ARM: dts: alt: use demuxer for I2C4

Make it possible to fallback to GPIO for I2C4 on the EXIO-B connector.

This is based on reference work for the I2C0 core of the lager/r8a7790
by Wolfram Sang.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
[wsa: rebased and fixed aliases]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

diff --git a/arch/arm/boot/dts/r8a7794-alt.dts b/arch/arm/boot/dts/r8a7794-alt.dts
index a3e7468..7270d42 100644 (file)
--- a/arch/arm/boot/dts/r8a7794-alt.dts
+++ b/arch/arm/boot/dts/r8a7794-alt.dts
@@ -18,6 +18,8 @@
 
        aliases {
                serial0 = &scif2;
+               i2c10 = &gpioi2c4;
+               i2c12 = &i2cexio4;
        };
 
        chosen {
@@ -135,6 +137,29 @@
                #clock-cells = <0>;
                clock-frequency = <148500000>;
        };
+
+       gpioi2c4: i2c-10 {
+               #address-cells = <1>;
+               #size-cells = <0>;
+               compatible = "i2c-gpio";
+               status = "disabled";
+               gpios = <&gpio4 9 GPIO_ACTIVE_HIGH /* sda */
+                        &gpio4 8 GPIO_ACTIVE_HIGH /* scl */
+                       >;
+               i2c-gpio,delay-us = <5>;
+       };
+
+       /*
+        * I2C4 is routed to EXIO connector B, pins 73 (SCL) + 74 (SDA).
+        * A fallback to GPIO is provided.
+        */
+       i2cexio4: i2c-14 {
+               compatible = "i2c-demux-pinctrl";
+               i2c-parent = <&i2c4>, <&gpioi2c4>;
+               i2c-bus-name = "i2c-exio4";
+               #address-cells = <1>;
+               #size-cells = <0>;
+       };
 };
 
 &du {
@@ -194,6 +219,11 @@
                function = "i2c1";
        };
 
+       i2c4_pins: i2c4 {
+               groups = "i2c4";
+               function = "i2c4";
+       };
+
        vin0_pins: vin0 {
                groups = "vin0_data8", "vin0_clk";
                function = "vin0";
@@ -314,6 +344,11 @@
        };
 };
 
+&i2c4 {
+       pinctrl-0 = <&i2c4_pins>;
+       pinctrl-names = "i2c-exio4";
+};
+
 &vin0 {
        status = "okay";
        pinctrl-0 = <&vin0_pins>;