEDS_CURVE0	0x0c
 #define SC27XX_LEDS_CURVE1	0x10

 #define SC27XX_CTRL_SHIFT	4
 #define SC27XX_LED_RUN		BIT(0)
 #define SC27XX_LED_TYPE		BIT(1)

 #define SC27XX_DUTY_SHIFT	8
 #define SC27XX_DUTY_MASK	GENMASK(15, 0)
 #define SC27XX_MOD_MASK		GENMASK(7, 0)

 #define SC27XX_CURVE_SHIFT	8
 #define SC27XX_CURVE_L_MASK	GENMASK(7, 0)
 #define SC27XX_CURVE_H_MASK	GENMASK(15, 8)

 #define SC27XX_LEDS_OFFSET	0x10
 #define SC27XX_LEDS_MAX		3
 #define SC27XX_LEDS_PATTERN_CNT	4
 /* Stage duration step, in milliseconds */
 #define SC27XX_LEDS_STEP	125
 /* Minimum and maximum duration, in milliseconds */
 #define SC27XX_DELTA_T_MIN	SC27XX_LEDS_STEP
 #define SC27XX_DELTA_T_MAX	(SC27XX_LEDS_STEP * 255)

 struct sc27xx_led {
 	char name[LED_MAX_NAME_SIZE];
 	struct led_classdev ldev;
 	struct sc27xx_led_priv *priv;
 	u8 line;
 	bool active;
 };

 struct sc27xx_led_priv {
 	struct sc27xx_led leds[SC27XX_LEDS_MAX];
 	struct regmap *regmap;
 	struct mutex lock;
 	u32 base;
 };

 #define to_sc27xx_led(ldev) \
 	container_of(ldev, struct sc27xx_led, ldev)

 static int sc27xx_led_init(struct regmap *regmap)
 {
 	int err;

 	err = regmap_update_bits(regmap, SC27XX_MODULE_EN0, SC27XX_BLTC_EN,
 				 SC27XX_BLTC_EN);
 	if (err)
 		return err;

 	err = regmap_update_bits(regmap, SC27XX_CLK_EN0, SC27XX_RTC_EN,
 				 SC27XX_RTC_EN);
 	if (err)
 		return err;

 	return regmap_update_bits(regmap, SC27XX_RGB_CTRL, SC27XX_RGB_PD, 0);
 }

 static u32 sc27xx_led_get_offset(struct sc27xx_led *leds)
 {
 	return leds->priv->base + SC27XX_LEDS_OFFSET * leds->line;
 }

 static int sc27xx_led_enable(struct sc27xx_led *leds, enum led_brightness value)
 {
 	u32 base = sc27xx_led_get_offset(leds);
 	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
 	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
 	struct regmap *regmap = leds->priv->regmap;
 	int err;

 	err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
 				 SC27XX_DUTY_MASK,
 				 (value << SC27XX_DUTY_SHIFT) |
 				 SC27XX_MOD_MASK);
 	if (err)
 		return err;

 	return regmap_update_bits(regmap, ctrl_base,
 			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift,
 			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift);
 }

 static int sc27xx_led_disable(struct sc27xx_led *leds)
 {
 	struct regmap *regmap = leds->priv->regmap;
 	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
 	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;

 	return regmap_update_bits(regmap, ctrl_base,
 			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);
 }

 static int sc27xx_led_set(struct led_classdev *ldev, enum led_brightness value)
 {
 	struct sc27xx_led *leds = to_sc27xx_led(ldev);
 	int err;

 	mutex_lock(&leds->priv->lock);

 	if (value == LED_OFF)
 		err = sc27xx_led_disable(leds);
 	else
 		err = sc27xx_led_enable(leds, value);

 	mutex_unlock(&leds->priv->lock);

 	return err;
 }

 static void sc27xx_led_clamp_align_delta_t(u32 *delta_t)
 {
 	u32 v, offset, t = *delta_t;

 	v = t + SC27XX_LEDS_STEP / 2;
 	v = clamp_t(u32, v, SC27XX_DELTA_T_MIN, SC27XX_DELTA_T_MAX);
 	offset = v - SC27XX_DELTA_T_MIN;
 	offset = SC27XX_LEDS_STEP * (offset / SC27XX_LEDS_STEP);

 	*delta_t = SC27XX_DELTA_T_MIN + offset;
 }

 static int sc27xx_led_pattern_clear(struct led_classdev *ldev)
 {
 	struct sc27xx_led *leds = to_sc27xx_led(ldev);
 	struct regmap *regmap = leds->priv->regmap;
 	u32 base = sc27xx_led_get_offset(leds);
 	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
 	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
 	int err;

 	mutex_lock(&leds->priv->lock);

