Re: How to set fops in "struct platform_pwm_backlight_data"?

Mark Zhang
2013-10-23T08:49:42Z

On 10/23/2013 04:00 PM, Thierry Reding wrote:
> On Wed, Oct 23, 2013 at 10:16:24AM +0800, Mark Zhang wrote:
>> On 10/22/2013 08:49 PM, Thierry Reding wrote:
>>> On Tue, Oct 22, 2013 at 04:55:09PM +0800, Mark Zhang wrote:
>>>> On 10/22/2013 03:24 PM, Thierry Reding wrote:
>>>>> On Fri, Oct 18, 2013 at 12:48:12PM +0800, Mark Zhang wrote:
>>>> [...]
>>>>>>>
>>>>>>
>>>>>> Okay, I just want to set the "notify" function pointer in "struct
>>>>>> platform_pwm_backlight_data", because I want to tune the brightness
>>>>>> value before the pwm-bl sets the brightness to hardware. I don't know
>>>>>> how to do that, unless we define the platform data explicitly.
>>>>>
>>>>> Okay, my question should have been what you need the functions for and
>>>>> why you think you need them.
>>>>>
>>>>
>>>> If I understanding you correctly, I suppose I've said that: "because I
>>>> want to tune the brightness value before the pwm-bl sets the brightness
>>>> to hardware".
>>>
>>> Why do you want to tune the brightness value? What are you trying to
>>> achieve?
>>>
>>
>> Oh, Tegra has a feature named PRISM(aka SmartDimmer). It changes the
>> color value to make the display looks bright so that we can reduce the
>> backlight brightness to save power. So everytime PRISM is triggered, we
>> call "backlight_update_status", then in the "notify" callback, we change
>> the brightness value which pwm-bl provides by considering the PRISM
>> compensations.
>
> If you automatically call backlight_update_status() everytime PRISM
> gives you new data, can't you just pass the correct value in in the
> first place so that you don't have to tweak it in the .notify()
> callback?

OK, how to do that? -- "pass the correct value in in the first place"?

Mark
>
> Thierry
>