Several users have been reporting that elants_i2c gives several errors
during probe and that their touchscreen does not work on their Lenovo AMD
based laptops with a touchscreen with a ELAN0001 ACPI hardware-id:
[ 0.550596] elants_i2c i2c-ELAN0001:00: i2c-ELAN0001:00 supply vcc33 not found, using dummy regulator
[ 0.551836] elants_i2c i2c-ELAN0001:00: i2c-ELAN0001:00 supply vccio not found, using dummy regulator
[ 0.560932] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[ 0.562427] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[ 0.595925] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[ 0.597974] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[ 0.621893] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[ 0.622504] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[ 0.632650] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (4d 61 69 6e): -121
[ 0.634256] elants_i2c i2c-ELAN0001:00: boot failed: -121
[ 0.699212] elants_i2c i2c-ELAN0001:00: invalid 'hello' packet: 00 00 ff ff
[ 1.630506] elants_i2c i2c-ELAN0001:00: Failed to read fw id: -121
[ 1.645508] elants_i2c i2c-ELAN0001:00: unknown packet 00 00 ff ff
Despite these errors, the elants_i2c driver stays bound to the device
(it returns 0 from its probe method despite the errors), blocking the
i2c-hid driver from binding.
Manually unbinding the elants_i2c driver and binding the i2c-hid driver
makes the touchscreen work.
Check if the ACPI-fwnode for the touchscreen contains one of the i2c-hid
compatiblity-id strings and if it has the I2C-HID spec's DSM to get the
HID descriptor address, If it has both then make elants_i2c not bind,
so that the i2c-hid driver can bind.
This assumes that non of the (older) elan touchscreens which actually
need the elants_i2c driver falsely advertise an i2c-hid compatiblity-id
+ DSM in their ACPI-fwnodes. If some of them actually do have this
false advertising, then this change may lead to regressions.
While at it also drop the unnecessary DEVICE_NAME prefixing of the
"I2C check functionality error", dev_err already outputs the driver-name.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207759
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210405202756.16830-1-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
65299e8bfb