 	/* Reset the rise, high, fall and low time to zero. */
 	regmap_write(regmap, base + SC27XX_LEDS_CURVE0, 0);
 	regmap_write(regmap, base + SC27XX_LEDS_CURVE1, 0);

 	err = regmap_update_bits(regmap, ctrl_base,
 			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);

 	ldev->brightness = LED_OFF;

 	mutex_unlock(&leds->priv->lock);

 	return err;
 }

 static int sc27xx_led_pattern_set(struct led_classdev *ldev,
 				  struct led_pattern *pattern,
 				  u32 len, int repeat)
 {
 	struct sc27xx_led *leds = to_sc27xx_led(ldev);
 	u32 base = sc27xx_led_get_offset(leds);
 	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
 	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
 	struct regmap *regmap = leds->priv->regmap;
 	int err;

 	/*
 	 * Must contain 4 tuples to configure the rise time, high time, fall
 	 * time and low time to enable the breathing mode.
 	 */
 	if (len != SC27XX_LEDS_PATTERN_CNT)
 		return -EINVAL;

 	mutex_lock(&leds->priv->lock);

 	sc27xx_led_clamp_align_delta_t(&pattern[0].delta_t);
 	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
 				 SC27XX_CURVE_L_MASK,
 				 pattern[0].delta_t / SC27XX_LEDS_STEP);
 	if (err)
 		goto out;

 	sc27xx_led_clamp_align_delta_t(&pattern[1].delta_t);
 	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
 				 SC27XX_CURVE_L_MASK,
 				 pattern[1].delta_t / SC27XX_LEDS_STEP);
 	if (err)
 		goto out;

 	sc27xx_led_clamp_align_delta_t(&pattern[2].delta_t);
 	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
 				 SC27XX_CURVE_H_MASK,
 				 (pattern[2].delta_t / SC27XX_LEDS_STEP) <<
 				 SC27XX_CURVE_SHIFT);
 	if (err)
 		goto out;

 	sc27xx_led_clamp_align_delta_t(&pattern[3].delta_t);
 	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
 				 SC27XX_CURVE_H_MASK,
 				 (pattern[3].delta_t / SC27XX_LEDS_STEP) <<
 				 SC27XX_CURVE_SHIFT);
 	if (err)
 		goto out;

 	err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
 				 SC27XX_DUTY_MASK,
 				 (pattern[1].brightness << SC27XX_DUTY_SHIFT) |
 				 SC27XX_MOD_MASK);
 	if (err)
 		goto out;

 	/* Enable the LED breathing mode */
 	err = regmap_update_bits(regmap, ctrl_base,
 				 SC27XX_LED_RUN << ctrl_shift,
 				 SC27XX_LED_RUN << ctrl_shift);
 	if (!err)
 		ldev->brightness = pattern[1].brightness;

 out:
 	mutex_unlock(&leds->priv->lock);

 	return err;
 }

 static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
 {
 	int i, err;

 	err = sc27xx_led_init(priv->regmap);
 	if (err)
 		return err;

 	for (i = 0; i < SC27XX_LEDS_MAX; i++) {
 		struct sc27xx_led *led = &priv->leds[i];

 		if (!led->active)
 			continue;

 		led->line = i;
 		led->priv = priv;
 		led->ldev.name = led->name;
 		led->ldev.brightness_set_blocking = sc27xx_led_set;
 		led->ldev.pattern_set = sc27xx_led_pattern_set;
 		led->ldev.pattern_clear = sc27xx_led_pattern_clear;
 		led->ldev.default_trigger = "pattern";

 		err = devm_led_classdev_register(dev, &led->ldev);
 		if (err)
 			return err;
 	}

 	return 0;
 }

 static int sc27xx_led_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node, *child;
 	struct sc27xx_led_priv *priv;
 	const char *str;
 	u32 base, count, reg;
 	int err;

 	count = of_get_child_count(np);
 	if (!count || count > SC27XX_LEDS_MAX)
 		return -EINVAL;

 	err = of_property_read_u32(np, "reg", &base);
 	if (err) {
 		dev_err(dev, "fail to get reg of property\n");
 		return err;
 	}

