On Fri, Feb 12, 2016 at 11:15 AM, Robert Nelson <[email protected]> wrote:
> On Fri, Feb 12, 2016 at 11:11 AM, Rafael Vega <[email protected]> wrote:
>> Hi.
>>
>> I have the following DTO that I've been using successfully in kernel 3.8 to
>> use pin P9_41 as an input:
>>
>>          ...
>>          P9_41A_i: P9_41A_in{pinctrl-single,pins = <0x1B4 0x37>;};
>>          P9_41A_o: P9_41A_out{pinctrl-single,pins = <0x1B4 0x0F  0x1A8
>> 0x37>;};
>>          ...
>>          P9_41A_mux {
>>             compatible = "bone-pinmux-helper";
>>             status = "okay";
>>             pinctrl-names = "input", "output";
>>             pinctrl-0 = <&P9_41A_i>;
>>             pinctrl-1 = <&P9_41A_o>;
>>          };
>>
>>
>> After compiling and loading the DTO in kernel 3.8, the
>> /sys/devices/ocp.4/P9_41_mux/status file is created and if I echo "input"
>> into it, I can read the pin as an input. However, in kernel 4.1, the
>> /sys/devices/platform/ocp/P9_41_mux/status file is created but when I echo
>> "input" to it, nothing happens and I can't read the value of the pin.
>>
>> What am I missing? What else do I need to use to enable P9_42 as an input?
>
> P9_41 is used by audio, so make sure you are using the
> *-nhdmi-overlay.dtb, *-emmc-overlay.dtb or *-overlay.dtb

ah p9_41.. so on mainline it's setup as clkout2_pin:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am335x-bone-common.dtsi#n98

I left it enabled for our 4.1.x branch:

https://github.com/beagleboard/linux/blob/4.1/arch/arm/boot/dts/am335x-bone-common.dtsi#L98-L102

It was first introduced here:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/arch/arm/boot/dts/am335x-bone-common.dtsi?id=2ba3549352277514a8e4790adff77a783ee1b9e2

anyone have a hint/reason why it should/shouldn't be enabled by default..

Regards,

-- 
Robert Nelson
https://rcn-ee.com/

-- 
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