Dear reviewers:
Didn't get any response about this backlight patch.
Is there any part need to be refined?
cy_huang <u0084500@xxxxxxxxx> 於 2020年12月17日 週四 下午11:01寫道：
>
> From: ChiYuan Huang <cy_huang@xxxxxxxxxxx>
>
> Adds support for Richtek RT4831 backlight.
>
> Signed-off-by: ChiYuan Huang <cy_huang@xxxxxxxxxxx>
> ---
> 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@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>
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