[FS#792] Reset button not working on Linksys WRT54GSv1

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Mirko Parthey (mpa) 

Attached to Project - LEDE Project
Summary - Reset button not working on Linksys WRT54GSv1
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - All
Due in Version - Undecided
Due Date - Undecided
Details - 
 Pressing the Reset button has no effect on the Linksys WRT54GSv1.

A short press should cause the device to reboot, and a long press should cause a factory reset.  With the following script added, there should be a log entry for each button press and release:

root at LEDE:~# cat /etc/hotplug.d/button/buttons
#!/bin/sh
logger "button $BUTTON $ACTION"

None of these effects can be observed on the Linksys WRT54GSv1, running either the LEDE master branch or the 17.01.1 release.

This is caused by a resource conflict for GPIO 6, which is claimed by both the adm6996 switch driver and the gpio_button_hotplug kernel module.

gpio-keys gpio-keys.0: unable to claim gpio 6, err=-16
gpio-keys: probe of gpio-keys.0 failed with error -16

After unbinding the switch driver:

echo adm6996_gpio > /sys/bus/platform/drivers/adm6996_gpio/unbind

the gpio_button_hotplug module can be loaded without error, and the Reset button works.

The switch driver requests this GPIO for the switch chip's RC pin, but never uses it, so it can be safely disabled.

I could come up with two possible solutions: replace the nvram entry gpio6=adm_rc to point to an unused GPIO, or patch the switch driver to not request the adm_eerc GPIO. I consider the nvram modification more risky and prefer the latter solution. What do you think?

Regards,
Mirko


More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=792