On Sat, Dec 6, 2014 at 1:40 AM, Ray Jui [off-list ref] wrote:

Document the GPIO device tree binding for Broadcom Cygnus SoC

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>

(...)

+- #gpio-cells:
+    Must be two. The first cell is the GPIO pin number (within the
+controller's domain) and the second cell is used for the following:
+    bit[0]: polarity (0 for normal and 1 for inverted)
+    bit[18:16]: internal pull up/down: 0 - pull up/down disabled
+                                       1 - pull up enabled
+                                       2 - pull down enabled
+    bit[22:20]: drive strength: 0 - 2 mA
+                                1 - 4 mA
+                                2 - 6 mA
+                                3 - 8 mA
+                                4 - 10 mA
+                                5 - 12 mA
+                                6 - 14 mA
+                                7 - 16 mA

No. This pull up/down and drive strength is pin controller
business, use a pin control backend behind the GPIO driver
see Documentation/pinctrl.txt.

Initial states for these configurations can be set up using
pin control hogs since pin control and GPIO is orthogonal.

Yours,
Linus Walleij