[PATCH] drm/imx: imx-tve: Make the 'dac' regulator optional

[Lucas Stach]

Am Dienstag, den 07.02.2017, 17:45 +0100 schrieb Philipp Zabel:
> On Fri, 2017-02-03 at 10:52 -0200, Fabio Estevam wrote:
> > Hi Philipp,
> > 
> > On Tue, Jan 3, 2017 at 5:11 PM, Fabio Estevam <festevam at gmail.com> wrote:
> > > From: Fabio Estevam <fabio.estevam at nxp.com>
> > >
> > > Commit deb65870b5d9d ("drm/imx: imx-tve: check the value returned by
> > > regulator_set_voltage()") exposes the following probe issue:
> > >
> > > 63ff0000.tve supply dac not found, using dummy regulator
> > > imx-drm display-subsystem: failed to bind 63ff0000.tve (ops imx_tve_ops): -22
> > >
> > > When the 'dac' regulator is not passed in the device tree,
> > > devm_regulator_get() will return NULL and when regulator_set_voltage()
> > > is called it returns an error.
> > >
> > > Fix the issue by making the 'dac' regulator optional.
> > >
> > > Fixes: deb65870b5d9d ("drm/imx: imx-tve: check the value returned by regulator_set_voltage()")
> > > Cc: <stable at vger.kernel.org> # 4.8+
> > > Signed-off-by: Fabio Estevam <fabio.estevam at nxp.com>
> > 
> > Any comments, please?
> 
> I've applied this to the fixes branch, since the current device trees
> don't have the regulator set.
> 
> Is this really optional, though? It would be better to add the correct
> dac-supply to the device trees.
> 
Why does the driver attempt to set the voltage? I guess the voltage is
fixed, even if it is hooked up to a configurable regulator.

Shouldn't we just remove the set_voltage call from the driver and make
sure the correct voltage is supplied by board level DT constraints?

Regards,
Lucas