drivers/video/backlight/mt6370-backlight.c - third_party/linux - Git at Google


            
            // SPDX-License-Identifier: GPL-2.0-only

            
            /*

            
             * Copyright (C) 2022 Richtek Technology Corp.

            
             *

            
             * Author: ChiaEn Wu <chiaen_wu@richtek.com>

            
             */


            #include <linux/backlight.h>

            
            #include <linux/bitfield.h>

            
            #include <linux/bits.h>

            
            #include <linux/gpio/consumer.h>

            
            #include <linux/kernel.h>

            
            #include <linux/minmax.h>

            
            #include <linux/module.h>

            
            #include <linux/platform_device.h>

            
            #include <linux/property.h>

            
            #include <linux/regmap.h>


            #define MT6370_REG_DEV_INFO		0x100

            
            #define MT6370_REG_BL_EN		0x1A0

            
            #define MT6370_REG_BL_BSTCTRL		0x1A1

            
            #define MT6370_REG_BL_PWM		0x1A2

            
            #define MT6370_REG_BL_DIM2		0x1A4


            #define MT6370_VENID_MASK		GENMASK(7, 4)

            
            #define MT6370_BL_EXT_EN_MASK		BIT(7)

            
            #define MT6370_BL_EN_MASK		BIT(6)

            
            #define MT6370_BL_CODE_MASK		BIT(0)

            
            #define MT6370_BL_CH_MASK		GENMASK(5, 2)

            
            #define MT6370_BL_CH_SHIFT		2

            
            #define MT6370_BL_DIM2_COMMON_MASK	GENMASK(2, 0)

            
            #define MT6370_BL_DIM2_COMMON_SHIFT	3

            
            #define MT6370_BL_DIM2_6372_MASK	GENMASK(5, 0)

            
            #define MT6370_BL_DIM2_6372_SHIFT	6

            
            #define MT6370_BL_PWM_EN_MASK		BIT(7)

            
            #define MT6370_BL_PWM_HYS_EN_MASK	BIT(2)

            
            #define MT6370_BL_PWM_HYS_SEL_MASK	GENMASK(1, 0)

            
            #define MT6370_BL_OVP_EN_MASK		BIT(7)

            
            #define MT6370_BL_OVP_SEL_MASK		GENMASK(6, 5)

            
            #define MT6370_BL_OVP_SEL_SHIFT		5

            
            #define MT6370_BL_OC_EN_MASK		BIT(3)

            
            #define MT6370_BL_OC_SEL_MASK		GENMASK(2, 1)

            
            #define MT6370_BL_OC_SEL_SHIFT		1


            #define MT6370_BL_PWM_HYS_TH_MIN_STEP	1

            
            #define MT6370_BL_PWM_HYS_TH_MAX_STEP	64

            
            #define MT6370_BL_OVP_MIN_UV		17000000

            
            #define MT6370_BL_OVP_MAX_UV		29000000

            
            #define MT6370_BL_OVP_STEP_UV		4000000

            
            #define MT6370_BL_OCP_MIN_UA		900000

            
            #define MT6370_BL_OCP_MAX_UA		1800000

            
            #define MT6370_BL_OCP_STEP_UA		300000

            
            #define MT6370_BL_MAX_COMMON_BRIGHTNESS	2048

            
            #define MT6370_BL_MAX_6372_BRIGHTNESS	16384

            
            #define MT6370_BL_MAX_CH		15


            enum {

            
            	MT6370_VID_COMMON = 1,

            
            	MT6370_VID_6372,

            
            };


            struct mt6370_priv {

            
            	u8 dim2_mask;

            
            	u8 dim2_shift;

            
            	int def_max_brightness;

            
            	struct backlight_device *bl;

            
            	struct device *dev;

            
            	struct gpio_desc *enable_gpio;

            
            	struct regmap *regmap;

            
            };


            static int mt6370_bl_update_status(struct backlight_device *bl_dev)

            
            {

            
            	struct mt6370_priv *priv = bl_get_data(bl_dev);

            
            	int brightness = backlight_get_brightness(bl_dev);

            
            	unsigned int enable_val;

            
            	u8 brightness_val[2];

