[thirdparty/u-boot.git] / include / clk-uclass.h

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Copyright (c) 2015 Google, Inc
 * Written by Simon Glass <sjg@chromium.org>
 * Copyright (c) 2016, NVIDIA CORPORATION.
 */

#ifndef _CLK_UCLASS_H
#define _CLK_UCLASS_H

/* See clk.h for background documentation. */

#include <clk.h>

struct ofnode_phandle_args;

/**
 * struct clk_ops - The functions that a clock driver must implement.
 * @of_xlate: Translate a client's device-tree (OF) clock specifier.
 * @request: Request a translated clock.
 * @round_rate: Adjust a rate to the exact rate a clock can provide.
 * @get_rate: Get current clock rate.
 * @set_rate: Set current clock rate.
 * @set_parent: Set current clock parent
 * @enable: Enable a clock.
 * @disable: Disable a clock.
 * @dump: Print clock information.
 *
 * The individual methods are described more fully below.
 */
struct clk_ops {
	int (*of_xlate)(struct clk *clock,
			struct ofnode_phandle_args *args);
	int (*request)(struct clk *clock);
	ulong (*round_rate)(struct clk *clk, ulong rate);
	ulong (*get_rate)(struct clk *clk);
	ulong (*set_rate)(struct clk *clk, ulong rate);
	int (*set_parent)(struct clk *clk, struct clk *parent);
	int (*enable)(struct clk *clk);
	int (*disable)(struct clk *clk);
#if IS_ENABLED(CONFIG_CMD_CLK)
	void (*dump)(struct udevice *dev);
#endif
};

#if 0 /* For documentation only */
/**
 * of_xlate() - Translate a client's device-tree (OF) clock specifier.
 * @clock:	The clock struct to hold the translation result.
 * @args:	The clock specifier values from device tree.
 *
 * The clock core calls this function as the first step in implementing
 * a client's clk_get_by_*() call.
 *
 * If this function pointer is set to NULL, the clock core will use a
 * default implementation, which assumes #clock-cells = <1>, and that
 * the DT cell contains a simple integer clock ID.
 *
 * This function should be a simple translation of @args into @clock->id and
 * (optionally) @clock->data. All other processing, allocation, or error
 * checking should take place in request().
 *
 * At present, the clock API solely supports device-tree. If this
 * changes, other xxx_xlate() functions may be added to support those
 * other mechanisms.
 *
 * Return:
 * * 0 on success
 * * -%EINVAL if @args does not have the correct format. For example, it could
 *   have too many/few arguments.
 * * -%ENOENT if @args has the correct format but cannot be translated. This can
 *   happen if translation involves a table lookup and @args is not present.
 */
int of_xlate(struct clk *clock, struct ofnode_phandle_args *args);

/**
 * request() - Request a translated clock.
 * @clock:	The clock struct to request; this has been filled in by
 *		a previoux xxx_xlate() function call, or by the caller
 *		of clk_request().
 *
 * The clock core calls this function as the second step in
 * implementing a client's clk_get_by_*() call, following a successful
 * xxx_xlate() call, or as the only step in implementing a client's
 * clk_request() call.
 *
 * This is the right place to do bounds checking (rejecting invalid or
 * unimplemented clocks), allocate resources, or perform other setup not done
 * during driver probe(). Most clock drivers should allocate resources in their
 * probe() function, but it is possible to lazily initialize something here.
 *
 * Return:
 * * 0 on success
 * * -%ENOENT, if there is no clock corresponding to @clock->id and
 *   @clock->data.
 */
int request(struct clk *clock);

/**
 * round_rate() - Adjust a rate to the exact rate a clock can provide.
 * @clk:	The clock to query.
 * @rate:	Desired clock rate in Hz.
 *
 * This function returns a new rate which can be provided to set_rate(). This
 * new rate should be the closest rate to @rate which can be set without
 * rounding. The following pseudo-code should hold::
 *
 *   for all rate in range(ULONG_MAX):
 *     rounded = round_rate(clk, rate)
 *     new_rate = set_rate(clk, rate)
 *     assert(IS_ERR_VALUE(new_rate) || new_rate == rounded)
 *
 * Return:
 * * The rounded rate in Hz on success
 * * A negative error value from another API (such as clk_get_rate()). This
 *   function must not return an error for any other reason.
 */
ulong round_rate(struct clk *clk, ulong rate);

