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clk: Add client API to HTML docs

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This converts the existing client (aka clk.h) documentation to kernel doc
format, and adds it to the HTML docs. I have tried to preserve existing
comments as much as possible, refraining from semantic changes.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/r/20211222171114.3091780-4-seanga2@gmail.com
[rebased onto u-boot/master and resolved conflicts]
Signed-off-by: Sean Anderson <seanga2@gmail.com>
This commit is contained in:
Sean Anderson 2021-12-22 12:11:12 -05:00
parent 14cacb019c
commit 9c88b13a90
3 changed files with 101 additions and 93 deletions
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13
doc/api/clk.rst Normal file
View file

@ -0,0 +1,13 @@
.. SPDX-License-Identifier: GPL-2.0+
Clock API
=========
.. kernel-doc:: include/clk.h
:doc: Overview
Client API
----------
.. kernel-doc:: include/clk.h
:internal:

1
doc/api/index.rst
View file

@ -6,6 +6,7 @@ U-Boot API documentation
.. toctree::
:maxdepth: 2
clk
dfu
dm
efi

180
include/clk.h
View file

@ -14,6 +14,8 @@
#include <linux/types.h>
/**
* DOC: Overview
*
* A clock is a hardware signal that oscillates autonomously at a specific
* frequency and duty cycle. Most hardware modules require one or more clock
* signal to drive their operation. Clock signals are typically generated
@ -34,22 +36,22 @@ struct udevice;
/**
* struct clk - A handle to (allowing control of) a single clock.
* @dev: The device which implements the clock signal.
* @rate: The clock rate (in HZ).
* @flags: Flags used across common clock structure (e.g. %CLK_)
* Clock IP blocks specific flags (i.e. mux, div, gate, etc) are defined
* in struct's for those devices (e.g. &struct clk_mux).
* @enable_count: The number of times this clock has been enabled.
* @id: The clock signal ID within the provider.
* @data: An optional data field for scenarios where a single integer ID is not
* sufficient. If used, it can be populated through an .of_xlate op and
* processed during the various clock ops.
*
* Clients provide storage for clock handles. The content of the structure is
* managed solely by the clock API and clock drivers. A clock struct is
* initialized by "get"ing the clock struct. The clock struct is passed to all
* other clock APIs to identify which clock signal to operate upon.
*
* @dev: The device which implements the clock signal.
* @rate: The clock rate (in HZ).
* @flags: Flags used across common clock structure (e.g. CLK_)
* Clock IP blocks specific flags (i.e. mux, div, gate, etc) are defined
* in struct's for those devices (e.g. struct clk_mux).
* @id: The clock signal ID within the provider.
* @data: An optional data field for scenarios where a single integer ID is not
* sufficient. If used, it can be populated through an .of_xlate op and
* processed during the various clock ops.
*
* Should additional information to identify and configure any clock signal
* for any provider be required in the future, the struct could be expanded to
* either (a) add more fields to allow clock providers to store additional
@ -72,15 +74,14 @@ struct clk {
/**
* struct clk_bulk - A handle to (allowing control of) a bulk of clocks.
* @clks: An array of clock handles.
* @count: The number of clock handles in the clks array.
*
* Clients provide storage for the clock bulk. The content of the structure is
* managed solely by the clock API. A clock bulk struct is
* initialized by "get"ing the clock bulk struct.
* The clock bulk struct is passed to all other bulk clock APIs to apply
* the API to all the clock in the bulk struct.
*
* @clks: An array of clock handles.
* @count: The number of clock handles in the clks array.
*/
struct clk_bulk {
struct clk *clks;
@ -91,16 +92,19 @@ struct clk_bulk {
struct phandle_1_arg;
/**
* clk_get_by_phandle() - Get a clock by its phandle information (of-platadata)
* @dev: Device containing the phandle
* @cells: Phandle info
* @clk: A pointer to a clock struct to initialise
*
* This function is used when of-platdata is enabled.
*
* This looks up a clock using the phandle info. With dtoc, each phandle in the
* 'clocks' property is transformed into an idx representing the device. For
* example:
* 'clocks' property is transformed into an idx representing the device.
* For example::
*
* clocks = <&dpll_mpu_ck 23>;
*
* might result in:
* might result in::
*
* .clocks = {1, {23}},},
*
@ -109,9 +113,6 @@ struct phandle_1_arg;
* this example it would return a clock containing the 'dpll_mpu_ck' device and
* the clock ID 23.
