On 16 February 2013 04:46, Doug Anderson <[email protected]> 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 <[email protected]>
Tested-by: Naveen Krishna Chatradhi <[email protected]>
The patch set [v3] is tested on snow with test case which uses i2c-4 from both
EC and AP side continuously for a more than a couple of minutes.
> ---
> 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 | 5 ++++-
> arch/arm/boot/dts/exynos5250-snow.dts | 25 +++++++++++++++++++++++++
> 2 files changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/cros5250-common.dtsi b/arch/arm/boot/dts/cros5250-common.dtsi
> index 46c0980..f451375 100644
> --- a/arch/arm/boot/dts/cros5250-common.dtsi
> +++ b/arch/arm/boot/dts/cros5250-common.dtsi
> @@ -58,7 +58,10 @@
> };
>
> i2c@12CA0000 {
> - status = "disabled";
> + samsung,i2c-sda-delay = <100>;
> + samsung,i2c-max-bus-freq = <66000>;
> + gpios = <&gpa2 0 3 3 0>,
> + <&gpa2 1 3 3 0>;
> };
>
> i2c@12CB0000 {
> diff --git a/arch/arm/boot/dts/exynos5250-snow.dts b/arch/arm/boot/dts/exynos5250-snow.dts
> index 17dd951..d2d4b48 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;
> + };
> +
> gpio-keys {
> compatible = "gpio-keys";
>
> @@ -29,6 +33,27 @@
> };
> };
>
> + i2c-arbitrator {
> + compatible = "i2c-arbitrator-cros-ec";
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + i2c-parent = <&{/i2c@12CA0000}>;
> +
> + ap-claim-gpio = <&gpf0 3 1 0x10000 0>;
> + ec-claim-gpio = <&gpe0 4 0 0x10003 0>;
> + 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
>
> --
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> Please read the FAQ at http://www.tux.org/lkml/
--
Shine bright,
(: Nav :)
Naveen Krishna Ch wrote:
> On 16 February 2013 04:46, Doug Anderson <[email protected]> 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 <[email protected]>
> Tested-by: Naveen Krishna Chatradhi <[email protected]>
> The patch set [v3] is tested on snow with test case which uses i2c-4 from both
> EC and AP side continuously for a more than a couple of minutes.
>
Thanks for your test and looks good to me.
BTW, Doug, I think, this should be re-worked to use pinctrl. Can you?
Thanks.
- Kukjin
> > ---
> > 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 | 5 ++++-
> > arch/arm/boot/dts/exynos5250-snow.dts | 25 +++++++++++++++++++++++++
> > 2 files changed, 29 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/boot/dts/cros5250-common.dtsi
> b/arch/arm/boot/dts/cros5250-common.dtsi
> > index 46c0980..f451375 100644
> > --- a/arch/arm/boot/dts/cros5250-common.dtsi
> > +++ b/arch/arm/boot/dts/cros5250-common.dtsi
> > @@ -58,7 +58,10 @@
> > };
> >
> > i2c@12CA0000 {
> > - status = "disabled";
> > + samsung,i2c-sda-delay = <100>;
> > + samsung,i2c-max-bus-freq = <66000>;
> > + gpios = <&gpa2 0 3 3 0>,
> > + <&gpa2 1 3 3 0>;
> > };
> >
> > i2c@12CB0000 {
> > diff --git a/arch/arm/boot/dts/exynos5250-snow.dts
> b/arch/arm/boot/dts/exynos5250-snow.dts
> > index 17dd951..d2d4b48 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;
> > + };
> > +
> > gpio-keys {
> > compatible = "gpio-keys";
> >
> > @@ -29,6 +33,27 @@
> > };
> > };
> >
> > + i2c-arbitrator {
> > + compatible = "i2c-arbitrator-cros-ec";
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + i2c-parent = <&{/i2c@12CA0000}>;
> > +
> > + ap-claim-gpio = <&gpf0 3 1 0x10000 0>;
> > + ec-claim-gpio = <&gpe0 4 0 0x10003 0>;
> > + 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
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to [email protected]
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at http://www.tux.org/lkml/
>
>
>
> --
> Shine bright,
> (: Nav :)
Kukjin,
On Wed, Mar 13, 2013 at 12:30 AM, Kukjin Kim <[email protected]> wrote:
> BTW, Doug, I think, this should be re-worked to use pinctrl. Can you?
Yes, I've already got this locally. I hadn't sent it up yet since I
wasn't sure whether pinctrl would land before or after this. I'll
send it up today against my local cherry-pick of Thomas's pinctrl
stuff (since it doesn't seem to be in linux-next nor in
arm-soc/for-next).
Naveen: I'm going to keep your Tested-by on all 3 patches if that's
OK. The only difference will be the gpio specifier in the device tree
and the change is trivial.
-Doug