[PATCH v2] backlight: pm8941-wled: Add default-brightness property
From: Bjorn Andersson
Date: Mon Aug 10 2015 - 16:14:05 EST
Default the brightness to 2048 and add possibility to override this in
device tree.
Suggested-by: Rob Clark <robdclark@xxxxxxxxx>
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
---
After going back and forth on this one I decided that the best unit of this
property (which could become a common backlight property) would be to use
"units of brightness". The value will either come from the boot loader picking
a value in some way or from a user finding a good value by tweaking sysfs -
both which will be in "units of brightness".
Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt | 2 ++
drivers/video/backlight/pm8941-wled.c | 8 ++++++++
2 files changed, 10 insertions(+)
diff --git a/Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt b/Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt
index 424f8444a6cd..e5b294dafc58 100644
--- a/Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt
+++ b/Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt
@@ -5,6 +5,8 @@ Required properties:
- reg: slave address
Optional properties:
+- default-brightness: brightness value on boot, value from: 0-4095
+ default: 2048
- label: The name of the backlight device
- qcom,cs-out: bool; enable current sink output
- qcom,cabc: bool; enable content adaptive backlight control
diff --git a/drivers/video/backlight/pm8941-wled.c b/drivers/video/backlight/pm8941-wled.c
index c704c3236034..e1298147bcbb 100644
--- a/drivers/video/backlight/pm8941-wled.c
+++ b/drivers/video/backlight/pm8941-wled.c
@@ -17,6 +17,9 @@
#include <linux/of_device.h>
#include <linux/regmap.h>
+/* From DT binding */
+#define PM8941_WLED_DEFAULT_BRIGHTNESS 2048
+
#define PM8941_WLED_REG_VAL_BASE 0x40
#define PM8941_WLED_REG_VAL_MAX 0xFFF
@@ -373,6 +376,7 @@ static int pm8941_wled_probe(struct platform_device *pdev)
struct backlight_device *bl;
struct pm8941_wled *wled;
struct regmap *regmap;
+ u32 val;
int rc;
regmap = dev_get_regmap(pdev->dev.parent, NULL);
@@ -395,8 +399,12 @@ static int pm8941_wled_probe(struct platform_device *pdev)
if (rc)
return rc;
+ val = PM8941_WLED_DEFAULT_BRIGHTNESS;
+ of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
+
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
+ props.brightness = val;
props.max_brightness = PM8941_WLED_REG_VAL_MAX;
bl = devm_backlight_device_register(&pdev->dev, wled->name,
&pdev->dev, wled,
--
1.8.2.2
--
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