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