1 /* 2 * Copyright (c) 2015 Google, Inc 3 * Written by Simon Glass <sjg@chromium.org> 4 * Copyright (c) 2016, NVIDIA CORPORATION. 5 * 6 * SPDX-License-Identifier: GPL-2.0+ 7 */ 8 9 #ifndef _CLK_H_ 10 #define _CLK_H_ 11 12 #include <linux/errno.h> 13 #include <linux/types.h> 14 15 /** 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 32 struct udevice; 33 34 /** 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 */ 54 struct 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. 59 */ 60 unsigned long id; 61 }; 62 63 /** 64 * struct clk_bulk - A handle to (allowing control of) a bulk of clocks. 65 * 66 * Clients provide storage for the clock bulk. The content of the structure is 67 * managed solely by the clock API. A clock bulk struct is 68 * initialized by "get"ing the clock bulk struct. 69 * The clock bulk struct is passed to all other bulk clock APIs to apply 70 * the API to all the clock in the bulk struct. 71 * 72 * @clks: An array of clock handles. 73 * @count: The number of clock handles in the clks array. 74 */ 75 struct clk_bulk { 76 struct clk *clks; 77 unsigned int count; 78 }; 79 80 #if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(CLK) 81 struct phandle_1_arg; 82 int clk_get_by_index_platdata(struct udevice *dev, int index, 83 struct phandle_1_arg *cells, struct clk *clk); 84 85 /** 86 * clock_get_by_index - Get/request a clock by integer index. 87 * 88 * This looks up and requests a clock. The index 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 indices 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 * @index: The index 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 */ 100 int clk_get_by_index(struct udevice *dev, int index, struct clk *clk); 101 102 /** 103 * clock_get_bulk - Get/request all clocks of a device. 104 * 105 * This looks up and requests all clocks of the client device; each device is 106 * assumed to have n clocks associated with it somehow, and this function finds 107 * and requests all of them in a separate structure. The mapping of client 108 * device clock indices to provider clocks may be via device-tree properties, 109 * board-provided mapping tables, or some other mechanism. 110 * 111 * @dev: The client device. 112 * @bulk A pointer to a clock bulk struct to initialize. 113 * @return 0 if OK, or a negative error code. 114 */ 115 int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk); 116 117 /** 118 * clock_get_by_name - Get/request a clock by name. 119 * 120 * This looks up and requests a clock. The name is relative to the client 121 * device; each device is assumed to have n clocks associated with it somehow, 122 * and this function finds and requests one of them. The mapping of client 123 * device clock names to provider clocks may be via device-tree properties, 124 * board-provided mapping tables, or some other mechanism. 125 * 126 * @dev: The client device. 127 * @name: The name of the clock to request, within the client's list of 128 * clocks. 129 * @clock: A pointer to a clock struct to initialize. 130 * @return 0 if OK, or a negative error code. 131 */ 132 int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk); 133 134 /** 135 * clk_release_all() - Disable (turn off)/Free an array of previously 136 * requested clocks. 137 * 138 * For each clock contained in the clock array, this function will check if 139 * clock has been previously requested and then will disable and free it. 140 * 141 * @clk: A clock struct array that was previously successfully 142 * requested by clk_request/get_by_*(). 143 * @count Number of clock contained in the array 144 * @return zero on success, or -ve error code. 145 */ 146 int clk_release_all(struct clk *clk, int count); 147 148 #else 149 static inline int clk_get_by_index(struct udevice *dev, int index, 150 struct clk *clk) 151 { 152 return -ENOSYS; 153 } 154 155 static inline int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk) 156 { 157 return -ENOSYS; 158 } 159 160 static inline int clk_get_by_name(struct udevice *dev, const char *name, 161 struct clk *clk) 162 { 163 return -ENOSYS; 164 } 165 166 static inline int clk_release_all(struct clk *clk, int count) 167 { 168 return -ENOSYS; 169 } 170 #endif 171 172 #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \ 173 CONFIG_IS_ENABLED(CLK) 174 /** 175 * clk_set_defaults - Process 'assigned-{clocks/clock-parents/clock-rates}' 176 * properties to configure clocks 177 * 178 * @dev: A device to process (the ofnode associated with this device 179 * will be processed). 