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/slab.h>
16 #include <linux/err.h>
27 struct pm_clock_entry {
28 struct list_head node;
31 enum pce_status status;
35 * pm_clk_enable - Enable a clock, reporting any errors
36 * @dev: The device for the given clock
37 * @clk: The clock being enabled.
39 static inline int __pm_clk_enable(struct device *dev, struct clk *clk)
41 int ret = clk_enable(clk);
43 dev_err(dev, "%s: failed to enable clk %p, error %d\n",
50 * pm_clk_acquire - Acquire a device clock.
51 * @dev: Device whose clock is to be acquired.
52 * @ce: PM clock entry corresponding to the clock.
54 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
56 ce->clk = clk_get(dev, ce->con_id);
57 if (IS_ERR(ce->clk)) {
58 ce->status = PCE_STATUS_ERROR;
61 ce->status = PCE_STATUS_ACQUIRED;
62 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
67 * pm_clk_add - Start using a device clock for power management.
68 * @dev: Device whose clock is going to be used for power management.
69 * @con_id: Connection ID of the clock.
71 * Add the clock represented by @con_id to the list of clocks used for
72 * the power management of @dev.
74 int pm_clk_add(struct device *dev, const char *con_id)
76 struct pm_subsys_data *psd = dev_to_psd(dev);
77 struct pm_clock_entry *ce;
82 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
84 dev_err(dev, "Not enough memory for clock entry.\n");
89 ce->con_id = kstrdup(con_id, GFP_KERNEL);
92 "Not enough memory for clock connection ID.\n");
98 pm_clk_acquire(dev, ce);
100 spin_lock_irq(&psd->lock);
101 list_add_tail(&ce->node, &psd->clock_list);
102 spin_unlock_irq(&psd->lock);
107 * __pm_clk_remove - Destroy PM clock entry.
108 * @ce: PM clock entry to destroy.
110 static void __pm_clk_remove(struct pm_clock_entry *ce)
115 if (ce->status < PCE_STATUS_ERROR) {
116 if (ce->status == PCE_STATUS_ENABLED)
117 clk_disable(ce->clk);
119 if (ce->status >= PCE_STATUS_ACQUIRED) {
120 clk_unprepare(ce->clk);
130 * pm_clk_remove - Stop using a device clock for power management.
131 * @dev: Device whose clock should not be used for PM any more.
132 * @con_id: Connection ID of the clock.
134 * Remove the clock represented by @con_id from the list of clocks used for
135 * the power management of @dev.
137 void pm_clk_remove(struct device *dev, const char *con_id)
139 struct pm_subsys_data *psd = dev_to_psd(dev);
140 struct pm_clock_entry *ce;
145 spin_lock_irq(&psd->lock);
147 list_for_each_entry(ce, &psd->clock_list, node) {
148 if (!con_id && !ce->con_id)
150 else if (!con_id || !ce->con_id)
152 else if (!strcmp(con_id, ce->con_id))
156 spin_unlock_irq(&psd->lock);
161 spin_unlock_irq(&psd->lock);
167 * pm_clk_init - Initialize a device's list of power management clocks.
168 * @dev: Device to initialize the list of PM clocks for.
170 * Initialize the lock and clock_list members of the device's pm_subsys_data
173 void pm_clk_init(struct device *dev)
175 struct pm_subsys_data *psd = dev_to_psd(dev);
177 INIT_LIST_HEAD(&psd->clock_list);
181 * pm_clk_create - Create and initialize a device's list of PM clocks.
182 * @dev: Device to create and initialize the list of PM clocks for.
184 * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
185 * members and make the @dev's power.subsys_data field point to it.
187 int pm_clk_create(struct device *dev)
189 return dev_pm_get_subsys_data(dev);
193 * pm_clk_destroy - Destroy a device's list of power management clocks.
194 * @dev: Device to destroy the list of PM clocks for.
196 * Clear the @dev's power.subsys_data field, remove the list of clock entries
197 * from the struct pm_subsys_data object pointed to by it before and free
200 void pm_clk_destroy(struct device *dev)
202 struct pm_subsys_data *psd = dev_to_psd(dev);
203 struct pm_clock_entry *ce, *c;
204 struct list_head list;
209 INIT_LIST_HEAD(&list);
211 spin_lock_irq(&psd->lock);
213 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
214 list_move(&ce->node, &list);
216 spin_unlock_irq(&psd->lock);
218 dev_pm_put_subsys_data(dev);
220 list_for_each_entry_safe_reverse(ce, c, &list, node) {
226 #endif /* CONFIG_PM */
228 #ifdef CONFIG_PM_RUNTIME
231 * pm_clk_suspend - Disable clocks in a device's PM clock list.
232 * @dev: Device to disable the clocks for.
234 int pm_clk_suspend(struct device *dev)
236 struct pm_subsys_data *psd = dev_to_psd(dev);
237 struct pm_clock_entry *ce;
240 dev_dbg(dev, "%s()\n", __func__);
245 spin_lock_irqsave(&psd->lock, flags);
247 list_for_each_entry_reverse(ce, &psd->clock_list, node) {
248 if (ce->status < PCE_STATUS_ERROR) {
249 if (ce->status == PCE_STATUS_ENABLED)
250 clk_disable(ce->clk);
251 ce->status = PCE_STATUS_ACQUIRED;
255 spin_unlock_irqrestore(&psd->lock, flags);
261 * pm_clk_resume - Enable clocks in a device's PM clock list.
262 * @dev: Device to enable the clocks for.