*
* @dev: Device containing the phandle
* @cells: Phandle info
* @clock: A pointer to a clock struct to initialise
* Return: 0 if OK, or a negative error code.
*/
int clk_get_by_phandle(struct udevice *dev, const struct phandle_1_arg *cells,
@ -119,6 +120,10 @@ int clk_get_by_phandle(struct udevice *dev, const struct phandle_1_arg *cells,
/**
* clk_get_by_index() - Get/request a clock by integer index.
* @dev: The client device.
* @index: The index of the clock to request, within the client's list of
* clocks.
* @clk: A pointer to a clock struct to initialize.
*
* This looks up and requests a clock. The index is relative to the client
* device; each device is assumed to have n clocks associated with it somehow,
@ -126,30 +131,26 @@ int clk_get_by_phandle(struct udevice *dev, const struct phandle_1_arg *cells,
* device clock indices to provider clocks may be via device-tree properties,
* board-provided mapping tables, or some other mechanism.
*
* @dev: The client device.
* @index: The index of the clock to request, within the client's list of
* clocks.
* @clock A pointer to a clock struct to initialize.
* Return: 0 if OK, or a negative error code.
*/
int clk_get_by_index(struct udevice *dev, int index, struct clk *clk);
/**
* clk_get_by_index_nodev - Get/request a clock by integer index
* without a device.
*
* This is a version of clk_get_by_index() that does not use a device.
*
* clk_get_by_index_nodev() - Get/request a clock by integer index without a
* device.
* @node: The client ofnode.
* @index: The index of the clock to request, within the client's list of
* clocks.
* @clock A pointer to a clock struct to initialize.
* @clk: A pointer to a clock struct to initialize.
*
* Return: 0 if OK, or a negative error code.
*/
int clk_get_by_index_nodev(ofnode node, int index, struct clk *clk);
/**
* clk_get_bulk - Get/request all clocks of a device.
* clk_get_bulk() - Get/request all clocks of a device.
* @dev: The client device.
* @bulk: A pointer to a clock bulk struct to initialize.
*
* This looks up and requests all clocks of the client device; each device is
* assumed to have n clocks associated with it somehow, and this function finds
@ -157,14 +158,16 @@ int clk_get_by_index_nodev(ofnode node, int index, struct clk *clk);
* device clock indices to provider clocks may be via device-tree properties,
* board-provided mapping tables, or some other mechanism.
*
* @dev: The client device.
* @bulk A pointer to a clock bulk struct to initialize.
* Return: 0 if OK, or a negative error code.
*/
int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk);
/**
* clk_get_by_name - Get/request a clock by name.
* clk_get_by_name() - Get/request a clock by name.
* @dev: The client device.
* @name: The name of the clock to request, within the client's list of
* clocks.
* @clk: A pointer to a clock struct to initialize.
*
* This looks up and requests a clock. The name is relative to the client
* device; each device is assumed to have n clocks associated with it somehow,
@ -172,55 +175,49 @@ int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk);
* device clock names to provider clocks may be via device-tree properties,
* board-provided mapping tables, or some other mechanism.
*
* @dev: The client device.
* @name: The name of the clock to request, within the client's list of
* clocks.
* @clock: A pointer to a clock struct to initialize.
* Return: 0 if OK, or a negative error code.
*/
int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
/**
* clk_get_by_name_nodev - Get/request a clock by name without a device.
*
* This is a version of clk_get_by_name() that does not use a device.
*
* @node: The client ofnode.
* @name: The name of the clock to request, within the client's list of
* clocks.
* @clock: A pointer to a clock struct to initialize.
* @clk: A pointer to a clock struct to initialize.
*
* Return: 0 if OK, or a negative error code.
*/
int clk_get_by_name_nodev(ofnode node, const char *name, struct clk *clk);
/**
* devm_clk_get - lookup and obtain a managed reference to a clock producer.
* devm_clk_get() - lookup and obtain a managed reference to a clock producer.
* @dev: device for clock "consumer"
* @id: clock consumer ID
*
* Returns a struct clk corresponding to the clock producer, or
* valid IS_ERR() condition containing errno. The implementation
* uses @dev and @id to determine the clock consumer, and thereby
* the clock producer. (IOW, @id may be identical strings, but
* clk_get may return different clock producers depending on @dev.)
* The implementation uses @dev and @id to determine the clock consumer, and
* thereby the clock producer. (IOW, @id may be identical strings, but clk_get
* may return different clock producers depending on @dev.)
