1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Copyright (c) 2015 Google, Inc
4 * Written by Simon Glass <sjg@chromium.org>
5 * Copyright (c) 2016, NVIDIA CORPORATION.
6 */
7
8 #ifndef _CLK_H_
9 #define _CLK_H_
10
11 #include <linux/errno.h>
12 #include <linux/types.h>
13
14 /**
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. clk-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
31 struct udevice;
32
33 /**
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 * @data: An optional data field for scenarios where a single integer ID is not
44 * sufficient. If used, it can be populated through an .of_xlate op and
45 * processed during the various clock ops.
46 *
47 * Should additional information to identify and configure any clock signal
48 * for any provider be required in the future, the struct could be expanded to
49 * either (a) add more fields to allow clock providers to store additional
50 * information, or (b) replace the id field with an opaque pointer, which the
51 * provider would dynamically allocated during its .of_xlate op, and process
52 * during is .request op. This may require the addition of an extra op to clean
53 * up the allocation.
54 */
55 struct clk {
56 struct udevice *dev;
57 /*
58 * Written by of_xlate. In the future, we might add more fields here.
59 */
60 unsigned long id;
61 unsigned long data;
62 };
63
64 /**
65 * struct clk_bulk - A handle to (allowing control of) a bulk of clocks.
66 *
67 * Clients provide storage for the clock bulk. The content of the structure is
68 * managed solely by the clock API. A clock bulk struct is
69 * initialized by "get"ing the clock bulk struct.
70 * The clock bulk struct is passed to all other bulk clock APIs to apply
71 * the API to all the clock in the bulk struct.
72 *
73 * @clks: An array of clock handles.
74 * @count: The number of clock handles in the clks array.
75 */
76 struct clk_bulk {
77 struct clk *clks;
78 unsigned int count;
79 };
80
81 #if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(CLK)
82 struct phandle_1_arg;
83 int clk_get_by_index_platdata(struct udevice *dev, int index,
84 struct phandle_1_arg *cells, struct clk *clk);
85
86 /**
87 * clock_get_by_index - Get/request a clock by integer index.
88 *
89 * This looks up and requests a clock. The index is relative to the client
90 * device; each device is assumed to have n clocks associated with it somehow,
91 * and this function finds and requests one of them. The mapping of client
92 * device clock indices to provider clocks may be via device-tree properties,
93 * board-provided mapping tables, or some other mechanism.
94 *
95 * @dev: The client device.
96 * @index: The index of the clock to request, within the client's list of
97 * clocks.
98 * @clock A pointer to a clock struct to initialize.
99 * @return 0 if OK, or a negative error code.
100 */
101 int clk_get_by_index(struct udevice *dev, int index, struct clk *clk);
102
103 /**
104 * clock_get_bulk - Get/request all clocks of a device.
105 *
106 * This looks up and requests all clocks of the client device; each device is
107 * assumed to have n clocks associated with it somehow, and this function finds
108 * and requests all of them in a separate structure. The mapping of client
109 * device clock indices to provider clocks may be via device-tree properties,
110 * board-provided mapping tables, or some other mechanism.
111 *
112 * @dev: The client device.
113 * @bulk A pointer to a clock bulk struct to initialize.
114 * @return 0 if OK, or a negative error code.
115 */
116 int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk);
117
118 /**
119 * clock_get_by_name - Get/request a clock by name.
120 *
121 * This looks up and requests a clock. The name is relative to the client
122 * device; each device is assumed to have n clocks associated with it somehow,
123 * and this function finds and requests one of them. The mapping of client
124 * device clock names to provider clocks may be via device-tree properties,
125 * board-provided mapping tables, or some other mechanism.
126 *
127 * @dev: The client device.
128 * @name: The name of the clock to request, within the client's list of
129 * clocks.
130 * @clock: A pointer to a clock struct to initialize.
131 * @return 0 if OK, or a negative error code.
132 */
133 int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
134
135 /**
136 * clk_release_all() - Disable (turn off)/Free an array of previously
137 * requested clocks.
138 *
139 * For each clock contained in the clock array, this function will check if
140 * clock has been previously requested and then will disable and free it.
141 *
142 * @clk: A clock struct array that was previously successfully
143 * requested by clk_request/get_by_*().
144 * @count Number of clock contained in the array
145 * @return zero on success, or -ve error code.
146 */
147 int clk_release_all(struct clk *clk, int count);
148
149 #else
clk_get_by_index(struct udevice * dev,int index,struct clk * clk)150 static inline int clk_get_by_index(struct udevice *dev, int index,
151 struct clk *clk)
152 {
153 return -ENOSYS;
154 }
155
clk_get_bulk(struct udevice * dev,struct clk_bulk * bulk)156 static inline int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk)
157 {
158 return -ENOSYS;
159 }
160
clk_get_by_name(struct udevice * dev,const char * name,struct clk * clk)161 static inline int clk_get_by_name(struct udevice *dev, const char *name,
162 struct clk *clk)
163 {
164 return -ENOSYS;
165 }
166
clk_release_all(struct clk * clk,int count)167 static inline int clk_release_all(struct clk *clk, int count)
168 {
169 return -ENOSYS;
170 }
171 #endif
172
173 #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
174 CONFIG_IS_ENABLED(CLK)
175 /**
176 * clk_set_defaults - Process 'assigned-{clocks/clock-parents/clock-rates}'
177 * properties to configure clocks
178 *
179 * @dev: A device to process (the ofnode associated with this device
180 * will be processed).
