[PATCH v2] ARM: dts: imx27-eukrea: Remove invalid spi-cpol

[PATCH v2] ARM: dts: imx27-eukrea: Remove invalid spi-cpol

[Fabio Estevam]

The ADS7846 timing diagrams show DCLK low when inactive, and its pin
descriptions specify that DIN is latched on the rising edge of DCLK
while DOUT is shifted on the falling edge. This corresponds to SPI mode
0, with CPOL=0 and CPHA=0.

The spi-cpol property without spi-cpha instead selects SPI mode 2,
which uses the opposite clock edges and does not match the ADS7846
serial interface. Remove the invalid property.

This also matches the driver behavior: ads7846_probe() clears
SPI_MODE_X_MASK and selects SPI_MODE_0 before calling spi_setup().

This fixes the following dtbs_check warning:

  imx27-eukrea-mbimxsd27-baseboard.dtb: ads7846@0 (ti,ads7846):
    Unevaluated properties are not allowed (spi-cpol was unexpected)

Signed-off-by: Fabio Estevam <festevam@gmail.com>
---
Changes since v1:

- Remove spi-cpol from the dts instead of adding it to the binding. (Sashiko)

 arch/arm/boot/dts/nxp/imx/imx27-eukrea-mbimxsd27-baseboard.dts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm/boot/dts/nxp/imx/imx27-eukrea-mbimxsd27-baseboard.dts b/arch/arm/boot/dts/nxp/imx/imx27-eukrea-mbimxsd27-baseboard.dts
index 26833ed3339e..cf5603ec6826 100644
--- a/arch/arm/boot/dts/nxp/imx/imx27-eukrea-mbimxsd27-baseboard.dts
+++ b/arch/arm/boot/dts/nxp/imx/imx27-eukrea-mbimxsd27-baseboard.dts
@@ -77,7 +77,6 @@ ads7846@0 {
 		pinctrl-0 = <&pinctrl_touch>;
 		reg = <0>;
 		interrupts-extended = <&gpio4 25 IRQ_TYPE_LEVEL_LOW>;
-		spi-cpol;
 		spi-max-frequency = <1500000>;
 		ti,keep-vref-on;
 	};
-- 
2.43.0