Commit 8b0bce05 authored by ChiYuan Huang's avatar ChiYuan Huang Committed by Lee Jones
Browse files

backlight: rt4831: Apply ocp level from devicetree 



Add 'richtek,bled-ocp-microamp' property parsing in
device_property_init function.

This value may configure prior to the kernel driver. If it's not specified in
devicetree, keep the original setting. Else, use clamp to align the
value in min/max range and also roundup to choose the best selector.

Reported-by: default avatarLucas Tsai <lucas_tsai@richtek.com>
Signed-off-by: default avatarChiYuan Huang <cy_huang@richtek.com>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/1655807788-24511-3-git-send-email-u0084500@gmail.com
parent 27e5c654

drivers/video/backlight/rt4831-backlight.c

+32 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#define RT4831_REG_BLCFG	0x02

#define RT4831_REG_BLDIML	0x04

#define RT4831_REG_ENABLE	0x08

#define RT4831_REG_BLOPT2	0x11



#define RT4831_BLMAX_BRIGHTNESS	2048
@@ -23,6 +24,11 @@ 
#define RT4831_BLDIML_MASK	GENMASK(2, 0)

#define RT4831_BLDIMH_MASK	GENMASK(10, 3)

#define RT4831_BLDIMH_SHIFT	3

#define RT4831_BLOCP_MASK	GENMASK(1, 0)



#define RT4831_BLOCP_MINUA	900000

#define RT4831_BLOCP_MAXUA	1800000

#define RT4831_BLOCP_STEPUA	300000



struct rt4831_priv {

	struct device *dev;
@@ -85,7 +91,7 @@ static int rt4831_parse_backlight_properties(struct rt4831_priv *priv, 
{

	struct device *dev = priv->dev;

	u8 propval;

	u32 brightness;

	u32 brightness, ocp_uA;

	unsigned int val = 0;

	int ret;
@@ -120,6 +126,31 @@ static int rt4831_parse_backlight_properties(struct rt4831_priv *priv, 
	if (ret)

		return ret;



	/*

	 * This OCP level is used to protect and limit the inductor current.

	 * If inductor peak current reach the level, low-side MOSFET will be

	 * turned off. Meanwhile, the output channel current may be limited.

	 * To match the configured channel current, the inductor chosen must

	 * be higher than the OCP level.

	 *

	 * Not like the OVP level, the default 21V can be used in the most

	 * application. But if the chosen OCP level is smaller than needed,

	 * it will also affect the backlight channel output current to be

	 * smaller than the register setting.

	 */

	ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",

				       &ocp_uA);

	if (!ret) {

		ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,

				   RT4831_BLOCP_MAXUA);

		val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,

				   RT4831_BLOCP_STEPUA);

		ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,

					 RT4831_BLOCP_MASK, val);

		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");