drivers/video/backlight/rt4831-backlight.c - linux - Git at Google

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

 #include <dt-bindings/leds/rt4831-backlight.h>
 #include <linux/backlight.h>
 #include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/regmap.h>

 #define RT4831_REG_BLCFG	0x02
 #define RT4831_REG_BLDIML	0x04
 #define RT4831_REG_ENABLE	0x08
 #define RT4831_REG_BLOPT2	0x11

 #define RT4831_BLMAX_BRIGHTNESS	2048

 #define RT4831_BLOVP_MASK	GENMASK(7, 5)
 #define RT4831_BLOVP_SHIFT	5
 #define RT4831_BLPWMEN_MASK	BIT(0)
 #define RT4831_BLEN_MASK	BIT(4)
 #define RT4831_BLCH_MASK	GENMASK(3, 0)
 #define RT4831_BLDIML_MASK	GENMASK(2, 0)
 #define RT4831_BLDIMH_MASK	GENMASK(10, 3)
 #define RT4831_BLDIMH_SHIFT	3
 #define RT4831_BLOCP_MASK	GENMASK(1, 0)

 #define RT4831_BLOCP_MINUA	900000
 #define RT4831_BLOCP_MAXUA	1800000
 #define RT4831_BLOCP_STEPUA	300000

 struct rt4831_priv {
 	struct device *dev;
 	struct regmap *regmap;
 	struct backlight_device *bl;
 };

 static int rt4831_bl_update_status(struct backlight_device *bl_dev)
 {
 	struct rt4831_priv *priv = bl_get_data(bl_dev);
 	int brightness = backlight_get_brightness(bl_dev);
 	unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
 	u8 v[2];
 	int ret;

 	if (brightness) {
 		v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
 		v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;

 		ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
 		if (ret)
 			return ret;
 	}

 	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);

 }

 static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
 {
 	struct rt4831_priv *priv = bl_get_data(bl_dev);
 	unsigned int val;
 	u8 v[2];
 	int ret;

 	ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
 	if (ret)
 		return ret;

 	if (!(val & RT4831_BLEN_MASK))
 		return 0;

 	ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
 	if (ret)
 		return ret;

 	ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;

 	return ret;
 }

 static const struct backlight_ops rt4831_bl_ops = {
 	.options = BL_CORE_SUSPENDRESUME,
 	.update_status = rt4831_bl_update_status,
 	.get_brightness = rt4831_bl_get_brightness,
 };

 static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
 					     struct backlight_properties *bl_props)
 {
 	struct device *dev = priv->dev;
 	u8 propval;
 	u32 brightness, ocp_uA;
 	unsigned int val = 0;
 	int ret;

 	/* common properties */
 	ret = device_property_read_u32(dev, "max-brightness", &brightness);
 	if (ret)
 		brightness = RT4831_BLMAX_BRIGHTNESS;

 	bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);

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

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

 	/* vendor properties */
 	if (device_property_read_bool(dev, "richtek,pwm-enable"))
 		val = RT4831_BLPWMEN_MASK;

 	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
 	if (ret)
 		return ret;

 	ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
 	if (ret)
 		propval = RT4831_BLOVPLVL_21V;

 	propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
 	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
 				 propval << RT4831_BLOVP_SHIFT);
 	if (ret)
 		return ret;

 	/*
 	 * This OCP level is used to protect and limit the inductor current.
 	 * If inductor peak current reach the level, low-side MOSFET will be
 	 * turned off. Meanwhile, the output channel current may be limited.
 	 * To match the configured channel current, the inductor chosen must
 	 * be higher than the OCP level.
 	 *
 	 * Not like the OVP level, the default 21V can be used in the most
 	 * application. But if the chosen OCP level is smaller than needed,
 	 * it will also affect the backlight channel output current to be
 	 * smaller than the register setting.
 	 */
 	ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",
 				       &ocp_uA);
 	if (!ret) {
 		ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,
 				   RT4831_BLOCP_MAXUA);
 		val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,
 				   RT4831_BLOCP_STEPUA);
 		ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,
 					 RT4831_BLOCP_MASK, val);
 		if (ret)
 			return ret;
 	}

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

 	if (!(propval & RT4831_BLCH_MASK)) {
 		dev_err(dev, "No channel specified\n");
 		return -EINVAL;
 	}

 	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
 }

 static int rt4831_bl_probe(struct platform_device *pdev)
 {
 	struct rt4831_priv *priv;
 	struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
 						 .scale = BACKLIGHT_SCALE_LINEAR };
 	int ret;

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

 	priv->dev = &pdev->dev;

 	priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 	if (!priv->regmap) {
 		dev_err(&pdev->dev, "Failed to init regmap\n");
 		return -ENODEV;
 	}

 	ret = rt4831_parse_backlight_properties(priv, &bl_props);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to parse backlight properties\n");
 		return ret;
 	}

 	priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
 						  &rt4831_bl_ops, &bl_props);
 	if (IS_ERR(priv->bl)) {
 		dev_err(&pdev->dev, "Failed to register backlight\n");
 		return PTR_ERR(priv->bl);
 	}

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

 	return 0;
 }

 static void rt4831_bl_remove(struct platform_device *pdev)
 {
 	struct rt4831_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 __maybe_unused rt4831_bl_of_match[] = {
 	{ .compatible = "richtek,rt4831-backlight", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);

 static struct platform_driver rt4831_bl_driver = {
 	.driver = {
 		.name = "rt4831-backlight",
 		.of_match_table = rt4831_bl_of_match,
 	},
 	.probe = rt4831_bl_probe,
 	.remove_new = rt4831_bl_remove,
 };
 module_platform_driver(rt4831_bl_driver);

 MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
 MODULE_DESCRIPTION("Richtek RT4831 Backlight Driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only

	#include <dt-bindings/leds/rt4831-backlight.h>
	#include <linux/backlight.h>
	#include <linux/bitops.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/property.h>
	#include <linux/regmap.h>

	#define RT4831_REG_BLCFG 0x02
	#define RT4831_REG_BLDIML 0x04
	#define RT4831_REG_ENABLE 0x08
	#define RT4831_REG_BLOPT2 0x11

	#define RT4831_BLMAX_BRIGHTNESS 2048

	#define RT4831_BLOVP_MASK GENMASK(7, 5)
	#define RT4831_BLOVP_SHIFT 5
	#define RT4831_BLPWMEN_MASK BIT(0)
	#define RT4831_BLEN_MASK BIT(4)
	#define RT4831_BLCH_MASK GENMASK(3, 0)
	#define RT4831_BLDIML_MASK GENMASK(2, 0)
	#define RT4831_BLDIMH_MASK GENMASK(10, 3)
	#define RT4831_BLDIMH_SHIFT 3
	#define RT4831_BLOCP_MASK GENMASK(1, 0)

	#define RT4831_BLOCP_MINUA 900000
	#define RT4831_BLOCP_MAXUA 1800000
	#define RT4831_BLOCP_STEPUA 300000

	struct rt4831_priv {
	struct device *dev;
	struct regmap *regmap;
	struct backlight_device *bl;
	};

	static int rt4831_bl_update_status(struct backlight_device *bl_dev)
	{
	struct rt4831_priv *priv = bl_get_data(bl_dev);
	int brightness = backlight_get_brightness(bl_dev);
	unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
	u8 v[2];
	int ret;

	if (brightness) {
	v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
	v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;

	ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
	if (ret)
	return ret;
	}

	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);

	}

	static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
	{
	struct rt4831_priv *priv = bl_get_data(bl_dev);
	unsigned int val;
	u8 v[2];
	int ret;

	ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
	if (ret)
	return ret;

	if (!(val & RT4831_BLEN_MASK))
	return 0;

	ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
	if (ret)
	return ret;

	ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;

	return ret;
	}

	static const struct backlight_ops rt4831_bl_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status = rt4831_bl_update_status,
	.get_brightness = rt4831_bl_get_brightness,
	};

	static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
	struct backlight_properties *bl_props)
	{
	struct device *dev = priv->dev;
	u8 propval;
	u32 brightness, ocp_uA;
	unsigned int val = 0;
	int ret;

	/* common properties */
	ret = device_property_read_u32(dev, "max-brightness", &brightness);
	if (ret)
	brightness = RT4831_BLMAX_BRIGHTNESS;

	bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);

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

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

	/* vendor properties */
	if (device_property_read_bool(dev, "richtek,pwm-enable"))
	val = RT4831_BLPWMEN_MASK;

	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
	if (ret)
	return ret;

	ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
	if (ret)
	propval = RT4831_BLOVPLVL_21V;

	propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
	propval << RT4831_BLOVP_SHIFT);
	if (ret)
	return ret;

	/*
	* This OCP level is used to protect and limit the inductor current.
	* If inductor peak current reach the level, low-side MOSFET will be
	* turned off. Meanwhile, the output channel current may be limited.
	* To match the configured channel current, the inductor chosen must
	* be higher than the OCP level.
	*
	* Not like the OVP level, the default 21V can be used in the most
	* application. But if the chosen OCP level is smaller than needed,
	* it will also affect the backlight channel output current to be
	* smaller than the register setting.
	*/
	ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",
	&ocp_uA);
	if (!ret) {
	ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,
	RT4831_BLOCP_MAXUA);
	val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,
	RT4831_BLOCP_STEPUA);
	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,
	RT4831_BLOCP_MASK, val);
	if (ret)
	return ret;
	}

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

	if (!(propval & RT4831_BLCH_MASK)) {
	dev_err(dev, "No channel specified\n");
	return -EINVAL;
	}

	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
	}

	static int rt4831_bl_probe(struct platform_device *pdev)
	{
	struct rt4831_priv *priv;
	struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
	.scale = BACKLIGHT_SCALE_LINEAR };
	int ret;

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

	priv->dev = &pdev->dev;

	priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!priv->regmap) {
	dev_err(&pdev->dev, "Failed to init regmap\n");
	return -ENODEV;
	}

	ret = rt4831_parse_backlight_properties(priv, &bl_props);
	if (ret) {
	dev_err(&pdev->dev, "Failed to parse backlight properties\n");
	return ret;
	}

	priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
	&rt4831_bl_ops, &bl_props);
	if (IS_ERR(priv->bl)) {
	dev_err(&pdev->dev, "Failed to register backlight\n");
	return PTR_ERR(priv->bl);
	}

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

	return 0;
	}

	static void rt4831_bl_remove(struct platform_device *pdev)
	{
	struct rt4831_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 __maybe_unused rt4831_bl_of_match[] = {
	{ .compatible = "richtek,rt4831-backlight", },
	{}
	};
	MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);

	static struct platform_driver rt4831_bl_driver = {
	.driver = {
	.name = "rt4831-backlight",
	.of_match_table = rt4831_bl_of_match,
	},
	.probe = rt4831_bl_probe,
	.remove_new = rt4831_bl_remove,
	};
	module_platform_driver(rt4831_bl_driver);

	MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
	MODULE_DESCRIPTION("Richtek RT4831 Backlight Driver");
	MODULE_LICENSE("GPL v2");