gpio: improve error path in gpiolib

At several places the gpiolib will proceed to handle a GPIO
descriptor even if it's ->chip member is NULL and no gpiochip
is associated.

Fix this by checking that both the descriptor cookie *and*
the chip pointer are valid.

Also bail out earlier with more specific diagnostic messages
on missing operations for setting as input/output or debounce.

ChangeLog v1->v2:
- Also return -EIO on gpiod_set_debounce() with missing
  operations in the vtable
- Fix indentations.

Suggested-by: Alexandre Courbot <[email protected]>
Acked-by: Alexandre Courbot <[email protected]>
Reviewed-by: Frank Rowand <[email protected]>
Cc: Tim Bird <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>

0 files changed, 0 insertions, 0 deletions