RE: [PATCH v5 2/3] ARM: dts: Add i2c-arbitrator bus for exynos5250-snow

From: Kukjin Kim
Date: Wed Apr 10 2013 - 06:59:24 EST


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.
>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>

I'm fine on 2nd and 3rd patches. Shall I take only two patches without 1st
one in samsung tree?

- Kukjin

> ---
> 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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