linux-kernel - Re: [PATCH 10/11] spi: dw: Add support for Pensando Elba SoC

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Message-ID: <CAK9rFnzp0+80dX_-NYidfVXWJ1sru5mNk1vgVDzoV7VeEekpwQ@mail.gmail.com>
Date:   Wed, 25 May 2022 14:54:47 -0700
From:   Brad Larson <brad@...sando.io>
To:     Serge Semin <fancer.lancer@...il.com>
Cc:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Arnd Bergmann <arnd@...db.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Mark Brown <broonie@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Olof Johansson <olof@...om.net>,
        David Clear <dac2@...sando.io>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        linux-spi <linux-spi@...r.kernel.org>,
        linux-mmc <linux-mmc@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 10/11] spi: dw: Add support for Pensando Elba SoC

Hi Sergey,

On Tue, Apr 12, 2022 at 4:06 AM Serge Semin <fancer.lancer@...il.com> wrote:
>
> > +static void elba_spics_set_cs(struct dw_spi_elba *dwselba, int cs, int enable)
> > +{
> > +     regmap_update_bits(dwselba->regmap, dwselba->reg, ELBA_SPICS_MASK(cs),
> > +                        ELBA_SPICS_SET(cs, enable));
> > +}
> > +
> > +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
>
> The methods naming is ambiguous. Moreover it breaks this module naming
> convention. Could you change them to something like:
> dw_spi_elba_override_cs()
> and
> dw_spi_elba_set_cs()
> ?

Yes, changed elba_spics_set_cs() -> dw_spi_elba_override_cs()

> > +     /* deassert cs */
>
> > +     elba_spics_set_cs(dwselba, 0, 1);
> > +     elba_spics_set_cs(dwselba, 1, 1);
>
> What if the CS lines are of the active-high type? In that case basically
> you get to do the opposite to what you claim in the comment here.
>
> Note the CS setting into the deactivated state is done in the spi_setup()
> method anyway, at the moment of the peripheral SPI device registration
> stage (see its calling the spi_set_cs() function). Thus what you are doing
> here is redundant.

Yes this is a redundant initialization and is removed.  For Elba these CS lines
are active-low only.

Regards,
Brad