Messages in this thread | | | Date | Fri, 21 Oct 2022 10:38:48 +0200 | From | neil.armstrong@linaro ... | Subject | Re: [PATCH] arm64: dts: meson: Enable active coling using gpio-fan on Odroid N2/N2+ |
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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
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