1 /* 2 * drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks 3 * 4 * Copyright (c) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp. 5 * 6 * This file is released under the GPLv2. 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/device.h> 11 #include <linux/io.h> 12 #include <linux/pm.h> 13 #include <linux/pm_clock.h> 14 #include <linux/clk.h> 15 #include <linux/clkdev.h> 16 #include <linux/slab.h> 17 #include <linux/err.h> 18 19 #ifdef CONFIG_PM 20 21 enum pce_status { 22 PCE_STATUS_NONE = 0, 23 PCE_STATUS_ACQUIRED, 24 PCE_STATUS_ENABLED, 25 PCE_STATUS_ERROR, 26 }; 27 28 struct pm_clock_entry { 29 struct list_head node; 30 char *con_id; 31 struct clk *clk; 32 enum pce_status status; 33 }; 34 35 /** 36 * pm_clk_enable - Enable a clock, reporting any errors 37 * @dev: The device for the given clock 38 * @ce: PM clock entry corresponding to the clock. 39 */ 40 static inline int __pm_clk_enable(struct device *dev, struct pm_clock_entry *ce) 41 { 42 int ret; 43 44 if (ce->status < PCE_STATUS_ERROR) { 45 ret = clk_enable(ce->clk); 46 if (!ret) 47 ce->status = PCE_STATUS_ENABLED; 48 else 49 dev_err(dev, "%s: failed to enable clk %p, error %d\n", 50 __func__, ce->clk, ret); 51 } 52 53 return ret; 54 } 55 56 /** 57 * pm_clk_acquire - Acquire a device clock. 58 * @dev: Device whose clock is to be acquired. 59 * @ce: PM clock entry corresponding to the clock. 60 */ 61 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce) 62 { 63 if (!ce->clk) 64 ce->clk = clk_get(dev, ce->con_id); 65 if (IS_ERR(ce->clk)) { 66 ce->status = PCE_STATUS_ERROR; 67 } else { 68 clk_prepare(ce->clk); 69 ce->status = PCE_STATUS_ACQUIRED; 70 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id); 71 } 72 } 73 74 static int __pm_clk_add(struct device *dev, const char *con_id, 75 struct clk *clk) 76 { 77 struct pm_subsys_data *psd = dev_to_psd(dev); 78 struct pm_clock_entry *ce; 79 80 if (!psd) 81 return -EINVAL; 82 83 ce = kzalloc(sizeof(*ce), GFP_KERNEL); 84 if (!ce) { 85 dev_err(dev, "Not enough memory for clock entry.\n"); 86 return -ENOMEM; 87 } 88 89 if (con_id) { 90 ce->con_id = kstrdup(con_id, GFP_KERNEL); 91 if (!ce->con_id) { 92 dev_err(dev, 93 "Not enough memory for clock connection ID.\n"); 94 kfree(ce); 95 return -ENOMEM; 96 } 97 } else { 98 if (IS_ERR(ce->clk) || !__clk_get(clk)) { 99 kfree(ce); 100 return -ENOENT; 101 } 102 ce->clk = clk; 103 } 104 105 pm_clk_acquire(dev, ce); 106 107 spin_lock_irq(&psd->lock); 108 list_add_tail(&ce->node, &psd->clock_list); 109 spin_unlock_irq(&psd->lock); 110 return 0; 111 } 112 113 /** 114 * pm_clk_add - Start using a device clock for power management. 115 * @dev: Device whose clock is going to be used for power management. 116 * @con_id: Connection ID of the clock. 117 * 118 * Add the clock represented by @con_id to the list of clocks used for 119 * the power management of @dev. 120 */ 121 int pm_clk_add(struct device *dev, const char *con_id) 122 { 123 return __pm_clk_add(dev, con_id, NULL); 124 } 125 126 /** 127 * pm_clk_add_clk - Start using a device clock for power management. 128 * @dev: Device whose clock is going to be used for power management. 129 * @clk: Clock pointer 130 * 131 * Add the clock to the list of clocks used for the power management of @dev. 132 * It will increment refcount on clock pointer, use clk_put() on it when done. 133 */ 134 int pm_clk_add_clk(struct device *dev, struct clk *clk) 135 { 136 return __pm_clk_add(dev, NULL, clk); 137 } 138 139 /** 140 * __pm_clk_remove - Destroy PM clock entry. 141 * @ce: PM clock entry to destroy. 142 */ 143 static void __pm_clk_remove(struct pm_clock_entry *ce) 144 { 145 if (!ce) 146 return; 147 148 if (ce->status < PCE_STATUS_ERROR) { 149 if (ce->status == PCE_STATUS_ENABLED) 150 clk_disable(ce->clk); 151 152 if (ce->status >= PCE_STATUS_ACQUIRED) { 153 clk_unprepare(ce->clk); 154 clk_put(ce->clk); 155 } 156 } 157 158 kfree(ce->con_id); 159 kfree(ce); 160 } 161 162 /** 163 * pm_clk_remove - Stop using a device clock for power management. 164 * @dev: Device whose clock should not be used for PM any more. 165 * @con_id: Connection ID of the clock. 