On Thu, Oct 30, 2025 at 07:57:46PM +0200, Dmitry Baryshkov wrote:
> On Thu, Oct 30, 2025 at 10:08:30AM +0800, yuanjiey wrote:
> > On Wed, Oct 29, 2025 at 02:20:13PM +0200, Dmitry Baryshkov wrote:
> > > On Wed, Oct 29, 2025 at 09:58:39AM +0800, yuanjiey wrote:
> > > > On Mon, Oct 27, 2025 at 02:22:04PM +0200, Dmitry Baryshkov wrote:
> > > > > On Fri, Oct 24, 2025 at 02:00:50PM +0800, yuanjiey wrote:
> > > > > > On Thu, Oct 23, 2025 at 03:14:38PM +0300, Dmitry Baryshkov wrote:
> > > > > > > On Thu, Oct 23, 2025 at 04:06:04PM +0800, yuanjie yang wrote:
> > > > > > > > From: Yuanjie Yang <[email protected]>
> > > > > > > > 
> > > > > > > > The NT37801 Sepc V1.0 chapter "5.7.1 Power On Sequence" states
> > > > > > > > VDDI=1.65V~1.95V, so set sufficient voltage for panel nt37801.
> > > > > > > > 
> > > > > > > > Signed-off-by: Yongxing Mou <[email protected]>
> > > > > > > > Signed-off-by: Yuanjie Yang <[email protected]>
> > > > > > > > ---
> > > > > > > >  drivers/gpu/drm/panel/panel-novatek-nt37801.c | 5 +++++
> > > > > > > >  1 file changed, 5 insertions(+)
> > > > > > > > 
> > > > > > > > diff --git a/drivers/gpu/drm/panel/panel-novatek-nt37801.c 
> > > > > > > > b/drivers/gpu/drm/panel/panel-novatek-nt37801.c
> > > > > > > > index d6a37d7e0cc6..7eda16e0c1f9 100644
> > > > > > > > --- a/drivers/gpu/drm/panel/panel-novatek-nt37801.c
> > > > > > > > +++ b/drivers/gpu/drm/panel/panel-novatek-nt37801.c
> > > > > > > > @@ -267,6 +267,11 @@ static int novatek_nt37801_probe(struct 
> > > > > > > > mipi_dsi_device *dsi)
> > > > > > > >         if (ret < 0)
> > > > > > > >                 return ret;
> > > > > > > >  
> > > > > > > > +       ret = regulator_set_voltage(ctx->supplies[0].consumer,
> > > > > > > > +                                   1650000, 1950000);
> > > > > > > 
> > > > > > > This should be done in the DT. Limit the voltage per the user.
> > > > > > Two reason:
> > > > > > 1.
> > > > > > I see https://patchwork.freedesktop.org/patch/354612/
> > > > > > 
> > > > > > panel panel-novatek-nt35510.c also use regulator_set_voltage set 
> > > > > > right voltage,
> > > > > > so I do the same work.
> > > > > 
> > > > > Please look for the majority rather than the exceptions. Out of all
> > > > > panel drivers only two set the voltage directly.
> > > > > 
> > > > > > 
> > > > > > 2.     Kaanapali vddio regulator:
> > > > > > 
> > > > > >             vreg_l12b_1p8: ldo12 {
> > > > > >                     regulator-name = "vreg_l12b_1p8";
> > > > > >                     regulator-min-microvolt = <1200000>;
> > > > > >                     regulator-max-microvolt = <1800000>;
> > > > > > 
> > > > > >     Voltage is from 1.2~.1.8 V , So I can not set it 1.65~1.95 V 
> > > > > > from DT(1.95V is beyond the allowed range).
> > > > > >     So I use regulator_set_voltage to set voltage, and 
> > > > > > regulator_set_voltage will choose the appropriate voltage.
> > > > > 
> > > > > DT has to list the voltage values that work for the devices on that
> > > > > particular platform. So, ldo12 should be listing 1.64 - 1.8 V.
> > > > get it. I check downstream DT,
> > > >   dosnstream DT:
> > > >    regulator-min-microvolt = <1800000>;
> > > >    regulator-max-microvolt = <1800000>;
> > > > 
> > > >   I test 1.8V works, So I will add 1.8V in next patch, do you think it 
> > > > is ok?
> > > 
> > > What does panel's datasheet say?
> > 
> > The NT37801 Sepc V1.0 chapter "5.7.1 Power On Sequence" states 
> > VDDI=1.65V~1.95V.
> > 
> > So I should follow datasheet to set DT ldo12: 1.64 - 1.8V ?
> 
> If the panel declares minimum voltage to 1.65 V, why are you declaring
> 1.64 V as the mimimal voltage for the rail?

Corrcet here:

DT ldo12 will be  1.65 - 1.8V

Thanks,
Yuanjie

 
> > 
> > if you think it is ture, I will fix it in next patch.
> -- 
> With best wishes
> Dmitry

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