DTS: ARM: gta04: introduce legacy spi-cs-high to make display work again
authorH. Nikolaus Schaller <hns@goldelico.com>
Fri, 20 Sep 2019 16:11:15 +0000 (18:11 +0200)
committerTony Lindgren <tony@atomide.com>
Mon, 23 Sep 2019 17:33:49 +0000 (10:33 -0700)
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>
Signed-off-by: Tony Lindgren <tony@atomide.com>
arch/arm/boot/dts/omap3-gta04.dtsi

index b295f6f..954c216 100644 (file)
                        spi-max-frequency = <100000>;
                        spi-cpol;
                        spi-cpha;
+                       spi-cs-high;
 
                        backlight= <&backlight>;
                        label = "lcd";