regulator: Allow boot_on regulators to be disabled by clients

Rather than incrementing the reference count for boot_on regulators
(which prevents them being disabled later on) simply force the
regulator to be enabled when applying the constraints. Previously
boot_on was essentially equivalent to always_on.

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

drivers/regulator/core.c

@@ -776,10 +776,6 @@ static int set_machine_constraints(struct regulator_dev *rdev,
 			}
 	}
 
-	/* are we enabled at boot time by firmware / bootloader */
-	if (rdev->constraints->boot_on)
-		rdev->use_count = 1;
-
 	/* do we need to setup our suspend state */
 	if (constraints->initial_state) {
 		ret = suspend_prepare(rdev, constraints->initial_state);
@@ -808,11 +804,10 @@ static int set_machine_constraints(struct regulator_dev *rdev,
 		}
 	}
 
-	/* if always_on is set then turn the regulator on if it's not
-	 * already on. */
-	if (constraints->always_on && ops->enable &&
-	    ((ops->is_enabled && !ops->is_enabled(rdev)) ||
-	     (!ops->is_enabled && !constraints->boot_on))) {
+	/* If the constraints say the regulator should be on at this point
+	 * and we have control then make sure it is enabled.
+	 */
+	if ((constraints->always_on || constraints->boot_on) && ops->enable) {
 		ret = ops->enable(rdev);
 		if (ret < 0) {
 			printk(KERN_ERR "%s: failed to enable %s\n",

include/linux/regulator/machine.h

@@ -73,7 +73,9 @@ struct regulator_state {
  *
  * @always_on: Set if the regulator should never be disabled.
  * @boot_on: Set if the regulator is enabled when the system is initially
- *           started.
+ *           started.  If the regulator is not enabled by the hardware or
+ *           bootloader then it will be enabled when the constraints are
+ *           applied.
  * @apply_uV: Apply the voltage constraint when initialising.
  *
  * @input_uV: Input voltage for regulator when supplied by another regulator.