Original patch by Marek Vasut, modified by Eric in:
1. use delayed work to simplify the debouncing
2. combine col_polarity/row_polarity into a single active_low field
3. use a generic bit array based XOR algorithm to detect key
press/release, which should make the column assertion time
shorter and code a bit cleaner
4. remove the ALT_FN handling, which is no way generic, the ALT_FN
key should be treated as no different from other keys, and
translation will be done by user space by commands like 'loadkeys'.
5. explicitly disable row IRQs and flush potential pending work,
and schedule an immediate scan after resuming as suggested
by Uli Luckas
6. incorporate review comments from many others
Patch tested on Littleton/PXA310 (though PXA310 has a dedicate keypad
controller, I have to configure those pins as generic GPIO to use this
driver, works quite well, though), and Sharp Zaurus model SL-C7x0
and SL-C1000.
[dtor@mail.ru: fix error unwinding path, support changing keymap
from userspace]
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Reviewed-by: Trilok Soni <soni.trilok@gmail.com>
Reviewed-by: Uli Luckas <u.luckas@road.de>
Reviewed-by: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
bab7614d6d