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From:   Simon Glass <sjg@chromium.org>
Date:   Wed, 9 Dec 2020 09:41:08 -0700
Message-ID: <CAPnjgZ1nV4FTvA9zAh046Vpki01WfVcowP8CPxrx1b3dONM-Og@mail.gmail.com>
Subject: Re: [PATCH 1/3] platform/chrome: cros_ec_spi: Don't overwrite spi::mode
To:     Stephen Boyd <swboyd@chromium.org>
Cc:     Mark Brown <broonie@kernel.org>, lk <linux-kernel@vger.kernel.org>,
        linux-spi@vger.kernel.org, Benson Leung <bleung@chromium.org>,
        linux-arm-msm@vger.kernel.org,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Gwendal Grignou <gwendal@chromium.org>,
        Douglas Anderson <dianders@chromium.org>,
        Alexandru M Stan <amstan@chromium.org>
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On Fri, 4 Dec 2020 at 12:35, Stephen Boyd <swboyd@chromium.org> wrote:
>
> There isn't any need to overwrite the mode here in the driver with what
> has been detected by the firmware, such as DT or ACPI. In fact, if we
> use the SPI CS gpio descriptor feature we will overwrite the mode with
> SPI_MODE_0 where it already contains SPI_MODE_0 and more importantly
> SPI_CS_HIGH. Clearing the SPI_CS_HIGH bit causes the CS line to toggle
> when the device is probed when it shouldn't change, confusing the driver
> and making it fail to probe. Drop the assignment and let the spi core
> take care of it.
>
> Fixes: a17d94f0b6e1 ("mfd: Add ChromeOS EC SPI driver")
> Cc: Simon Glass <sjg@chromium.org>
> Cc: Gwendal Grignou <gwendal@chromium.org>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> Tested-by: Douglas Anderson <dianders@chromium.org>
> Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Cc: Alexandru M Stan <amstan@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>  drivers/platform/chrome/cros_ec_spi.c | 1 -
>  1 file changed, 1 deletion(-)


Reviewed-by: Simon Glass <sjg@chromium.org>


>
>
> diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
> index dfa1f816a45f..f9df218fc2bb 100644
> --- a/drivers/platform/chrome/cros_ec_spi.c
> +++ b/drivers/platform/chrome/cros_ec_spi.c
> @@ -742,7 +742,6 @@ static int cros_ec_spi_probe(struct spi_device *spi)
>         int err;
>
>         spi->bits_per_word = 8;
> -       spi->mode = SPI_MODE_0;
>         spi->rt = true;
>         err = spi_setup(spi);
>         if (err < 0)
> --
> https://chromeos.dev
>