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regulator: Support disabling of unused regulators by machines

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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>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
This commit is contained in:
Mark Brown 2009-03-16 19:36:34 +00:00 committed by Liam Girdwood
parent 50f075963f
commit ca7255614e
2 changed files with 94 additions and 0 deletions
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92
drivers/regulator/core.c
View File

@ -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
@ -2142,6 +2143,23 @@ 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);

2
include/linux/regulator/machine.h
View File

@ -166,4 +166,6 @@ struct regulator_init_data {
int regulator_suspend_prepare(suspend_state_t state);
void regulator_has_full_constraints(void);
#endif