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

 	platform_set_drvdata(pdev, priv);
 	mutex_init(&priv->lock);
 	priv->base = base;
 	priv->regmap = dev_get_regmap(dev->parent, NULL);
 	if (!priv->regmap) {
 		err = -ENODEV;
 		dev_err(dev, "failed to get regmap: %d\n", err);
 		return err;
 	}

 	for_each_child_of_node(np, child) {
 		err = of_property_read_u32(child, "reg", &reg);
 		if (err) {
 			of_node_put(child);
 			mutex_destroy(&priv->lock);
 			return err;
 		}

 		if (reg >= SC27XX_LEDS_MAX || priv->leds[reg].active) {
 			of_node_put(child);
 			mutex_destroy(&priv->lock);
 			return -EINVAL;
 		}

 		priv->leds[reg].active = true;

 		err = of_property_read_string(child, "label", &str);
 		if (err)
 			snprintf(priv->leds[reg].name, LED_MAX_NAME_SIZE,
 				 "sc27xx::");
 		else
 			snprintf(priv->leds[reg].name, LED_MAX_NAME_SIZE,
 				 "sc27xx:%s", str);
 	}

 	err = sc27xx_led_register(dev, priv);
 	if (err)
 		mutex_destroy(&priv->lock);

 	return err;
 }

 static int sc27xx_led_remove(struct platform_device *pdev)
 {
 	struct sc27xx_led_priv *priv = platform_get_drvdata(pdev);

 	mutex_destroy(&priv->lock);
 	return 0;
 }

 static const struct of_device_id sc27xx_led_of_match[] = {
 	{ .compatible = "sprd,sc2731-bltc", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, sc27xx_led_of_match);

 static struct platform_driver sc27xx_led_driver = {
 	.driver = {
 		.name = "sprd-bltc",
 		.of_match_table = sc27xx_led_of_match,
 	},
 	.probe = sc27xx_led_probe,
 	.remove = sc27xx_led_remove,
 };

 module_platform_driver(sc27xx_led_driver);

 MODULE_DESCRIPTION("Spreadtrum SC27xx breathing light controller driver");
 MODULE_AUTHOR("Xiaotong Lu <xiaotong.lu@spreadtrum.com>");
 MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	// Copyright (C) 2018 Spreadtrum Communications Inc.

	#include <linux/leds.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <uapi/linux/uleds.h>

	/* PMIC global control register definition */
	#define SC27XX_MODULE_EN0 0xc08
	#define SC27XX_CLK_EN0 0xc18
	#define SC27XX_RGB_CTRL 0xebc

	#define SC27XX_BLTC_EN BIT(9)
	#define SC27XX_RTC_EN BIT(7)
	#define SC27XX_RGB_PD BIT(0)

	/* Breathing light controller register definition */
	#define SC27XX_LEDS_CTRL 0x00
	#define SC27XX_LEDS_PRESCALE 0x04
	#define SC27XX_LEDS_DUTY 0x08
	#define SC27XX_LEDS_CURVE0 0x0c
	#define SC27XX_LEDS_CURVE1 0x10

	#define SC27XX_CTRL_SHIFT 4
	#define SC27XX_LED_RUN BIT(0)
	#define SC27XX_LED_TYPE BIT(1)

	#define SC27XX_DUTY_SHIFT 8
	#define SC27XX_DUTY_MASK GENMASK(15, 0)
	#define SC27XX_MOD_MASK GENMASK(7, 0)

	#define SC27XX_CURVE_SHIFT 8
	#define SC27XX_CURVE_L_MASK GENMASK(7, 0)
	#define SC27XX_CURVE_H_MASK GENMASK(15, 8)

	#define SC27XX_LEDS_OFFSET 0x10
	#define SC27XX_LEDS_MAX 3
	#define SC27XX_LEDS_PATTERN_CNT 4
	/* Stage duration step, in milliseconds */
	#define SC27XX_LEDS_STEP 125
	/* Minimum and maximum duration, in milliseconds */
	#define SC27XX_DELTA_T_MIN SC27XX_LEDS_STEP
	#define SC27XX_DELTA_T_MAX (SC27XX_LEDS_STEP * 255)

	struct sc27xx_led {
	char name[LED_MAX_NAME_SIZE];
	struct led_classdev ldev;
	struct sc27xx_led_priv *priv;
	u8 line;
	bool active;
	};

	struct sc27xx_led_priv {
	struct sc27xx_led leds[SC27XX_LEDS_MAX];
	struct regmap *regmap;
	struct mutex lock;
	u32 base;
	};

