| Message ID | 5c979df0d9eb68c234686c85e6e22f84b143c7ed.1606899361.git.hns@goldelico.com |
|---|---|
| State | Accepted |
| Commit | 181739822cf6f8f4e12b173913af2967a28906c0 |
| Headers | show |
| Series | None | expand |
diff --git a/arch/arm/boot/dts/omap3-gta04.dtsi b/arch/arm/boot/dts/omap3-gta04.dtsi index 7c4c0124e20d45..76344b9c294512 100644 --- a/arch/arm/boot/dts/omap3-gta04.dtsi +++ b/arch/arm/boot/dts/omap3-gta04.dtsi @@ -139,7 +139,7 @@ spi_lcd: spi_lcd { gpio-sck = <&gpio1 12 GPIO_ACTIVE_HIGH>; gpio-miso = <&gpio1 18 GPIO_ACTIVE_HIGH>; gpio-mosi = <&gpio1 20 GPIO_ACTIVE_HIGH>; - cs-gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>; + cs-gpios = <&gpio1 19 GPIO_ACTIVE_LOW>; num-chipselects = <1>; /* lcd panel */
Historically the panel driver did know the polarity and the device tree introduced by commit c2e138bc8ed8 ("ARM: dts: omap3-gta04: Add display support") as cs-gpios = <&gpio1 19 0>; The 0 was ignored because the spi-gpio driver did only look at the presence of an spi-cs-high property. Since it was not present, the CS was active low. commit 3a637e008e54 ("ARM: dts: Use defined GPIO constants in flags cell for OMAP2+ boards") replaced the constant 0 by the constant GPIO_ACTIVE_HIGH which was no problem because it was still ignored. Starting with commit 6953c57ab172 ("gpio: of: Handle SPI chipselect legacy bindings") the gpiolib and spi-gpio drivers tried to handle both properties by making an inversion for GPIO_ACTIVE_HIGH definitions. To keep the device tree compatible with older kernels which ignored the GPIO_ACTIVE property we just added spi-cs-high;. This tells the inversion logic that we want an active low chip select as defined by the rule documented by the commit message of commit 6953c57ab172 ("gpio: of: Handle SPI chipselect legacy bindings") "If the line is tagged as active high in the device tree with the second cell flag and has no "spi-cs-high" property we enforce active low semantics (as this is the exception we can just tag on the flag)." This went well until commit 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors") arrived which effectively removes the inversion logic rule. Removing spi-cs-high; in a separate patch already solves the urgent problem, but to remove [ 3.629791] td028ttec1@0 enforce active low on chipselect handle and to be safe against future changes of such rules we also define the cs-gpio explicitly as GPIO_ACTIVE_LOW. Note that this patch breaks all kernels between commit 6953c57ab172 ("gpio: of: Handle SPI chipselect legacy bindings") and commit 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors") Fixes: 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors") CC: stable@vger.kernel.org Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com> --- arch/arm/boot/dts/omap3-gta04.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)