[PATCH V6 2/6] drm: bridge: samsung-dsim: Fix PMS Calculator on imx8m[mnp]

Jagan Teki jagan at amarulasolutions.com
Thu May 18 11:52:26 UTC 2023


On Tue, May 16, 2023 at 5:27 AM Adam Ford <aford173 at gmail.com> wrote:
>
> According to Table 13-45 of the i.MX8M Mini Reference Manual, the min
> and max values for M and the frequency range for the VCO_out
> calculator were incorrect.  This information was contradicted in other
> parts of the mini, nano and plus manuals.  After reaching out to my
> NXP Rep, when confronting him about discrepencies in the Nano manual,
> he responded with:
>  "Yes it is definitely wrong, the one that is part
>   of the NOTE in MIPI_DPHY_M_PLLPMS register table against PMS_P,
>   PMS_M and PMS_S is not correct. I will report this to Doc team,
>   the one customer should be take into account is the Table 13-40
>   DPHY PLL Parameters and the Note above."
>
> These updated values also match what is used in the NXP downstream
> kernel.
>
> To fix this, make new variables to hold the min and max values of m
> and the minimum value of VCO_out, and update the PMS calculator to
> use these new variables instead of using hard-coded values to keep
> the backwards compatibility with other parts using this driver.
>
> Fixes: 4d562c70c4dc ("drm: bridge: samsung-dsim: Add i.MX8M Mini/Nano support")
> Signed-off-by: Adam Ford <aford173 at gmail.com>
> Reviewed-by: Lucas Stach <l.stach at pengutronix.de>
> Tested-by: Chen-Yu Tsai <wenst at chromium.org>
> Tested-by: Frieder Schrempf <frieder.schrempf at kontron.de>
> Reviewed-by: Frieder Schrempf <frieder.schrempf at kontron.de>
> ---

Reviewed-by: Jagan Teki <jagan at amarulasolutions.com>
Tested-by: Jagan Teki <jagan at amarulasolutions.com> # imx8mm-icore


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