166 * 167 * Remove the clock represented by @con_id from the list of clocks used for 168 * the power management of @dev. 169 */ 170 void pm_clk_remove(struct device *dev, const char *con_id) 171 { 172 struct pm_subsys_data *psd = dev_to_psd(dev); 173 struct pm_clock_entry *ce; 174 175 if (!psd) 176 return; 177 178 spin_lock_irq(&psd->lock); 179 180 list_for_each_entry(ce, &psd->clock_list, node) { 181 if (!con_id && !ce->con_id) 182 goto remove; 183 else if (!con_id || !ce->con_id) 184 continue; 185 else if (!strcmp(con_id, ce->con_id)) 186 goto remove; 187 } 188 189 spin_unlock_irq(&psd->lock); 190 return; 191 192 remove: 193 list_del(&ce->node); 194 spin_unlock_irq(&psd->lock); 195 196 __pm_clk_remove(ce); 197 } 198 199 /** 200 * pm_clk_init - Initialize a device's list of power management clocks. 201 * @dev: Device to initialize the list of PM clocks for. 202 * 203 * Initialize the lock and clock_list members of the device's pm_subsys_data 204 * object. 205 */ 206 void pm_clk_init(struct device *dev) 207 { 208 struct pm_subsys_data *psd = dev_to_psd(dev); 209 if (psd) 210 INIT_LIST_HEAD(&psd->clock_list); 211 } 212 213 /** 214 * pm_clk_create - Create and initialize a device's list of PM clocks. 215 * @dev: Device to create and initialize the list of PM clocks for. 216 * 217 * Allocate a struct pm_subsys_data object, initialize its lock and clock_list 218 * members and make the @dev's power.subsys_data field point to it. 219 */ 220 int pm_clk_create(struct device *dev) 221 { 222 return dev_pm_get_subsys_data(dev); 223 } 224 225 /** 226 * pm_clk_destroy - Destroy a device's list of power management clocks. 227 * @dev: Device to destroy the list of PM clocks for. 228 * 229 * Clear the @dev's power.subsys_data field, remove the list of clock entries 230 * from the struct pm_subsys_data object pointed to by it before and free 231 * that object. 232 */ 233 void pm_clk_destroy(struct device *dev) 234 { 235 struct pm_subsys_data *psd = dev_to_psd(dev); 236 struct pm_clock_entry *ce, *c; 237 struct list_head list; 238 239 if (!psd) 240 return; 241 242 INIT_LIST_HEAD(&list); 243 244 spin_lock_irq(&psd->lock); 245 246 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node) 247 list_move(&ce->node, &list); 248 249 spin_unlock_irq(&psd->lock); 250 251 dev_pm_put_subsys_data(dev); 252 253 list_for_each_entry_safe_reverse(ce, c, &list, node) { 254 list_del(&ce->node); 255 __pm_clk_remove(ce); 256 } 257 } 258 259 /** 260 * pm_clk_suspend - Disable clocks in a device's PM clock list. 261 * @dev: Device to disable the clocks for. 262 */ 263 int pm_clk_suspend(struct device *dev) 264 { 265 struct pm_subsys_data *psd = dev_to_psd(dev); 266 struct pm_clock_entry *ce; 267 unsigned long flags; 268 269 dev_dbg(dev, "%s()\n", __func__); 270 271 if (!psd) 272 return 0; 273 274 spin_lock_irqsave(&psd->lock, flags); 275 276 list_for_each_entry_reverse(ce, &psd->clock_list, node) { 277 if (ce->status < PCE_STATUS_ERROR) { 278 if (ce->status == PCE_STATUS_ENABLED) 279 clk_disable(ce->clk); 280 ce->status = PCE_STATUS_ACQUIRED; 281 } 282 } 283 284 spin_unlock_irqrestore(&psd->lock, flags); 285 286 return 0; 287 } 288 289 /** 290 * pm_clk_resume - Enable clocks in a device's PM clock list. 291 * @dev: Device to enable the clocks for. 292 */ 293 int pm_clk_resume(struct device *dev) 294 { 295 struct pm_subsys_data *psd = dev_to_psd(dev); 296 struct pm_clock_entry *ce; 297 unsigned long flags; 298 299 dev_dbg(dev, "%s()\n", __func__); 300 301 if (!psd) 302 return 0; 303 304 spin_lock_irqsave(&psd->lock, flags); 305 306 list_for_each_entry(ce, &psd->clock_list, node) 307 __pm_clk_enable(dev, ce); 308 309 spin_unlock_irqrestore(&psd->lock, flags); 310 311 return 0; 312 } 313 314 /** 315 * pm_clk_notify - Notify routine for device addition and removal. 316 * @nb: Notifier block object this function is a member of. 317 * @action: Operation being carried out by the caller. 318 * @data: Device the routine is being run for. 319 * 320 * For this function to work, @nb must be a member of an object of type 321 * struct pm_clk_notifier_block containing all of the requisite data. 322 * Specifically, the pm_domain member of that object is copied to the device's 323 * pm_domain field and its con_ids member is used to populate the device's list 324 * of PM clocks, depending on @action. 