            
            	int ret;


            	if (brightness) {

            
            		brightness_val[0] = (brightness - 1) & priv->dim2_mask;

            
            		brightness_val[1] = (brightness - 1) >> priv->dim2_shift;


            		ret = regmap_raw_write(priv->regmap, MT6370_REG_BL_DIM2,

            
            				       brightness_val, sizeof(brightness_val));

            
            		if (ret)

            
            			return ret;

            
            	}


            	gpiod_set_value(priv->enable_gpio, !!brightness);


            	enable_val = brightness ? MT6370_BL_EN_MASK : 0;

            
            	return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN,

            
            				  MT6370_BL_EN_MASK, enable_val);

            
            }


            static int mt6370_bl_get_brightness(struct backlight_device *bl_dev)

            
            {

            
            	struct mt6370_priv *priv = bl_get_data(bl_dev);

            
            	unsigned int enable;

            
            	u8 brightness_val[2];

            
            	int brightness, ret;


            	ret = regmap_read(priv->regmap, MT6370_REG_BL_EN, &enable);

            
            	if (ret)

            
            		return ret;


            	if (!(enable & MT6370_BL_EN_MASK))

            
            		return 0;


            	ret = regmap_raw_read(priv->regmap, MT6370_REG_BL_DIM2,

            
            			      brightness_val, sizeof(brightness_val));

            
            	if (ret)

            
            		return ret;


            	brightness = brightness_val[1] << priv->dim2_shift;

            
            	brightness += brightness_val[0] & priv->dim2_mask;


            	return brightness + 1;

            
            }


            static const struct backlight_ops mt6370_bl_ops = {

            
            	.options = BL_CORE_SUSPENDRESUME,

            
            	.update_status = mt6370_bl_update_status,

            
            	.get_brightness = mt6370_bl_get_brightness,

            
            };


            static int mt6370_init_backlight_properties(struct mt6370_priv *priv,

            
            					    struct backlight_properties *props)

            
            {

            
            	struct device *dev = priv->dev;

            
            	u8 prop_val;

            
            	u32 brightness, ovp_uV, ocp_uA;

            
            	unsigned int mask, val;

            
            	int ret;


            	/* Vendor optional properties */

            
            	val = 0;

            
            	if (device_property_read_bool(dev, "mediatek,bled-pwm-enable"))

            
            		val |= MT6370_BL_PWM_EN_MASK;


            	if (device_property_read_bool(dev, "mediatek,bled-pwm-hys-enable"))

            
            		val |= MT6370_BL_PWM_HYS_EN_MASK;


            	ret = device_property_read_u8(dev,

            
            				      "mediatek,bled-pwm-hys-input-th-steps",

            
            				      &prop_val);

            
            	if (!ret) {

            
            		prop_val = clamp_val(prop_val,

            
            				     MT6370_BL_PWM_HYS_TH_MIN_STEP,

            
            				     MT6370_BL_PWM_HYS_TH_MAX_STEP);

            
            		prop_val = prop_val <= 1 ? 0 :

            
            			   prop_val <= 4 ? 1 :

            
            			   prop_val <= 16 ? 2 : 3;

            
            		val |= prop_val;

            
            	}


            	ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_PWM,

            
            				 val, val);

            
            	if (ret)

            
            		return ret;


            	val = 0;

            
            	if (device_property_read_bool(dev, "mediatek,bled-ovp-shutdown"))

            
            		val |= MT6370_BL_OVP_EN_MASK;


            	ret = device_property_read_u32(dev, "mediatek,bled-ovp-microvolt",

            
            				       &ovp_uV);

            
            	if (!ret) {

            
            		ovp_uV = clamp_val(ovp_uV, MT6370_BL_OVP_MIN_UV,

            
            				   MT6370_BL_OVP_MAX_UV);

            
            		ovp_uV = DIV_ROUND_UP(ovp_uV - MT6370_BL_OVP_MIN_UV,

            
            				      MT6370_BL_OVP_STEP_UV);

            
            		val |= ovp_uV << MT6370_BL_OVP_SEL_SHIFT;

            
            	}


            	if (device_property_read_bool(dev, "mediatek,bled-ocp-shutdown"))

