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Date: Fri, 12 Jan 2024 10:51:59 +0100
Message-Id: <CYCMVXHYVDCI.HVH1TR8MWEUK@fairphone.com>
Subject: Re: [PATCH v2 2/4] drm/panel: Add driver for DJN HX83112A LCD panel
From: "Luca Weiss" <luca.weiss@fairphone.com>
To: <neil.armstrong@linaro.org>, "Linus Walleij" <linus.walleij@linaro.org>
Cc: "Jessica Zhang" <quic_jesszhan@quicinc.com>, "Sam Ravnborg"
 <sam@ravnborg.org>, "David Airlie" <airlied@gmail.com>, "Daniel Vetter"
 <daniel@ffwll.ch>, "Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
 "Maxime Ripard" <mripard@kernel.org>, "Thomas Zimmermann"
 <tzimmermann@suse.de>, "Rob Herring" <robh+dt@kernel.org>, "Krzysztof
 Kozlowski" <krzysztof.kozlowski+dt@linaro.org>, "Conor Dooley"
 <conor+dt@kernel.org>, "Bjorn Andersson" <andersson@kernel.org>, "Konrad
 Dybcio" <konrad.dybcio@linaro.org>, "Andy Gross" <agross@kernel.org>,
 <devicetree@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
 <linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
 <~postmarketos/upstreaming@lists.sr.ht>, <phone-devel@vger.kernel.org>
References: <20240110-fp4-panel-v2-0-8ad11174f65b@fairphone.com>
 <20240110-fp4-panel-v2-2-8ad11174f65b@fairphone.com>
 <CACRpkdaWTfPDCin_L6pefHsokjNyO8Mo6hWPdzPLLi1EUkKUuA@mail.gmail.com>
 <CYBZEZ4IM6IL.VR04W7933VI@fairphone.com>
 <CACRpkdZQbVXfBa70nhDOqfWPbsh-6DgX-uvZOxr19pzMmF2giQ@mail.gmail.com>
 <CYCLSCKPPBOC.1B1MP3VOOC0Q8@fairphone.com>
 <cdc18e2a-b7eb-4b54-a513-481148fb3b0d@linaro.org>
In-Reply-To: <cdc18e2a-b7eb-4b54-a513-481148fb3b0d@linaro.org>

On Fri Jan 12, 2024 at 10:14 AM CET, Neil Armstrong wrote:
> On 12/01/2024 10:00, Luca Weiss wrote:
> > On Thu Jan 11, 2024 at 8:05 PM CET, Linus Walleij wrote:
> >> On Thu, Jan 11, 2024 at 4:28=E2=80=AFPM Luca Weiss <luca.weiss@fairpho=
ne.com> wrote:
> >>
> >>> In some internal documentation it says "LCD Driver IC" "HX83112A" and=
 I
> >>> don't see any reference to Truly 5P65 anywhere.
> >>
> >> In the Android directory I pointed to I see this file:
> >> HX83112_Android_Driver/Truly_5p65_module_fw/UpdateFW.bat
> >>
> >> (Notice the 5p65 fw dir is *inside* the HX82112 dir)
> >>
> >> And in that file:
> >> adb push TRULY_5P65_1080_2160_HX83112A_D01C01.bin
> >> /system/etc/firmware/Himax_firmware.bin
> >>
> >> Clearly indicating that they are pushing a Truly 5P65 firmware into
> >> the Himax display firmware directory.
> >>
> >> To be fair, that is the driver for the touchscreen part of HX83112A,
> >> but ... Truly is a well known manufacturer of display controllers?
> >>
> >> But... given that you have a @fairphone.com mal address and
> >> a working relationship with them, can't you just ask?
> >>
> >>> On their website they have this sentence:
> >>
> >> All OEMs want to look like everything is their own product. It is
> >> business as usual.
> >=20
> > I can't tell you anything there that I don't know, sorry.
> >=20
> >>
> >> Further on the same note since I guess you have a datasheet)
> >> please bring in #defines for the commands (the first byte in the
> >> write sequences, for examples:
> >>
> >> +       mipi_dsi_dcs_write_seq(dsi, 0xbd, 0x02);
> >> +       mipi_dsi_dcs_write_seq(dsi, 0xd8,
> >> +                              0xaa, 0xff, 0xff, 0xff, 0xff, 0xff, 0xa=
a, 0xff,
> >> +                              0xff, 0xff, 0xff, 0xff);
> >> +       mipi_dsi_dcs_write_seq(dsi, 0xbd, 0x03);
> >>
> >> Clearly 0xbd is HX83112_CMD_SETREGBANK?
> >> (This is easily spotted from the similar structure in the
> >> existing panel-himax-hx8394.c.) So please add #defines
> >> for all commands you know, especially if you have a datasheet
> >> because we reviewers don't have them and "it's just magic
> >> bytes" isn't very compelling. It adds a lot to understanding.
> >=20
> > Right, the register names seem to match more or less the ones from that
> > driver, plus some new ones and some differently named ones. Will send a
> > v3 with that.
> >=20
> >>
> >> I strongly suspect other Himax displays such as HX8394 to
> >> be using a Truly controller as well, hence the similarities.
> >>
> >> In a datasheet for their TFT800480-84-V1-E display controller
> >> Truly kept the init sequence name of void LCD_INIT_HX8290(void)
> >> for example.
> >=20
> > In that datasheet (assuming I'm looking at the same one?) it says
> > "Driver IC" "HX8290-A[...]" so there the display driver is manufactured
> > by Himax and not Truly to my understanding. Truly is assembling togethe=
r
> > Driver + all the other parts that go into an LCD.
> >=20
> > For the panel used on Fairphone 4 that part is done by the company DJN.
>
> Looking at the discussion, this seems to confirm the Display+Touch IC is =
HX83112A,
> and Truly is the panel manufacturer and all assembled by DJN, so IMHO the=
 initial driver is right.
>
> Perhaps the compatible should be djn,hx83112a-truly-5p65 to reflect that =
?

Since there's zero indication Truly is involved in this panel in my
documentation - much less the number 5P65 - I'm not going to add that.

One other number I'm certain of is from DJN's side the model number of
this panel is 9A-3R063-1102B, which I assume is the specific combination
of components + frame and everything for Fairphone 4 device.

That one you can also find in this document (Ctrl-F for DJN)
https://www.fairphone.com/wp-content/uploads/2022/09/FP4_Information-for-re=
pairers-and-recyclers.pdf
. or on this picture:
https://guide-images.cdn.ifixit.com/igi/HgTquQPABg1mAMHD.huge

So something like djn,9a-3r063-1102b would also be somewhat valid I
guess?

So in short this panel is the model 9A-3R063-1102B from DJN, which uses
a Himax HX83112A driver IC.

And there's also AU Optronics listed as =E7=8E=BB=E7=92=83=E5=8E=82=E5=AE=
=B6 ("glass manufacturer"?)
fwiw, though the display also uses Corning Gorilla Glass 5 so not sure
who's supplying what.

Regards
Luca

>
> Neil
>
> >=20
> > Regards
> > Luca
> >=20
> >>
> >> Yours,
> >> Linus Walleij
> >=20