2 * drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks
4 * Copyright (c) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
6 * This file is released under the GPLv2.
9 #include <linux/kernel.h>
10 #include <linux/device.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 #include <linux/pm_domain.h>
19 #include <linux/pm_runtime.h>
30 struct pm_clock_entry {
31 struct list_head node;
34 enum pce_status status;
38 * pm_clk_enable - Enable a clock, reporting any errors
39 * @dev: The device for the given clock
40 * @ce: PM clock entry corresponding to the clock.
42 static inline void __pm_clk_enable(struct device *dev, struct pm_clock_entry *ce)
46 if (ce->status < PCE_STATUS_ERROR) {
47 ret = clk_enable(ce->clk);
49 ce->status = PCE_STATUS_ENABLED;
51 dev_err(dev, "%s: failed to enable clk %p, error %d\n",
52 __func__, ce->clk, ret);
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.
61 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
64 ce->clk = clk_get(dev, ce->con_id);
65 if (IS_ERR(ce->clk)) {
66 ce->status = PCE_STATUS_ERROR;
69 ce->status = PCE_STATUS_ACQUIRED;
70 dev_dbg(dev, "Clock %pC con_id %s managed by runtime PM.\n",
75 static int __pm_clk_add(struct device *dev, const char *con_id,
78 struct pm_subsys_data *psd = dev_to_psd(dev);
79 struct pm_clock_entry *ce;
84 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
89 ce->con_id = kstrdup(con_id, GFP_KERNEL);
92 "Not enough memory for clock connection ID.\n");
104 pm_clk_acquire(dev, ce);
106 spin_lock_irq(&psd->lock);
107 list_add_tail(&ce->node, &psd->clock_list);
108 spin_unlock_irq(&psd->lock);
113 * pm_clk_add - Start using a device clock for power management.
114 * @dev: Device whose clock is going to be used for power management.
115 * @con_id: Connection ID of the clock.
117 * Add the clock represented by @con_id to the list of clocks used for
118 * the power management of @dev.
120 int pm_clk_add(struct device *dev, const char *con_id)
122 return __pm_clk_add(dev, con_id, NULL);
126 * pm_clk_add_clk - Start using a device clock for power management.
127 * @dev: Device whose clock is going to be used for power management.
128 * @clk: Clock pointer
130 * Add the clock to the list of clocks used for the power management of @dev.
131 * The power-management code will take control of the clock reference, so
132 * callers should not call clk_put() on @clk after this function sucessfully
135 int pm_clk_add_clk(struct device *dev, struct clk *clk)
137 return __pm_clk_add(dev, NULL, clk);
141 * __pm_clk_remove - Destroy PM clock entry.
142 * @ce: PM clock entry to destroy.
144 static void __pm_clk_remove(struct pm_clock_entry *ce)
149 if (ce->status < PCE_STATUS_ERROR) {
150 if (ce->status == PCE_STATUS_ENABLED)
151 clk_disable(ce->clk);
153 if (ce->status >= PCE_STATUS_ACQUIRED) {
154 clk_unprepare(ce->clk);
164 * pm_clk_remove - Stop using a device clock for power management.
165 * @dev: Device whose clock should not be used for PM any more.
166 * @con_id: Connection ID of the clock.
168 * Remove the clock represented by @con_id from the list of clocks used for
169 * the power management of @dev.
171 void pm_clk_remove(struct device *dev, const char *con_id)
173 struct pm_subsys_data *psd = dev_to_psd(dev);
174 struct pm_clock_entry *ce;
179 spin_lock_irq(&psd->lock);
181 list_for_each_entry(ce, &psd->clock_list, node) {
182 if (!con_id && !ce->con_id)
184 else if (!con_id || !ce->con_id)
186 else if (!strcmp(con_id, ce->con_id))
190 spin_unlock_irq(&psd->lock);
195 spin_unlock_irq(&psd->lock);
201 * pm_clk_init - Initialize a device's list of power management clocks.
202 * @dev: Device to initialize the list of PM clocks for.
204 * Initialize the lock and clock_list members of the device's pm_subsys_data
207 void pm_clk_init(struct device *dev)
209 struct pm_subsys_data *psd = dev_to_psd(dev);
211 INIT_LIST_HEAD(&psd->clock_list);
215 * pm_clk_create - Create and initialize a device's list of PM clocks.
216 * @dev: Device to create and initialize the list of PM clocks for.
218 * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
219 * members and make the @dev's power.subsys_data field point to it.
221 int pm_clk_create(struct device *dev)
223 return dev_pm_get_subsys_data(dev);
227 * pm_clk_destroy - Destroy a device's list of power management clocks.
228 * @dev: Device to destroy the list of PM clocks for.
230 * Clear the @dev's power.subsys_data field, remove the list of clock entries
231 * from the struct pm_subsys_data object pointed to by it before and free
234 void pm_clk_destroy(struct device *dev)
236 struct pm_subsys_data *psd = dev_to_psd(dev);
237 struct pm_clock_entry *ce, *c;
238 struct list_head list;
243 INIT_LIST_HEAD(&list);
245 spin_lock_irq(&psd->lock);
247 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
248 list_move(&ce->node, &list);
250 spin_unlock_irq(&psd->lock);
252 dev_pm_put_subsys_data(dev);
254 list_for_each_entry_safe_reverse(ce, c, &list, node) {
261 * pm_clk_suspend - Disable clocks in a device's PM clock list.
262 * @dev: Device to disable the clocks for.