            
            		val |= MT6370_BL_OC_EN_MASK;


            	ret = device_property_read_u32(dev, "mediatek,bled-ocp-microamp",

            
            				       &ocp_uA);

            
            	if (!ret) {

            
            		ocp_uA = clamp_val(ocp_uA, MT6370_BL_OCP_MIN_UA,

            
            				   MT6370_BL_OCP_MAX_UA);

            
            		ocp_uA = DIV_ROUND_UP(ocp_uA - MT6370_BL_OCP_MIN_UA,

            
            				      MT6370_BL_OCP_STEP_UA);

            
            		val |= ocp_uA << MT6370_BL_OC_SEL_SHIFT;

            
            	}


            	ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_BSTCTRL,

            
            				 val, val);

            
            	if (ret)

            
            		return ret;


            	/* Common properties */

            
            	ret = device_property_read_u32(dev, "max-brightness", &brightness);

            
            	if (ret)

            
            		brightness = priv->def_max_brightness;


            	props->max_brightness = min_t(u32, brightness, priv->def_max_brightness);


            	ret = device_property_read_u32(dev, "default-brightness", &brightness);

            
            	if (ret)

            
            		brightness = props->max_brightness;


            	props->brightness = min_t(u32, brightness, props->max_brightness);


            	val = 0;

            
            	if (device_property_read_bool(dev, "mediatek,bled-exponential-mode-enable")) {

            
            		val |= MT6370_BL_CODE_MASK;

            
            		props->scale = BACKLIGHT_SCALE_NON_LINEAR;

            
            	} else

            
            		props->scale = BACKLIGHT_SCALE_LINEAR;


            	ret = device_property_read_u8(dev, "mediatek,bled-channel-use",

            
            				      &prop_val);

            
            	if (ret) {

            
            		dev_err(dev, "mediatek,bled-channel-use DT property missing\n");

            
            		return ret;

            
            	}


            	if (!prop_val || prop_val > MT6370_BL_MAX_CH) {

            
            		dev_err(dev,

            
            			"No channel specified or over than upper bound (%d)\n",

            
            			prop_val);

            
            		return -EINVAL;

            
            	}


            	mask = MT6370_BL_EXT_EN_MASK | MT6370_BL_CH_MASK;

            
            	val |= prop_val << MT6370_BL_CH_SHIFT;


            	if (priv->enable_gpio)

            
            		val |= MT6370_BL_EXT_EN_MASK;


            	return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, mask, val);

            
            }


            static int mt6370_check_vendor_info(struct mt6370_priv *priv)

            
            {

            
            	/*

            
            	 * Because MT6372 uses 14 bits to control the brightness,

            
            	 * MT6370 and MT6371 use 11 bits. This function is used

            
            	 * to check the vendor's ID and set the relative hardware

            
            	 * mask, shift and default maximum brightness value that

            
            	 * should be used.

            
            	 */

            
            	unsigned int dev_info, hw_vid, of_vid;

            
            	int ret;


            	ret = regmap_read(priv->regmap, MT6370_REG_DEV_INFO, &dev_info);

            
            	if (ret)

            
            		return ret;


            	of_vid = (uintptr_t)device_get_match_data(priv->dev);

            
            	hw_vid = FIELD_GET(MT6370_VENID_MASK, dev_info);

            
            	hw_vid = (hw_vid == 0x9 || hw_vid == 0xb) ? MT6370_VID_6372 : MT6370_VID_COMMON;

            
            	if (hw_vid != of_vid)

            
            		return dev_err_probe(priv->dev, -EINVAL,

            
            				     "Buggy DT, wrong compatible string\n");


            	if (hw_vid == MT6370_VID_6372) {

            
            		priv->dim2_mask = MT6370_BL_DIM2_6372_MASK;

            
            		priv->dim2_shift = MT6370_BL_DIM2_6372_SHIFT;

            
            		priv->def_max_brightness = MT6370_BL_MAX_6372_BRIGHTNESS;

            
            	} else {

            
            		priv->dim2_mask = MT6370_BL_DIM2_COMMON_MASK;

            
            		priv->dim2_shift = MT6370_BL_DIM2_COMMON_SHIFT;

            
            		priv->def_max_brightness = MT6370_BL_MAX_COMMON_BRIGHTNESS;

