Messages in this thread | | | From | Clément Péron <> | Date | Tue, 14 Apr 2020 21:16:39 +0200 | Subject | Re: [PATCH 2/2] drm/panfrost: add devfreq regulator support |
| |
Hi Mark,
On Tue, 14 Apr 2020 at 20:55, Mark Brown <broonie@kernel.org> wrote: > > On Tue, Apr 14, 2020 at 08:20:23PM +0200, Clément Péron wrote: > > Hi Liam and Mark, > > You might want to flag stuff like this in the subject line, I very > nearly deleted this without opening it since most of the email I get > about panfrost appears to be coming from me having sent patches rather > than being relevant.
Ok will do next time,
> > > We are having an issue with Panfrost driver registering two times the > > same regulator and giving an error when trying to create the debugfs > > folder. > > > Could you clarify if it is allowed for a device to register two times > > the same regulator? > > > I check Documentation/power/regulator/regulator.rst but this point is > > not specified. > > We don't actively prevent it and I can't think what other than debugfs > might run into problems (and that's just a warning) but it does seem > like a weird thing to want to do and like it's pointing to some > confusion in your code with two different parts of the device > controlling the same supply independently. What's the use case here?
Panfrost first probe clock, reset and regulator in device_init: https://elixir.bootlin.com/linux/v5.7-rc1/source/drivers/gpu/drm/panfrost/panfrost_drv.c#L602 Then it probe for optional devfreq, devfreq will get opp tables and also get regulator again. https://elixir.bootlin.com/linux/v5.7-rc1/source/drivers/gpu/drm/panfrost/panfrost_drv.c#L609
That's can be reworked and Panfrost can only probe regulator if there is no opp-table.
But if multiple regulator is not an issue and as each request is logic. The first in device_init assure to enable the regulator and the second in OPP assure the voltage level.
Maybe we can just fix this warning?
Thanks, Clement
| |