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References: <20230515235713.232939-1-aford173@gmail.com> <20230515235713.232939-3-aford173@gmail.com>
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From:   Jagan Teki <jagan@amarulasolutions.com>
Date:   Thu, 18 May 2023 17:22:26 +0530
Message-ID: <CAMty3ZB9xrO+LPGVCcoDfdWo9CP_DLVhaKm33y768+ix6nP7cQ@mail.gmail.com>
Subject: Re: [PATCH V6 2/6] drm: bridge: samsung-dsim: Fix PMS Calculator on imx8m[mnp]
To:     Adam Ford <aford173@gmail.com>
Cc:     dri-devel@lists.freedesktop.org, aford@beaconembedded.com,
        Lucas Stach <l.stach@pengutronix.de>,
        Chen-Yu Tsai <wenst@chromium.org>,
        Frieder Schrempf <frieder.schrempf@kontron.de>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Robert Foss <rfoss@kernel.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Inki Dae <inki.dae@samsung.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Marek Vasut <marex@denx.de>, linux-kernel@vger.kernel.org
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On Tue, May 16, 2023 at 5:27=E2=80=AFAM Adam Ford <aford173@gmail.com> wrot=
e:
>
> 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 sup=
port")
> Signed-off-by: Adam Ford <aford173@gmail.com>
> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> Tested-by: Chen-Yu Tsai <wenst@chromium.org>
> Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
> Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
> ---

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