From: ChiYuan Huang cy_huang@richtek.com
Adds support for Richtek RT4831 backlight.
Signed-off-by: ChiYuan Huang cy_huang@richtek.com --- drivers/video/backlight/Kconfig | 8 ++ drivers/video/backlight/Makefile | 1 + drivers/video/backlight/rt4831-backlight.c | 219 +++++++++++++++++++++++++++++ 3 files changed, 228 insertions(+) create mode 100644 drivers/video/backlight/rt4831-backlight.c
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index d83c87b..666bdb0 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -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 commont 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 diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index 685f3f1..cae2c83 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -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 diff --git a/drivers/video/backlight/rt4831-backlight.c b/drivers/video/backlight/rt4831-backlight.c new file mode 100644 index 00000000..816c4d6 --- /dev/null +++ b/drivers/video/backlight/rt4831-backlight.c @@ -0,0 +1,219 @@ +// 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/mutex.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 BL_MAX_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 regmap *regmap; + struct mutex lock; + 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; + + mutex_lock(&priv->lock); + + 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) + goto unlock; + } + + ret = regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable); + +unlock: + mutex_unlock(&priv->lock); + return ret; +} + +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; + + mutex_lock(&priv->lock); + + ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val); + if (ret) + return ret; + + if (!(val & RT4831_BLEN_MASK)) { + ret = 0; + goto unlock; + } + + ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v)); + if (ret) + goto unlock; + + ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1; + +unlock: + mutex_unlock(&priv->lock); + 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_init_device_properties(struct rt4831_priv *priv, struct device *dev, + struct backlight_properties *bl_props) +{ + u8 propval; + u32 brightness; + unsigned int val = 0; + int ret; + + /* common properties */ + ret = device_property_read_u32(dev, "max-brightness", &brightness); + if (ret) { + dev_warn(dev, "max-brightness DT property missing, use HW max as default\n"); + brightness = BL_MAX_BRIGHTNESS; + } + + bl_props->max_brightness = min_t(u32, brightness, BL_MAX_BRIGHTNESS); + + ret = device_property_read_u32(dev, "default-brightness", &brightness); + if (ret) { + dev_warn(dev, "default-brightness DT property missing, use max limit as default\n"); + 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) { + dev_warn(dev, "richtek,bled-ovp-sel DT property missing, use default 21V\n"); + 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, }; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + mutex_init(&priv->lock); + + priv->regmap = dev_get_regmap(pdev->dev.parent, NULL); + if (IS_ERR(priv->regmap)) { + dev_err(&pdev->dev, "Failed to init regmap\n"); + return PTR_ERR(priv->regmap); + } + + ret = rt4831_init_device_properties(priv, &pdev->dev, &bl_props); + if (ret) { + dev_err(&pdev->dev, "Failed to init device 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");