Re: [PATCH] OMAPDSS: Do not require a VDDS_DSI regulator on am35xx

["Raphaël Assénat" <raph@8d.com>]

On 31/07/12 04:45 AM, Tomi Valkeinen wrote:
> On Thu, 2012-07-19 at 16:04 -0400, Raphael Assenat wrote:
>> On our AM3505 based board, dpi.c complains that there is no VDSS_DSI regulator
>> and the framebuffer cannot be enabled. However, this check does not seem to
>> apply to AM3505/17 chips.
>>
>> I am not the first facing this issue, see this thread from Nov. 2011:
>> http://marc.info/?l=linux-omap&m\x132147745930213&w=2
>>
>> The string 'vdds_dsi' does appear once in the technical reference manual[1]
>> but there is no corresponding power pin on the package[2]. I failed to 
>> locate any signal that could be an equivalent. I am trying to obtain some
>> clarifications on TI's forum[3]...
>>
>> In any case, I am currently running with the patch below. In order to keep
>> cpu_is_xx uses to a minimum, I check for am35xx once at init time and allow
>> dpi.vdds_dsi_reg to be NULL from then on, getting rid of all the other
>> cpu_is_omap34xx uses in the process.
>>
>> Your comments would be appreciated. Please also consider for merging.
> 
> VDDS_DSI is used to power up some of the DSS pins on OMAP3. I don't know
> why the HW was designed like that... If you have a correct image without
> the power, then obviously it's not needed.

Yes, I confirm the image is displayed properly.

> We don't currently deal with AM3xxx SoCs in any way in the driver. It's
> difficult enough trying to handle just OMAP DSS versions, and now we
> need to add AM3xxx to the mix. Sigh =).
> 
> However, I don't want to apply this patch, as we're trying to remove the
> cpu_is checks (soc_is goes in the same category).
> 
> I guess we need to add entries for the AM3xxx SoCs in the
> dss_features.c.
> 
> Any idea what other differences AM3xxx has compared to OMAP3?

This is the only one I am aware of.


Best regards,
Raphaël Assénat