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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 Yamadaad1cf782016-01-13 13:16:09 +090012#include <linux/types.h>
13
Stephen Warren135aa952016-06-17 09:44:00 -060014/**
15 * A clock is a hardware signal that oscillates autonomously at a specific
16 * frequency and duty cycle. Most hardware modules require one or more clock
17 * signal to drive their operation. Clock signals are typically generated
18 * externally to the HW module consuming them, by an entity this API calls a
19 * clock provider. This API provides a standard means for drivers to enable and
20 * disable clocks, and to set the rate at which they oscillate.
21 *
22 * A driver that implements UCLASS_CLOCK is a clock provider. A provider will
23 * often implement multiple separate clocks, since the hardware it manages
24 * often has this capability. clock_uclass.h describes the interface which
25 * clock providers must implement.
26 *
27 * Clock consumers/clients are the HW modules driven by the clock signals. This
28 * header file describes the API used by drivers for those HW modules.
29 */
30
Masahiro Yamadaad1cf782016-01-13 13:16:09 +090031struct udevice;
32
Stephen Warren135aa952016-06-17 09:44:00 -060033/**
34 * struct clk - A handle to (allowing control of) a single clock.
35 *
36 * Clients provide storage for clock handles. The content of the structure is
37 * managed solely by the clock API and clock drivers. A clock struct is
38 * initialized by "get"ing the clock struct. The clock struct is passed to all
39 * other clock APIs to identify which clock signal to operate upon.
40 *
41 * @dev: The device which implements the clock signal.
42 * @id: The clock signal ID within the provider.
43 *
44 * Currently, the clock API assumes that a single integer ID is enough to
45 * identify and configure any clock signal for any clock provider. If this
46 * assumption becomes invalid in the future, the struct could be expanded to
47 * either (a) add more fields to allow clock providers to store additional
48 * information, or (b) replace the id field with an opaque pointer, which the
49 * provider would dynamically allocated during its .of_xlate op, and process
50 * during is .request op. This may require the addition of an extra op to clean
51 * up the allocation.
52 */
53struct clk {
54 struct udevice *dev;
55 /*
56 * Written by of_xlate. We assume a single id is enough for now. In the
57 * future, we might add more fields here.
Simon Glassf26c8a82015-06-23 15:39:15 -060058 */
Stephen Warren135aa952016-06-17 09:44:00 -060059 unsigned long id;
Simon Glassf26c8a82015-06-23 15:39:15 -060060};
61
Simon Glasse70cc432016-01-20 19:43:02 -070062#if CONFIG_IS_ENABLED(OF_CONTROL)
Simon Glass7423daa2016-07-04 11:58:03 -060063struct phandle_2_cell;
64int clk_get_by_index_platdata(struct udevice *dev, int index,
65 struct phandle_2_cell *cells, struct clk *clk);
66
Simon Glasse70cc432016-01-20 19:43:02 -070067/**
Stephen Warren135aa952016-06-17 09:44:00 -060068 * clock_get_by_index - Get/request a clock by integer index.
Simon Glasse70cc432016-01-20 19:43:02 -070069 *
Stephen Warren135aa952016-06-17 09:44:00 -060070 * This looks up and requests a clock. The index is relative to the client
71 * device; each device is assumed to have n clocks associated with it somehow,
72 * and this function finds and requests one of them. The mapping of client
73 * device clock indices to provider clocks may be via device-tree properties,
74 * board-provided mapping tables, or some other mechanism.
Simon Glasse70cc432016-01-20 19:43:02 -070075 *
Stephen Warren135aa952016-06-17 09:44:00 -060076 * @dev: The client device.
77 * @index: The index of the clock to request, within the client's list of
78 * clocks.
79 * @clock A pointer to a clock struct to initialize.
80 * @return 0 if OK, or a negative error code.
Simon Glasse70cc432016-01-20 19:43:02 -070081 */
Stephen Warren135aa952016-06-17 09:44:00 -060082int clk_get_by_index(struct udevice *dev, int index, struct clk *clk);
83
84/**
85 * clock_get_by_name - Get/request a clock by name.
86 *
87 * This looks up and requests a clock. The name is relative to the client
88 * device; each device is assumed to have n clocks associated with it somehow,
89 * and this function finds and requests one of them. The mapping of client
90 * device clock names to provider clocks may be via device-tree properties,
91 * board-provided mapping tables, or some other mechanism.
92 *
93 * @dev: The client device.
94 * @name: The name of the clock to request, within the client's list of
95 * clocks.
96 * @clock: A pointer to a clock struct to initialize.
97 * @return 0 if OK, or a negative error code.
98 */
99int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
Simon Glasse70cc432016-01-20 19:43:02 -0700100#else
101static inline int clk_get_by_index(struct udevice *dev, int index,
Stephen Warren135aa952016-06-17 09:44:00 -0600102 struct clk *clk)
103{
104 return -ENOSYS;
105}
106
107static int clk_get_by_name(struct udevice *dev, const char *name,
108 struct clk *clk)
Simon Glasse70cc432016-01-20 19:43:02 -0700109{
110 return -ENOSYS;
111}
112#endif
113
Stephen Warren135aa952016-06-17 09:44:00 -0600114/**
115 * clk_request - Request a clock by provider-specific ID.
116 *
117 * This requests a clock using a provider-specific ID. Generally, this function
118 * should not be used, since clk_get_by_index/name() provide an interface that
119 * better separates clients from intimate knowledge of clock providers.
120 * However, this function may be useful in core SoC-specific code.
121 *
122 * @dev: The clock provider device.
123 * @clock: A pointer to a clock struct to initialize. The caller must
124 * have already initialized any field in this struct which the
125 * clock provider uses to identify the clock.
126 * @return 0 if OK, or a negative error code.
127 */
128int clk_request(struct udevice *dev, struct clk *clk);
129
130/**
131 * clock_free - Free a previously requested clock.
132 *
133 * @clock: A clock struct that was previously successfully requested by
134 * clk_request/get_by_*().
135 * @return 0 if OK, or a negative error code.
136 */
137int clk_free(struct clk *clk);
138
139/**
140 * clk_get_rate() - Get current clock rate.
141 *
142 * @clk: A clock struct that was previously successfully requested by
143 * clk_request/get_by_*().
144 * @return clock rate in Hz, or -ve error code.
145 */
146ulong clk_get_rate(struct clk *clk);
147
148/**
149 * clk_set_rate() - Set current clock rate.
150 *
151 * @clk: A clock struct that was previously successfully requested by
152 * clk_request/get_by_*().
153 * @rate: New clock rate in Hz.
154 * @return new rate, or -ve error code.
155 */
156ulong clk_set_rate(struct clk *clk, ulong rate);
157
158/**
159 * clk_enable() - Enable (turn on) a clock.
160 *
161 * @clk: A clock struct that was previously successfully requested by
162 * clk_request/get_by_*().
163 * @return zero on success, or -ve error code.
164 */
165int clk_enable(struct clk *clk);
166
167/**
168 * clk_disable() - Disable (turn off) a clock.
169 *
170 * @clk: A clock struct that was previously successfully requested by
171 * clk_request/get_by_*().
172 * @return zero on success, or -ve error code.
173 */
174int clk_disable(struct clk *clk);
175
176int soc_clk_dump(void);
177
178#endif