            
            	}


            	return 0;

            
            }


            static int mt6370_bl_probe(struct platform_device *pdev)

            
            {

            
            	struct backlight_properties props = {

            
            		.type = BACKLIGHT_RAW,

            
            	};

            
            	struct device *dev = &pdev->dev;

            
            	struct mt6370_priv *priv;

            
            	int ret;


            	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);

            
            	if (!priv)

            
            		return -ENOMEM;


            	priv->dev = dev;


            	priv->regmap = dev_get_regmap(dev->parent, NULL);

            
            	if (!priv->regmap)

            
            		return dev_err_probe(dev, -ENODEV, "Failed to get regmap\n");


            	ret = mt6370_check_vendor_info(priv);

            
            	if (ret)

            
            		return dev_err_probe(dev, ret, "Failed to check vendor info\n");


            	priv->enable_gpio = devm_gpiod_get_optional(dev, "enable",

            
            						    GPIOD_OUT_HIGH);

            
            	if (IS_ERR(priv->enable_gpio))

            
            		return dev_err_probe(dev, PTR_ERR(priv->enable_gpio),

            
            				     "Failed to get 'enable' gpio\n");


            	ret = mt6370_init_backlight_properties(priv, &props);

            
            	if (ret)

            
            		return dev_err_probe(dev, ret,

            
            				     "Failed to init backlight properties\n");


            	priv->bl = devm_backlight_device_register(dev, pdev->name, dev, priv,

            
            						  &mt6370_bl_ops, &props);

            
            	if (IS_ERR(priv->bl))

            
            		return dev_err_probe(dev, PTR_ERR(priv->bl),

            
            				     "Failed to register backlight\n");


            	backlight_update_status(priv->bl);

            
            	platform_set_drvdata(pdev, priv);


            	return 0;

            
            }


            static void mt6370_bl_remove(struct platform_device *pdev)

            
            {

            
            	struct mt6370_priv *priv = platform_get_drvdata(pdev);

            
            	struct backlight_device *bl_dev = priv->bl;


            	bl_dev->props.brightness = 0;

            
            	backlight_update_status(priv->bl);

            
            }


            static const struct of_device_id mt6370_bl_of_match[] = {

            
            	{ .compatible = "mediatek,mt6370-backlight", .data = (void *)MT6370_VID_COMMON },

            
            	{ .compatible = "mediatek,mt6372-backlight", .data = (void *)MT6370_VID_6372 },

            
            	{}

            
            };

            
            MODULE_DEVICE_TABLE(of, mt6370_bl_of_match);


            static struct platform_driver mt6370_bl_driver = {

            
            	.driver = {

            
            		.name = "mt6370-backlight",

            
            		.of_match_table = mt6370_bl_of_match,

            
            	},

            
            	.probe = mt6370_bl_probe,

            
            	.remove = mt6370_bl_remove,

            
            };

            
            module_platform_driver(mt6370_bl_driver);


            MODULE_AUTHOR("ChiaEn Wu <chiaen_wu@richtek.com>");

            
            MODULE_DESCRIPTION("MediaTek MT6370 Backlight Driver");

            
            MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2022 Richtek Technology Corp.
	*
	* Author: ChiaEn Wu <chiaen_wu@richtek.com>
	*/

	#include <linux/backlight.h>
	#include <linux/bitfield.h>
	#include <linux/bits.h>
	#include <linux/gpio/consumer.h>
	#include <linux/kernel.h>
	#include <linux/minmax.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/property.h>
	#include <linux/regmap.h>

	#define MT6370_REG_DEV_INFO 0x100
	#define MT6370_REG_BL_EN 0x1A0
	#define MT6370_REG_BL_BSTCTRL 0x1A1
	#define MT6370_REG_BL_PWM 0x1A2
	#define MT6370_REG_BL_DIM2 0x1A4