180 */ 181 int clk_set_defaults(struct udevice *dev); 182 #else 183 static inline int clk_set_defaults(struct udevice *dev) 184 { 185 return 0; 186 } 187 #endif 188 189 /** 190 * clk_release_bulk() - Disable (turn off)/Free an array of previously 191 * requested clocks in a clock bulk struct. 192 * 193 * For each clock contained in the clock bulk struct, this function will check 194 * if clock has been previously requested and then will disable and free it. 195 * 196 * @clk: A clock bulk struct that was previously successfully 197 * requested by clk_get_bulk(). 198 * @return zero on success, or -ve error code. 199 */ 200 static inline int clk_release_bulk(struct clk_bulk *bulk) 201 { 202 return clk_release_all(bulk->clks, bulk->count); 203 } 204 205 /** 206 * clk_request - Request a clock by provider-specific ID. 207 * 208 * This requests a clock using a provider-specific ID. Generally, this function 209 * should not be used, since clk_get_by_index/name() provide an interface that 210 * better separates clients from intimate knowledge of clock providers. 211 * However, this function may be useful in core SoC-specific code. 212 * 213 * @dev: The clock provider device. 214 * @clock: A pointer to a clock struct to initialize. The caller must 215 * have already initialized any field in this struct which the 216 * clock provider uses to identify the clock. 217 * @return 0 if OK, or a negative error code. 218 */ 219 int clk_request(struct udevice *dev, struct clk *clk); 220 221 /** 222 * clock_free - Free a previously requested clock. 223 * 224 * @clock: A clock struct that was previously successfully requested by 225 * clk_request/get_by_*(). 226 * @return 0 if OK, or a negative error code. 227 */ 228 int clk_free(struct clk *clk); 229 230 /** 231 * clk_get_rate() - Get current clock rate. 232 * 233 * @clk: A clock struct that was previously successfully requested by 234 * clk_request/get_by_*(). 235 * @return clock rate in Hz, or -ve error code. 236 */ 237 ulong clk_get_rate(struct clk *clk); 238 239 /** 240 * clk_set_rate() - Set current clock rate. 241 * 242 * @clk: A clock struct that was previously successfully requested by 243 * clk_request/get_by_*(). 244 * @rate: New clock rate in Hz. 245 * @return new rate, or -ve error code. 246 */ 247 ulong clk_set_rate(struct clk *clk, ulong rate); 248 249 /** 250 * clk_set_parent() - Set current clock parent. 251 * 252 * @clk: A clock struct that was previously successfully requested by 253 * clk_request/get_by_*(). 254 * @parent: A clock struct that was previously successfully requested by 255 * clk_request/get_by_*(). 256 * @return new rate, or -ve error code. 257 */ 258 int clk_set_parent(struct clk *clk, struct clk *parent); 259 260 /** 261 * clk_enable() - Enable (turn on) a clock. 262 * 263 * @clk: A clock struct that was previously successfully requested by 264 * clk_request/get_by_*(). 265 * @return zero on success, or -ve error code. 266 */ 267 int clk_enable(struct clk *clk); 268 269 /** 270 * clk_enable_bulk() - Enable (turn on) all clocks in a clock bulk struct. 271 * 272 * @bulk: A clock bulk struct that was previously successfully requested 273 * by clk_get_bulk(). 274 * @return zero on success, or -ve error code. 275 */ 276 int clk_enable_bulk(struct clk_bulk *bulk); 277 278 /** 279 * clk_disable() - Disable (turn off) a clock. 280 * 281 * @clk: A clock struct that was previously successfully requested by 282 * clk_request/get_by_*(). 283 * @return zero on success, or -ve error code. 284 */ 285 int clk_disable(struct clk *clk); 286 287 /** 288 * clk_disable_bulk() - Disable (turn off) all clocks in a clock bulk struct. 289 * 290 * @bulk: A clock bulk struct that was previously successfully requested 291 * by clk_get_bulk(). 292 * @return zero on success, or -ve error code. 293 */ 294 int clk_disable_bulk(struct clk_bulk *bulk); 295 296 int soc_clk_dump(void); 297 298 #endif 299