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HID: i2c-hid: Add sleep between POWER ON and RESET
authorBrendan McGrath <redmcg@redmandi.dyndns.org>
Fri, 6 Jan 2017 21:01:38 +0000 (08:01 +1100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 5 Jul 2017 12:40:24 +0000 (14:40 +0200)
commit582c1ca0ea1d13a9e2912c5a7530f0728b3c3d1c
treed4cff1c67949cd4ba72efe3ceb8077c3620c9b2c
parentc78b8de5c05c73ff451b7c5a085766b421920ccd
HID: i2c-hid: Add sleep between POWER ON and RESET

[ Upstream commit a89af4abdf9b353cdd6f61afc0eaaac403304873 ]

Support for the Asus Touchpad was recently added. It turns out this
device can fail initialisation (and become unusable) when the RESET
command is sent too soon after the POWER ON command.

Unfortunately the i2c-hid specification does not specify the need for
a delay between these two commands. But it was discovered the Windows
driver has a 1ms delay.

As a result, this patch modifies the i2c-hid module to add a sleep
inbetween the POWER ON and RESET commands which lasts between 1ms and 5ms.

See https://github.com/vlasenko/hid-asus-dkms/issues/24 for further
details.

Signed-off-by: Brendan McGrath <redmcg@redmandi.dyndns.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/hid/i2c-hid/i2c-hid.c