From: ChiYuan Huang <[email protected]>
This patch series is to add the backlight ocp level property parsing.
Since v4
- Fix wrong macro usage, must be 'DIV_ROUND_UP', not 'roundup'
Since v3
- Refine the description for backlight ocp property.
- Use the enum to list the supported value.
Since v2
- change the property name from the register style 'richtek,bled-ocp-cel' to
'richtek,bled-ocp-microamp'.
- Use the clamp and roundup to get the ovp level selector.
ChiYuan Huang (2):
dt-bindings: backlight: rt4831: Add the new ocp level property
backlight: rt4831: Apply ocp level from devicetree
.../leds/backlight/richtek,rt4831-backlight.yaml | 5 ++++
drivers/video/backlight/rt4831-backlight.c | 33 +++++++++++++++++++++-
2 files changed, 37 insertions(+), 1 deletion(-)
--
2.7.4
From: ChiYuan Huang <[email protected]>
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 <[email protected]>
Signed-off-by: ChiYuan Huang <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
---
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");
--
2.7.4
From: ChiYuan Huang <[email protected]>
Add 'richtek,bled-ocp-microamp' property to make it chooseable.
The wrong backlight ocp level may affect the backlight channel output
current smaller than configured.
Signed-off-by: ChiYuan Huang <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Krzysztof Kozlowski <[email protected]>
---
Since v3:
- Refine the description for backlight ocp property.
- Use the enum to list the supported value.
Since v2:
- Change the property name from 'richtek,bled-ocp-sel' to 'richtek,bled-ocp-microamp'.
---
.../devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
index e0ac686..99e9e13 100644
--- a/Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
+++ b/Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
@@ -47,6 +47,11 @@ properties:
minimum: 0
maximum: 3
+ richtek,bled-ocp-microamp:
+ description: |
+ Backlight over current protection level.
+ enum: [900000, 1200000, 1500000, 1800000]
+
richtek,channel-use:
description: |
Backlight LED channel to be used.
--
2.7.4
On Tue, 21 Jun 2022, cy_huang wrote:
> From: ChiYuan Huang <[email protected]>
>
> Add 'richtek,bled-ocp-microamp' property to make it chooseable.
>
> The wrong backlight ocp level may affect the backlight channel output
> current smaller than configured.
>
> Signed-off-by: ChiYuan Huang <[email protected]>
> Reviewed-by: Daniel Thompson <[email protected]>
> Reviewed-by: Krzysztof Kozlowski <[email protected]>
> ---
> Since v3:
> - Refine the description for backlight ocp property.
> - Use the enum to list the supported value.
>
> Since v2:
> - Change the property name from 'richtek,bled-ocp-sel' to 'richtek,bled-ocp-microamp'.
>
> ---
> .../devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml | 5 +++++
> 1 file changed, 5 insertions(+)
Applied, thanks.
--
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog
On Tue, 21 Jun 2022, cy_huang wrote:
> From: ChiYuan Huang <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: ChiYuan Huang <[email protected]>
> Reviewed-by: Daniel Thompson <[email protected]>
> ---
> 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(-)
Applied, thanks.
--
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog