diff mbox

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

Message ID 1365543270-10736-2-git-send-email-dianders@chromium.org (mailing list archive)
State New, archived
Headers show

Commit Message

Doug Anderson April 9, 2013, 9:34 p.m. UTC
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>
---
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(-)

Comments

Kim Kukjin April 10, 2013, 10:59 a.m. UTC | #1
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@chromium.org>

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
Wolfram Sang April 10, 2013, 11:02 a.m. UTC | #2
On Wed, Apr 10, 2013 at 07:59:17PM +0900, Kukjin Kim wrote:
> 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@chromium.org>
> 
> I'm fine on 2nd and 3rd patches. Shall I take only two patches without 1st
> one in samsung tree?

Please wait for my OK on patch 1. Or ack patches 2 and 3 and I will pick
them up. I am fine with both.
Kim Kukjin April 10, 2013, 2:12 p.m. UTC | #3
On 04/10/13 20:02, Wolfram Sang wrote:
> On Wed, Apr 10, 2013 at 07:59:17PM +0900, Kukjin Kim wrote:
>> 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@chromium.org>
>>
>> I'm fine on 2nd and 3rd patches. Shall I take only two patches without 1st
>> one in samsung tree?
>
> Please wait for my OK on patch 1. Or ack patches 2 and 3 and I will pick
> them up. I am fine with both.
>
OK, I will wait for your reply on this. Because I suppose if the dt 
patches in your tree could make useless conflicts. Anyway let me know 
your opinion on that.

Thanks.

- Kukjin
diff mbox

Patch

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.