ARM: dts: Add i2c-arbitrator bus for exynos5250-snow

We need to use the i2c-arbitrator to talk to any of the devices on i2c
bus 4 on exynos5250-snow so that we don't confuse the embedded
controller (EC).  Add the i2c-arbitrator to the device tree.  As we
add future devices (keyboard, sbs, tps65090) we'll add them on top of
this.

The arbitrated bus is numbered 104 simply as a convenience to make it
easier for people poking around to guess that it might have something
to do with the physical bus 4.

The addition is split between the cros5250-common and the snow device
tree file since not all cros5250-class devices use arbitration.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

diff --git a/arch/arm/boot/dts/cros5250-common.dtsi b/arch/arm/boot/dts/cros5250-common.dtsi
index 8a5b3a6..0a61bbb 100644 (file)
--- a/arch/arm/boot/dts/cros5250-common.dtsi
+++ b/arch/arm/boot/dts/cros5250-common.dtsi
@@ -193,7 +193,8 @@
        };
 
        i2c@12CA0000 {
-               status = "disabled";
+               samsung,i2c-sda-delay = <100>;
+               samsung,i2c-max-bus-freq = <66000>;
        };
 
        i2c@12CB0000 {

diff --git a/arch/arm/boot/dts/exynos5250-snow.dts b/arch/arm/boot/dts/exynos5250-snow.dts
index 581ffae..fa85f58 100644 (file)
--- a/arch/arm/boot/dts/exynos5250-snow.dts
+++ b/arch/arm/boot/dts/exynos5250-snow.dts
@@ -16,6 +16,10 @@
        model = "Google Snow";
        compatible = "google,snow", "samsung,exynos5250";
 
+       aliases {
+               i2c104 = &i2c_104;
+       };
+
        pinctrl@11400000 {
                sd3_clk: sd3-clk {
                        samsung,pin-drv = <0>;
@@ -44,6 +48,27 @@
                };
        };
 
+       i2c-arbitrator {
+               compatible = "i2c-arb-gpio-challenge";
+               #address-cells = <1>;
+               #size-cells = <0>;
+
+               i2c-parent = <&{/i2c@12CA0000}>;
+
+               our-claim-gpio = <&gpf0 3 1>;
+               their-claim-gpios = <&gpe0 4 1>;
+               slew-delay-us = <10>;
+               wait-retry-us = <3000>;
+               wait-free-us = <50000>;
+
+               /* Use ID 104 as a hint that we're on physical bus 4 */
+               i2c_104: i2c@0 {
+                       reg = <0>;
+                       #address-cells = <1>;
+                       #size-cells = <0>;
+               };
+       };
+
        /*
         * On Snow we've got SIP WiFi and so can keep drive strengths low to
         * reduce EMI.