Re: [PATCH 00/20] drm/bridge: tc358775: proper bridge bringup and code cleanup

From: Michael Walle
Date: Mon Jun 03 2024 - 07:47:39 EST


On Mon May 6, 2024 at 3:34 PM CEST, Michael Walle wrote:
> This patchset fixes the bridge initialization according to the
> datasheet. Not sure how that even worked before. Maybe because the
> initialization was done prior to linux (?).
>
> The bridge has some peculiarities:
> (1) The reset has to be deasserted in LP-11 mode
> (2) For I2C access the bridge needs the DSI clock
> (3) The bridge has to be configured while the video stream is
> disabled.
> (4) The bridge has limitations on the display timings. In particular,
> the horizontal pulse width has to be at least 8 pixels wide and
> both the horizontal pulse width as well as the back porch has to
> be even. According to the datasheet the horizontal front porch as
> well but in line sync mode, this is ignored. Also line sync is the
> only supported mode for this bridge, therefore, the front porch
> is always ignored.
>
> The most controversial patch is probably "drm/bridge: add
> dsi_lp11_notify mechanism" which is needed for (1) above. Some time ago
> there was a series [1] to add a manual power-up, which was abandoned and
> which didn't suite the needs for this bridge anyway.
>
> Also, this will gradually change the tc_ prefix to tc358775_ while the
> functions are refactored.
>
> The bridge was successfully tested on a Mediatek MT8195 SoC with the
> following panels:
> - Innolux G101ICE
> - AUO G121EAN01.0
> - Innolux G156HCE (dual-link LVDS)
>
> [1] https://lore.kernel.org/r/20231016165355.1327217-1-dmitry.baryshkov@xxxxxxxxxx/

Any comments on this series, besides the discussion on how to do the
reset during LP11?

Most of the other patches should be more or less self contained.

-michael

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