linux-kernel - Re: [PATCH 07/12] drm/panel: Set sufficient voltage for panel nt37801

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aPsWEhM7i+gDjXE0@yuanjiey.ap.qualcomm.com>
Date: Fri, 24 Oct 2025 14:00:50 +0800
From: yuanjiey <yuanjie.yang@....qualcomm.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: robin.clark@....qualcomm.com, lumag@...nel.org, abhinav.kumar@...ux.dev,
        sean@...rly.run, marijn.suijten@...ainline.org, airlied@...il.com,
        simona@...ll.ch, maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
        tzimmermann@...e.de, robh@...nel.org, krzk+dt@...nel.org,
        conor+dt@...nel.org, quic_mkrishn@...cinc.com, jonathan@...ek.ca,
        quic_khsieh@...cinc.com, neil.armstrong@...aro.org,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, tingwei.zhang@....qualcomm.com,
        aiqun.yu@....qualcomm.com, yongxing.mou@....qualcomm.com
Subject: Re: [PATCH 07/12] drm/panel: Set sufficient voltage for panel nt37801

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 <yuanjie.yang@....qualcomm.com>
> > 
> > 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 <yongxing.mou@....qualcomm.com>
> > Signed-off-by: Yuanjie Yang <yuanjie.yang@....qualcomm.com>
> > ---
> >  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.

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.


Thanks,
Yuanjie

> > +	if (ret < 0)
> > +		return ret;
> > +
> >  	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> >  	if (IS_ERR(ctx->reset_gpio))
> >  		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
> > -- 
> > 2.34.1
> > 
> 
> -- 
> With best wishes
> Dmitry