| Message ID | 1366129742-16048-2-git-send-email-dianders@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 16, 2013 at 09:29:01AM -0700, 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> Acked-by: Olof Johansson <olof@lixom.net> -Olof
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.
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 v6: None 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(-)