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 v3:
Fix duplicate links
Add vcc-supply and vdd-supply
Fix missing type for ti,slew-rate
Lower-case hex values and use defines for EYESCAN registers
Remove equalizer code (unlikely to be used)
Remove attributes (no longer useful, undocumented)
Fix build for 6.17 kernel
Use devm_drm_bridge_alloc
Sort includes and add linux/bitfield.h
Check chip type and complain on mismatch
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 | 150 +++++++
drivers/gpu/drm/bridge/Kconfig | 11 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/ti-tmds181.c | 409 ++++++++++++++++++
4 files changed, 571 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.looijm...@topic.nl
W: www.topic.nl
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