[PATCH v2 1/3] devicetree/bindings: add reset-gpios and vcc-supply for panel-dpi

[PATCH v2 1/3] devicetree/bindings: add reset-gpios and vcc-supply for panel-dpi

[Uwe Kleine-König]

Some displays have a reset input and/or need a regulator to function
properly. Allow to specify them for panel-dpi devices.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 Documentation/devicetree/bindings/display/panel/panel-dpi.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
index 216c894d4f99..b52ac52757df 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
+++ b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
@@ -7,6 +7,8 @@ Required properties:
 Optional properties:
 - label: a symbolic name for the panel
 - enable-gpios: panel enable gpio
+- reset-gpios: GPIO to control the RESET pin
+- vcc-supply: phandle of regulator that will be used to enable power to the display
 
 Required nodes:
 - "panel-timing" containing video timings
-- 
2.6.2

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Re: [PATCH v2 1/3] devicetree/bindings: add reset-gpios and vcc-supply for panel-dpi

[Rob Herring]

On Sun, Dec 20, 2015 at 12:13:20PM +0100, Uwe Kleine-König wrote:
> Some displays have a reset input and/or need a regulator to function
> properly. Allow to specify them for panel-dpi devices.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  Documentation/devicetree/bindings/display/panel/panel-dpi.txt | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
> index 216c894d4f99..b52ac52757df 100644
> --- a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
> +++ b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
> @@ -7,6 +7,8 @@ Required properties:
>  Optional properties:
>  - label: a symbolic name for the panel
>  - enable-gpios: panel enable gpio
> +- reset-gpios: GPIO to control the RESET pin

The problem with this in a generic binding is what if the panel has 
ordering requirements like enable gpio has to be inactive when reset 
is deasserted?

> +- vcc-supply: phandle of regulator that will be used to enable power to the display

What if there are 2 supplies?

While there are limits to what can be described here, I'm okay with 
allowing these, so:

Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Rob
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Re: [PATCH v2 1/3] devicetree/bindings: add reset-gpios and vcc-supply for panel-dpi

[Geert Uytterhoeven]

On Tue, Dec 29, 2015 at 9:54 PM, Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> On Sun, Dec 20, 2015 at 12:13:20PM +0100, Uwe Kleine-König wrote:
>> Some displays have a reset input and/or need a regulator to function
>> properly. Allow to specify them for panel-dpi devices.
>>
>> Signed-off-by: Uwe Kleine-König <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
>> ---
>>  Documentation/devicetree/bindings/display/panel/panel-dpi.txt | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>> index 216c894d4f99..b52ac52757df 100644
>> --- a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>> +++ b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>> @@ -7,6 +7,8 @@ Required properties:
>>  Optional properties:
>>  - label: a symbolic name for the panel
>>  - enable-gpios: panel enable gpio
>> +- reset-gpios: GPIO to control the RESET pin
>
> The problem with this in a generic binding is what if the panel has
> ordering requirements like enable gpio has to be inactive when reset
> is deasserted?
>
>> +- vcc-supply: phandle of regulator that will be used to enable power to the display
>
> What if there are 2 supplies?

So it should be "vcc-supplies". Most properties containing phandles use plural
naming, even if Linux supports a single phandle only (e.g. "power-domains").
You also may want to add an optional "vcc-supply-names" property to
differentiate.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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Re: [PATCH v2 1/3] devicetree/bindings: add reset-gpios and vcc-supply for panel-dpi

[Rob Herring]

On Wed, Dec 30, 2015 at 4:29 AM, Geert Uytterhoeven
<geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org> wrote:
> On Tue, Dec 29, 2015 at 9:54 PM, Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>> On Sun, Dec 20, 2015 at 12:13:20PM +0100, Uwe Kleine-König wrote:
>>> Some displays have a reset input and/or need a regulator to function
>>> properly. Allow to specify them for panel-dpi devices.
>>>
>>> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
>>> ---
>>>  Documentation/devicetree/bindings/display/panel/panel-dpi.txt | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>>> index 216c894d4f99..b52ac52757df 100644
>>> --- a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>>> +++ b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>>> @@ -7,6 +7,8 @@ Required properties:
>>>  Optional properties:
>>>  - label: a symbolic name for the panel
>>>  - enable-gpios: panel enable gpio
>>> +- reset-gpios: GPIO to control the RESET pin
>>
>> The problem with this in a generic binding is what if the panel has
>> ordering requirements like enable gpio has to be inactive when reset
>> is deasserted?
>>
>>> +- vcc-supply: phandle of regulator that will be used to enable power to the display
>>
>> What if there are 2 supplies?
>
> So it should be "vcc-supplies". Most properties containing phandles use plural
> naming, even if Linux supports a single phandle only (e.g. "power-domains").
> You also may want to add an optional "vcc-supply-names" property to
> differentiate.

True, but the regulator binding is an exception and we don't do that
with it. The prefix is the name and other supplies are not going to be
called Vcc.

Rob
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Re: [PATCH v2 1/3] devicetree/bindings: add reset-gpios and vcc-supply for panel-dpi

[Tomi Valkeinen]

[-- Attachment #1: Type: text/plain, Size: 1730 bytes --]



On 29/12/15 22:54, Rob Herring wrote:
> On Sun, Dec 20, 2015 at 12:13:20PM +0100, Uwe Kleine-König wrote:
>> Some displays have a reset input and/or need a regulator to function
>> properly. Allow to specify them for panel-dpi devices.
>>
>> Signed-off-by: Uwe Kleine-König <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
>> ---
>>  Documentation/devicetree/bindings/display/panel/panel-dpi.txt | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>> index 216c894d4f99..b52ac52757df 100644
>> --- a/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>> +++ b/Documentation/devicetree/bindings/display/panel/panel-dpi.txt
>> @@ -7,6 +7,8 @@ Required properties:
>>  Optional properties:
>>  - label: a symbolic name for the panel
>>  - enable-gpios: panel enable gpio
>> +- reset-gpios: GPIO to control the RESET pin
> 
> The problem with this in a generic binding is what if the panel has 
> ordering requirements like enable gpio has to be inactive when reset 
> is deasserted?
> 
>> +- vcc-supply: phandle of regulator that will be used to enable power to the display
> 
> What if there are 2 supplies?

Yes, I think it's an impossible task to create a really generic driver
wrt. gpios and supplies. There may be a bunch of them, and a particular
sequence to enable/disable needed, and even particular delays required
in between.

So I think the best we can do is to support (hopefully) most of the
panels by defining one sequence panel-dpi uses. If a particular panel
falls outside that, a separate driver is needed.

 Tomi


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