[PATCH] ARM: dts: bcm2711-rpi-cm4-io: Add rtc on i2c0

[Stefan Wahren]

Hi,

Am 30.11.21 um 13:02 schrieb nicolas saenz julienne:
> + Stephan, feel free to chime in.
>
> On Mon, 2021-11-22 at 16:33 +0000, Dave Stevenson wrote:
>> Hi
>>
>> On Mon, 22 Nov 2021 at 15:27, Uwe Kleine-König <uwe at kleine-koenig.org> wrote:
>>> The cm4-io board comes with an PCF85063. Add it to the device tree to make
>>> it usable.
>>>
>>> Signed-off-by: Uwe Kleine-König <uwe at kleine-koenig.org>
>>> ---
>>>  arch/arm/boot/dts/bcm2711-rpi-cm4-io.dts | 11 +++++++++++
>>>  1 file changed, 11 insertions(+)
>>>
>>> diff --git a/arch/arm/boot/dts/bcm2711-rpi-cm4-io.dts b/arch/arm/boot/dts/bcm2711-rpi-cm4-io.dts
>>> index 19600b629be5..1b67ad65e228 100644
>>> --- a/arch/arm/boot/dts/bcm2711-rpi-cm4-io.dts
>>> +++ b/arch/arm/boot/dts/bcm2711-rpi-cm4-io.dts
>>> @@ -20,6 +20,17 @@ led-pwr {
>>>         };
>>>  };
>>>
>>> +&i2c0 {
>>> +       pinctrl-0 = <&i2c0_gpio44>;
>> This will break the assumption that most users will make that i2c0 is
>> on GPIOs 0&1 (pins 27&28 on the 40 pin header). This is the case on
>> all other Pi variants, so having it different on the CM4IO is going to
>> catch some out.
>>
>> You can use the i2c-mux-pinctrl module to expose both pin mappings of
>> the BSC0 peripheral as separate I2C buses, which is what the
>> downstream device tree does.
> +1
>
> I think it can be done without breaking anything as long as we enable
> CONFIG_I2C_MUX_PINCTRL in arm64's defconfig.

i didn't test Dave's suggestion, but it sounds like the better approach
to me. Even this results in more changes ...

Thanks

>
> Regards,
> Nicolas