	#define MT6370_VENID_MASK GENMASK(7, 4)
	#define MT6370_BL_EXT_EN_MASK BIT(7)
	#define MT6370_BL_EN_MASK BIT(6)
	#define MT6370_BL_CODE_MASK BIT(0)
	#define MT6370_BL_CH_MASK GENMASK(5, 2)
	#define MT6370_BL_CH_SHIFT 2
	#define MT6370_BL_DIM2_COMMON_MASK GENMASK(2, 0)
	#define MT6370_BL_DIM2_COMMON_SHIFT 3
	#define MT6370_BL_DIM2_6372_MASK GENMASK(5, 0)
	#define MT6370_BL_DIM2_6372_SHIFT 6
	#define MT6370_BL_PWM_EN_MASK BIT(7)
	#define MT6370_BL_PWM_HYS_EN_MASK BIT(2)
	#define MT6370_BL_PWM_HYS_SEL_MASK GENMASK(1, 0)
	#define MT6370_BL_OVP_EN_MASK BIT(7)
	#define MT6370_BL_OVP_SEL_MASK GENMASK(6, 5)
	#define MT6370_BL_OVP_SEL_SHIFT 5
	#define MT6370_BL_OC_EN_MASK BIT(3)
	#define MT6370_BL_OC_SEL_MASK GENMASK(2, 1)
	#define MT6370_BL_OC_SEL_SHIFT 1

	#define MT6370_BL_PWM_HYS_TH_MIN_STEP 1
	#define MT6370_BL_PWM_HYS_TH_MAX_STEP 64
	#define MT6370_BL_OVP_MIN_UV 17000000
	#define MT6370_BL_OVP_MAX_UV 29000000
	#define MT6370_BL_OVP_STEP_UV 4000000
	#define MT6370_BL_OCP_MIN_UA 900000
	#define MT6370_BL_OCP_MAX_UA 1800000
	#define MT6370_BL_OCP_STEP_UA 300000
	#define MT6370_BL_MAX_COMMON_BRIGHTNESS 2048
	#define MT6370_BL_MAX_6372_BRIGHTNESS 16384
	#define MT6370_BL_MAX_CH 15

	enum {
	MT6370_VID_COMMON = 1,
	MT6370_VID_6372,
	};

	struct mt6370_priv {
	u8 dim2_mask;
	u8 dim2_shift;
	int def_max_brightness;
	struct backlight_device *bl;
	struct device *dev;
	struct gpio_desc *enable_gpio;
	struct regmap *regmap;
	};

	static int mt6370_bl_update_status(struct backlight_device *bl_dev)
	{
	struct mt6370_priv *priv = bl_get_data(bl_dev);
	int brightness = backlight_get_brightness(bl_dev);
	unsigned int enable_val;
	u8 brightness_val[2];
	int ret;

	if (brightness) {
	brightness_val[0] = (brightness - 1) & priv->dim2_mask;
	brightness_val[1] = (brightness - 1) >> priv->dim2_shift;

	ret = regmap_raw_write(priv->regmap, MT6370_REG_BL_DIM2,
	brightness_val, sizeof(brightness_val));
	if (ret)
	return ret;
	}

	gpiod_set_value(priv->enable_gpio, !!brightness);

	enable_val = brightness ? MT6370_BL_EN_MASK : 0;
	return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN,
	MT6370_BL_EN_MASK, enable_val);
	}

	static int mt6370_bl_get_brightness(struct backlight_device *bl_dev)
	{
	struct mt6370_priv *priv = bl_get_data(bl_dev);
	unsigned int enable;
	u8 brightness_val[2];
	int brightness, ret;

	ret = regmap_read(priv->regmap, MT6370_REG_BL_EN, &enable);
	if (ret)
	return ret;

	if (!(enable & MT6370_BL_EN_MASK))
	return 0;

	ret = regmap_raw_read(priv->regmap, MT6370_REG_BL_DIM2,
	brightness_val, sizeof(brightness_val));
	if (ret)
	return ret;

	brightness = brightness_val[1] << priv->dim2_shift;
	brightness += brightness_val[0] & priv->dim2_mask;

	return brightness + 1;
	}

	static const struct backlight_ops mt6370_bl_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status = mt6370_bl_update_status,
	.get_brightness = mt6370_bl_get_brightness,
	};

	static int mt6370_init_backlight_properties(struct mt6370_priv *priv,
	struct backlight_properties *props)
	{
	struct device *dev = priv->dev;
	u8 prop_val;
	u32 brightness, ovp_uV, ocp_uA;
	unsigned int mask, val;
	int ret;

