[PATCH 1/2] regulator: Don't increment use_count for boot_on regulators

[PATCH 1/2] regulator: Don't increment use_count for boot_on regulators

[Mark Brown]

Don't set use_count for regulators that are enabled at boot since this
stops the supply being disabled by well-behaved consumers which do
balanced enables and disabled. Any consumers which don't do disables
which are not matched by enables are unable to share regulators - shared
regulators are the common case so the API should facilitate them.

Consumers that want to disable regulators that are enabled when they
start have two options:

 - Do a regulator_enable() prior to the disable to bring the use count
   in sync with the hardware state; this will ensure that if the
   regulator was enabled by another driver then this consumer will play
   nicely with it.
 - Use regulator_force_disable(); this explicitly bypasses any checks
   done by the core and documents the inability of the driver to share
   the supply.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
---
 drivers/regulator/core.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 9448875..8588a24 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -814,7 +814,6 @@ static int set_machine_constraints(struct regulator_dev *rdev,
 			rdev->constraints = NULL;
 			goto out;
 		}
-		rdev->use_count = 1;
 	}
 
 	print_constraints(rdev);
-- 
1.6.2

[PATCH 2/2] regulator: Support disabling of unused regulators by machines

[Mark Brown]

At present it is not possible for machine constraints to disable
regulators which have been left on when the system starts, for example
as a result of fixed default configurations in hardware. This means that
power may be wasted by these regulators if they are not in use.

Provide intial support for this with a late_initcall which will disable
any unused regulators if the machine has enabled this feature by calling
regulator_has_full_constraints(). If this has not been called then print
a warning to encourage users to fully specify their constraints so that
we can change this to be the default behaviour in future.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
---
 drivers/regulator/core.c          |   92 +++++++++++++++++++++++++++++++++++++
 include/linux/regulator/machine.h |    2 +
 2 files changed, 94 insertions(+), 0 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 8588a24..01f7702 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -28,6 +28,7 @@
 static DEFINE_MUTEX(regulator_list_mutex);
 static LIST_HEAD(regulator_list);
 static LIST_HEAD(regulator_map_list);
+static int has_full_constraints;
 
 /*
  * struct regulator_map
@@ -2143,6 +2144,23 @@ out:
 EXPORT_SYMBOL_GPL(regulator_suspend_prepare);
 
 /**
+ * regulator_has_full_constraints - the system has fully specified constraints
+ *
+ * Calling this function will cause the regulator API to disable all
+ * regulators which have a zero use count and don't have an always_on
+ * constraint in a late_initcall.
+ *
+ * The intention is that this will become the default behaviour in a
+ * future kernel release so users are encouraged to use this facility
+ * now.
+ */
+void regulator_has_full_constraints(void)
+{
+	has_full_constraints = 1;
+}
+EXPORT_SYMBOL_GPL(regulator_has_full_constraints);
+
+/**
  * rdev_get_drvdata - get rdev regulator driver data
  * @rdev: regulator
  *
@@ -2209,3 +2227,77 @@ static int __init regulator_init(void)
 
 /* init early to allow our consumers to complete system booting */
 core_initcall(regulator_init);
+
+static int __init regulator_init_complete(void)
+{
+	struct regulator_dev *rdev;
+	struct regulator_ops *ops;
+	struct regulation_constraints *c;
+	int enabled, ret;
+	const char *name;
+
+	mutex_lock(&regulator_list_mutex);
+
+	/* If we have a full configuration then disable any regulators
+	 * which are not in use or always_on.  This will become the
+	 * default behaviour in the future.
+	 */
+	list_for_each_entry(rdev, &regulator_list, list) {
+		ops = rdev->desc->ops;
+		c = rdev->constraints;
+
+		if (c->name)
+			name = c->name;
+		else if (rdev->desc->name)
+			name = rdev->desc->name;
+		else
+			name = "regulator";
+
+		if (!ops->disable || c->always_on)
+			continue;
+
+		mutex_lock(&rdev->mutex);
+
+		if (rdev->use_count)
+			goto unlock;
+
+		/* If we can't read the status assume it's on. */
+		if (ops->is_enabled)
+			enabled = ops->is_enabled(rdev);
+		else
+			enabled = 1;
+
+		if (!enabled)
+			goto unlock;
+
+		if (has_full_constraints) {
+			/* We log since this may kill the system if it
+			 * goes wrong. */
+			printk(KERN_INFO "%s: disabling %s\n",
+			       __func__, name);
+			ret = ops->disable(rdev);
+			if (ret != 0) {
+				printk(KERN_ERR
+				       "%s: couldn't disable %s: %d\n",
+				       __func__, name, ret);
+			}
+		} else {
+			/* The intention is that in future we will
+			 * assume that full constraints are provided
+			 * so warn even if we aren't going to do
+			 * anything here.
+			 */
+			printk(KERN_WARNING
+			       "%s: incomplete constraints, leaving %s on\n",
+			       __func__, name);
+		}
+
+unlock:
+		mutex_unlock(&rdev->mutex);
+	}
+
+	mutex_unlock(&regulator_list_mutex);
+
+	return 0;
+}
+late_initcall(regulator_init_complete);
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 5de7aa3..bac64fa 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -166,4 +166,6 @@ struct regulator_init_data {
 
 int regulator_suspend_prepare(suspend_state_t state);
 
+void regulator_has_full_constraints(void);
+
 #endif
-- 
1.6.2

Re: [PATCH 2/2] regulator: Support disabling of unused regulators by machines

[Liam Girdwood]

On Mon, 2009-03-16 at 19:36 +0000, Mark Brown wrote:
> At present it is not possible for machine constraints to disable
> regulators which have been left on when the system starts, for example
> as a result of fixed default configurations in hardware. This means that
> power may be wasted by these regulators if they are not in use.
> 
> Provide intial support for this with a late_initcall which will disable
> any unused regulators if the machine has enabled this feature by calling
> regulator_has_full_constraints(). If this has not been called then print
> a warning to encourage users to fully specify their constraints so that
> we can change this to be the default behaviour in future.
> 
> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> ---
>  drivers/regulator/core.c          |   92 +++++++++++++++++++++++++++++++++++++
>  include/linux/regulator/machine.h |    2 +
>  2 files changed, 94 insertions(+), 0 deletions(-)
> 

Applied.

Thanks

Liam

Re: [PATCH 1/2] regulator: Don't increment use_count for boot_on regulators

[Liam Girdwood]

On Mon, 2009-03-16 at 19:36 +0000, Mark Brown wrote:
> Don't set use_count for regulators that are enabled at boot since this
> stops the supply being disabled by well-behaved consumers which do
> balanced enables and disabled. Any consumers which don't do disables
> which are not matched by enables are unable to share regulators - shared
> regulators are the common case so the API should facilitate them.
> 
> Consumers that want to disable regulators that are enabled when they
> start have two options:
> 
>  - Do a regulator_enable() prior to the disable to bring the use count
>    in sync with the hardware state; this will ensure that if the
>    regulator was enabled by another driver then this consumer will play
>    nicely with it.
>  - Use regulator_force_disable(); this explicitly bypasses any checks
>    done by the core and documents the inability of the driver to share
>    the supply.
> 
> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> ---
>  drivers/regulator/core.c |    1 -
>  1 files changed, 0 insertions(+), 1 deletions(-)

Applied.

Thanks

Liam