This commit fixes a functional regression introduced by the commit 82f09a637d
("HID: ft260: improve error handling of ft260_hid_feature_report_get()")
when upon USB disconnect, the FTDI FT260 i2c device is still available within
the /dev folder.
In my company's product, where the host USB to FT260 USB connection is
hard-wired in the PCB, the issue is not reproducible. To reproduce it, I used
the VirtualBox Ubuntu 20.04 VM and the UMFT260EV1A development module for the
FTDI FT260 chip:
Plug the UMFT260EV1A module into a USB port and attach it to VM.
The VM shows 2 i2c devices under the /dev:
michael@michael-VirtualBox:~$ ls /dev/i2c-*
/dev/i2c-0 /dev/i2c-1
The i2c-0 is not related to the FTDI FT260:
michael@michael-VirtualBox:~$ cat /sys/bus/i2c/devices/i2c-0/name
SMBus PIIX4 adapter at 4100
The i2c-1 is created by hid-ft260.ko:
michael@michael-VirtualBox:~$ cat /sys/bus/i2c/devices/i2c-1/name
FT260 usb-i2c bridge on hidraw1
Now, detach the FTDI FT260 USB device from VM. We expect the /dev/i2c-1
to disappear, but it's still here:
michael@michael-VirtualBox:~$ ls /dev/i2c-*
/dev/i2c-0 /dev/i2c-1
And the kernel log shows:
[ +0.001202] usb 2-2: USB disconnect, device number 3
[ +0.000109] ft260 0003:0403:6030.0002: failed to retrieve system status
[ +0.000316] ft260 0003:0403:6030.0003: failed to retrieve system status
It happens because the commit 82f09a637d changed the ft260_get_system_config()
return logic. This caused the ft260_is_interface_enabled() to exit with error
upon the FT260 device USB disconnect, which in turn, aborted the ft260_remove()
before deleting the FT260 i2c device and cleaning its sysfs stuff.
This commit restores the FT260 USB removal functionality and improves the
ft260_is_interface_enabled() code to handle correctly all chip modes defined
by the device interface configuration pins DCNF0 and DCNF1.
Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
Acked-by: Aaron Jones (FTDI-UK) <aaron.jones@ftdichip.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
db8d3a2127