264 int pm_clk_suspend(struct device *dev)
266 struct pm_subsys_data *psd = dev_to_psd(dev);
267 struct pm_clock_entry *ce;
270 dev_dbg(dev, "%s()\n", __func__);
275 spin_lock_irqsave(&psd->lock, flags);
277 list_for_each_entry_reverse(ce, &psd->clock_list, node) {
278 if (ce->status < PCE_STATUS_ERROR) {
279 if (ce->status == PCE_STATUS_ENABLED)
280 clk_disable(ce->clk);
281 ce->status = PCE_STATUS_ACQUIRED;
285 spin_unlock_irqrestore(&psd->lock, flags);
291 * pm_clk_resume - Enable clocks in a device's PM clock list.
292 * @dev: Device to enable the clocks for.
294 int pm_clk_resume(struct device *dev)
296 struct pm_subsys_data *psd = dev_to_psd(dev);
297 struct pm_clock_entry *ce;
300 dev_dbg(dev, "%s()\n", __func__);
305 spin_lock_irqsave(&psd->lock, flags);
307 list_for_each_entry(ce, &psd->clock_list, node)
308 __pm_clk_enable(dev, ce);
310 spin_unlock_irqrestore(&psd->lock, flags);
316 * pm_clk_notify - Notify routine for device addition and removal.
317 * @nb: Notifier block object this function is a member of.
318 * @action: Operation being carried out by the caller.
319 * @data: Device the routine is being run for.
321 * For this function to work, @nb must be a member of an object of type
322 * struct pm_clk_notifier_block containing all of the requisite data.
323 * Specifically, the pm_domain member of that object is copied to the device's
324 * pm_domain field and its con_ids member is used to populate the device's list
325 * of PM clocks, depending on @action.
327 * If the device's pm_domain field is already populated with a value different
328 * from the one stored in the struct pm_clk_notifier_block object, the function
331 static int pm_clk_notify(struct notifier_block *nb,
332 unsigned long action, void *data)
334 struct pm_clk_notifier_block *clknb;
335 struct device *dev = data;
339 dev_dbg(dev, "%s() %ld\n", __func__, action);
341 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
344 case BUS_NOTIFY_ADD_DEVICE:
348 error = pm_clk_create(dev);
352 dev_pm_domain_set(dev, clknb->pm_domain);
353 if (clknb->con_ids[0]) {
354 for (con_id = clknb->con_ids; *con_id; con_id++)
355 pm_clk_add(dev, *con_id);
357 pm_clk_add(dev, NULL);
361 case BUS_NOTIFY_DEL_DEVICE:
362 if (dev->pm_domain != clknb->pm_domain)
365 dev_pm_domain_set(dev, NULL);
373 int pm_clk_runtime_suspend(struct device *dev)
377 dev_dbg(dev, "%s\n", __func__);
379 ret = pm_generic_runtime_suspend(dev);
381 dev_err(dev, "failed to suspend device\n");
385 ret = pm_clk_suspend(dev);
387 dev_err(dev, "failed to suspend clock\n");
388 pm_generic_runtime_resume(dev);
395 int pm_clk_runtime_resume(struct device *dev)
399 dev_dbg(dev, "%s\n", __func__);
401 ret = pm_clk_resume(dev);
403 dev_err(dev, "failed to resume clock\n");
407 return pm_generic_runtime_resume(dev);
410 #else /* !CONFIG_PM_CLK */
413 * enable_clock - Enable a device clock.
414 * @dev: Device whose clock is to be enabled.
415 * @con_id: Connection ID of the clock.
417 static void enable_clock(struct device *dev, const char *con_id)
421 clk = clk_get(dev, con_id);
423 clk_prepare_enable(clk);
425 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
430 * disable_clock - Disable a device clock.
431 * @dev: Device whose clock is to be disabled.
432 * @con_id: Connection ID of the clock.
434 static void disable_clock(struct device *dev, const char *con_id)
438 clk = clk_get(dev, con_id);
440 clk_disable_unprepare(clk);
442 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
447 * pm_clk_notify - Notify routine for device addition and removal.
448 * @nb: Notifier block object this function is a member of.
449 * @action: Operation being carried out by the caller.
450 * @data: Device the routine is being run for.
452 * For this function to work, @nb must be a member of an object of type
453 * struct pm_clk_notifier_block containing all of the requisite data.
454 * Specifically, the con_ids member of that object is used to enable or disable
455 * the device's clocks, depending on @action.
457 static int pm_clk_notify(struct notifier_block *nb,
458 unsigned long action, void *data)
460 struct pm_clk_notifier_block *clknb;
461 struct device *dev = data;
464 dev_dbg(dev, "%s() %ld\n", __func__, action);
466 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
469 case BUS_NOTIFY_BIND_DRIVER:
470 if (clknb->con_ids[0]) {
471 for (con_id = clknb->con_ids; *con_id; con_id++)
472 enable_clock(dev, *con_id);
474 enable_clock(dev, NULL);
477 case BUS_NOTIFY_DRIVER_NOT_BOUND:
478 case BUS_NOTIFY_UNBOUND_DRIVER:
479 if (clknb->con_ids[0]) {
480 for (con_id = clknb->con_ids; *con_id; con_id++)
481 disable_clock(dev, *con_id);
483 disable_clock(dev, NULL);
491 #endif /* !CONFIG_PM_CLK */
494 * pm_clk_add_notifier - Add bus type notifier for power management clocks.
495 * @bus: Bus type to add the notifier to.
496 * @clknb: Notifier to be added to the given bus type.
498 * The nb member of @clknb is not expected to be initialized and its
499 * notifier_call member will be replaced with pm_clk_notify(). However,
500 * the remaining members of @clknb should be populated prior to calling this
503 void pm_clk_add_notifier(struct bus_type *bus,
504 struct pm_clk_notifier_block *clknb)
509 clknb->nb.notifier_call = pm_clk_notify;
510 bus_register_notifier(bus, &clknb->nb);