linux-kernel - Re: [PATCH v2 05/11] drm/panel: Add panel driver for Samsung SOFEF01 DDIC

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Message-ID: <aU6Z6pqinEYgSGd1@SoMainline.org>
Date: Fri, 26 Dec 2025 15:23:02 +0100
From: Marijn Suijten <marijn.suijten@...ainline.org>
To: Linus Walleij <linusw@...nel.org>
Cc: Neil Armstrong <neil.armstrong@...aro.org>, 
	Sam Ravnborg <sam@...nborg.org>, David Airlie <airlied@...il.com>, 
	Rob Herring <robh+dt@...nel.org>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, 
	Conor Dooley <conor+dt@...nel.org>, Andy Gross <agross@...nel.org>, 
	Bjorn Andersson <andersson@...nel.org>, Jessica Zhang <jesszhan0024@...il.com>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, Simona Vetter <simona@...ll.ch>, 
	Casey Connolly <casey.connolly@...aro.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Simona Vetter <simona.vetter@...ll.ch>, 
	~postmarketos/upstreaming@...ts.sr.ht, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...ainline.org>, Martin Botka <martin.botka@...ainline.org>, 
	Jami Kettunen <jami.kettunen@...ainline.org>, dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
	Kuogee Hsieh <quic_khsieh@...cinc.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Konrad Dybcio <konrad.dybcio@....qualcomm.com>, 
	Konrad Dybcio <konradybcio@...nel.org>, Dmitry Baryshkov <lumag@...nel.org>
Subject: Re: [PATCH v2 05/11] drm/panel: Add panel driver for Samsung SOFEF01
 DDIC

On 2025-12-26 15:16:30, Marijn Suijten wrote:
> On 2025-12-26 14:21:37, Linus Walleij wrote:
> ...
> > Only nitpicks follow:
> > 
> > > +       if (ctx->panel_type == PANEL_TYPE_TC01 ||
> > > +           ctx->panel_type == PANEL_TYPE_UT01 ||
> > > +           ctx->panel_type == PANEL_TYPE_UT04) {
> > > +               mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0x5a, 0x5a);
> > 
> > The sofef00 driver tell us exactly what this sequence is:
> > 
> > #define sofef00_test_key_on_lvl2(ctx) \
> >         mipi_dsi_dcs_write_seq_multi(ctx, 0xf0, 0x5a, 0x5a)
> > #define sofef00_test_key_off_lvl2(ctx) \
> >         mipi_dsi_dcs_write_seq_multi(ctx, 0xf0, 0xa5, 0xa5)
> > 
> > I would just rename these two to sofef01_test_key_on/off_lvl2()
> > and use the same helpers in this driver to follow the sofef00 pattern.
> 
> Right, yes.  I think I already brought this up in V1, that some existing
> Samsung drivers call this (the 0xf0 part) the MCS PASSWORD, others call it the
> LEVEL_2_KEY or USER_KEY or ACCESSPROT.
> 
> I'm curious (though should probably look up the patch history) where these names
> come from, which of these names match the sofef01/03/souxp00 DDICs provided
> here, and what they're supposed to mean (MCS: Magic Command Sequence?).

I should have probably looked this up before asking; Manufacturer Command
Sequence.

Likely a generic prefix someone came up with to label commands that are not
part of DCS.

> Then there are possibly a lot more constants we can glean from other drivers,
> though again without confirmation that it's identical on this DDIC.
> 
> - Marijn