A bunch of GPIO fixes for the v4.7 series:

- Drop the lock before reading out the GPIO direction
  setting in drivers supporting the .get_direction()
  callback: some of them may be slowpath.

- Flush GPIO direction setting before locking a GPIO as an
  IRQ: some electronics or other poking around in the
  registers behind our back may have happened, so flush
  the direction status before trying to lock the line for
  use by IRQs.

- Bail out silently when asked to perform operations on
  NULL GPIO descriptors. That is what all the get_*_optional()
  is about: we get optional GPIO handles, if they are not
  there, we get NULL.

- Handle compatible ioctl() correctly: we need to convert
  the ioctl() pointer using compat_ptr() here like everyone
  else.

- Disable the broken .to_irq() on the LPC32xx platform.
  The whole irqchip infrastructure was replaced in the
  last merge window, and a new implementation will be
  needed.
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gpio: drop lock before reading GPIO direction

When adding the gpiochip, the GPIO HW drivers' callback get_direction()
could get called in atomic context. Some of the GPIO HW drivers may
sleep when accessing the register.

Move the lock before initializing the descriptors.

Reported-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
1 file changed