Re: [PATCH] drm/sun4i: uncouple DSI dotclock divider from TCON0_DCLK_REG

[Frank Oltmanns <frank@oltmanns.dev>]

Hi Roman,

On 2023-03-29 at 21:58:02 +0200, Maxime Ripard <maxime@cerno.tech> wrote:
> On Tue, Mar 28, 2023 at 01:48:33AM +0200, Roman Beranek wrote:
>> On Mon Mar 27, 2023 at 10:20 PM CEST, Maxime Ripard wrote:
>> >
>> > On Sat, Mar 25, 2023 at 12:40:04PM +0100, Frank Oltmanns wrote:
>> > > Claiming to set the divider to a different value (bpp / lanes) than what we’re actually using in
>> > > the end (SUN6I_DSIO_TCON_DIV) is somehow bugging me. I feel like the proposal that I submitted is
>> > > more direct: <https://lore.kernel.org/all/20230319160704.9858-2-frank@oltmanns.dev/>
>> >
>> > Yeah, this patch looks better to me too: it's simpler, more straightforward. If Roman can confirm it
>> > works with his testing, I'll be happy to merge it.
>> >
>>
>> So I've just found out that my understanding of what sun4i_dotclock is
>> was wrong the whole time. I treated it as a virtual clock representing
>> the true CRTC pixel clock and only coincidentally also matching what
>> A64 Reference Manual labels as TCON0 data clock (a coincidence to which
>> DSI is an exception).
>>
>> Now that I finally see dotclock as 'what could dclk be an abbreviation
>> to', I to agree that it's not only straightforward but also correct to
>> keep the divider at 4 and adjust the rate as is done it the patch Frank
>> submitted.
>>
>> In order to preserve semantic correctness however, I propose to preface
>> the change with a patch that renames sun4i_dotclock and tcon-pixel-clock
>> such that dot/pixel is replaced with d/data. What do you think?
>
> I don't think it's exposed to the userspace in any way so it makes sense to me

Roman, will you please submit a V2 of the patch I submitted then? Or do
you want me to do it?

Thanks,
  Frank

>
> Maxime
>


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