lkml.org 
[lkml]   [2022]   [Oct]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] arm64: dts: meson: Enable active coling using gpio-fan on Odroid N2/N2+
On 21/10/2022 07:07, Anand Moon wrote:
> Hi Martin / Neil,
>
> On Thu, 20 Oct 2022 at 02:10, Martin Blumenstingl
> <martin.blumenstingl@googlemail.com> wrote:
>>
>> Hi Anand,
>>
>> On Wed, Oct 19, 2022 at 7:17 PM Anand Moon <linux.amoon@gmail.com> wrote:
>> [...]
>>>>> +&pwm_AO_ab {
>>>>
>>>> &pwm_AO_cd not _ab
>>>>
>>> No it has a conflict with CPU_B (vddcpu_b) PWM
>> Uh, you're right. That's probably why the Hardkernel team uses a
>> software based PWM implementation: [0]
>> In hindsight they should have used a different pad either for VDDCPU_B
>> or the fan.
>>
>> I think the most pragmatic approach (since the "GPIO PWM" driver is
>> not upstream and I don't know if something like that would be accepted
>> upstream) is to use a GPIO based fan as you did in your initial patch.
>> Not sure what others think though.
>>
>
> When I use gpio-fan I get the following output with gpioinfo
> Feature it woks as expected.
>
> $ .sudo gpioinfo
> ....
> gpiochip1 - 15 lines:
> line 0: unnamed unused input active-high
> line 1: unnamed unused input active-high
> line 2: unnamed "enable" output active-high [used]
> line 3: unnamed unused input active-high
> line 4: unnamed unused output active-high
> line 5: unnamed unused input active-high
> line 6: unnamed unused input active-high
> line 7: unnamed unused input active-high
> line 8: unnamed "regulator-tflash_vdd" output active-high [used]
> line 9: unnamed "TF_IO" output active-high [used]
> line 10: unnamed "gpio-fan" output active-high [used]
> line 11: unnamed "n2:blue" output active-high [used]
> line 12: unnamed unused input active-high
> line 13: unnamed unused input active-high
> line 14: unnamed unused input active-high
>
> When I am using pwm-fan using *pwm_ao_d_10_pins* pin is not getting
> registered below hence it is not working on my end.

It's expected because it's not used as a GPIO but another function, you should look
in the pinctrl debugfs files to see it.

>
> $ .sudo gpioinfo
> ....
> gpiochip1 - 15 lines:
> line 0: unnamed unused input active-high
> line 1: unnamed unused input active-high
> line 2: unnamed "enable" output active-high [used]
> line 3: unnamed unused input active-high
> line 4: unnamed unused output active-high
> line 5: unnamed unused input active-high
> line 6: unnamed unused input active-high
> line 7: unnamed unused input active-high
> line 8: unnamed "regulator-tflash_vdd" output active-high [used]
> line 9: unnamed "TF_IO" output active-high [used]
> line 10: unnamed unused output active-high
> line 11: unnamed "n2:blue" output active-high [used]
> line 12: unnamed unused input active-high
> line 13: unnamed unused input active-high
> line 14: unnamed unused input active-high
>
> Thanks
> -Anand
>
>
>
>
>>
>> Best regards,
>> Martin
>>
>>
>> [0] https://github.com/hardkernel/linux/blob/c109dec94e7e819554830acfac4b6ed96e230179/arch/arm64/boot/dts/amlogic/meson64_odroidn2.dtsi#L356-L359

\
 
 \ /
  Last update: 2022-10-21 10:40    [W:3.900 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site