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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Tue, 14 Mar 2023 08:27:45 +0100
Message-ID: <CAPDyKFrC3a5-VP2DvCYGYUzKtX4Jc7cvNQOKfutW0sha=szOyg@mail.gmail.com>
Subject: Re: [RFC PATCH] brcmfmac: add 43751 SDIO ids and initialization
To:     Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        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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On Mon, 13 Mar 2023 at 22:42, Marc Gonzalez <marc.w.gonzalez@free.fr> wrote=
:
>
> On 13/03/2023 21:04, Martin Blumenstingl wrote:
>
> > On Mon, Mar 13, 2023 at 6:09=E2=80=AFPM Marc Gonzalez wrote:
> > [...]
> >> 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".
>
> They are distinct indeed (the props have the same name & similar purpose =
though).

Correct.

>
> host->ios.power_delay_ms is set via:
>
> drivers/mmc/core/host.c:        device_property_read_u32(dev, "post-power=
-on-delay-ms",

This is a property that may be specified in the host's OF node. See
Documentation/devicetree/bindings/mmc/mmc-controller.yaml.

> drivers/mmc/core/host.c-                                 &host->ios.power=
_delay_ms);

Note that the default value is set to 10 ms, in mmc_alloc_host(). So,
if you need a different value, that can be specified in DT.

>
>
> pwrseq->post_power_on_delay_ms is set via:
>
> drivers/mmc/core/pwrseq_simple.c:       device_property_read_u32(dev, "po=
st-power-on-delay-ms",

This is a property that may be specified in the pwrseq OF node. See
Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.yaml.

> drivers/mmc/core/pwrseq_simple.c-                                &pwrseq-=
>post_power_on_delay_ms);
>
>
> However, they are both used to delay mmc_power_up(),
> and the host delay is used to sleep twice, which I
> found confusing ;)

It's certainly a bit hairy to follow, but I think you have understood
things correctly.

>
> Regards
>

Looks like you are getting closer to the solution, at least for the
first step to make sure the SDIO card is getting detected properly.
Nice!

Kind regards
Uffe