	#define to_sc27xx_led(ldev) \
	container_of(ldev, struct sc27xx_led, ldev)

	static int sc27xx_led_init(struct regmap *regmap)
	{
	int err;

	err = regmap_update_bits(regmap, SC27XX_MODULE_EN0, SC27XX_BLTC_EN,
	SC27XX_BLTC_EN);
	if (err)
	return err;

	err = regmap_update_bits(regmap, SC27XX_CLK_EN0, SC27XX_RTC_EN,
	SC27XX_RTC_EN);
	if (err)
	return err;

	return regmap_update_bits(regmap, SC27XX_RGB_CTRL, SC27XX_RGB_PD, 0);
	}

	static u32 sc27xx_led_get_offset(struct sc27xx_led *leds)
	{
	return leds->priv->base + SC27XX_LEDS_OFFSET * leds->line;
	}

	static int sc27xx_led_enable(struct sc27xx_led *leds, enum led_brightness value)
	{
	u32 base = sc27xx_led_get_offset(leds);
	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
	struct regmap *regmap = leds->priv->regmap;
	int err;

	err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
	SC27XX_DUTY_MASK,
	(value << SC27XX_DUTY_SHIFT) \|
	SC27XX_MOD_MASK);
	if (err)
	return err;

	return regmap_update_bits(regmap, ctrl_base,
	(SC27XX_LED_RUN \| SC27XX_LED_TYPE) << ctrl_shift,
	(SC27XX_LED_RUN \| SC27XX_LED_TYPE) << ctrl_shift);
	}

	static int sc27xx_led_disable(struct sc27xx_led *leds)
	{
	struct regmap *regmap = leds->priv->regmap;
	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;

	return regmap_update_bits(regmap, ctrl_base,
	(SC27XX_LED_RUN \| SC27XX_LED_TYPE) << ctrl_shift, 0);
	}

	static int sc27xx_led_set(struct led_classdev *ldev, enum led_brightness value)
	{
	struct sc27xx_led *leds = to_sc27xx_led(ldev);
	int err;

	mutex_lock(&leds->priv->lock);

	if (value == LED_OFF)
	err = sc27xx_led_disable(leds);
	else
	err = sc27xx_led_enable(leds, value);

	mutex_unlock(&leds->priv->lock);

	return err;
	}

	static void sc27xx_led_clamp_align_delta_t(u32 *delta_t)
	{
	u32 v, offset, t = *delta_t;

	v = t + SC27XX_LEDS_STEP / 2;
	v = clamp_t(u32, v, SC27XX_DELTA_T_MIN, SC27XX_DELTA_T_MAX);
	offset = v - SC27XX_DELTA_T_MIN;
	offset = SC27XX_LEDS_STEP * (offset / SC27XX_LEDS_STEP);

	*delta_t = SC27XX_DELTA_T_MIN + offset;
	}

	static int sc27xx_led_pattern_clear(struct led_classdev *ldev)
	{
	struct sc27xx_led *leds = to_sc27xx_led(ldev);
	struct regmap *regmap = leds->priv->regmap;
	u32 base = sc27xx_led_get_offset(leds);
	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
	int err;

	mutex_lock(&leds->priv->lock);

	/* Reset the rise, high, fall and low time to zero. */
	regmap_write(regmap, base + SC27XX_LEDS_CURVE0, 0);
	regmap_write(regmap, base + SC27XX_LEDS_CURVE1, 0);

	err = regmap_update_bits(regmap, ctrl_base,
	(SC27XX_LED_RUN \| SC27XX_LED_TYPE) << ctrl_shift, 0);

	ldev->brightness = LED_OFF;

	mutex_unlock(&leds->priv->lock);

	return err;
	}

	static int sc27xx_led_pattern_set(struct led_classdev *ldev,
	struct led_pattern *pattern,
	u32 len, int repeat)
	{
	struct sc27xx_led *leds = to_sc27xx_led(ldev);
	u32 base = sc27xx_led_get_offset(leds);
	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
	struct regmap *regmap = leds->priv->regmap;
	int err;

	/*
	* Must contain 4 tuples to configure the rise time, high time, fall
	* time and low time to enable the breathing mode.
	*/
	if (len != SC27XX_LEDS_PATTERN_CNT)
	return -EINVAL;

	mutex_lock(&leds->priv->lock);

	sc27xx_led_clamp_align_delta_t(&pattern[0].delta_t);
	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
	SC27XX_CURVE_L_MASK,
	pattern[0].delta_t / SC27XX_LEDS_STEP);
	if (err)
	goto out;

	sc27xx_led_clamp_align_delta_t(&pattern[1].delta_t);
	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
	SC27XX_CURVE_L_MASK,
	pattern[1].delta_t / SC27XX_LEDS_STEP);
	if (err)
	goto out;

