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From: Mike Looijmans <mike.looijmans@topic.nl>
To: dri-devel@lists.freedesktop.org
Cc: Mike Looijmans <mike.looijmans@topic.nl>,
	Andrzej Hajda <andrzej.hajda@intel.com>,
	Conor Dooley <conor+dt@kernel.org>,
	David Airlie <airlied@gmail.com>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Rob Herring <robh@kernel.org>, Robert Foss <rfoss@kernel.org>,
	Simona Vetter <simona@ffwll.ch>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 0/2] drm: bridge: Add TI tmds181 and sn65dp159 driver (RFC)
Date: Tue, 19 Aug 2025 07:31:13 +0200	[thread overview]
Message-ID: <20250819053205.9976-1-mike.looijmans@topic.nl> (raw)
In-Reply-To: <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.926dbb5e-6af2-4dff-910b-4ccd35fd5ca1@emailsignatures365.codetwo.com>


In the past I've seen (and contributed to) hacks that model the chips as
phy or even (really!) clock drivers. Since the chip usually sits between
a signal that is (almost) HDMI and a HDMI connector, I decided to stop
lying and write it as a DRM bridge driver.

Our experience with these chips is that they work best under manual control
enabling them only once the signal is active. At low resolutions (under 4k),
the optimal setting is usually to only use redriver mode. Setting the
termination to 150-300 Ohms improves EMC performance at lower resolutions,
hence the driver enables 75-150 Ohms for HDMI2 modes and defaults to
150-300 Ohm termination for other modes.


Changes in v2:
Document driver specific bindings like slew-rate and threshold
Use atomic_enable/disable
Use #defines for bit fields in registers
Allow HDMI 2 compliance
Filter modes on clock range
Use cross-over pixel frequency instead of manual overides
Devicetree bindings according to standards

Mike Looijmans (2):
  dt-bindings: drm/bridge: ti-tmds181: Add TI TMDS181 and SN65DP159
    bindings
  drm: bridge: Add TI tmds181 and sn65dp159 driver

 .../bindings/display/bridge/ti,tmds181.yaml   | 143 +++++
 drivers/gpu/drm/bridge/Kconfig                |  11 +
 drivers/gpu/drm/bridge/Makefile               |   1 +
 drivers/gpu/drm/bridge/ti-tmds181.c           | 561 ++++++++++++++++++
 4 files changed, 716 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
 create mode 100644 drivers/gpu/drm/bridge/ti-tmds181.c

-- 
2.43.0

base-commit: 53e760d8949895390e256e723e7ee46618310361
branch: drm-ti-tmds181

Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: +31 (0) 499 33 69 69
E: mike.looijmans@topic.nl
W: www.topic.nl

Please consider the environment before printing this e-mail

       reply	other threads:[~2025-08-19  5:32 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.926dbb5e-6af2-4dff-910b-4ccd35fd5ca1@emailsignatures365.codetwo.com>
2025-08-19  5:31 ` Mike Looijmans [this message]
     [not found]   ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.f1878466-8551-4b5d-bf2e-1706e377d436@emailsignatures365.codetwo.com>
2025-08-19  5:31     ` [PATCH v2 1/2] dt-bindings: drm/bridge: ti-tmds181: Add TI TMDS181 and SN65DP159 bindings Mike Looijmans
2025-08-19  6:44       ` Rob Herring (Arm)
2025-08-19  7:03       ` Krzysztof Kozlowski
2025-08-19  7:40         ` Mike Looijmans
     [not found]   ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.9365be0b-205e-4d59-ad18-c1924bf45277@emailsignatures365.codetwo.com>
2025-08-19  5:31     ` [PATCH v2 2/2] drm: bridge: Add TI tmds181 and sn65dp159 driver Mike Looijmans
2025-08-19  7:03       ` Krzysztof Kozlowski
2025-08-19 13:22       ` Maxime Ripard
2025-08-19 14:25         ` Mike Looijmans
2025-08-25 14:14           ` Maxime Ripard
2025-08-27 14:41             ` Mike Looijmans
2025-08-19 23:35       ` kernel test robot

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