linux-kernel - [PATCH 0/7] drm/bridge: tc358768: Long command support

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Message-Id: <20251021-tc358768-v1-0-d590dc6a1a0c@ideasonboard.com>
Date: Tue, 21 Oct 2025 16:22:56 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Parth Pancholi <parth.pancholi@...adex.com>, 
 Francesco Dolcini <francesco.dolcini@...adex.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 Tomi Valkeinen <tomi.valkeinen@...asonboard.com>, 
 Dmitry Osipenko <digetx@...il.com>
Subject: [PATCH 0/7] drm/bridge: tc358768: Long command support

This series makes some small improvements to the tc358768 driver, and
then adds support for long commands, commands that have more than 8
bytes of payload.

This has been tested on Toradex Verdin AM62 board, with a ST7703 based
DSI panel which requires initial configuration using commands that have
8+ bytes.

I tested the following combinations, by observing the panel visually and
the DSI lanes with an oscilloscope:

- HS command transfer, continuous clock
- HS command transfer, non-continuous clock
- LP command transfer, continuous clock
- LP command transfer, non-continuous clock

All except LP + continuous clock work fine. While observing the lanes
with normal oscilloscope is a very high level and vague view of what
exactly is going on the lanes, it still looks good to me: initial
commands are sent in LP, and then video data is being sent in HS, and
clock lane is continuous. However, the panel stays black, so something
is not quite right.

As it doesn't make sense to send commands in LP during initial
configuration, especially with longer commands, I will leave that
particular combination unresolved. I'd be interested to hear if it works
on some other panel.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
---
Parth Pancholi (1):
      drm/bridge: tc358768: Set pre_enable_prev_first for reverse order

Tomi Valkeinen (6):
      drm/bridge: tc358768: Fix typo in TC358768_DSI_CONTROL_DIS_MODE
      drm/bridge: tc358768: Separate indirect register writes
      drm/bridge: tc358768: Support non-continuous clock
      drm/bridge: tc358768: Add LP mode command support
      drm/bridge: tc358768: Separate video format config
      drm/bridge: tc358768: Add support for long command tx via video buffer

 drivers/gpu/drm/bridge/tc358768.c | 202 +++++++++++++++++++++++++++++---------
 1 file changed, 157 insertions(+), 45 deletions(-)
---
base-commit: e5f0a698b34ed76002dc5cff3804a61c80233a7a
change-id: 20251021-tc358768-93eb23689b7a

Best regards,
-- 
Tomi Valkeinen <tomi.valkeinen@...asonboard.com>