commit 6953c57ab172 "gpio: of: Handle SPI chipselect legacy bindings"
did introduce logic to centrally handle the legacy spi-cs-high property in combination with cs-gpios. This assumes that the polarity of the CS has to be inverted if spi-cs-high is missing, even and especially if non-legacy GPIO_ACTIVE_HIGH is specified.
The DTS for the GTA04 was orginally introduced under the assumption that there is no need for spi-cs-high if the gpio is defined with proper polarity GPIO_ACTIVE_HIGH.
This was not a problem until gpiolib changed the interpretation of GPIO_ACTIVE_HIGH and missing spi-cs-high.
The effect is that the missing spi-cs-high is now interpreted as CS being low (despite GPIO_ACTIVE_HIGH) which turns off the SPI interface when the panel is to be programmed by the panel driver.
Therefore, we have to add the redundant and legacy spi-cs-high property to properly activate CS.
Cc: stable@vger.kernel.org Signed-off-by: H. Nikolaus Schaller hns@goldelico.com --- arch/arm/boot/dts/omap3-gta04.dtsi | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/arm/boot/dts/omap3-gta04.dtsi b/arch/arm/boot/dts/omap3-gta04.dtsi index b295f6fad2a5..954c216140ad 100644 --- a/arch/arm/boot/dts/omap3-gta04.dtsi +++ b/arch/arm/boot/dts/omap3-gta04.dtsi @@ -120,6 +120,7 @@ spi-max-frequency = <100000>; spi-cpol; spi-cpha; + spi-cs-high;
backlight= <&backlight>; label = "lcd";
* H. Nikolaus Schaller hns@goldelico.com [190920 09:12]:
commit 6953c57ab172 "gpio: of: Handle SPI chipselect legacy bindings"
did introduce logic to centrally handle the legacy spi-cs-high property in combination with cs-gpios. This assumes that the polarity of the CS has to be inverted if spi-cs-high is missing, even and especially if non-legacy GPIO_ACTIVE_HIGH is specified.
The DTS for the GTA04 was orginally introduced under the assumption that there is no need for spi-cs-high if the gpio is defined with proper polarity GPIO_ACTIVE_HIGH.
This was not a problem until gpiolib changed the interpretation of GPIO_ACTIVE_HIGH and missing spi-cs-high.
The effect is that the missing spi-cs-high is now interpreted as CS being low (despite GPIO_ACTIVE_HIGH) which turns off the SPI interface when the panel is to be programmed by the panel driver.
Therefore, we have to add the redundant and legacy spi-cs-high property to properly activate CS.
Thanks applying into fixes.
Tony