Re: [PATCHv15 2/7] video: add display_timing and videomode

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

[-- Attachment #1: Type: text/plain, Size: 1286 bytes --]

On 2012-12-06 12:07, Grant Likely wrote:
> On Mon, 26 Nov 2012 16:39:58 +0100, Steffen Trumtrar <s.trumtrar@pengutronix.de> wrote:
>> On Mon, Nov 26, 2012 at 02:37:26PM +0200, Tomi Valkeinen wrote:
>>> On 2012-11-26 11:07, Steffen Trumtrar wrote:
>>>
>>>> +/*
>>>> + * Subsystem independent description of a videomode.
>>>> + * Can be generated from struct display_timing.
>>>> + */
>>>> +struct videomode {
>>>> +	u32 pixelclock;		/* pixelclock in Hz */
>>>
>>> I don't know if this is of any importance, but the linux clock framework
>>> manages clock rates with unsigned long. Would it be better to use the
>>> same type here?
>>>
>>
>> Hm, I don't know. Anyone? u32 should be large enough for a pixelclock.
> 
> 4GHz is a pretty large pixel clock. I have no idea how conceivable it is
> that hardware will get to that speed. However, if it will ever be
> larger, then you'll need to account for that in the DT binding so that
> the pixel clock can be specified using 2 cells.

I didn't mention the type because of the size of the field, but only
because to me it makes sense to use the same type for clock rates all
around the kernel. In many cases the value will be passed to clk_set_rate().

I can't see any real issues with u32, though.

 Tomi



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 899 bytes --]