backlight: rt4831: Adds support for Richtek RT4831 backlight (190ccab3) · Commits · EulixOS / Software / Kernel

drivers/video/backlight/Kconfig

+8 −0

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		@@ -289,6 +289,14 @@ config BACKLIGHT_QCOM_WLED
		If you have the Qualcomm PMIC, say Y to enable a driver for the
		WLED block. Currently it supports PM8941 and PMI8998.

		config BACKLIGHT_RT4831
		tristate "Richtek RT4831 Backlight Driver"
		depends on MFD_RT4831
		help
		This enables support for Richtek RT4831 Backlight driver.
		It's commonly used to drive the display WLED. There're four channels
		inisde, and each channel can provide up to 30mA current.

		config BACKLIGHT_SAHARA
		tristate "Tabletkiosk Sahara Touch-iT Backlight Driver"
		depends on X86

drivers/video/backlight/Makefile

+1 −0

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		@@ -49,6 +49,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA) += pandora_bl.o
		obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
		obj-$(CONFIG_BACKLIGHT_PWM) += pwm_bl.o
		obj-$(CONFIG_BACKLIGHT_QCOM_WLED) += qcom-wled.o
		obj-$(CONFIG_BACKLIGHT_RT4831) += rt4831-backlight.o
		obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o
		obj-$(CONFIG_BACKLIGHT_SKY81452) += sky81452-backlight.o
		obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o

drivers/video/backlight/rt4831-backlight.c

0 → 100644

+203 −0

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		// 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_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

		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;
		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;

		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 int 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);

		return 0;
		}

		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 = rt4831_bl_remove,
		};
		module_platform_driver(rt4831_bl_driver);

		MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
		MODULE_LICENSE("GPL v2");