pinctrl: implement pinctrl deferred probing

If drivers try to obtain pinctrl handles for a pin controller that
has not yet registered to the subsystem, we need to be able to
back out and retry with deferred probing. So let's return
-EPROBE_DEFER whenever this location fails. Also downgrade the
errors to info, maybe we will even set them to debug once the
deferred probing is commonplace.

Change-Id: I621368a66637485001f77c1a9d74c5198ba0c342
Cc: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Git-commit: c05127c4e2c6e7d9949347a76fd05c337bcd5e84
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Hanumant Singh <hanumant@codeaurora.org>
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
index 5ef2feb..fcb1de4 100644
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -121,11 +121,11 @@
 	for (;;) {
 		np_pctldev = of_get_next_parent(np_pctldev);
 		if (!np_pctldev || of_node_is_root(np_pctldev)) {
-			dev_err(p->dev, "could not find pctldev for node %s\n",
+			dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n",
 				np_config->full_name);
 			of_node_put(np_pctldev);
-			/* FIXME: This should trigger deferrered probe */
-			return -ENODEV;
+			/* OK let's just assume this will appear later then */
+			return -EPROBE_DEFER;
 		}
 		pctldev = find_pinctrl_by_of_node(np_pctldev);
 		if (pctldev)