	sc27xx_led_clamp_align_delta_t(&pattern[2].delta_t);
	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
	SC27XX_CURVE_H_MASK,
	(pattern[2].delta_t / SC27XX_LEDS_STEP) <<
	SC27XX_CURVE_SHIFT);
	if (err)
	goto out;

	sc27xx_led_clamp_align_delta_t(&pattern[3].delta_t);
	err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
	SC27XX_CURVE_H_MASK,
	(pattern[3].delta_t / SC27XX_LEDS_STEP) <<
	SC27XX_CURVE_SHIFT);
	if (err)
	goto out;

	err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
	SC27XX_DUTY_MASK,
	(pattern[1].brightness << SC27XX_DUTY_SHIFT) \|
	SC27XX_MOD_MASK);
	if (err)
	goto out;

	/* Enable the LED breathing mode */
	err = regmap_update_bits(regmap, ctrl_base,
	SC27XX_LED_RUN << ctrl_shift,
	SC27XX_LED_RUN << ctrl_shift);
	if (!err)
	ldev->brightness = pattern[1].brightness;

	out:
	mutex_unlock(&leds->priv->lock);

	return err;
	}

	static int sc27xx_led_register(struct device dev, struct sc27xx_led_priv priv)
	{
	int i, err;

	err = sc27xx_led_init(priv->regmap);
	if (err)
	return err;

	for (i = 0; i < SC27XX_LEDS_MAX; i++) {
	struct sc27xx_led *led = &priv->leds[i];

	if (!led->active)
	continue;

	led->line = i;
	led->priv = priv;
	led->ldev.name = led->name;
	led->ldev.brightness_set_blocking = sc27xx_led_set;
	led->ldev.pattern_set = sc27xx_led_pattern_set;
	led->ldev.pattern_clear = sc27xx_led_pattern_clear;
	led->ldev.default_trigger = "pattern";

	err = devm_led_classdev_register(dev, &led->ldev);
	if (err)
	return err;
	}

	return 0;
	}

	static int sc27xx_led_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct device_node np = dev->of_node, child;
	struct sc27xx_led_priv *priv;
	const char *str;
	u32 base, count, reg;
	int err;

	count = of_get_child_count(np);
	if (!count \|\| count > SC27XX_LEDS_MAX)
	return -EINVAL;

	err = of_property_read_u32(np, "reg", &base);
	if (err) {
	dev_err(dev, "fail to get reg of property\n");
	return err;
	}

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

	platform_set_drvdata(pdev, priv);
	mutex_init(&priv->lock);
	priv->base = base;
	priv->regmap = dev_get_regmap(dev->parent, NULL);
	if (!priv->regmap) {
	err = -ENODEV;
	dev_err(dev, "failed to get regmap: %d\n", err);
	return err;
	}

	for_each_child_of_node(np, child) {
	err = of_property_read_u32(child, "reg", &reg);
	if (err) {
	of_node_put(child);
	mutex_destroy(&priv->lock);
	return err;
	}

	if (reg >= SC27XX_LEDS_MAX \|\| priv->leds[reg].active) {
	of_node_put(child);
	mutex_destroy(&priv->lock);
	return -EINVAL;
	}

	priv->leds[reg].active = true;

	err = of_property_read_string(child, "label", &str);
	if (err)
	snprintf(priv->leds[reg].name, LED_MAX_NAME_SIZE,
	"sc27xx::");
	else
	snprintf(priv->leds[reg].name, LED_MAX_NAME_SIZE,
	"sc27xx:%s", str);
	}

	err = sc27xx_led_register(dev, priv);
	if (err)
	mutex_destroy(&priv->lock);

	return err;
	}

	static int sc27xx_led_remove(struct platform_device *pdev)
	{
	struct sc27xx_led_priv *priv = platform_get_drvdata(pdev);

	mutex_destroy(&priv->lock);
	return 0;
	}

	static const struct of_device_id sc27xx_led_of_match[] = {
	{ .compatible = "sprd,sc2731-bltc", },
	{ }
	};
	MODULE_DEVICE_TABLE(of, sc27xx_led_of_match);

	static struct platform_driver sc27xx_led_driver = {
	.driver = {
	.name = "sprd-bltc",
	.of_match_table = sc27xx_led_of_match,
	},
	.probe = sc27xx_led_probe,
	.remove = sc27xx_led_remove,
	};

	module_platform_driver(sc27xx_led_driver);

	MODULE_DESCRIPTION("Spreadtrum SC27xx breathing light controller driver");
	MODULE_AUTHOR("Xiaotong Lu <xiaotong.lu@spreadtrum.com>");
	MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>");
	MODULE_LICENSE("GPL v2");