/**
 * get_rate() - Get current clock rate.
 * @clk:	The clock to query.
 *
 * This returns the current rate of a clock. If the clock is disabled, it
 * returns the rate at which the clock would run if it was enabled. The
 * following pseudo-code should hold::
 *
 *   disable(clk)
 *   rate = get_rate(clk)
 *   enable(clk)
 *   assert(get_rate(clk) == rate)
 *
 * Return:
 * * The rate of @clk
 * * -%ENOSYS if this function is not implemented for @clk
 * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
 *   this check in request().
 * * Another negative error value (such as %EIO or %ECOMM) if the rate could
 *   not be determined due to a bus error.
 */
ulong get_rate(struct clk *clk);

/**
 * set_rate() - Set current clock rate.
 * @clk:	The clock to manipulate.
 * @rate:	New clock rate in Hz.
 *
 * Set the rate of @clk to @rate. The actual rate may be rounded. However,
 * excessive rounding should be avoided. It is left to the driver author's
 * discretion when this function should attempt to round and when it should
 * return an error. For example, a dividing clock might use the following
 * pseudo-logic when implemening this function::
 *
 *   divisor = parent_rate / rate
 *   if divisor < min || divisor > max:
 *     return -EINVAL
 *
 * If there is any concern about rounding, prefer to let consumers make the
 * decision by calling round_rate().
 *
 * Return:
 * * The new rate on success
 * * -%ENOSYS if this function is not implemented for @clk
 * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
 *   this check in request().
 * * -%EINVAL if @rate is not valid for @clk.
 * * Another negative error value (such as %EIO or %ECOMM) if the rate could
 *   not be set due to a bus error.
 */
ulong set_rate(struct clk *clk, ulong rate);

/**
 * set_parent() - Set current clock parent
 * @clk:        The clock to manipulate.
 * @parent:     New clock parent.
 *
 * Set the current parent of @clk to @parent. The rate of the clock may be
 * modified by this call. If @clk was enabled before this function, it should
 * remain enabled after this function, although it may be temporarily disabled
 * if necessary.
 *
 * Return:
 * * 0 on success
 * * -%ENOSYS if this function is not implemented for @clk
 * * -%ENOENT if @clk->id or @parent->id is invalid. Prefer using an assert
 *   instead, and doing this check in request().
 * * -%EINVAL if @parent is not a valid parent for @clk.
 * * Another negative error value (such as %EIO or %ECOMM) if the parent could
 *   not be set due to a bus error.
 */
int set_parent(struct clk *clk, struct clk *parent);

/**
 * enable() - Enable a clock.
 * @clk:	The clock to manipulate.
 *
 * Enable (un-gate) the clock. This function should not modify the rate of the
 * clock (see get_rate() for details).
 *
 * Return:
 * * 0 on success
 * * -%ENOSYS if this function is not implemented for @clk
 * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
 *   this check in request().
 * * Another negative error value (such as %EIO or %ECOMM) if the clock could
 *   not be enabled due to a bus error.
 */
int enable(struct clk *clk);

/**
 * disable() - Disable a clock.
 * @clk:	The clock to manipulate.
 *
 * Disable (gate) the clock. This function should not modify the rate of the
 * clock (see get_rate() for details).
 *
 * * 0 on success
 * * -%ENOSYS if this function is not implemented for @clk
 * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
 *   this check in request().
 * * Another negative error value (such as %EIO or %ECOMM) if the clock could
 *   not be disabled due to a bus error.
 */
int disable(struct clk *clk);

/**
 * dump() - Print clock information.
 * @dev:	The clock device to dump.
 *
 * If present, this function is called by "clk dump" command for each
 * bound device.
 */
void dump(struct udevice *dev);
#endif

