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 <diand...@chromium.org>
---
Changes in v5:
- Adjust bindings as per Wolfram Sang.
Changes in v4:
- Changed mux gpio syntax to work atop Thomas's "ARM: dts: add pin
state information in client nodes for Exynos5 platforms"; avoid
adding gpios property to i2c@12CA0000 for the same reason.
Changes in v3: None
Changes in v2:
- Use new device tree property names / compatible string.
- Include that the GPIOs for arbitration are active low.
arch/arm/boot/dts/cros5250-common.dtsi | 3 ++-
arch/arm/boot/dts/exynos5250-snow.dts | 25 +++++++++++++++++++++++++
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/cros5250-common.dtsi
b/arch/arm/boot/dts/cros5250-common.dtsi
index 8a5b3a6..0a61bbb 100644
--- 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
--- 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.
--
1.8.1.3
--
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