[PATCH 1/4] ARM: dts: imx6dl-alti6p: Fix the SPI chipselect polarity

[Fabio Estevam]

Hi Shawn,

On Sat, Jul 17, 2021 at 1:57 AM Oleksij Rempel <o.rempel at pengutronix.de> wrote:
>
> 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 at 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 at gmail.com>
>
> Reviewed-by: Oleksij Rempel <o.rempel at pengutronix.de>
> Thank you!

A gentle ping on this series.