This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().
Acked-by: NWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Performing a read operation on the IRQ Status register will clear the
IRQ latch. Since a read operation on the IRQ Status register must be
performed in the IRQ handler in order to determine if the IRQ was in
fact generated by the device, the IRQ latch is consequently cleared by
the IRQ handler. A spinlock is used to guarantee that each IRQ is
serviced in the order it was received.
Signed-off-by: NWilliam Breathitt Gray <vilhelm.gray@gmail.com>

The ACCES 104-IDI-48 family of PC/104 utility boards feature 48
individually optically isolated digital inputs. Enabled inputs feature
change-of-state detection capability; if change-of-state detection is
enabled, an interrupt is fired off if a change of input level
(low-to-high or high-to-low) is detected. Change-of-state IRQs are
enabled/disabled on 8-bit boundaries, for a total of six boundaries.

This driver provides GPIO and IRQ support for these 48 channels of
digital input. The base port address for the device may be configured
via the idi_48_base module parameter. The interrupt line number for the
device may be configured via the idi_48_irq module parameter.
Signed-off-by: NWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>