Re: [PATCH] backlight: pm8941-wled: Add default-brightness property
From: Bjorn Andersson <hidden>
Date: 2015-07-29 23:51:46
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linux-arm-msm, linux-fbdev, lkml
On Fri 24 Jul 08:29 PDT 2015, Rob Herring wrote:
On Thu, Jul 23, 2015 at 2:52 PM, Bjorn Andersson [off-list ref] wrote:quoted
Add the possibility of specifying the default brightness in DT. Signed-off-by: Bjorn Andersson <redacted> --- This depends on the patch moving pm8941-wled to backlight [1]. The dt property is used by several other backlight drivers, so I considered this to be a "common" property and it's hence not prefixed with "qcom,".Well, we have "default-brightness" and "default-brightness-level" used by 1 driver each. But default-brightness-level is much more commonly used (in dts files) since it is in the pwm backlight binding, so we should go with it. I'd like to see this moved to a common backlight doc.
As I looked at these, the default-brightness used in tps65217 is a value between 0 and 100, so that can be interpreted as a percentage. The pwm binding however uses a separate array of "brightness-levels" and then default-brightness-level is supposed to be an index into that array. As we're trying to specify a default brightness within the range [0, max_brightness) the latter doesn't make much sense. Therefor my suggestion is that we make the "default-brightness" the common property and we define it as a percentage of [0,max_brightness).
Really, I think all the backlight documentation should be merged with LEDs docs. Things like "default-on" are common. But I won't ask to do that here.
I think the backlight framework should be merged with the LED framework. There's several hw blocks that are split between the two, with an mfd tying them together... Regards, Bjorn