*
* Drivers must assume that the clock source is not enabled.
*
* devm_clk_get should not be called from within interrupt context.
*
* The clock will automatically be freed when the device is unbound
* from the bus.
*
* Return:
* a struct clk corresponding to the clock producer, or
* valid IS_ERR() condition containing errno
*/
struct clk *devm_clk_get(struct udevice *dev, const char *id);
/**
* devm_clk_get_optional - lookup and obtain a managed reference to an optional
* clock producer.
* devm_clk_get_optional() - lookup and obtain a managed reference to an
* optional clock producer.
* @dev: device for clock "consumer"
* @id: clock consumer ID
*
* Behaves the same as devm_clk_get() except where there is no clock producer.
* In this case, instead of returning -ENOENT, the function returns NULL.
* In this case, instead of returning -%ENOENT, the function returns NULL.
*/
static inline struct clk *devm_clk_get_optional(struct udevice *dev,
const char *id)
@ -236,13 +233,13 @@ static inline struct clk *devm_clk_get_optional(struct udevice *dev,
/**
* clk_release_all() - Disable (turn off)/Free an array of previously
* requested clocks.
* @clk: A clock struct array that was previously successfully
* requested by clk_request/get_by_*().
* @count: Number of clock contained in the array
*
* For each clock contained in the clock array, this function will check if
* clock has been previously requested and then will disable and free it.
*
* @clk: A clock struct array that was previously successfully
* requested by clk_request/get_by_*().
* @count Number of clock contained in the array
* Return: zero on success, or -ve error code.
*/
int clk_release_all(struct clk *clk, int count);
@ -294,13 +291,12 @@ static inline int clk_release_all(struct clk *clk, int count)
* clk_get_by_name_nodev_optional - Get/request an optinonal clock by name
* without a device.
* @node: The client ofnode.
* @name: The name of the clock to request.
* @name: The name of the clock to request, within the client's list of
* clocks.
* @clock: A pointer to a clock struct to initialize.
* @clk: A pointer to a clock struct to initialize.
*
* Behaves the same as clk_get_by_name_nodev() except where there is
* no clock producer, in this case, skip the error number -ENODATA, and
* no clock producer, in this case, skip the error number -%ENODATA, and
* the function returns 0.
*/
static inline int clk_get_by_name_nodev_optional(ofnode node, const char *name,
@ -340,12 +336,13 @@ enum clk_defaults_stage {
#if CONFIG_IS_ENABLED(OF_REAL) && CONFIG_IS_ENABLED(CLK)
/**
* clk_set_defaults - Process 'assigned-{clocks/clock-parents/clock-rates}'
* clk_set_defaults - Process ``assigned-{clocks/clock-parents/clock-rates}``
* properties to configure clocks
*
* @dev: A device to process (the ofnode associated with this device
* will be processed).
* @stage: The stage of the probing process this function is called during.
*
* Return: zero on success, or -ve error code.
*/
int clk_set_defaults(struct udevice *dev, enum clk_defaults_stage stage);
#else
@ -358,12 +355,12 @@ static inline int clk_set_defaults(struct udevice *dev, int stage)
/**
* clk_release_bulk() - Disable (turn off)/Free an array of previously
* requested clocks in a clock bulk struct.
* @bulk: A clock bulk struct that was previously successfully
* requested by clk_get_bulk().
*
* For each clock contained in the clock bulk struct, this function will check
* if clock has been previously requested and then will disable and free it.
*
* @clk: A clock bulk struct that was previously successfully
* requested by clk_get_bulk().
* Return: zero on success, or -ve error code.
*/
static inline int clk_release_bulk(struct clk_bulk *bulk)
@ -373,35 +370,35 @@ static inline int clk_release_bulk(struct clk_bulk *bulk)
#if CONFIG_IS_ENABLED(CLK)
/**
* clk_request - Request a clock by provider-specific ID.
* clk_request() - Request a clock by provider-specific ID.
* @dev: The clock provider device.
* @clk: A pointer to a clock struct to initialize. The caller must
* have already initialized any field in this struct which the
* clock provider uses to identify the clock.
*
* This requests a clock using a provider-specific ID. Generally, this function
* should not be used, since clk_get_by_index/name() provide an interface that
* better separates clients from intimate knowledge of clock providers.
* However, this function may be useful in core SoC-specific code.
*
* @dev: The clock provider device.
* @clock: A pointer to a clock struct to initialize. The caller must
* have already initialized any field in this struct which the
* clock provider uses to identify the clock.