#endif
Commit	Line	Data
83d290c5	1	/* SPDX-License-Identifier: GPL-2.0+ */
135aa950 SW	2	/*
	3	* Copyright (c) 2015 Google, Inc
	4	* Written by Simon Glass <sjg@chromium.org>
	5	* Copyright (c) 2016, NVIDIA CORPORATION.
135aa950 SW	6	*/
	7
	8	#ifndef _CLK_UCLASS_H
	9	#define _CLK_UCLASS_H
	10
	11	/* See clk.h for background documentation. */
	12
	13	#include <clk.h>
a4e0ef50 SG	14
a4e0ef50 SG	15	struct ofnode_phandle_args;
135aa950 SW	16
	17	/**
	18	* struct clk_ops - The functions that a clock driver must implement.
a0abea86 SA	19	* @of_xlate: Translate a client's device-tree (OF) clock specifier.
a0abea86 SA	20	* @request: Request a translated clock.
a0abea86 SA	21	* @round_rate: Adjust a rate to the exact rate a clock can provide.
	22	* @get_rate: Get current clock rate.
	23	* @set_rate: Set current clock rate.
	24	* @set_parent: Set current clock parent
	25	* @enable: Enable a clock.
	26	* @disable: Disable a clock.
505ef5f6	27	* @dump: Print clock information.
a0abea86 SA	28	*
a0abea86 SA	29	* The individual methods are described more fully below.
135aa950 SW	30	*/
135aa950 SW	31	struct clk_ops {
135aa950	32	int (of_xlate)(struct clk clock,
a4e0ef50	33	struct ofnode_phandle_args *args);
135aa950	34	int (request)(struct clk clock);
2983ad55	35	ulong (round_rate)(struct clk clk, ulong rate);
135aa950	36	ulong (get_rate)(struct clk clk);
135aa950	37	ulong (set_rate)(struct clk clk, ulong rate);
f7d1046d	38	int (set_parent)(struct clk clk, struct clk *parent);
135aa950	39	int (enable)(struct clk clk);
135aa950	40	int (disable)(struct clk clk);
505ef5f6 IP	41	#if IS_ENABLED(CONFIG_CMD_CLK)
	42	void (dump)(struct udevice dev);
	43	#endif
135aa950 SW	44	};
135aa950 SW	45
a0abea86 SA	46	#if 0 /* For documentation only */
	47	/**
	48	* of_xlate() - Translate a client's device-tree (OF) clock specifier.
	49	* @clock: The clock struct to hold the translation result.
	50	* @args: The clock specifier values from device tree.
	51	*
	52	* The clock core calls this function as the first step in implementing
	53	* a client's clk_get_by_*() call.
	54	*
	55	* If this function pointer is set to NULL, the clock core will use a
	56	* default implementation, which assumes #clock-cells = <1>, and that
	57	* the DT cell contains a simple integer clock ID.
	58	*
0bfbb830 SA	59	* This function should be a simple translation of @args into @clock->id and
	60	* (optionally) @clock->data. All other processing, allocation, or error
	61	* checking should take place in request().
	62	*
a0abea86 SA	63	* At present, the clock API solely supports device-tree. If this
	64	* changes, other xxx_xlate() functions may be added to support those
	65	* other mechanisms.
	66	*
0bfbb830 SA	67	* Return:
	68	* * 0 on success
	69	* * -%EINVAL if @args does not have the correct format. For example, it could
	70	* have too many/few arguments.
	71	* * -%ENOENT if @args has the correct format but cannot be translated. This can
	72	* happen if translation involves a table lookup and @args is not present.
a0abea86 SA	73	*/
	74	int of_xlate(struct clk clock, struct ofnode_phandle_args args);
	75
	76	/**
	77	* request() - Request a translated clock.
52029b78	78	* @clock: The clock struct to request; this has been filled in by
a0abea86 SA	79	* a previoux xxx_xlate() function call, or by the caller
	80	* of clk_request().
	81	*
	82	* The clock core calls this function as the second step in
	83	* implementing a client's clk_get_by_*() call, following a successful
	84	* xxx_xlate() call, or as the only step in implementing a client's
	85	* clk_request() call.
	86	*
0bfbb830 SA	87	* This is the right place to do bounds checking (rejecting invalid or
	88	* unimplemented clocks), allocate resources, or perform other setup not done
	89	* during driver probe(). Most clock drivers should allocate resources in their
	90	* probe() function, but it is possible to lazily initialize something here.
	91	*
	92	* Return:
	93	* * 0 on success
	94	* * -%ENOENT, if there is no clock corresponding to @clock->id and
	95	* @clock->data.
a0abea86 SA	96	*/
	97	int request(struct clk *clock);
	98
a0abea86 SA	99	/**
a0abea86 SA	100	* round_rate() - Adjust a rate to the exact rate a clock can provide.
0bfbb830 SA	101	* @clk: The clock to query.
0bfbb830 SA	102	* @rate: Desired clock rate in Hz.
a0abea86	103	*
0bfbb830 SA	104	* This function returns a new rate which can be provided to set_rate(). This
	105	* new rate should be the closest rate to @rate which can be set without
	106	* rounding. The following pseudo-code should hold::
	107	*
	108	* for all rate in range(ULONG_MAX):
	109	* rounded = round_rate(clk, rate)
	110	* new_rate = set_rate(clk, rate)
	111	* assert(IS_ERR_VALUE(new_rate) \|\| new_rate == rounded)
