From: ChiYuan Huang cy_huang@richtek.com
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: Lucas Tsai lucas_tsai@richtek.com Signed-off-by: ChiYuan Huang cy_huang@richtek.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org --- Hi, Daniel:
I may use the wrong macro, must be 'DIV_ROUND_UP', not 'roundup'. the v4 is to fix it.
Since v4 - Fix wrong macro usage, must be 'DIV_ROUND_UP', not 'roundup'
Since v2: - Prase the 'richtek,bled-ocp-microamp', clamp the value in min/max range, and roundup to get the best selector.
--- drivers/video/backlight/rt4831-backlight.c | 33 +++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/drivers/video/backlight/rt4831-backlight.c b/drivers/video/backlight/rt4831-backlight.c index 42155c7..eb8c59e 100644 --- a/drivers/video/backlight/rt4831-backlight.c +++ b/drivers/video/backlight/rt4831-backlight.c @@ -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");