Re: [PATCH 1/4] ARM: dts: imx6dl-alti6p: Fix the SPI chipselect polarity
From: Shawn Guo <shawnguo@kernel.org>
Date: 2021-09-22 01:25:39
On Sat, Aug 14, 2021 at 10:27:13AM -0300, Fabio Estevam wrote:
Hi Shawn, On Sat, Jul 17, 2021 at 1:57 AM Oleksij Rempel [off-list ref] wrote:quoted
On Fri, Jul 16, 2021 at 10:36:56AM -0300, Fabio Estevam wrote:quoted
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>Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de> Thank you!A gentle ping on this series.
Should we have Fixes tags for the patches? Shawn _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel