Reset controller API¶
Introduction¶
Reset controllers are central units that control the reset signals to multiple peripherals. The reset controller API is split into two parts: the consumer driver interface (API reference), which allows peripheral drivers to request control over their reset input signals, and the reset controller driver interface (API reference), which is used by drivers for reset controller devices to register their reset controls to provide them to the consumers.
While some reset controller hardware units also implement system restart functionality, restart handlers are out of scope for the reset controller API.
Glossary¶
The reset controller API uses these terms with a specific meaning:
Reset line
Physical reset line carrying a reset signal from a reset controller hardware unit to a peripheral module.
Reset control
Control method that determines the state of one or multiple reset lines. Most commonly this is a single bit in reset controller register space that either allows direct control over the physical state of the reset line, or is self-clearing and can be used to trigger a predetermined pulse on the reset line. In more complicated reset controls, a single trigger action can launch a carefully timed sequence of pulses on multiple reset lines.
Reset controller
A hardware module that provides a number of reset controls to control a number of reset lines.
Reset consumer
Peripheral module or external IC that is put into reset by the signal on a reset line.
Consumer driver interface¶
This interface provides an API that is similar to the kernel clock framework. Consumer drivers use get and put operations to acquire and release reset controls. Functions are provided to assert and deassert the controlled reset lines, trigger reset pulses, or to query reset line status.
When requesting reset controls, consumers can use symbolic names for their reset inputs, which are mapped to an actual reset control on an existing reset controller device by the core.
A stub version of this API is provided when the reset controller framework is not in use in order to minimize the need to use ifdefs.
Assertion and deassertion¶
Consumer drivers use the reset_control_assert()
and reset_control_deassert()
functions to assert and deassert reset lines.
For shared reset controls, calls to the two functions must be balanced.
Note that since multiple consumers may be using a shared reset control, there
is no guarantee that calling reset_control_assert()
on a shared reset control
will actually cause the reset line to be asserted.
Consumer drivers using shared reset controls should assume that the reset line
may be kept deasserted at all times.
The API only guarantees that the reset line can not be asserted as long as any
consumer has requested it to be deasserted.
Triggering¶
Consumer drivers use reset_control_reset()
to trigger a reset pulse on a
self-deasserting reset control.
In general, these resets can not be shared between multiple consumers, since
requesting a pulse from any consumer driver will reset all connected
peripherals.
The reset controller API allows requesting self-deasserting reset controls as
shared, but for those only the first trigger request causes an actual pulse to
be issued on the reset line.
All further calls to this function have no effect until all consumers have
called reset_control_rearm()
.
For shared reset controls, calls to the two functions must be balanced.
This allows devices that only require an initial reset at any point before the
driver is probed or resumed to share a pulsed reset line.
Querying¶
Only some reset controllers support querying the current status of a reset
line, via reset_control_status()
.
If supported, this function returns a positive non-zero value if the given
reset line is asserted.
The reset_control_status()
function does not accept a
reset control array handle as its input parameter.
Optional resets¶
Often peripherals require a reset line on some platforms but not on others.
For this, reset controls can be requested as optional using
devm_reset_control_get_optional_exclusive()
or
devm_reset_control_get_optional_shared()
.
These functions return a NULL pointer instead of an error when the requested
reset control is not specified in the device tree.
Passing a NULL pointer to the reset_control functions causes them to return
quietly without an error.
Reset control arrays¶
Some drivers need to assert a bunch of reset lines in no particular order.
devm_reset_control_array_get()
returns an opaque reset control handle that can
be used to assert, deassert, or trigger all specified reset controls at once.
The reset control API does not guarantee the order in which the individual
controls therein are handled.
Reset controller driver interface¶
Drivers for reset controller modules provide the functionality necessary to assert or deassert reset signals, to trigger a reset pulse on a reset line, or to query its current state. All functions are optional.
Initialization¶
Drivers fill a struct reset_controller_dev
and register it with
reset_controller_register()
in their probe function.
The actual functionality is implemented in callback functions via a struct
reset_control_ops
.
API reference¶
The reset controller API is documented here in two parts: the reset consumer API and the reset controller driver API.
Reset consumer API¶
Reset consumers can control a reset line using an opaque reset control handle,
which can be obtained from devm_reset_control_get_exclusive()
or
devm_reset_control_get_shared()
.
Given the reset control, consumers can call reset_control_assert()
and
reset_control_deassert()
, trigger a reset pulse using reset_control_reset()
, or
query the reset line status using reset_control_status()
.
-
struct
reset_control_bulk_data
¶ Data used for bulk reset control operations.
Definition
struct reset_control_bulk_data {
const char *id;
struct reset_control *rstc;
};
Members
id
reset control consumer ID
rstc
struct reset_control * to store the associated reset control
Description
The reset APIs provide a series of reset_control_bulk_*() API calls as a convenience to consumers which require multiple reset controls. This structure is used to manage data for these calls.
-
struct reset_control *
reset_control_get_exclusive
(struct device *dev, const char *id)¶ Lookup and obtain an exclusive reference to a reset controller.
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Returns a struct reset_control or IS_ERR() condition containing errno. If this function is called more than once for the same reset_control it will return -EBUSY.
See reset_control_get_shared()
for details on shared references to
reset-controls.
Use of id names is optional.
-
int
reset_control_bulk_get_exclusive
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ Lookup and obtain exclusive references to multiple reset controllers.
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Fills the rstcs array with pointers to exclusive reset controls and returns 0, or an IS_ERR() condition containing errno.
-
struct reset_control *
reset_control_get_exclusive_released
(struct device *dev, const char *id)¶ Lookup and obtain a temoprarily exclusive reference to a reset controller.
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Returns a struct reset_control or IS_ERR() condition containing errno.
reset-controls returned by this function must be acquired via
reset_control_acquire()
before they can be used and should be released
via reset_control_release()
afterwards.
Use of id names is optional.
-
int
reset_control_bulk_get_exclusive_released
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ Lookup and obtain temporarily exclusive references to multiple reset controllers.
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Fills the rstcs array with pointers to exclusive reset controls and returns 0, or an IS_ERR() condition containing errno. reset-controls returned by this function must be acquired via reset_control_bulk_acquire() before they can be used and should be released via reset_control_bulk_release() afterwards.
-
int
reset_control_bulk_get_optional_exclusive_released
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ Lookup and obtain optional temporarily exclusive references to multiple reset controllers.
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Optional variant of reset_control_bulk_get_exclusive_released()
. If the
requested reset is not specified in the device tree, this function returns 0
instead of an error and missing rtsc is set to NULL.
See reset_control_bulk_get_exclusive_released()
for more information.
Lookup and obtain a shared reference to a reset controller.
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Returns a struct reset_control or IS_ERR() condition containing errno. This function is intended for use with reset-controls which are shared between hardware blocks.
When a reset-control is shared, the behavior of reset_control_assert / deassert is changed, the reset-core will keep track of a deassert_count and only (re-)assert the reset after reset_control_assert has been called as many times as reset_control_deassert was called. Also see the remark about shared reset-controls in the reset_control_assert docs.
Calling reset_control_assert without first calling reset_control_deassert is not allowed on a shared reset control. Calling reset_control_reset is also not allowed on a shared reset control.
Use of id names is optional.
Lookup and obtain shared references to multiple reset controllers.
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Fills the rstcs array with pointers to shared reset controls and returns 0, or an IS_ERR() condition containing errno.
-
struct reset_control *
reset_control_get_optional_exclusive
(struct device *dev, const char *id)¶ optional
reset_control_get_exclusive()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Optional variant of reset_control_get_exclusive()
. If the requested reset
is not specified in the device tree, this function returns NULL instead of
an error.
See reset_control_get_exclusive()
for more information.
-
int
reset_control_bulk_get_optional_exclusive
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ optional
reset_control_bulk_get_exclusive()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Optional variant of reset_control_bulk_get_exclusive()
. If any of the
requested resets are not specified in the device tree, this function sets
them to NULL instead of returning an error.
See reset_control_bulk_get_exclusive()
for more information.
optional
reset_control_get_shared()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Optional variant of reset_control_get_shared()
. If the requested reset
is not specified in the device tree, this function returns NULL instead of
an error.
See reset_control_get_shared()
for more information.
optional
reset_control_bulk_get_shared()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Optional variant of reset_control_bulk_get_shared()
. If the requested resets
are not specified in the device tree, this function sets them to NULL
instead of returning an error.
See reset_control_bulk_get_shared()
for more information.
-
struct reset_control *
of_reset_control_get_exclusive
(struct device_node *node, const char *id)¶ Lookup and obtain an exclusive reference to a reset controller.
Parameters
struct device_node *node
device to be reset by the controller
const char *id
reset line name
Description
Returns a struct reset_control or IS_ERR() condition containing errno.
Use of id names is optional.
Lookup and obtain a shared reference to a reset controller.
Parameters
struct device_node *node
device to be reset by the controller
const char *id
reset line name
Description
When a reset-control is shared, the behavior of reset_control_assert / deassert is changed, the reset-core will keep track of a deassert_count and only (re-)assert the reset after reset_control_assert has been called as many times as reset_control_deassert was called. Also see the remark about shared reset-controls in the reset_control_assert docs.
Calling reset_control_assert without first calling reset_control_deassert is not allowed on a shared reset control. Calling reset_control_reset is also not allowed on a shared reset control. Returns a struct reset_control or IS_ERR() condition containing errno.
Use of id names is optional.
-
struct reset_control *
of_reset_control_get_exclusive_by_index
(struct device_node *node, int index)¶ Lookup and obtain an exclusive reference to a reset controller by index.
Parameters
struct device_node *node
device to be reset by the controller
int index
index of the reset controller
Description
This is to be used to perform a list of resets for a device or power domain in whatever order. Returns a struct reset_control or IS_ERR() condition containing errno.
Lookup and obtain a shared reference to a reset controller by index.
Parameters
struct device_node *node
device to be reset by the controller
int index
index of the reset controller
Description
When a reset-control is shared, the behavior of reset_control_assert / deassert is changed, the reset-core will keep track of a deassert_count and only (re-)assert the reset after reset_control_assert has been called as many times as reset_control_deassert was called. Also see the remark about shared reset-controls in the reset_control_assert docs.
Calling reset_control_assert without first calling reset_control_deassert is not allowed on a shared reset control. Calling reset_control_reset is also not allowed on a shared reset control. Returns a struct reset_control or IS_ERR() condition containing errno.
This is to be used to perform a list of resets for a device or power domain in whatever order. Returns a struct reset_control or IS_ERR() condition containing errno.
-
struct reset_control *
devm_reset_control_get_exclusive
(struct device *dev, const char *id)¶ resource managed
reset_control_get_exclusive()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Managed reset_control_get_exclusive()
. For reset controllers returned
from this function, reset_control_put()
is called automatically on driver
detach.
See reset_control_get_exclusive()
for more information.
-
int
devm_reset_control_bulk_get_exclusive
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ resource managed
reset_control_bulk_get_exclusive()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Managed reset_control_bulk_get_exclusive()
. For reset controllers returned
from this function, reset_control_put()
is called automatically on driver
detach.
See reset_control_bulk_get_exclusive()
for more information.
-
struct reset_control *
devm_reset_control_get_exclusive_released
(struct device *dev, const char *id)¶ resource managed
reset_control_get_exclusive_released()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Managed reset_control_get_exclusive_released()
. For reset controllers
returned from this function, reset_control_put()
is called automatically on
driver detach.
See reset_control_get_exclusive_released()
for more information.
-
int
devm_reset_control_bulk_get_exclusive_released
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ resource managed
reset_control_bulk_get_exclusive_released()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Managed reset_control_bulk_get_exclusive_released()
. For reset controllers
returned from this function, reset_control_put()
is called automatically on
driver detach.
See reset_control_bulk_get_exclusive_released()
for more information.
-
struct reset_control *
devm_reset_control_get_optional_exclusive_released
(struct device *dev, const char *id)¶ resource managed reset_control_get_optional_exclusive_released()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Managed-and-optional variant of reset_control_get_exclusive_released()
. For
reset controllers returned from this function, reset_control_put()
is called
automatically on driver detach.
See reset_control_get_exclusive_released()
for more information.
-
int
devm_reset_control_bulk_get_optional_exclusive_released
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ resource managed reset_control_bulk_optional_get_exclusive_released()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Managed reset_control_bulk_optional_get_exclusive_released(). For reset
controllers returned from this function, reset_control_put()
is called
automatically on driver detach.
See reset_control_bulk_optional_get_exclusive_released() for more information.
resource managed
reset_control_get_shared()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Managed reset_control_get_shared()
. For reset controllers returned from
this function, reset_control_put()
is called automatically on driver detach.
See reset_control_get_shared()
for more information.
resource managed
reset_control_bulk_get_shared()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Managed reset_control_bulk_get_shared()
. For reset controllers returned
from this function, reset_control_put()
is called automatically on driver
detach.
See reset_control_bulk_get_shared()
for more information.
-
struct reset_control *
devm_reset_control_get_optional_exclusive
(struct device *dev, const char *id)¶ resource managed
reset_control_get_optional_exclusive()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Managed reset_control_get_optional_exclusive()
. For reset controllers
returned from this function, reset_control_put()
is called automatically on
driver detach.
See reset_control_get_optional_exclusive()
for more information.
-
int
devm_reset_control_bulk_get_optional_exclusive
(struct device *dev, int num_rstcs, struct reset_control_bulk_data *rstcs)¶ resource managed
reset_control_bulk_get_optional_exclusive()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Managed reset_control_bulk_get_optional_exclusive()
. For reset controllers
returned from this function, reset_control_put()
is called automatically on
driver detach.
See reset_control_bulk_get_optional_exclusive()
for more information.
resource managed
reset_control_get_optional_shared()
Parameters
struct device *dev
device to be reset by the controller
const char *id
reset line name
Description
Managed reset_control_get_optional_shared()
. For reset controllers returned
from this function, reset_control_put()
is called automatically on driver
detach.
See reset_control_get_optional_shared()
for more information.
resource managed
reset_control_bulk_get_optional_shared()
Parameters
struct device *dev
device to be reset by the controller
int num_rstcs
number of entries in rstcs array
struct reset_control_bulk_data *rstcs
array of
struct reset_control_bulk_data
with reset line names set
Description
Managed reset_control_bulk_get_optional_shared()
. For reset controllers
returned from this function, reset_control_put()
is called automatically on
driver detach.
See reset_control_bulk_get_optional_shared()
for more information.
-
struct reset_control *
devm_reset_control_get_exclusive_by_index
(struct device *dev, int index)¶ resource managed
reset_control_get_exclusive()
Parameters
struct device *dev
device to be reset by the controller
int index
index of the reset controller
Description
Managed reset_control_get_exclusive()
. For reset controllers returned from
this function, reset_control_put()
is called automatically on driver
detach.
See reset_control_get_exclusive()
for more information.
resource managed reset_control_get_shared
Parameters
struct device *dev
device to be reset by the controller
int index
index of the reset controller
Description
Managed reset_control_get_shared()
. For reset controllers returned from
this function, reset_control_put()
is called automatically on driver detach.
See reset_control_get_shared()
for more information.
-
int
reset_control_reset
(struct reset_control *rstc)¶ reset the controlled device
Parameters
struct reset_control *rstc
reset controller
Description
On a shared reset line the actual reset pulse is only triggered once for the lifetime of the reset_control instance: for all but the first caller this is a no-op. Consumers must not use reset_control_(de)assert on shared reset lines when reset_control_reset has been used.
If rstc is NULL it is an optional reset and the function will just return 0.
-
int
reset_control_rearm
(struct reset_control *rstc)¶ allow shared reset line to be re-triggered”
Parameters
struct reset_control *rstc
reset controller
Description
On a shared reset line the actual reset pulse is only triggered once for the lifetime of the reset_control instance, except if this call is used.
Calls to this function must be balanced with calls to reset_control_reset, a warning is thrown in case triggered_count ever dips below 0.
Consumers must not use reset_control_(de)assert on shared reset lines when reset_control_reset or reset_control_rearm have been used.
If rstc is NULL the function will just return 0.
-
int
reset_control_assert
(struct reset_control *rstc)¶ asserts the reset line
Parameters
struct reset_control *rstc
reset controller
Description
Calling this on an exclusive reset controller guarantees that the reset will be asserted. When called on a shared reset controller the line may still be deasserted, as long as other users keep it so.
For shared reset controls a driver cannot expect the hw’s registers and internal state to be reset, but must be prepared for this to happen. Consumers must not use reset_control_reset on shared reset lines when reset_control_(de)assert has been used.
If rstc is NULL it is an optional reset and the function will just return 0.
-
int
reset_control_deassert
(struct reset_control *rstc)¶ deasserts the reset line
Parameters
struct reset_control *rstc
reset controller
Description
After calling this function, the reset is guaranteed to be deasserted. Consumers must not use reset_control_reset on shared reset lines when reset_control_(de)assert has been used.
If rstc is NULL it is an optional reset and the function will just return 0.
-
int
reset_control_status
(struct reset_control *rstc)¶ returns a negative errno if not supported, a positive value if the reset line is asserted, or zero if the reset line is not asserted or if the desc is NULL (optional reset).
Parameters
struct reset_control *rstc
reset controller
-
int
reset_control_acquire
(struct reset_control *rstc)¶ acquires a reset control for exclusive use
Parameters
struct reset_control *rstc
reset control
Description
This is used to explicitly acquire a reset control for exclusive use. Note
that exclusive resets are requested as acquired by default. In order for a
second consumer to be able to control the reset, the first consumer has to
release it first. Typically the easiest way to achieve this is to call the
reset_control_get_exclusive_released()
to obtain an instance of the reset
control. Such reset controls are not acquired by default.
Consumers implementing shared access to an exclusive reset need to follow
a specific protocol in order to work together. Before consumers can change
a reset they must acquire exclusive access using reset_control_acquire()
.
After they are done operating the reset, they must release exclusive access
with a call to reset_control_release()
. Consumers are not granted exclusive
access to the reset as long as another consumer hasn’t released a reset.
See also: reset_control_release()
-
void
reset_control_release
(struct reset_control *rstc)¶ releases exclusive access to a reset control
Parameters
struct reset_control *rstc
reset control
Description
Releases exclusive access right to a reset control previously obtained by a
call to reset_control_acquire()
. Until a consumer calls this function, no
other consumers will be granted exclusive access.
See also: reset_control_acquire()
-
void
reset_control_put
(struct reset_control *rstc)¶ free the reset controller
Parameters
struct reset_control *rstc
reset controller
-
int
of_reset_control_get_count
(struct device_node *node)¶ Count number of resets available with a device
Parameters
struct device_node *node
device node that contains ‘resets’.
Description
Returns positive reset count on success, or error number on failure and on count being zero.
-
struct reset_control *
of_reset_control_array_get
(struct device_node *np, bool shared, bool optional, bool acquired)¶ Get a list of reset controls using device node.
Parameters
struct device_node *np
device node for the device that requests the reset controls array
bool shared
whether reset controls are shared or not
bool optional
whether it is optional to get the reset controls
bool acquired
only one reset control may be acquired for a given controller and ID
Description
Returns pointer to allocated reset_control on success or error on failure
-
struct reset_control *
devm_reset_control_array_get
(struct device *dev, bool shared, bool optional)¶ Resource managed reset control array get
Parameters
struct device *dev
device that requests the list of reset controls
bool shared
whether reset controls are shared or not
bool optional
whether it is optional to get the reset controls
Description
The reset control array APIs are intended for a list of resets that just have to be asserted or deasserted, without any requirements on the order.
