From: Shawn Guo <shawnguo@kernel.org>
To: Fabio Estevam <festevam@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org, o.rempel@pengutronix.de,
Markus.Niebel@tq-group.com
Subject: Re: [PATCH 1/4] ARM: dts: imx6dl-alti6p: Fix the SPI chipselect polarity
Date: Wed, 22 Sep 2021 11:04:39 +0800 [thread overview]
Message-ID: <20210922030438.GG10217@dragon> (raw)
In-Reply-To: <20210716133659.3372047-1-festevam@gmail.com>
On Fri, Jul 16, 2021 at 10:36:56AM -0300, Fabio Estevam wrote:
> The conversion of the spi-imx driver to use GPIO descriptors
> in commit 8cdcd8aeee28 ("spi: imx/fsl-lpspi: Convert to GPIO descriptors")
> helped to detect the following SPI chipselect polarity mismatch on an
> imx6q-sabresd for example:
>
> [ 4.854337] m25p80@0 enforce active low on chipselect handle
>
> Prior to the above commit, the chipselect polarity passed via cs-gpios
> property was ignored and considered active-low.
>
> The reason for such mismatch is clearly explained in the comments inside
> drivers/gpio/gpiolib-of.c:
>
> * SPI children have active low chip selects
> * by default. This can be specified negatively
> * by just omitting "spi-cs-high" in the
> * device node, or actively by tagging on
> * GPIO_ACTIVE_LOW as flag in the device
> * tree. If the line is simultaneously
> * tagged as active low in the device tree
> * and has the "spi-cs-high" set, we get a
> * conflict and the "spi-cs-high" flag will
> * take precedence.
>
> To properly represent the SPI chipselect polarity, change it to active-low
> when the "spi-cs-high" property is absent.
>
> Signed-off-by: Fabio Estevam <festevam@gmail.com>
Applied all, thanks!
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prev parent reply other threads:[~2021-09-22 3:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-16 13:36 [PATCH 1/4] ARM: dts: imx6dl-alti6p: Fix the SPI chipselect polarity Fabio Estevam
2021-07-16 13:36 ` [PATCH 2/4] ARM: dts: imx6qp-prtwd3: " Fabio Estevam
2021-07-17 4:58 ` Oleksij Rempel
2021-09-22 3:02 ` Shawn Guo
2021-07-16 13:36 ` [PATCH 3/4] ARM: dts: imx6qdl-tqma6: " Fabio Estevam
2021-07-16 13:36 ` [PATCH 4/4] ARM: dts: imx7d-sdb: " Fabio Estevam
2021-07-17 4:57 ` [PATCH 1/4] ARM: dts: imx6dl-alti6p: " Oleksij Rempel
2021-08-14 13:27 ` Fabio Estevam
2021-09-22 1:23 ` Shawn Guo
2021-09-22 1:28 ` Fabio Estevam
2021-09-22 2:03 ` Shawn Guo
2021-09-22 2:04 ` Fabio Estevam
2021-09-22 3:04 ` Shawn Guo [this message]
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