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References: <20210329015938.20316-1-brad@pensando.io> <20210329015938.20316-4-brad@pensando.io>
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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 29 Mar 2021 13:43:03 +0300
Message-ID: <CAHp75VfmSKVRB+Rm+sWDjZaJwdX4qt56Qj6aehe4YnA5d6+a6Q@mail.gmail.com>
Subject: Re: [PATCH v2 03/13] spi: dw: Add support for Pensando Elba SoC SPI
To:     Brad Larson <brad@pensando.io>
Cc:     linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Mark Brown <broonie@kernel.org>,
        Serge Semin <fancer.lancer@gmail.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Olof Johansson <olof@lixom.net>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        linux-spi <linux-spi@vger.kernel.org>,
        linux-mmc <linux-mmc@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Mar 29, 2021 at 5:01 AM Brad Larson <brad@pensando.io> wrote:
>
> The Pensando Elba SoC uses a GPIO based chip select
> for two DW SPI busses with each bus having two
> chip selects.

...

> +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
> +{
> +       struct dw_spi *dws = spi_master_get_devdata(spi->master);
> +
> +       if (!enable) {

Can you use positive conditional?

> +               /*
> +                * Using a GPIO-based chip-select, the DW SPI
> +                * controller still needs its own CS bit selected
> +                * to start the serial engine.  On Elba the specific
> +                * CS doesn't matter to start the serial engine,
> +                * so using CS0.
> +                */
> +               dw_writel(dws, DW_SPI_SER, BIT(0));
> +       } else {
> +               dw_writel(dws, DW_SPI_SER, 0);
> +       }
> +}

-- 
With Best Regards,
Andy Shevchenko