	/* Vendor optional properties */
	val = 0;
	if (device_property_read_bool(dev, "mediatek,bled-pwm-enable"))
	val \|= MT6370_BL_PWM_EN_MASK;

	if (device_property_read_bool(dev, "mediatek,bled-pwm-hys-enable"))
	val \|= MT6370_BL_PWM_HYS_EN_MASK;

	ret = device_property_read_u8(dev,
	"mediatek,bled-pwm-hys-input-th-steps",
	&prop_val);
	if (!ret) {
	prop_val = clamp_val(prop_val,
	MT6370_BL_PWM_HYS_TH_MIN_STEP,
	MT6370_BL_PWM_HYS_TH_MAX_STEP);
	prop_val = prop_val <= 1 ? 0 :
	prop_val <= 4 ? 1 :
	prop_val <= 16 ? 2 : 3;
	val \|= prop_val;
	}

	ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_PWM,
	val, val);
	if (ret)
	return ret;

	val = 0;
	if (device_property_read_bool(dev, "mediatek,bled-ovp-shutdown"))
	val \|= MT6370_BL_OVP_EN_MASK;

	ret = device_property_read_u32(dev, "mediatek,bled-ovp-microvolt",
	&ovp_uV);
	if (!ret) {
	ovp_uV = clamp_val(ovp_uV, MT6370_BL_OVP_MIN_UV,
	MT6370_BL_OVP_MAX_UV);
	ovp_uV = DIV_ROUND_UP(ovp_uV - MT6370_BL_OVP_MIN_UV,
	MT6370_BL_OVP_STEP_UV);
	val \|= ovp_uV << MT6370_BL_OVP_SEL_SHIFT;
	}

	if (device_property_read_bool(dev, "mediatek,bled-ocp-shutdown"))
	val \|= MT6370_BL_OC_EN_MASK;

	ret = device_property_read_u32(dev, "mediatek,bled-ocp-microamp",
	&ocp_uA);
	if (!ret) {
	ocp_uA = clamp_val(ocp_uA, MT6370_BL_OCP_MIN_UA,
	MT6370_BL_OCP_MAX_UA);
	ocp_uA = DIV_ROUND_UP(ocp_uA - MT6370_BL_OCP_MIN_UA,
	MT6370_BL_OCP_STEP_UA);
	val \|= ocp_uA << MT6370_BL_OC_SEL_SHIFT;
	}

	ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_BSTCTRL,
	val, val);
	if (ret)
	return ret;

	/* Common properties */
	ret = device_property_read_u32(dev, "max-brightness", &brightness);
	if (ret)
	brightness = priv->def_max_brightness;

	props->max_brightness = min_t(u32, brightness, priv->def_max_brightness);

	ret = device_property_read_u32(dev, "default-brightness", &brightness);
	if (ret)
	brightness = props->max_brightness;

	props->brightness = min_t(u32, brightness, props->max_brightness);

	val = 0;
	if (device_property_read_bool(dev, "mediatek,bled-exponential-mode-enable")) {
	val \|= MT6370_BL_CODE_MASK;
	props->scale = BACKLIGHT_SCALE_NON_LINEAR;
	} else
	props->scale = BACKLIGHT_SCALE_LINEAR;

	ret = device_property_read_u8(dev, "mediatek,bled-channel-use",
	&prop_val);
	if (ret) {
	dev_err(dev, "mediatek,bled-channel-use DT property missing\n");
	return ret;
	}

	if (!prop_val \|\| prop_val > MT6370_BL_MAX_CH) {
	dev_err(dev,
	"No channel specified or over than upper bound (%d)\n",
	prop_val);
	return -EINVAL;
	}

	mask = MT6370_BL_EXT_EN_MASK \| MT6370_BL_CH_MASK;
	val \|= prop_val << MT6370_BL_CH_SHIFT;

	if (priv->enable_gpio)
	val \|= MT6370_BL_EXT_EN_MASK;

