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Simon Glassf26c8a82015-06-23 15:39:15 -06001/*
2 * Copyright (c) 2015 Google, Inc
3 * Written by Simon Glass <sjg@chromium.org>
Stephen Warren135aa952016-06-17 09:44:00 -06004 * Copyright (c) 2016, NVIDIA CORPORATION.
Simon Glassf26c8a82015-06-23 15:39:15 -06005 *
6 * SPDX-License-Identifier: GPL-2.0+
7 */
8
Michal Simek08d0d6f2013-11-21 13:39:02 -08009#ifndef _CLK_H_
10#define _CLK_H_
11
Masahiro Yamada1221ce42016-09-21 11:28:55 +090012#include <linux/errno.h>
Masahiro Yamadaad1cf782016-01-13 13:16:09 +090013#include <linux/types.h>
14
Stephen Warren135aa952016-06-17 09:44:00 -060015/**
16 * A clock is a hardware signal that oscillates autonomously at a specific
17 * frequency and duty cycle. Most hardware modules require one or more clock
18 * signal to drive their operation. Clock signals are typically generated
19 * externally to the HW module consuming them, by an entity this API calls a
20 * clock provider. This API provides a standard means for drivers to enable and
21 * disable clocks, and to set the rate at which they oscillate.
22 *
23 * A driver that implements UCLASS_CLOCK is a clock provider. A provider will
24 * often implement multiple separate clocks, since the hardware it manages
25 * often has this capability. clock_uclass.h describes the interface which
26 * clock providers must implement.
27 *
28 * Clock consumers/clients are the HW modules driven by the clock signals. This
29 * header file describes the API used by drivers for those HW modules.
30 */
31
Masahiro Yamadaad1cf782016-01-13 13:16:09 +090032struct udevice;
33
Stephen Warren135aa952016-06-17 09:44:00 -060034/**
35 * struct clk - A handle to (allowing control of) a single clock.
36 *
37 * Clients provide storage for clock handles. The content of the structure is
38 * managed solely by the clock API and clock drivers. A clock struct is
39 * initialized by "get"ing the clock struct. The clock struct is passed to all
40 * other clock APIs to identify which clock signal to operate upon.
41 *
42 * @dev: The device which implements the clock signal.
43 * @id: The clock signal ID within the provider.
44 *
45 * Currently, the clock API assumes that a single integer ID is enough to
46 * identify and configure any clock signal for any clock provider. If this
47 * assumption becomes invalid in the future, the struct could be expanded to
48 * either (a) add more fields to allow clock providers to store additional
49 * information, or (b) replace the id field with an opaque pointer, which the
50 * provider would dynamically allocated during its .of_xlate op, and process
51 * during is .request op. This may require the addition of an extra op to clean
52 * up the allocation.
53 */
54struct clk {
55 struct udevice *dev;
56 /*
57 * Written by of_xlate. We assume a single id is enough for now. In the
58 * future, we might add more fields here.
Simon Glassf26c8a82015-06-23 15:39:15 -060059 */
Stephen Warren135aa952016-06-17 09:44:00 -060060 unsigned long id;
Simon Glassf26c8a82015-06-23 15:39:15 -060061};
62
Paul Burton3f96f872016-09-08 07:47:28 +010063#if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(CLK)
Simon Glass7423daa2016-07-04 11:58:03 -060064struct phandle_2_cell;
65int clk_get_by_index_platdata(struct udevice *dev, int index,
66 struct phandle_2_cell *cells, struct clk *clk);
67
Simon Glasse70cc432016-01-20 19:43:02 -070068/**
Stephen Warren135aa952016-06-17 09:44:00 -060069 * clock_get_by_index - Get/request a clock by integer index.
Simon Glasse70cc432016-01-20 19:43:02 -070070 *
Stephen Warren135aa952016-06-17 09:44:00 -060071 * This looks up and requests a clock. The index is relative to the client
72 * device; each device is assumed to have n clocks associated with it somehow,
73 * and this function finds and requests one of them. The mapping of client
74 * device clock indices to provider clocks may be via device-tree properties,
75 * board-provided mapping tables, or some other mechanism.
Simon Glasse70cc432016-01-20 19:43:02 -070076 *
Stephen Warren135aa952016-06-17 09:44:00 -060077 * @dev: The client device.
78 * @index: The index of the clock to request, within the client's list of
79 * clocks.
80 * @clock A pointer to a clock struct to initialize.
