linux-kernel - [RFC] What to base new driver for Raystar RDX0063 display panel using Sitronix ST75156 chip on?

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-next>] [day] [month] [year] [list]

Message-ID:
 <AS2PR02MB89157A26C4CFF62811208A739FCCA@AS2PR02MB8915.eurprd02.prod.outlook.com>
Date: Wed, 12 Nov 2025 15:08:08 +0000
From: Lars Rask <Lars.Rask@...s.com>
To: "david@...hnology.com" <david@...hnology.com>,
	"marcus.folkesson@...il.com" <marcus.folkesson@...il.com>,
	"jagan@...rulasolutions.com" <jagan@...rulasolutions.com>, "agx@...xcpu.org"
	<agx@...xcpu.org>, "dri-devel@...ts.freedesktop.org"
	<dri-devel@...ts.freedesktop.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Kernel
	<Kernel@...s.com>, Amir Dawd Seid <Amir.Seid@...s.com>, Johan Adolfsson
	<Johan.Adolfsson@...s.com>, Daniel Larsson Persson
	<Daniel.Larsson.Persson@...s.com>
Subject: [RFC] What to base new driver for Raystar RDX0063 display panel using
 Sitronix ST75156 chip on?

Hi,
I'm trying to create a driver for a small lcd display called Raystar RDX0063 that is using the
Sitronix ST75156 chip. The display is used in SPI 4 wire mode similar to many other tiny MIPI
DBI displays, but the register set and framebuffer format is not MIPI DBI compliant, since each
byte sent is actually 1 column of 8 rows.

The datasheets for the Raystar RDX0063 display and the Sitronix ST75156 chip are unfortunately
not publicly available, but you can find the datasheet for Sitronix ST7567 (which is similar to 
ST75156) here: https://www.topwaydisplay.com/sites/default/files/2020-05/ST7567.pdf

The main difference seems to be that ST75156 supports a higher resolution than ST7567,
as can be seen here: 
https://www.sitronix.com.tw/en/products/industrial-display-driver-ic/mono-stn-lcd-driver-ic

As a first attempt to create the driver, the panel-mipi-dbi driver was extended with "tweaks"
to support non MIPI DBI panels. This seems to work. However, after some discussion with the
maintainer that is no longer active (https://github.com/notro/panel-mipi-dbi/discussions/14)
the conclusion was that these "tweaks" were not upstreamable, and that I need to create a new
driver specifically for the Raystar RDX0063 display panel using the Sitronix st75156 chip
instead.

In order to make my driver upstreamable, which driver should I be "inspired" by (i.e copy and modify)
and base my work on? The drivers in drivers/gpu/drm/sitronix/ and drivers/gpu/drm/tiny/ usually uses
struct mipi_dbi_dev and mipi_db_command() helpers, but drivers/gpu/drm/panel/panel-sitronix-st7789v.c
does not.

Should I create my new driver as /gpu/drm/sitronix/st75156.c and use mipi_dbi helpers where applicable?
If it is preferable to avoid using the mipi dbi helpers, is there another set of helper functions that
I should use instead?

Best regards
/Lars Rask