Returns pointer to allocated reset_control on success or error on failure
Parameters
struct device *dev
device for which to return the number of resets
Description
Returns positive reset count on success, or error number on failure and on count being zero.
Reset controller driver API¶
Reset controller drivers are supposed to implement the necessary functions in
a static constant structure reset_control_ops
, allocate and fill out
a struct reset_controller_dev
, and register it using
devm_reset_controller_register()
.
-
struct
reset_control_ops
¶ reset controller driver callbacks
Definition
struct reset_control_ops {
int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);
int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);
int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);
int (*status)(struct reset_controller_dev *rcdev, unsigned long id);
};
Members
reset
for self-deasserting resets, does all necessary things to reset the device
assert
manually assert the reset line, if supported
deassert
manually deassert the reset line, if supported
status
return the status of the reset line, if supported
-
struct
reset_control_lookup
¶ represents a single lookup entry
Definition
struct reset_control_lookup {
struct list_head list;
const char *provider;
unsigned int index;
const char *dev_id;
const char *con_id;
};
Members
list
internal list of all reset lookup entries
provider
name of the reset controller device controlling this reset line
index
ID of the reset controller in the reset controller device
dev_id
name of the device associated with this reset line
con_id
name of the reset line (can be NULL)
-
struct
reset_controller_dev
¶ reset controller entity that might provide multiple reset controls
Definition
struct reset_controller_dev {
const struct reset_control_ops *ops;
struct module *owner;
struct list_head list;
struct list_head reset_control_head;
struct device *dev;
struct device_node *of_node;
int of_reset_n_cells;
int (*of_xlate)(struct reset_controller_dev *rcdev, const struct of_phandle_args *reset_spec);
unsigned int nr_resets;
};
Members
ops
a pointer to device specific
struct reset_control_ops
owner
kernel module of the reset controller driver
list
internal list of reset controller devices
reset_control_head
head of internal list of requested reset controls
dev
corresponding driver model device struct
of_node
corresponding device tree node as phandle target
of_reset_n_cells
number of cells in reset line specifiers
of_xlate
translation function to translate from specifier as found in the device tree to id as given to the reset control ops, defaults to
of_reset_simple_xlate()
.nr_resets
number of reset controls in this reset controller device
-
int
of_reset_simple_xlate
(struct reset_controller_dev *rcdev, const struct of_phandle_args *reset_spec)¶ translate reset_spec to the reset line number
Parameters
struct reset_controller_dev *rcdev
a pointer to the reset controller device
const struct of_phandle_args *reset_spec
reset line specifier as found in the device tree
Description
This static translation function is used by default if of_xlate in
reset_controller_dev
is not set. It is useful for all reset
controllers with 1:1 mapping, where reset lines can be indexed by number
without gaps.
-
int
reset_controller_register
(struct reset_controller_dev *rcdev)¶ register a reset controller device
Parameters
struct reset_controller_dev *rcdev
a pointer to the initialized reset controller device
-
void
reset_controller_unregister
(struct reset_controller_dev *rcdev)¶ unregister a reset controller device
Parameters
struct reset_controller_dev *rcdev
a pointer to the reset controller device
-
int
devm_reset_controller_register
(struct device *dev, struct reset_controller_dev *rcdev)¶ resource managed
reset_controller_register()
Parameters
struct device *dev
device that is registering this reset controller
struct reset_controller_dev *rcdev
a pointer to the initialized reset controller device
Description
Managed reset_controller_register()
. For reset controllers registered by
this function, reset_controller_unregister()
is automatically called on
driver detach. See reset_controller_register()
for more information.
-
void
reset_controller_add_lookup
(struct reset_control_lookup *lookup, unsigned int num_entries)¶ register a set of lookup entries
Parameters
struct reset_control_lookup *lookup
array of reset lookup entries
unsigned int num_entries
number of entries in the lookup array