81 * @return 0 if OK, or a negative error code.
Simon Glasse70cc432016-01-20 19:43:02 -070082 */
Stephen Warren135aa952016-06-17 09:44:00 -060083int clk_get_by_index(struct udevice *dev, int index, struct clk *clk);
84
85/**
86 * clock_get_by_name - Get/request a clock by name.
87 *
88 * This looks up and requests a clock. The name is relative to the client
89 * device; each device is assumed to have n clocks associated with it somehow,
90 * and this function finds and requests one of them. The mapping of client
91 * device clock names to provider clocks may be via device-tree properties,
92 * board-provided mapping tables, or some other mechanism.
93 *
94 * @dev: The client device.
95 * @name: The name of the clock to request, within the client's list of
96 * clocks.
97 * @clock: A pointer to a clock struct to initialize.
98 * @return 0 if OK, or a negative error code.
99 */
100int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
Patrice Chotardb108d8a2017-07-25 13:24:45 +0200101
102/**
103 * clk_release_all() - Disable (turn off)/Free an array of previously
104 * requested clocks.
105 *
106 * For each clock contained in the clock array, this function will check if
107 * clock has been previously requested and then will disable and free it.
108 *
109 * @clk: A clock struct array that was previously successfully
110 * requested by clk_request/get_by_*().
111 * @count Number of clock contained in the array
112 * @return zero on success, or -ve error code.
113 */
114int clk_release_all(struct clk *clk, int count);
115
Masahiro Yamada021abf62016-09-26 20:45:27 +0900116#else
117static inline int clk_get_by_index(struct udevice *dev, int index,
118 struct clk *clk)
119{
120 return -ENOSYS;
121}
122
123static inline int clk_get_by_name(struct udevice *dev, const char *name,
124 struct clk *clk)
125{
126 return -ENOSYS;
127}
Patrice Chotardb108d8a2017-07-25 13:24:45 +0200128
129static inline int clk_release_all(struct clk *clk, int count)
130{
131 return -ENOSYS;
132}
133
Masahiro Yamada021abf62016-09-26 20:45:27 +0900134#endif
Simon Glasse70cc432016-01-20 19:43:02 -0700135
Stephen Warren135aa952016-06-17 09:44:00 -0600136/**
137 * clk_request - Request a clock by provider-specific ID.
138 *
139 * This requests a clock using a provider-specific ID. Generally, this function
140 * should not be used, since clk_get_by_index/name() provide an interface that
141 * better separates clients from intimate knowledge of clock providers.
142 * However, this function may be useful in core SoC-specific code.
143 *
144 * @dev: The clock provider device.
145 * @clock: A pointer to a clock struct to initialize. The caller must
146 * have already initialized any field in this struct which the
147 * clock provider uses to identify the clock.
148 * @return 0 if OK, or a negative error code.
149 */
150int clk_request(struct udevice *dev, struct clk *clk);
151
152/**
153 * clock_free - Free a previously requested clock.
154 *
155 * @clock: A clock struct that was previously successfully requested by
156 * clk_request/get_by_*().
157 * @return 0 if OK, or a negative error code.
158 */
159int clk_free(struct clk *clk);
160
161/**
162 * clk_get_rate() - Get current clock rate.
163 *
164 * @clk: A clock struct that was previously successfully requested by
165 * clk_request/get_by_*().
166 * @return clock rate in Hz, or -ve error code.
167 */
168ulong clk_get_rate(struct clk *clk);
169
170/**
171 * clk_set_rate() - Set current clock rate.
172 *
173 * @clk: A clock struct that was previously successfully requested by
174 * clk_request/get_by_*().
175 * @rate: New clock rate in Hz.
176 * @return new rate, or -ve error code.
177 */
178ulong clk_set_rate(struct clk *clk, ulong rate);
179
180/**
181 * clk_enable() - Enable (turn on) a clock.
182 *
183 * @clk: A clock struct that was previously successfully requested by
184 * clk_request/get_by_*().
185 * @return zero on success, or -ve error code.
186 */
187int clk_enable(struct clk *clk);
188
189/**
190 * clk_disable() - Disable (turn off) a clock.
191 *
192 * @clk: A clock struct that was previously successfully requested by
193 * clk_request/get_by_*().
194 * @return zero on success, or -ve error code.
195 */
196int clk_disable(struct clk *clk);
197
198int soc_clk_dump(void);
199
200#endif