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author | Fabio Estevam <festevam@gmail.com> | 2020-08-19 18:04:24 -0300 |
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committer | Shawn Guo <shawnguo@kernel.org> | 2020-08-30 09:37:20 +0800 |
commit | 2bfdd113d0ee1ea40fbb49f181fea352a7e5e1a7 (patch) | |
tree | f8ca59a746d02d138630720c740f8ba0c76b5f68 /arch/arm/mach-sti/Kconfig | |
parent | 0b784a7b1c53c3989e9ee2dfdd3fc9b6b14b5256 (diff) | |
download | linux-2bfdd113d0ee1ea40fbb49f181fea352a7e5e1a7.tar.bz2 |
ARM: dts: imx: Fix the SPI chipselect polarity
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:
[ 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: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Diffstat (limited to 'arch/arm/mach-sti/Kconfig')
0 files changed, 0 insertions, 0 deletions