| Message ID | c031340840daba810bb2a612c35eea7fab307e56.1568995874.git.hns@goldelico.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] DTS: ARM: gta04: introduce legacy spi-cs-high to make display work again | expand |
* 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
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";
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(+)