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[v1,0/9] drm/bridge: tc358768: various fixes on PLL calculation and DSI timings

Message ID 20230427142934.55435-1-francesco@dolcini.it
Headers
Series drm/bridge: tc358768: various fixes on PLL calculation and DSI timings |

Message

Francesco Dolcini April 27, 2023, 2:29 p.m. UTC 
  From: Francesco Dolcini <francesco.dolcini@toradex.com>

This series includes multiple fixes on the tc358768 parallel RGB to DSI driver.

With the following changes I am able to have a stable display output using a TI
SN65DSI83 (DSI-LVDS bridge) and a 1280 x 800 LVDS display panel and the
register values are coherent with Toshiba documentation and configuration
spreadsheet, I was not able to test any other display sink.

= DSI Video Mode =

The driver uses the MIPI_DSI_MODE_LPM flag not correctly, because of that no HS
Video is sent at all when this flag is set by the DSI slave.

= DSI Timing Parameters =

Multiple DSI timing parameters are not correct and this was leading to black or
not stable images on some display output. The new formulas were verified with
the datasheet and a configuration spread sheet from Toshiba.

I did split the change in multiple commits, I can squash all of them together
if this is considered better for any reason, including bisect-ability.

= PLL computation =

Two issues on the PLL computation, one is a required fix to have the bridge
working when the parallel RGB input width is not 24, the second one is just
following a prescription from the Toshiba documentation. In my test it was not
making any difference.

Francesco Dolcini (9):
  drm/bridge: tc358768: always enable HS video mode
  drm/bridge: tc358768: fix PLL parameters computation
  drm/bridge: tc358768: fix PLL target frequency
  drm/bridge: tc358768: fix TCLK_ZEROCNT computation
  drm/bridge: tc358768: fix TCLK_TRAILCNT computation
  drm/bridge: tc358768: fix THS_ZEROCNT computation
  drm/bridge: tc358768: fix TXTAGOCNT computation
  drm/bridge: tc358768: fix THS_TRAILCNT computation
  drm/bridge: tc358768: remove unused variable

 drivers/gpu/drm/bridge/tc358768.c | 53 +++++++++++++++++--------------
 1 file changed, 30 insertions(+), 23 deletions(-)

Comments

Robert Foss May 5, 2023, 6:14 p.m. UTC | #1 
From: Robert Foss <rfoss@kernel.org>

On Thu, 27 Apr 2023 16:29:25 +0200, Francesco Dolcini wrote:
> From: Francesco Dolcini <francesco.dolcini@toradex.com>
> 
> This series includes multiple fixes on the tc358768 parallel RGB to DSI driver.
> 
> With the following changes I am able to have a stable display output using a TI
> SN65DSI83 (DSI-LVDS bridge) and a 1280 x 800 LVDS display panel and the
> register values are coherent with Toshiba documentation and configuration
> spreadsheet, I was not able to test any other display sink.
> 
> [...]

Applied, thanks!

[1/9] drm/bridge: tc358768: always enable HS video mode
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=ee18698e212b
[2/9] drm/bridge: tc358768: fix PLL parameters computation
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=ee18698e212b
[3/9] drm/bridge: tc358768: fix PLL target frequency
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=ee18698e212b
[4/9] drm/bridge: tc358768: fix TCLK_ZEROCNT computation
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=ee18698e212b
[5/9] drm/bridge: tc358768: fix TCLK_TRAILCNT computation
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=ee18698e212b
[6/9] drm/bridge: tc358768: fix THS_ZEROCNT computation
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=77a089328da7
[7/9] drm/bridge: tc358768: fix TXTAGOCNT computation
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=3666aad8185a
[8/9] drm/bridge: tc358768: fix THS_TRAILCNT computation
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=bac7842cd179
[9/9] drm/bridge: tc358768: remove unused variable
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=e4a5e4442a80



Rob