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Commit 54f1a83c authored by Adam Ford's avatar Adam Ford Committed by Neil Armstrong
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drm: bridge: samsung-dsim: Fix PMS Calculator on imx8m[mnp]

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: 4d562c70

 ("drm: bridge: samsung-dsim: Add i.MX8M Mini/Nano support")
Signed-off-by: default avatarAdam Ford <aford173@gmail.com>
Reviewed-by: default avatarLucas Stach <l.stach@pengutronix.de>
Tested-by: default avatarChen-Yu Tsai <wenst@chromium.org>
Tested-by: default avatarFrieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: default avatarFrieder Schrempf <frieder.schrempf@kontron.de>
Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: default avatarJagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> # imx8mm-icore
Signed-off-by: default avatarNeil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230526030559.326566-3-aford173@gmail.com
parent a617b33f
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