Re: [PATCH v1 2/4] ARM: dts: Add i2c-arbitrator bus for exynos5250-snow

[Stephen Warren <swarren@wwwdotorg.org>]

On 02/13/2013 11:02 AM, Doug Anderson wrote:
> 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.

> diff --git a/arch/arm/boot/dts/cros5250-common.dtsi b/arch/arm/boot/dts/cros5250-common.dtsi

>  	i2c@12CA0000 {
> -		status = "disabled";
> +		samsung,i2c-sda-delay = <100>;
> +		samsung,i2c-max-bus-freq = <66000>;

Shouldn't that use the standard clock-frequency property?

> diff --git a/arch/arm/boot/dts/exynos5250-snow.dts b/arch/arm/boot/dts/exynos5250-snow.dts

> +	i2c-arbitrator {
> +		compatible = "i2c-arbitrator";
> +		#address-cells = <1>;
> +		#size-cells = <0>;

> +		/* Use ID 104 as a hint that we're on physical bus 4 */
> +		i2c_104: i2c@0 {

Does something use that hint? It sounds a little odd.