regulator: Allow regulators to set the initial operating mode

This is useful when wishing to run in a fixed operating mode that isn't
the default.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/core.c

@@ -724,6 +724,23 @@ static int set_machine_constraints(struct regulator_dev *rdev,
 		}
 	}
 
+	if (constraints->initial_mode) {
+		if (!ops->set_mode) {
+			printk(KERN_ERR "%s: no set_mode operation for %s\n",
+			       __func__, name);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ret = ops->set_mode(rdev, constraints->initial_mode);
+		if (ret < 0) {
+			printk(KERN_ERR
+			       "%s: failed to set initial mode for %s: %d\n",
+			       __func__, name, ret);
+			goto out;
+		}
+	}
+
 	/* if always_on is set then turn the regulator on if it's not
 	 * already on. */
 	if (constraints->always_on && ops->enable &&

include/linux/regulator/machine.h

@@ -83,6 +83,7 @@ struct regulator_state {
  * @state_standby: State for regulator when system is suspended in standby
  *                 mode.
  * @initial_state: Suspend state to set by default.
+ * @initial_mode: Mode to set at startup.
  */
 struct regulation_constraints {
 
@@ -111,6 +112,9 @@ struct regulation_constraints {
 	struct regulator_state state_standby;
 	suspend_state_t initial_state; /* suspend state to set at init */
 
+	/* mode to set on startup */
+	unsigned int initial_mode;
+
 	/* constriant flags */
 	unsigned always_on:1;	/* regulator never off when system is on */
 	unsigned boot_on:1;	/* bootloader/firmware enabled regulator */