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From:   Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date:   Mon, 13 Mar 2023 21:04:14 +0100
Message-ID: <CAFBinCDHRhLSyFsEv7cdhSgZorj-TdR3HhqSBnAQcUtEsecV=Q@mail.gmail.com>
Subject: Re: [RFC PATCH] brcmfmac: add 43751 SDIO ids and initialization
To:     Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc:     Ulf Hansson <ulf.hansson@linaro.org>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Arend van Spriel <aspriel@gmail.com>,
        Franky Lin <franky.lin@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Kalle Valo <kvalo@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>,
        Alexander Prutskov <alep@cypress.com>,
        Joseph chuang <jiac@cypress.com>,
        Kevin Hilman <khilman@baylibre.com>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Angus Ainslie <angus@akkea.ca>,
        Pierre-Hugues Husson <phh@phh.me>,
        linux-wireless@vger.kernel.org, linux-mmc@vger.kernel.org,
        linux-amlogic@lists.infradead.org
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Hi Marc,

On Mon, Mar 13, 2023 at 6:09=E2=80=AFPM Marc Gonzalez <marc.w.gonzalez@free=
.fr> wrote:
[...]
> > Wrapping mmc_send_io_op_cond() in a loop
> > makes it work on the second try.
>
> Almost there, I think, I hope :)
>
> DT prop "post-power-on-delay-ms" looks like what I needed all along.
> It exists both for host (default 10 ms) and for pwrseq_simple (default 0 =
apparently).
I think you're on the right track here!

[...]
> QUESTION:
> It's not clear to me why we sleep twice for host->ios.power_delay_ms?
I'm not sure but I think host->ios.power_delay_ms is independent from
the post-power-on-delay-ms property of "mmc-pwrseq-simple".

> Looks like all I need is to add post-power-on-delay-ms =3D <100>; to
>
>         sdio_pwrseq: sdio-pwrseq {
>                 compatible =3D "mmc-pwrseq-simple";
>                 reset-gpios =3D <&gpio GPIOX_6 GPIO_ACTIVE_LOW>;
>                 clocks =3D <&wifi32k>;
>                 clock-names =3D "ext_clock";
>         };
I found the following code in the vendor RTL8822CS driver [0].
Simplified version:
    for (i =3D 0; i <=3D 50; i++) {
       msleep(10);
        if (sdhci_device_attached())
           break;
   }
(so a delay of up to 500ms)

Also I found this code [1] in the same repo:
    mmc_pm_gpio_ctrl("rtl8189es_vdd_en", 1);
    udelay(100);
    mmc_pm_gpio_ctrl("rtl8189es_vcc_en", 1);
    udelay(50);

So like I said above: I think you're going in the right direction!


Best regards,
Martin


[0] https://github.com/chewitt/RTL8822CS/blob/main/platform/platform_sprd_s=
dio.c#L55-L62
[1] https://github.com/chewitt/RTL8822CS/blob/main/platform/platform_ARM_SU=
NxI_sdio.c#L35-L43