From da07ecd93b196819dcec488b7ebec69a71f3819e Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Sun, 11 Sep 2011 09:53:50 +0100 Subject: regulator: Implement deferred disable support It is a reasonably common pattern for hardware to require some delay after being quiesced before the disable has finalised, especially in mixed signal devices. For example, an active discharge may be required to ensure that the circuit starts up again in a known state. Avoid having to implement such delays in the regulator API by providing regulator_deferred_disable() which will do a regulator_disable() a specified number of milliseconds after it is called. Due to the reference counting done on regulators a deferred disable can be cancelled by doing another regulator_enable(). Signed-off-by: Mark Brown Acked-by: Liam Girdwood --- drivers/regulator/core.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'drivers/regulator') diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index d8e6a429e8ba..d0bde70f3466 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1552,6 +1552,63 @@ int regulator_force_disable(struct regulator *regulator) } EXPORT_SYMBOL_GPL(regulator_force_disable); +static void regulator_disable_work(struct work_struct *work) +{ + struct regulator_dev *rdev = container_of(work, struct regulator_dev, + disable_work.work); + int count, i, ret; + + mutex_lock(&rdev->mutex); + + BUG_ON(!rdev->deferred_disables); + + count = rdev->deferred_disables; + rdev->deferred_disables = 0; + + for (i = 0; i < count; i++) { + ret = _regulator_disable(rdev); + if (ret != 0) + rdev_err(rdev, "Deferred disable failed: %d\n", ret); + } + + mutex_unlock(&rdev->mutex); + + if (rdev->supply) { + for (i = 0; i < count; i++) { + ret = regulator_disable(rdev->supply); + if (ret != 0) { + rdev_err(rdev, + "Supply disable failed: %d\n", ret); + } + } + } +} + +/** + * regulator_disable_deferred - disable regulator output with delay + * @regulator: regulator source + * @ms: miliseconds until the regulator is disabled + * + * Execute regulator_disable() on the regulator after a delay. This + * is intended for use with devices that require some time to quiesce. + * + * NOTE: this will only disable the regulator output if no other consumer + * devices have it enabled, the regulator device supports disabling and + * machine constraints permit this operation. + */ +int regulator_disable_deferred(struct regulator *regulator, int ms) +{ + struct regulator_dev *rdev = regulator->rdev; + + mutex_lock(&rdev->mutex); + rdev->deferred_disables++; + mutex_unlock(&rdev->mutex); + + return schedule_delayed_work(&rdev->disable_work, + msecs_to_jiffies(ms)); +} +EXPORT_SYMBOL_GPL(regulator_disable_deferred); + static int _regulator_is_enabled(struct regulator_dev *rdev) { /* If we don't know then assume that the regulator is always on */ @@ -2622,6 +2679,7 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc, INIT_LIST_HEAD(&rdev->consumer_list); INIT_LIST_HEAD(&rdev->list); BLOCKING_INIT_NOTIFIER_HEAD(&rdev->notifier); + INIT_DELAYED_WORK(&rdev->disable_work, regulator_disable_work); /* preform any regulator specific init */ if (init_data->regulator_init) { @@ -2729,6 +2787,7 @@ void regulator_unregister(struct regulator_dev *rdev) #ifdef CONFIG_DEBUG_FS debugfs_remove_recursive(rdev->debugfs); #endif + flush_work_sync(&rdev->disable_work.work); WARN_ON(rdev->open_count); unset_regulator_supplies(rdev); list_del(&rdev->list); -- cgit v1.2.3