Re: [PATCH] ARM: dts: enable pwm backlight on exynos5250-snow

[Tomasz Figa <t.figa@samsung.com>]

On 08.05.2014 17:55, Andreas Färber wrote:
> Hi,
> 
> Am 07.05.2014 22:50, schrieb Tomasz Figa:
>> On 07.05.2014 22:47, Ajay kumar wrote:
>>> On Thu, May 8, 2014 at 2:04 AM, Tomasz Figa <tomasz.figa@gmail.com>
>>> wrote:
>>>> On 07.05.2014 14:56, Ajay Kumar wrote:
>>>>>
>>>>> Add PWM backlight node for exynos5250 and enable the same on exynos5250
>>>>> based snow board.
>>>>>
>>>>> Signed-off-by: Olof Johansson <olof@lixom.net>
>>>>> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
>>>>> ---
>>>>>    arch/arm/boot/dts/exynos5250-pinctrl.dtsi |    7 +++++++
>>>>>    arch/arm/boot/dts/exynos5250-snow.dts     |    5 +++++
>>>>>    arch/arm/boot/dts/exynos5250.dtsi         |   10 ++++++++++
>>>>>    3 files changed, 22 insertions(+)
>>>>>
>>>>> diff --git a/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
>>>>> b/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
>>>>> index 9a49e68..2a4680c 100644
>>>>> --- a/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
>>>>> +++ b/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
>>>>> @@ -351,6 +351,13 @@
>>>>>                          samsung,pin-drv = <0>;
>>>>>                  };
>>>>>
>>>>> +               backlight_pwm: backlight-pwm {
>>>>> +                       samsung,pins = "gpb2-0";
>>>>> +                       samsung,pin-function = <2>;
>>>>> +                       samsung,pin-pud = <0>;
>>>>> +                       samsung,pin-drv = <0>;
>>>>> +               };
>>>>
>>>>
>>>> This looks like a generic PWM output function, not specific to
>>>> backlight in
>>>> any way.
>>>>
>>>> Please see patch [1] adding PWM output pin groups for Exynos5420 for
>>>> reference.
>>>>
>>>> [1]
>>>> https://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg29869.html
>>>>
>>> Right! I just referred to the manual again, and it actually reads TOUT_0.
>>> So, I should be probably renaming this as "pwm0_out" like in the other
>>> patch?
>>
>> Yes, please. You should also add remaining ones, while at it. Basically
>> same patch as [1] but for Exynos5250.
> 
> Don't we also need patches to exynos_defconfig? linux.git only has
> CONFIG_S3C24XX_PWM=y but for snow I've seen github.com/linux-exynos add:
> CONFIG_PWM=y
> CONFIG_PWM_SAMSUNG=y
> CONFIG_BACKLIGHT_PWM=y

Right. The current exynos_defconfig lacks many other options as well.
But this should be fixed by separate patch. Feel free to send a patch to
enable what you need on your hardware.

Best regards,
Tomasz