overlays: gpio-keys: Avoid open-drain warnings

The i2c-gpio driver expects to use a GPIO in open-drain mode. Failure
to configure it in that way causes alarming warnings in the kernel log.
The BCM283x and BCM2711 GPIO blocks don't support open-drain mode,
but i2c-gpio works anyway. Silence the warning by declaring that
open-drain mode has been enabled by other means.

See: https://github.com/raspberrypi/firmware/issues/1381

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

diff --git a/arch/arm/boot/dts/overlays/i2c-gpio-overlay.dts b/arch/arm/boot/dts/overlays/i2c-gpio-overlay.dts
index 39e7bc5..def139d 100644 (file)
--- a/arch/arm/boot/dts/overlays/i2c-gpio-overlay.dts
+++ b/arch/arm/boot/dts/overlays/i2c-gpio-overlay.dts
@@ -16,6 +16,8 @@
                                         &gpio 24 0 /* scl */
                                        >;
                                i2c-gpio,delay-us = <2>;        /* ~100 kHz */
+                               i2c-gpio,sda-open-drain;
+                               i2c-gpio,scl-open-drain;
                                #address-cells = <1>;
                                #size-cells = <0>;
                        };