* Return: 0 if OK, or a negative error code.
*/
int clk_request(struct udevice *dev, struct clk *clk);
/**
* clk_free - Free a previously requested clock.
*
* @clock: A clock struct that was previously successfully requested by
* clk_free() - Free a previously requested clock.
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
*
* Return: 0 if OK, or a negative error code.
*/
int clk_free(struct clk *clk);
/**
* clk_get_rate() - Get current clock rate.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
*
* Return: clock rate in Hz on success, 0 for invalid clock, or -ve error code
* for other errors.
*/
@ -409,98 +406,98 @@ ulong clk_get_rate(struct clk *clk);
/**
* clk_get_parent() - Get current clock's parent.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
*
* Return: pointer to parent's struct clk, or error code passed as pointer
*/
struct clk *clk_get_parent(struct clk *clk);
/**
* clk_get_parent_rate() - Get parent of current clock rate.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
*
* Return: clock rate in Hz, or -ve error code.
*/
long long clk_get_parent_rate(struct clk *clk);
/**
* clk_round_rate() - Adjust a rate to the exact rate a clock can provide
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
* @rate: desired clock rate in Hz.
*
* This answers the question "if I were to pass @rate to clk_set_rate(),
* what clock rate would I end up with?" without changing the hardware
* in any way. In other words:
* in any way. In other words::
*
* rate = clk_round_rate(clk, r);
*
* and:
* and::
*
* rate = clk_set_rate(clk, r);
*
* are equivalent except the former does not modify the clock hardware
* in any way.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
* @rate: desired clock rate in Hz.
* Return: rounded rate in Hz, or -ve error code.
*/
ulong clk_round_rate(struct clk *clk, ulong rate);
/**
* clk_set_rate() - Set current clock rate.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
* @rate: New clock rate in Hz.
*
* Return: new rate, or -ve error code.
*/
ulong clk_set_rate(struct clk *clk, ulong rate);
/**
* clk_set_parent() - Set current clock parent.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
* @parent: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
*
* Return: new rate, or -ve error code.
*/
int clk_set_parent(struct clk *clk, struct clk *parent);
/**
* clk_enable() - Enable (turn on) a clock.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
*
* Return: zero on success, or -ve error code.
*/
int clk_enable(struct clk *clk);
/**
* clk_enable_bulk() - Enable (turn on) all clocks in a clock bulk struct.
*
* @bulk: A clock bulk struct that was previously successfully requested
* by clk_get_bulk().
*
* Return: zero on success, or -ve error code.
*/
int clk_enable_bulk(struct clk_bulk *bulk);
/**
* clk_disable() - Disable (turn off) a clock.
*
* @clk: A clock struct that was previously successfully requested by
* clk_request/get_by_*().
*
* Return: zero on success, or -ve error code.
*/
int clk_disable(struct clk *clk);
/**
* clk_disable_bulk() - Disable (turn off) all clocks in a clock bulk struct.
*
* @bulk: A clock bulk struct that was previously successfully requested
* by clk_get_bulk().
*
* Return: zero on success, or -ve error code.
*/
int clk_disable_bulk(struct clk_bulk *bulk);
@ -510,28 +507,25 @@ int clk_disable_bulk(struct clk_bulk *bulk);
* @p: clk compared against q
* @q: clk compared against p
*
* Returns true if the two struct clk pointers both point to the same hardware
* clock node.
*
* Returns false otherwise. Note that two NULL clks are treated as matching.
* Return:
* %true if the two struct clk pointers both point to the same hardware clock
* node, and %false otherwise. Note that two %NULL clks are treated as matching.
*/
bool clk_is_match(const struct clk *p, const struct clk *q);
/**
* clk_get_by_id() - Get the clock by its ID
*
* @id: The clock ID to search for
*
* @clkp: A pointer to clock struct that has been found among added clocks
* to UCLASS_CLK
*
* Return: zero on success, or -ENOENT on error
*/
int clk_get_by_id(ulong id, struct clk **clkp);
/**
* clk_dev_binded() - Check whether the clk has a device binded
*
* @clk A pointer to the clk
* @clk: A pointer to the clk
*
* Return: true on binded, or false on no
*/
@ -617,8 +611,8 @@ static inline bool clk_dev_binded(struct clk *clk)
/**
* clk_valid() - check if clk is valid
*
* @clk: the clock to check
*
* Return: true if valid, or false
*/
static inline bool clk_valid(struct clk *clk)