264 int pm_clk_resume(struct device *dev)
266 struct pm_subsys_data *psd = dev_to_psd(dev);
267 struct pm_clock_entry *ce;
271 dev_dbg(dev, "%s()\n", __func__);
276 spin_lock_irqsave(&psd->lock, flags);
278 list_for_each_entry(ce, &psd->clock_list, node) {
279 if (ce->status < PCE_STATUS_ERROR) {
280 ret = __pm_clk_enable(dev, ce->clk);
282 ce->status = PCE_STATUS_ENABLED;
286 spin_unlock_irqrestore(&psd->lock, flags);
292 * pm_clk_notify - Notify routine for device addition and removal.
293 * @nb: Notifier block object this function is a member of.
294 * @action: Operation being carried out by the caller.
295 * @data: Device the routine is being run for.
297 * For this function to work, @nb must be a member of an object of type
298 * struct pm_clk_notifier_block containing all of the requisite data.
299 * Specifically, the pm_domain member of that object is copied to the device's
300 * pm_domain field and its con_ids member is used to populate the device's list
301 * of PM clocks, depending on @action.
303 * If the device's pm_domain field is already populated with a value different
304 * from the one stored in the struct pm_clk_notifier_block object, the function
307 static int pm_clk_notify(struct notifier_block *nb,
308 unsigned long action, void *data)
310 struct pm_clk_notifier_block *clknb;
311 struct device *dev = data;
315 dev_dbg(dev, "%s() %ld\n", __func__, action);
317 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
320 case BUS_NOTIFY_ADD_DEVICE:
324 error = pm_clk_create(dev);
328 dev->pm_domain = clknb->pm_domain;
329 if (clknb->con_ids[0]) {
330 for (con_id = clknb->con_ids; *con_id; con_id++)
331 pm_clk_add(dev, *con_id);
333 pm_clk_add(dev, NULL);
337 case BUS_NOTIFY_DEL_DEVICE:
338 if (dev->pm_domain != clknb->pm_domain)
341 dev->pm_domain = NULL;
349 #else /* !CONFIG_PM_RUNTIME */
354 * pm_clk_suspend - Disable clocks in a device's PM clock list.
355 * @dev: Device to disable the clocks for.
357 int pm_clk_suspend(struct device *dev)
359 struct pm_subsys_data *psd = dev_to_psd(dev);
360 struct pm_clock_entry *ce;
363 dev_dbg(dev, "%s()\n", __func__);
365 /* If there is no driver, the clocks are already disabled. */
366 if (!psd || !dev->driver)
369 spin_lock_irqsave(&psd->lock, flags);
371 list_for_each_entry_reverse(ce, &psd->clock_list, node)
372 clk_disable(ce->clk);
374 spin_unlock_irqrestore(&psd->lock, flags);
380 * pm_clk_resume - Enable clocks in a device's PM clock list.
381 * @dev: Device to enable the clocks for.
383 int pm_clk_resume(struct device *dev)
385 struct pm_subsys_data *psd = dev_to_psd(dev);
386 struct pm_clock_entry *ce;
389 dev_dbg(dev, "%s()\n", __func__);
391 /* If there is no driver, the clocks should remain disabled. */
392 if (!psd || !dev->driver)
395 spin_lock_irqsave(&psd->lock, flags);
397 list_for_each_entry(ce, &psd->clock_list, node)
398 __pm_clk_enable(dev, ce->clk);
400 spin_unlock_irqrestore(&psd->lock, flags);
405 #endif /* CONFIG_PM */
408 * enable_clock - Enable a device clock.
409 * @dev: Device whose clock is to be enabled.
410 * @con_id: Connection ID of the clock.
412 static void enable_clock(struct device *dev, const char *con_id)
416 clk = clk_get(dev, con_id);
418 clk_prepare_enable(clk);
420 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
425 * disable_clock - Disable a device clock.
426 * @dev: Device whose clock is to be disabled.
427 * @con_id: Connection ID of the clock.
429 static void disable_clock(struct device *dev, const char *con_id)
433 clk = clk_get(dev, con_id);
435 clk_disable_unprepare(clk);
437 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
442 * pm_clk_notify - Notify routine for device addition and removal.
443 * @nb: Notifier block object this function is a member of.
444 * @action: Operation being carried out by the caller.
445 * @data: Device the routine is being run for.
447 * For this function to work, @nb must be a member of an object of type
448 * struct pm_clk_notifier_block containing all of the requisite data.
449 * Specifically, the con_ids member of that object is used to enable or disable
450 * the device's clocks, depending on @action.
452 static int pm_clk_notify(struct notifier_block *nb,
453 unsigned long action, void *data)
455 struct pm_clk_notifier_block *clknb;
456 struct device *dev = data;
459 dev_dbg(dev, "%s() %ld\n", __func__, action);
461 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
464 case BUS_NOTIFY_BIND_DRIVER:
465 if (clknb->con_ids[0]) {
466 for (con_id = clknb->con_ids; *con_id; con_id++)
467 enable_clock(dev, *con_id);
469 enable_clock(dev, NULL);
472 case BUS_NOTIFY_UNBOUND_DRIVER:
473 if (clknb->con_ids[0]) {
474 for (con_id = clknb->con_ids; *con_id; con_id++)
475 disable_clock(dev, *con_id);
477 disable_clock(dev, NULL);
485 #endif /* !CONFIG_PM_RUNTIME */
488 * pm_clk_add_notifier - Add bus type notifier for power management clocks.
489 * @bus: Bus type to add the notifier to.
490 * @clknb: Notifier to be added to the given bus type.
492 * The nb member of @clknb is not expected to be initialized and its
493 * notifier_call member will be replaced with pm_clk_notify(). However,
494 * the remaining members of @clknb should be populated prior to calling this
497 void pm_clk_add_notifier(struct bus_type *bus,
498 struct pm_clk_notifier_block *clknb)
503 clknb->nb.notifier_call = pm_clk_notify;
504 bus_register_notifier(bus, &clknb->nb);