Bug#810894: src:linux: GPIO probe failure on Linkstation LS-WXL/WSXL
Hello Roger,
On 01/14/2016 04:43 PM, Roger Shimizu wrote:
> On Thu, Jan 14, 2016 at 11:32 PM, Roger Shimizu <rogershimizu@gmail.com> wrote:
>> On Thu, Jan 14, 2016 at 11:08 PM, Uwe Kleine-König
>> <uwe+debian@kleine-koenig.org> wrote:
>>>>>> I need to run the following command to enable USB port on Linkstation
>>>>>> LS-WXL/WSXL (armel/kirkwood with DTS [0] ):
>>>>>> echo 37 >/sys/class/gpio/export
>>>>>> echo out > /sys/class/gpio/gpio37/direction
>>>>>> echo 1 > /sys/class/gpio/gpio37/value
>>>
>>> Can you post the contents of /sys/kernel/debug/gpio when the broken
>>> kernel is running?
>>
>> Thanks for the debugging tool!
>> It seems there's clue ...
>>
>> Here's the log for working & non-working kernel:
>>
>> # uname -a
>> Linux LS-WXL 4.2.0-0.bpo.1-kirkwood #1 Debian 4.2.6-3~bpo8+2
>> (2015-12-14) armv5tel GNU/Linux
>> # mount -t debugfs none /sys/kernel/debug
For me this doesn't need to be mounted explicitly. Maybe the relevant
difference is that I'm using systemd and you don't?
>> # cat /sys/kernel/debug/gpio
>> GPIOs 0-31, platform/f1010100.gpio, f1010100.gpio:
>> gpio-28 (HDD0 Power ) out hi
>> gpio-29 (HDD1 Power ) out hi
>>
>> GPIOs 32-49, platform/f1010140.gpio, f1010140.gpio:
>> gpio-34 (? ) out hi
>> gpio-35 (? ) out hi
>> gpio-37 (? ) out lo
>> gpio-38 (? ) out hi
>> gpio-40 (? ) out hi
This is the kernel where exporting works? I don't understand that one.
Is this before or after exporting the gpio to userspace?
>> # uname -a
>> Linux LS-WXL 3.16.0-4-kirkwood #1 Debian 3.16.7-ckt7-1 (2015-03-01)
>> armv5tel GNU/Linux
>> # mount -t debugfs none /sys/kernel/debug
>> # cat /sys/kernel/debug/gpio
>> GPIOs 0-31, platform/f1010100.gpio, f1010100.gpio:
>> gpio-28 (HDD0 Power ) out hi
>> gpio-29 (HDD1 Power ) out hi
>>
>> GPIOs 32-49, platform/f1010140.gpio, f1010140.gpio:
>> gpio-34 (lswxl:red:hdderr0 ) out hi
>> gpio-35 (lswxl:red:hdderr1 ) out hi
>> gpio-37 (lswxl:red:func ) out lo
>> gpio-38 (lswxl:amber:info ) out hi
>> gpio-40 (lswxl:blue:power ) out hi
>
> For above gpio-XX and it's string, I know there're gpio pin definition
> errors for gpio 32-49.
> Now I understand gpio 32-49 should be defined as gpio1 XX, and XX
> should be real pinnumber - 32.
> e.g. GPIO 37 should be defined as "gpio1 5"
Yeah, when looking at the dts link you provided I wondered about the 37
in there. But not enough to mention it here.
> After I modified DTS as above new gpio[01] pinnumber, the debug info is like:
>
> GPIOs 0-31, platform/f1010100.gpio, f1010100.gpio:
> gpio-28 (HDD0 Power ) out hi
> gpio-29 (HDD1 Power ) out hi
>
> GPIOs 32-49, platform/f1010140.gpio, f1010140.gpio:
> gpio-37 (USB Power ) out hi
> gpio-41 (Function Button ) in hi (act lo) - IRQ edge (clear )
> gpio-42 (Power-on Switch ) in lo (act hi) - IRQ edge (clear )
> gpio-43 (Power-auto Switch ) in hi (act lo) - IRQ edge (clear )
>
> So gpio-37 is HIGH by default now.
> Although gpio export is still not working on previously reported
> kernel version, my problem seems get solved.
When a gpio is in use by a driver it is normal and expected that you
cannot export it to userspace. So I'm not sure what is the remaining
problem now. Also I failed to see the commit that made the difference
for you when (quickly) looking through the differences between
3.16.7-ckt4-3 and 3.16.7-ckt7-1.
Best regards
Uwe
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