181 */
182 int clk_set_defaults(struct udevice *dev);
183 #else
clk_set_defaults(struct udevice * dev)184 static inline int clk_set_defaults(struct udevice *dev)
185 {
186 return 0;
187 }
188 #endif
189
190 /**
191 * clk_release_bulk() - Disable (turn off)/Free an array of previously
192 * requested clocks in a clock bulk struct.
193 *
194 * For each clock contained in the clock bulk struct, this function will check
195 * if clock has been previously requested and then will disable and free it.
196 *
197 * @clk: A clock bulk struct that was previously successfully
198 * requested by clk_get_bulk().
199 * @return zero on success, or -ve error code.
200 */
clk_release_bulk(struct clk_bulk * bulk)201 static inline int clk_release_bulk(struct clk_bulk *bulk)
202 {
203 return clk_release_all(bulk->clks, bulk->count);
204 }
205
206 /**
207 * clk_request - Request a clock by provider-specific ID.
208 *
209 * This requests a clock using a provider-specific ID. Generally, this function
210 * should not be used, since clk_get_by_index/name() provide an interface that
211 * better separates clients from intimate knowledge of clock providers.
212 * However, this function may be useful in core SoC-specific code.
213 *
214 * @dev: The clock provider device.
215 * @clock: A pointer to a clock struct to initialize. The caller must
216 * have already initialized any field in this struct which the
217 * clock provider uses to identify the clock.
218 * @return 0 if OK, or a negative error code.
219 */
220 int clk_request(struct udevice *dev, struct clk *clk);
221
222 /**
223 * clock_free - Free a previously requested clock.
224 *
225 * @clock: A clock struct that was previously successfully requested by
226 * clk_request/get_by_*().
227 * @return 0 if OK, or a negative error code.
228 */
229 int clk_free(struct clk *clk);
230
231 /**
232 * clk_get_rate() - Get current clock rate.
233 *
234 * @clk: A clock struct that was previously successfully requested by
235 * clk_request/get_by_*().
236 * @return clock rate in Hz, or -ve error code.
237 */
238 ulong clk_get_rate(struct clk *clk);
239
240 /**
241 * clk_set_rate() - Set current clock rate.
242 *
243 * @clk: A clock struct that was previously successfully requested by
244 * clk_request/get_by_*().
245 * @rate: New clock rate in Hz.
246 * @return new rate, or -ve error code.
247 */
248 ulong clk_set_rate(struct clk *clk, ulong rate);
249
250 /**
251 * clk_set_parent() - Set current clock parent.
252 *
253 * @clk: A clock struct that was previously successfully requested by
254 * clk_request/get_by_*().
255 * @parent: A clock struct that was previously successfully requested by
256 * clk_request/get_by_*().
257 * @return new rate, or -ve error code.
258 */
259 int clk_set_parent(struct clk *clk, struct clk *parent);
260
261 /**
262 * clk_enable() - Enable (turn on) a clock.
263 *
264 * @clk: A clock struct that was previously successfully requested by
265 * clk_request/get_by_*().
266 * @return zero on success, or -ve error code.
267 */
268 int clk_enable(struct clk *clk);
269
270 /**
271 * clk_enable_bulk() - Enable (turn on) all clocks in a clock bulk struct.
272 *
273 * @bulk: A clock bulk struct that was previously successfully requested
274 * by clk_get_bulk().
275 * @return zero on success, or -ve error code.
276 */
277 int clk_enable_bulk(struct clk_bulk *bulk);
278
279 /**
280 * clk_disable() - Disable (turn off) a clock.
281 *
282 * @clk: A clock struct that was previously successfully requested by
283 * clk_request/get_by_*().
284 * @return zero on success, or -ve error code.
285 */
286 int clk_disable(struct clk *clk);
287
288 /**
289 * clk_disable_bulk() - Disable (turn off) all clocks in a clock bulk struct.
290 *
291 * @bulk: A clock bulk struct that was previously successfully requested
292 * by clk_get_bulk().
293 * @return zero on success, or -ve error code.
294 */
295 int clk_disable_bulk(struct clk_bulk *bulk);
296
297 int soc_clk_dump(void);
298
299 /**
300 * clk_valid() - check if clk is valid
301 *
302 * @clk: the clock to check
303 * @return true if valid, or false
304 */
clk_valid(struct clk * clk)305 static inline bool clk_valid(struct clk *clk)
306 {
307 return !!clk->dev;
308 }
309 #endif
310