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From:   Fabio Estevam <festevam@gmail.com>
Date:   Fri, 4 Sep 2020 10:57:13 -0300
Message-ID: <CAOMZO5C7yyA11EOQvU0Fq-uDd5RK-B7WmbtvAy8OtPzfThYXRg@mail.gmail.com>
Subject: Re: (EXT) Re: [PATCH] spi-imx: remove num-cs support, set
 num_chipselect to 4
To:     Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Cc:     Mark Brown <broonie@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        NXP Linux Team <linux-imx@nxp.com>,
        linux-spi <linux-spi@vger.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Fri, Sep 4, 2020 at 10:02 AM Matthias Schiffer
<matthias.schiffer@ew.tq-group.com> wrote:

> This would make num_chipselect default to 1 again (set by
> __spi_alloc_controller()), breaking every i.MX board that uses more
> than 1 native CS.

Which boards are that? Are you referring to non-DT i.MX boards?

If so, I have sent a patch removing all non-DT i.MX boards.

> I'm aware that using cs-gpios instead of native CS is probably a good
> idea in any case, as the native CS of this SPI controller is kinda
> flaky (and at a glance it looks like all in-tree DTs do this; not sure
> about board files that don't use DTs?), but I'm not convinced that
> breaking native CS support completely is desirable either.

Initial i.MX chips with this SPI IP had issues in using chip-select in
native mode and GPIO chip-select has been used since them.

Do we have i.MX dts that make use of native chip select?