[PATCH v5 5/6] backlight: rt4831: Adds support for Richtek RT4831 backlight

ChiYuan Huang u0084500 at gmail.com
Thu Mar 25 08:22:11 UTC 2021


Dear reviewers:

           Didn't get any response about this backlight patch.
Is there any part need to be refined?

cy_huang <u0084500 at gmail.com> 於 2020年12月17日 週四 下午11:01寫道:
>
> From: ChiYuan Huang <cy_huang at richtek.com>
>
> Adds support for Richtek RT4831 backlight.
>
> Signed-off-by: ChiYuan Huang <cy_huang at 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 at richtek.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>


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