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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Aug 19, 2020 at 07:02:19PM -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 Applied, thanks. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel