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PM / OPP: Update kernel documentation

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kernel doc has gotten bit-rotted over time. Re-sync with Locking and
Return information. document all functions properly and ensure that
./scripts/kernel-doc -v  ./drivers/base/power/opp.c >/dev/null returns
no errors

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Nishanth Menon 2014-12-24 11:22:57 -06:00 committed by Rafael J. Wysocki
parent 327854c871
commit 984f16c849
1 changed files with 114 additions and 13 deletions
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127
drivers/base/power/opp.c
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@ -123,7 +123,7 @@ do { \
* Search list of device OPPs for one containing matching device. Does a RCU
* reader operation to grab the pointer needed.
*
* Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or
* Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
* -EINVAL based on type of error.
*
* Locking: This function must be called under rcu_read_lock(). device_opp
@ -153,7 +153,7 @@ static struct device_opp *_find_device_opp(struct device *dev)
* dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
* @opp: opp for which voltage has to be returned for
*
* Return voltage in micro volt corresponding to the opp, else
* Return: voltage in micro volt corresponding to the opp, else
* return 0
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
@ -183,7 +183,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
* dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
* @opp: opp for which frequency has to be returned for
*
* Return frequency in hertz corresponding to the opp, else
* Return: frequency in hertz corresponding to the opp, else
* return 0
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
@ -213,7 +213,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
* dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
* @dev: device for which we do this operation
*
* This function returns the number of available opps if there are any,
* Return: This function returns the number of available opps if there are any,
* else returns 0 if none or the corresponding error value.
*
* Locking: This function takes rcu_read_lock().
@ -251,9 +251,9 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
* @freq: frequency to search for
* @available: true/false - match for available opp
*
* Searches for exact match in the opp list and returns pointer to the matching
* opp if found, else returns ERR_PTR in case of error and should be handled
* using IS_ERR. Error return values can be:
* Return: Searches for exact match in the opp list and returns pointer to the
* matching opp if found, else returns ERR_PTR in case of error and should
* be handled using IS_ERR. Error return values can be:
* EINVAL: for bad pointer
* ERANGE: no match found for search
* ENODEV: if device not found in list of registered devices
@ -307,7 +307,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
* Search for the matching ceil *available* OPP from a starting freq
* for a device.
*
* Returns matching *opp and refreshes *freq accordingly, else returns
* Return: matching *opp and refreshes *freq accordingly, else returns
* ERR_PTR in case of error and should be handled using IS_ERR. Error return
* values can be:
* EINVAL: for bad pointer
@ -357,7 +357,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
* Search for the matching floor *available* OPP from a starting freq
* for a device.
*
* Returns matching *opp and refreshes *freq accordingly, else returns
* Return: matching *opp and refreshes *freq accordingly, else returns
* ERR_PTR in case of error and should be handled using IS_ERR. Error return
* values can be:
* EINVAL: for bad pointer
@ -403,6 +403,15 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
/**
* _add_device_opp() - Allocate a new device OPP table
* @dev: device for which we do this operation
*
* New device node which uses OPPs - used when multiple devices with OPP tables
* are maintained.
*
* Return: valid device_opp pointer if success, else NULL.
*/
static struct device_opp *_add_device_opp(struct device *dev)
{
struct device_opp *dev_opp;
@ -424,6 +433,33 @@ static struct device_opp *_add_device_opp(struct device *dev)
return dev_opp;
}
/**
* _opp_add_dynamic() - Allocate a dynamic OPP.
* @dev: device for which we do this operation
* @freq: Frequency in Hz for this OPP
* @u_volt: Voltage in uVolts for this OPP
* @dynamic: Dynamically added OPPs.
*
* This function adds an opp definition to the opp list and returns status.
* The opp is made available by default and it can be controlled using
* dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
*
* NOTE: "dynamic" parameter impacts OPPs added by the of_init_opp_table and
* freed by of_free_opp_table.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function internally uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*
* Return:
* 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
* -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
* -ENOMEM Memory allocation failure
*/
static int _opp_add_dynamic(struct device *dev, unsigned long freq,
long u_volt, bool dynamic)
{
@ -519,11 +555,11 @@ static int _opp_add_dynamic(struct device *dev, unsigned long freq,
* mutex cannot be locked.
*
* Return:
* 0: On success OR
* 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
* -EEXIST: Freq are same and volt are different OR
* -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
* -ENOMEM: Memory allocation failure
* -ENOMEM Memory allocation failure
*/
int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
{
@ -531,6 +567,10 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
}
EXPORT_SYMBOL_GPL(dev_pm_opp_add);
/**
* _kfree_opp_rcu() - Free OPP RCU handler
* @head: RCU head
*/
static void _kfree_opp_rcu(struct rcu_head *head)
{
struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
@ -538,6 +578,10 @@ static void _kfree_opp_rcu(struct rcu_head *head)
kfree_rcu(opp, rcu_head);
}
/**
* _kfree_device_rcu() - Free device_opp RCU handler
* @head: RCU head
*/
static void _kfree_device_rcu(struct rcu_head *head)
{
struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);
@ -545,6 +589,17 @@ static void _kfree_device_rcu(struct rcu_head *head)
kfree_rcu(device_opp, rcu_head);
}
/**
* _opp_remove() - Remove an OPP from a table definition
* @dev_opp: points back to the device_opp struct this opp belongs to
* @opp: pointer to the OPP to remove
*
* This function removes an opp definition from the opp list.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* It is assumed that the caller holds required mutex for an RCU updater
* strategy.
*/
static void _opp_remove(struct device_opp *dev_opp,
struct dev_pm_opp *opp)
{
@ -569,6 +624,12 @@ static void _opp_remove(struct device_opp *dev_opp,
* @freq: OPP to remove with matching 'freq'
*
* This function removes an opp from the opp list.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function internally uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*/
void dev_pm_opp_remove(struct device *dev, unsigned long freq)
{
@ -611,7 +672,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
* Set the availability of an OPP with an RCU operation, opp_{enable,disable}
* share a common logic which is isolated here.
*
* Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the
* Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
* copy operation, returns 0 if no modifcation was done OR modification was
* successful.
*
@ -700,6 +761,10 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
* integrity of the internal data structures. Callers should ensure that
* this function is *NOT* called under RCU protection or in contexts where
* mutex locking or synchronize_rcu() blocking calls cannot be used.
*
* Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
* copy operation, returns 0 if no modifcation was done OR modification was
* successful.
*/
int dev_pm_opp_enable(struct device *dev, unsigned long freq)
{
@ -722,6 +787,10 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
* integrity of the internal data structures. Callers should ensure that
* this function is *NOT* called under RCU protection or in contexts where
* mutex locking or synchronize_rcu() blocking calls cannot be used.
*
* Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
* copy operation, returns 0 if no modifcation was done OR modification was
* successful.
*/
int dev_pm_opp_disable(struct device *dev, unsigned long freq)
{
@ -732,6 +801,16 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
/**
* dev_pm_opp_get_notifier() - find notifier_head of the device with opp
* @dev: device pointer used to lookup device OPPs.
*
* Return: pointer to notifier head if found, otherwise -ENODEV or
* -EINVAL based on type of error casted as pointer. value must be checked
* with IS_ERR to determine valid pointer or error result.
*
* Locking: This function must be called under rcu_read_lock(). dev_opp is a RCU
* protected pointer. The reason for the same is that the opp pointer which is
* returned will remain valid for use with opp_get_{voltage, freq} only while
* under the locked area. The pointer returned must be used prior to unlocking
* with rcu_read_unlock() to maintain the integrity of the pointer.
*/
struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
{
@ -750,6 +829,22 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
* @dev: device pointer used to lookup device OPPs.
*
* Register the initial OPP table with the OPP library for given device.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function indirectly uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*
* Return:
* 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
* -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
* -ENOMEM Memory allocation failure
* -ENODEV when 'operating-points' property is not found or is invalid data
* in device node.
* -ENODATA when empty 'operating-points' property is found
*/
int of_init_opp_table(struct device *dev)
{
@ -793,6 +888,12 @@ EXPORT_SYMBOL_GPL(of_init_opp_table);
* @dev: device pointer used to lookup device OPPs.
*
* Free OPPs created using static entries present in DT.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function indirectly uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*/
void of_free_opp_table(struct device *dev)
{