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

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Message-ID: <CAD++jLn0cFtDhg9WFU2LS6g+cLa7ZMzzcHAJ_W9REVHodFYpAw@mail.gmail.com>
Date: Fri, 26 Dec 2025 18:43:03 +0100
From: Linus Walleij <linusw@...nel.org>
To: Marijn Suijten <marijn.suijten@...ainline.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, 
	Abhinav Kumar <quic_abhinavk@...cinc.com>, Kuogee Hsieh <quic_khsieh@...cinc.com>, 
	Jessica Zhang <quic_jesszhan@...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 Fri, Dec 26, 2025 at 3:16 PM Marijn Suijten
<marijn.suijten@...ainline.org> wrote:
> On 2025-12-26 14:21:37, Linus Walleij wrote:

> > 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.

Actually all of the samsung s6e panels are suspected to be s0fef0/1
display controller variants, which you see if you look inside
panel-samsung-s6e*, for example panel-samsung-s6e3fc2x01.c has this:

#define s6e3fc2x01_test_key_on_lvl1(ctx) \
        mipi_dsi_dcs_write_seq_multi(ctx, 0x9f, 0xa5, 0xa5)
#define s6e3fc2x01_test_key_off_lvl1(ctx) \
        mipi_dsi_dcs_write_seq_multi(ctx, 0x9f, 0x5a, 0x5a)
#define s6e3fc2x01_test_key_on_lvl2(ctx) \
        mipi_dsi_dcs_write_seq_multi(ctx, 0xf0, 0x5a, 0x5a)
#define s6e3fc2x01_test_key_off_lvl2(ctx) \
        mipi_dsi_dcs_write_seq_multi(ctx, 0xf0, 0xa5, 0xa5)
#define s6e3fc2x01_test_key_on_lvl3(ctx) \
        mipi_dsi_dcs_write_seq_multi(ctx, 0xfc, 0x5a, 0x5a)
#define s6e3fc2x01_test_key_off_lvl3(ctx) \
        mipi_dsi_dcs_write_seq_multi(ctx, 0xfc, 0xa5, 0xa5)

So there is also the explanation of the 0xfc command.

> 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.

I think the s0fef0/1 drivers and all the panel-samsung-s6e* drivers
should probably be unified a bit maybe we can just create a
local s0fef.h file with the above for all these drivers to use?

(If someone has actual datasheets for s0fef0/1 that would be great.)

Yours,
Linus Walleij