	112	*
	113	* Return:
	114	* * The rounded rate in Hz on success
	115	* * A negative error value from another API (such as clk_get_rate()). This
	116	* function must not return an error for any other reason.
a0abea86 SA	117	*/
	118	ulong round_rate(struct clk *clk, ulong rate);
	119
	120	/**
	121	* get_rate() - Get current clock rate.
	122	* @clk: The clock to query.
	123	*
0bfbb830 SA	124	* This returns the current rate of a clock. If the clock is disabled, it
	125	* returns the rate at which the clock would run if it was enabled. The
	126	* following pseudo-code should hold::
	127	*
	128	* disable(clk)
	129	* rate = get_rate(clk)
	130	* enable(clk)
	131	* assert(get_rate(clk) == rate)
	132	*
	133	* Return:
	134	* * The rate of @clk
	135	* * -%ENOSYS if this function is not implemented for @clk
	136	* * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
	137	* this check in request().
	138	* * Another negative error value (such as %EIO or %ECOMM) if the rate could
	139	* not be determined due to a bus error.
a0abea86 SA	140	*/
	141	ulong get_rate(struct clk *clk);
	142
	143	/**
	144	* set_rate() - Set current clock rate.
	145	* @clk: The clock to manipulate.
	146	* @rate: New clock rate in Hz.
	147	*
0bfbb830 SA	148	* Set the rate of @clk to @rate. The actual rate may be rounded. However,
	149	* excessive rounding should be avoided. It is left to the driver author's
	150	* discretion when this function should attempt to round and when it should
	151	* return an error. For example, a dividing clock might use the following
	152	* pseudo-logic when implemening this function::
	153	*
	154	* divisor = parent_rate / rate
	155	* if divisor < min \|\| divisor > max:
	156	* return -EINVAL
	157	*
	158	* If there is any concern about rounding, prefer to let consumers make the
	159	* decision by calling round_rate().
	160	*
	161	* Return:
	162	* * The new rate on success
	163	* * -%ENOSYS if this function is not implemented for @clk
	164	* * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
	165	* this check in request().
	166	* * -%EINVAL if @rate is not valid for @clk.
	167	* * Another negative error value (such as %EIO or %ECOMM) if the rate could
	168	* not be set due to a bus error.
a0abea86 SA	169	*/
	170	ulong set_rate(struct clk *clk, ulong rate);
	171
	172	/**
	173	* set_parent() - Set current clock parent
	174	* @clk: The clock to manipulate.
	175	* @parent: New clock parent.
	176	*
0bfbb830 SA	177	* Set the current parent of @clk to @parent. The rate of the clock may be
	178	* modified by this call. If @clk was enabled before this function, it should
	179	* remain enabled after this function, although it may be temporarily disabled
	180	* if necessary.
	181	*
	182	* Return:
	183	* * 0 on success
	184	* * -%ENOSYS if this function is not implemented for @clk
	185	* * -%ENOENT if @clk->id or @parent->id is invalid. Prefer using an assert
	186	* instead, and doing this check in request().
	187	* * -%EINVAL if @parent is not a valid parent for @clk.
	188	* * Another negative error value (such as %EIO or %ECOMM) if the parent could
	189	* not be set due to a bus error.
a0abea86 SA	190	*/
	191	int set_parent(struct clk clk, struct clk parent);
	192
	193	/**
	194	* enable() - Enable a clock.
	195	* @clk: The clock to manipulate.
	196	*
0bfbb830 SA	197	* Enable (un-gate) the clock. This function should not modify the rate of the
	198	* clock (see get_rate() for details).
	199	*
	200	* Return:
	201	* * 0 on success
	202	* * -%ENOSYS if this function is not implemented for @clk
	203	* * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
	204	* this check in request().
	205	* * Another negative error value (such as %EIO or %ECOMM) if the clock could
	206	* not be enabled due to a bus error.
a0abea86 SA	207	*/
	208	int enable(struct clk *clk);
	209
	210	/**
	211	* disable() - Disable a clock.
	212	* @clk: The clock to manipulate.
	213	*
0bfbb830 SA	214	* Disable (gate) the clock. This function should not modify the rate of the
	215	* clock (see get_rate() for details).
	216	*
	217	* * 0 on success
	218	* * -%ENOSYS if this function is not implemented for @clk
	219	* * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing
	220	* this check in request().
	221	* * Another negative error value (such as %EIO or %ECOMM) if the clock could
	222	* not be disabled due to a bus error.
a0abea86 SA	223	*/
a0abea86 SA	224	int disable(struct clk *clk);
505ef5f6 IP	225
	226	/**
	227	* dump() - Print clock information.
	228	* @dev: The clock device to dump.
	229	*
	230	* If present, this function is called by "clk dump" command for each
	231	* bound device.
	232	*/
	233	void dump(struct udevice *dev);
a0abea86 SA	234	#endif
a0abea86 SA	235
135aa950	236	#endif