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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);
Masahiro Yamada021abf62016-09-26 20:45:27 +0900101#else
102static inline int clk_get_by_index(struct udevice *dev, int index,
103 struct clk *clk)
104{
105 return -ENOSYS;
106}
107
108static inline int clk_get_by_name(struct udevice *dev, const char *name,
109 struct clk *clk)
110{
111 return -ENOSYS;
112}
113#endif
Simon Glasse70cc432016-01-20 19:43:02 -0700114
Stephen Warren135aa952016-06-17 09:44:00 -0600115/**
116 * clk_request - Request a clock by provider-specific ID.
117 *
118 * This requests a clock using a provider-specific ID. Generally, this function
119 * should not be used, since clk_get_by_index/name() provide an interface that
120 * better separates clients from intimate knowledge of clock providers.
121 * However, this function may be useful in core SoC-specific code.
122 *
123 * @dev: The clock provider device.
124 * @clock: A pointer to a clock struct to initialize. The caller must
125 * have already initialized any field in this struct which the
126 * clock provider uses to identify the clock.
127 * @return 0 if OK, or a negative error code.
128 */
129int clk_request(struct udevice *dev, struct clk *clk);
130
131/**
132 * clock_free - Free a previously requested clock.
133 *
134 * @clock: A clock struct that was previously successfully requested by
135 * clk_request/get_by_*().
136 * @return 0 if OK, or a negative error code.
137 */
138int clk_free(struct clk *clk);
139
140/**
141 * clk_get_rate() - Get current clock rate.
142 *
143 * @clk: A clock struct that was previously successfully requested by
144 * clk_request/get_by_*().
145 * @return clock rate in Hz, or -ve error code.
146 */
147ulong clk_get_rate(struct clk *clk);
148
149/**
150 * clk_set_rate() - Set current clock rate.
151 *
152 * @clk: A clock struct that was previously successfully requested by
153 * clk_request/get_by_*().
154 * @rate: New clock rate in Hz.
155 * @return new rate, or -ve error code.
156 */
157ulong clk_set_rate(struct clk *clk, ulong rate);
158
159/**
160 * clk_enable() - Enable (turn on) a clock.
161 *
162 * @clk: A clock struct that was previously successfully requested by
163 * clk_request/get_by_*().
164 * @return zero on success, or -ve error code.
165 */
166int clk_enable(struct clk *clk);
167
168/**
169 * clk_disable() - Disable (turn off) a clock.
170 *
171 * @clk: A clock struct that was previously successfully requested by
172 * clk_request/get_by_*().
173 * @return zero on success, or -ve error code.
174 */
175int clk_disable(struct clk *clk);
176
177int soc_clk_dump(void);
178
179#endif