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Date:   Mon, 26 Apr 2021 11:19:55 +0100
From:   Daniel Thompson <daniel.thompson@linaro.org>
To:     cy_huang <u0084500@gmail.com>
Cc:     lee.jones@linaro.org, lgirdwood@gmail.com, broonie@kernel.org,
        jingoohan1@gmail.com, b.zolnierkie@samsung.com, pavel@ucw.cz,
        robh+dt@kernel.org, dri-devel@lists.freedesktop.org,
        linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-leds@vger.kernel.org, devicetree@vger.kernel.org,
        cy_huang@richtek.com
Subject: Re: [RESEND PATCH v6 4/4] backlight: rt4831: Adds support for
 Richtek RT4831 backlight
Message-ID: <20210426101955.uvuzzsiig27xyuxc@maple.lan>
References: <1619421491-31494-1-git-send-email-u0084500@gmail.com>
 <1619421491-31494-4-git-send-email-u0084500@gmail.com>
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On Mon, Apr 26, 2021 at 03:18:11PM +0800, cy_huang wrote:
> From: ChiYuan Huang <cy_huang@richtek.com>
> 
> Adds support for Richtek RT4831 backlight.
> 
> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
> Resend this v6 patch series to loop devicetree reviewers.
> 
> For next, if the typo in Kconfig 'common' to 'commonly' can be added the below line
> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---

This isn't the best way to handle feedback from multiple maintainers.

It is great to see you are keeping track of feedback. However it doesn't
make sense to RESEND an old patchset and acknowledge that you haven't
fixed a typo yet.

It would be better to fix the typo and to resend a v7.


Daniel.


>  drivers/video/backlight/Kconfig            |   8 ++
>  drivers/video/backlight/Makefile           |   1 +
>  drivers/video/backlight/rt4831-backlight.c | 203 +++++++++++++++++++++++++++++
>  3 files changed, 212 insertions(+)
>  create mode 100644 drivers/video/backlight/rt4831-backlight.c
> 
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index d83c87b..de96441 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 common 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..42155c7
> --- /dev/null
> +++ b/drivers/video/backlight/rt4831-backlight.c
> @@ -0,0 +1,203 @@
> +// 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");
> -- 
> 2.7.4
>