325 * 326 * If the device's pm_domain field is already populated with a value different 327 * from the one stored in the struct pm_clk_notifier_block object, the function 328 * does nothing. 329 */ 330 static int pm_clk_notify(struct notifier_block *nb, 331 unsigned long action, void *data) 332 { 333 struct pm_clk_notifier_block *clknb; 334 struct device *dev = data; 335 char **con_id; 336 int error; 337 338 dev_dbg(dev, "%s() %ld\n", __func__, action); 339 340 clknb = container_of(nb, struct pm_clk_notifier_block, nb); 341 342 switch (action) { 343 case BUS_NOTIFY_ADD_DEVICE: 344 if (dev->pm_domain) 345 break; 346 347 error = pm_clk_create(dev); 348 if (error) 349 break; 350 351 dev->pm_domain = clknb->pm_domain; 352 if (clknb->con_ids[0]) { 353 for (con_id = clknb->con_ids; *con_id; con_id++) 354 pm_clk_add(dev, *con_id); 355 } else { 356 pm_clk_add(dev, NULL); 357 } 358 359 break; 360 case BUS_NOTIFY_DEL_DEVICE: 361 if (dev->pm_domain != clknb->pm_domain) 362 break; 363 364 dev->pm_domain = NULL; 365 pm_clk_destroy(dev); 366 break; 367 } 368 369 return 0; 370 } 371 372 #else /* !CONFIG_PM */ 373 374 /** 375 * enable_clock - Enable a device clock. 376 * @dev: Device whose clock is to be enabled. 377 * @con_id: Connection ID of the clock. 378 */ 379 static void enable_clock(struct device *dev, const char *con_id) 380 { 381 struct clk *clk; 382 383 clk = clk_get(dev, con_id); 384 if (!IS_ERR(clk)) { 385 clk_prepare_enable(clk); 386 clk_put(clk); 387 dev_info(dev, "Runtime PM disabled, clock forced on.\n"); 388 } 389 } 390 391 /** 392 * disable_clock - Disable a device clock. 393 * @dev: Device whose clock is to be disabled. 394 * @con_id: Connection ID of the clock. 395 */ 396 static void disable_clock(struct device *dev, const char *con_id) 397 { 398 struct clk *clk; 399 400 clk = clk_get(dev, con_id); 401 if (!IS_ERR(clk)) { 402 clk_disable_unprepare(clk); 403 clk_put(clk); 404 dev_info(dev, "Runtime PM disabled, clock forced off.\n"); 405 } 406 } 407 408 /** 409 * pm_clk_notify - Notify routine for device addition and removal. 410 * @nb: Notifier block object this function is a member of. 411 * @action: Operation being carried out by the caller. 412 * @data: Device the routine is being run for. 413 * 414 * For this function to work, @nb must be a member of an object of type 415 * struct pm_clk_notifier_block containing all of the requisite data. 416 * Specifically, the con_ids member of that object is used to enable or disable 417 * the device's clocks, depending on @action. 418 */ 419 static int pm_clk_notify(struct notifier_block *nb, 420 unsigned long action, void *data) 421 { 422 struct pm_clk_notifier_block *clknb; 423 struct device *dev = data; 424 char **con_id; 425 426 dev_dbg(dev, "%s() %ld\n", __func__, action); 427 428 clknb = container_of(nb, struct pm_clk_notifier_block, nb); 429 430 switch (action) { 431 case BUS_NOTIFY_BIND_DRIVER: 432 if (clknb->con_ids[0]) { 433 for (con_id = clknb->con_ids; *con_id; con_id++) 434 enable_clock(dev, *con_id); 435 } else { 436 enable_clock(dev, NULL); 437 } 438 break; 439 case BUS_NOTIFY_UNBOUND_DRIVER: 440 if (clknb->con_ids[0]) { 441 for (con_id = clknb->con_ids; *con_id; con_id++) 442 disable_clock(dev, *con_id); 443 } else { 444 disable_clock(dev, NULL); 445 } 446 break; 447 } 448 449 return 0; 450 } 451 452 #endif /* !CONFIG_PM */ 453 454 /** 455 * pm_clk_add_notifier - Add bus type notifier for power management clocks. 456 * @bus: Bus type to add the notifier to. 457 * @clknb: Notifier to be added to the given bus type. 458 * 459 * The nb member of @clknb is not expected to be initialized and its 460 * notifier_call member will be replaced with pm_clk_notify(). However, 461 * the remaining members of @clknb should be populated prior to calling this 462 * routine. 463 */ 464 void pm_clk_add_notifier(struct bus_type *bus, 465 struct pm_clk_notifier_block *clknb) 466 { 467 if (!bus || !clknb) 468 return; 469 470 clknb->nb.notifier_call = pm_clk_notify; 471 bus_register_notifier(bus, &clknb->nb); 472 } 473