	return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, mask, val);
	}

	static int mt6370_check_vendor_info(struct mt6370_priv *priv)
	{
	/*
	* Because MT6372 uses 14 bits to control the brightness,
	* MT6370 and MT6371 use 11 bits. This function is used
	* to check the vendor's ID and set the relative hardware
	* mask, shift and default maximum brightness value that
	* should be used.
	*/
	unsigned int dev_info, hw_vid, of_vid;
	int ret;

	ret = regmap_read(priv->regmap, MT6370_REG_DEV_INFO, &dev_info);
	if (ret)
	return ret;

	of_vid = (uintptr_t)device_get_match_data(priv->dev);
	hw_vid = FIELD_GET(MT6370_VENID_MASK, dev_info);
	hw_vid = (hw_vid == 0x9 \|\| hw_vid == 0xb) ? MT6370_VID_6372 : MT6370_VID_COMMON;
	if (hw_vid != of_vid)
	return dev_err_probe(priv->dev, -EINVAL,
	"Buggy DT, wrong compatible string\n");

	if (hw_vid == MT6370_VID_6372) {
	priv->dim2_mask = MT6370_BL_DIM2_6372_MASK;
	priv->dim2_shift = MT6370_BL_DIM2_6372_SHIFT;
	priv->def_max_brightness = MT6370_BL_MAX_6372_BRIGHTNESS;
	} else {
	priv->dim2_mask = MT6370_BL_DIM2_COMMON_MASK;
	priv->dim2_shift = MT6370_BL_DIM2_COMMON_SHIFT;
	priv->def_max_brightness = MT6370_BL_MAX_COMMON_BRIGHTNESS;
	}

	return 0;
	}

	static int mt6370_bl_probe(struct platform_device *pdev)
	{
	struct backlight_properties props = {
	.type = BACKLIGHT_RAW,
	};
	struct device *dev = &pdev->dev;
	struct mt6370_priv *priv;
	int ret;

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

	priv->dev = dev;

	priv->regmap = dev_get_regmap(dev->parent, NULL);
	if (!priv->regmap)
	return dev_err_probe(dev, -ENODEV, "Failed to get regmap\n");

	ret = mt6370_check_vendor_info(priv);
	if (ret)
	return dev_err_probe(dev, ret, "Failed to check vendor info\n");

	priv->enable_gpio = devm_gpiod_get_optional(dev, "enable",
	GPIOD_OUT_HIGH);
	if (IS_ERR(priv->enable_gpio))
	return dev_err_probe(dev, PTR_ERR(priv->enable_gpio),
	"Failed to get 'enable' gpio\n");

	ret = mt6370_init_backlight_properties(priv, &props);
	if (ret)
	return dev_err_probe(dev, ret,
	"Failed to init backlight properties\n");

	priv->bl = devm_backlight_device_register(dev, pdev->name, dev, priv,
	&mt6370_bl_ops, &props);
	if (IS_ERR(priv->bl))
	return dev_err_probe(dev, PTR_ERR(priv->bl),
	"Failed to register backlight\n");

	backlight_update_status(priv->bl);
	platform_set_drvdata(pdev, priv);

	return 0;
	}

	static void mt6370_bl_remove(struct platform_device *pdev)
	{
	struct mt6370_priv *priv = platform_get_drvdata(pdev);
	struct backlight_device *bl_dev = priv->bl;

	bl_dev->props.brightness = 0;
	backlight_update_status(priv->bl);
	}

	static const struct of_device_id mt6370_bl_of_match[] = {
	{ .compatible = "mediatek,mt6370-backlight", .data = (void *)MT6370_VID_COMMON },
	{ .compatible = "mediatek,mt6372-backlight", .data = (void *)MT6370_VID_6372 },
	{}
	};
	MODULE_DEVICE_TABLE(of, mt6370_bl_of_match);

	static struct platform_driver mt6370_bl_driver = {
	.driver = {
	.name = "mt6370-backlight",
	.of_match_table = mt6370_bl_of_match,
	},
	.probe = mt6370_bl_probe,
	.remove = mt6370_bl_remove,
	};
	module_platform_driver(mt6370_bl_driver);

	MODULE_AUTHOR("ChiaEn Wu <chiaen_wu@richtek.com>");
	MODULE_DESCRIPTION("MediaTek MT6370 Backlight Driver");
	MODULE_LICENSE("GPL v2");