of/gpio: stop using device_node data pointer to find gpio_chip

Currently the kernel uses the struct device_node.data pointer to resolve
a struct gpio_chip pointer from a device tree node.  However, the .data
member doesn't provide any type checking and there aren't any rules
enforced on what it should be used for.  There's no guarantee that the
data stored in it actually points to an gpio_chip pointer.

Instead of relying on the .data pointer, this patch modifies the code
to add a lookup function which scans through the registered gpio_chips
and returns the gpio_chip that has a pointer to the specified
device_node.

Signed-off-by: Grant Likely <[email protected]>
CC: Andrew Morton <[email protected]>
CC: Anton Vorontsov <[email protected]>
CC: Grant Likely <[email protected]>
CC: David Brownell <[email protected]>
CC: Bill Gatliff <[email protected]>
CC: Dmitry Eremin-Solenikov <[email protected]>
CC: Benjamin Herrenschmidt <[email protected]>
CC: Jean Delvare <[email protected]>
CC: [email protected]
CC: [email protected]

0 files changed, 0 insertions, 0 deletions