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_runtime.h>
29 struct pm_clock_entry {
30 struct list_head node;
33 enum pce_status status;
37 * pm_clk_enable - Enable a clock, reporting any errors
38 * @dev: The device for the given clock
39 * @ce: PM clock entry corresponding to the clock.
41 static inline void __pm_clk_enable(struct device *dev, struct pm_clock_entry *ce)
45 if (ce->status < PCE_STATUS_ERROR) {
46 ret = clk_enable(ce->clk);
48 ce->status = PCE_STATUS_ENABLED;
50 dev_err(dev, "%s: failed to enable clk %p, error %d\n",
51 __func__, ce->clk, ret);
56 * pm_clk_acquire - Acquire a device clock.
57 * @dev: Device whose clock is to be acquired.
58 * @ce: PM clock entry corresponding to the clock.
60 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
63 ce->clk = clk_get(dev, ce->con_id);
64 if (IS_ERR(ce->clk)) {
65 ce->status = PCE_STATUS_ERROR;
68 ce->status = PCE_STATUS_ACQUIRED;
69 dev_dbg(dev, "Clock %pC con_id %s managed by runtime PM.\n",
74 static int __pm_clk_add(struct device *dev, const char *con_id,
77 struct pm_subsys_data *psd = dev_to_psd(dev);
78 struct pm_clock_entry *ce;
83 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
88 ce->con_id = kstrdup(con_id, GFP_KERNEL);
91 "Not enough memory for clock connection ID.\n");
96 if (IS_ERR(clk) || !__clk_get(clk)) {
103 pm_clk_acquire(dev, ce);
105 spin_lock_irq(&psd->lock);
106 list_add_tail(&ce->node, &psd->clock_list);
107 spin_unlock_irq(&psd->lock);
112 * pm_clk_add - Start using a device clock for power management.
113 * @dev: Device whose clock is going to be used for power management.
114 * @con_id: Connection ID of the clock.
116 * Add the clock represented by @con_id to the list of clocks used for
117 * the power management of @dev.
119 int pm_clk_add(struct device *dev, const char *con_id)
121 return __pm_clk_add(dev, con_id, NULL);
125 * pm_clk_add_clk - Start using a device clock for power management.
126 * @dev: Device whose clock is going to be used for power management.
127 * @clk: Clock pointer
129 * Add the clock to the list of clocks used for the power management of @dev.
130 * It will increment refcount on clock pointer, use clk_put() on it when done.
132 int pm_clk_add_clk(struct device *dev, struct clk *clk)
134 return __pm_clk_add(dev, NULL, clk);
138 * __pm_clk_remove - Destroy PM clock entry.
139 * @ce: PM clock entry to destroy.
141 static void __pm_clk_remove(struct pm_clock_entry *ce)
146 if (ce->status < PCE_STATUS_ERROR) {
147 if (ce->status == PCE_STATUS_ENABLED)
148 clk_disable(ce->clk);
150 if (ce->status >= PCE_STATUS_ACQUIRED) {
151 clk_unprepare(ce->clk);
161 * pm_clk_remove - Stop using a device clock for power management.
162 * @dev: Device whose clock should not be used for PM any more.
163 * @con_id: Connection ID of the clock.
165 * Remove the clock represented by @con_id from the list of clocks used for
166 * the power management of @dev.
168 void pm_clk_remove(struct device *dev, const char *con_id)
170 struct pm_subsys_data *psd = dev_to_psd(dev);
171 struct pm_clock_entry *ce;
176 spin_lock_irq(&psd->lock);
178 list_for_each_entry(ce, &psd->clock_list, node) {
179 if (!con_id && !ce->con_id)
181 else if (!con_id || !ce->con_id)
183 else if (!strcmp(con_id, ce->con_id))
187 spin_unlock_irq(&psd->lock);
192 spin_unlock_irq(&psd->lock);
198 * pm_clk_init - Initialize a device's list of power management clocks.
199 * @dev: Device to initialize the list of PM clocks for.
201 * Initialize the lock and clock_list members of the device's pm_subsys_data
204 void pm_clk_init(struct device *dev)
206 struct pm_subsys_data *psd = dev_to_psd(dev);
208 INIT_LIST_HEAD(&psd->clock_list);
212 * pm_clk_create - Create and initialize a device's list of PM clocks.
213 * @dev: Device to create and initialize the list of PM clocks for.
215 * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
216 * members and make the @dev's power.subsys_data field point to it.
218 int pm_clk_create(struct device *dev)
220 return dev_pm_get_subsys_data(dev);
224 * pm_clk_destroy - Destroy a device's list of power management clocks.
225 * @dev: Device to destroy the list of PM clocks for.
227 * Clear the @dev's power.subsys_data field, remove the list of clock entries
228 * from the struct pm_subsys_data object pointed to by it before and free
231 void pm_clk_destroy(struct device *dev)
233 struct pm_subsys_data *psd = dev_to_psd(dev);
234 struct pm_clock_entry *ce, *c;
235 struct list_head list;
240 INIT_LIST_HEAD(&list);
242 spin_lock_irq(&psd->lock);
244 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
245 list_move(&ce->node, &list);
247 spin_unlock_irq(&psd->lock);
249 dev_pm_put_subsys_data(dev);
251 list_for_each_entry_safe_reverse(ce, c, &list, node) {
258 * pm_clk_suspend - Disable clocks in a device's PM clock list.
259 * @dev: Device to disable the clocks for.
261 int pm_clk_suspend(struct device *dev)
263 struct pm_subsys_data *psd = dev_to_psd(dev);
264 struct pm_clock_entry *ce;
267 dev_dbg(dev, "%s()\n", __func__);
272 spin_lock_irqsave(&psd->lock, flags);
274 list_for_each_entry_reverse(ce, &psd->clock_list, node) {
275 if (ce->status < PCE_STATUS_ERROR) {
276 if (ce->status == PCE_STATUS_ENABLED)
277 clk_disable(ce->clk);
278 ce->status = PCE_STATUS_ACQUIRED;
282 spin_unlock_irqrestore(&psd->lock, flags);
288 * pm_clk_resume - Enable clocks in a device's PM clock list.
289 * @dev: Device to enable the clocks for.
291 int pm_clk_resume(struct device *dev)
293 struct pm_subsys_data *psd = dev_to_psd(dev);
294 struct pm_clock_entry *ce;
297 dev_dbg(dev, "%s()\n", __func__);
302 spin_lock_irqsave(&psd->lock, flags);
304 list_for_each_entry(ce, &psd->clock_list, node)
305 __pm_clk_enable(dev, ce);
307 spin_unlock_irqrestore(&psd->lock, flags);
313 * pm_clk_notify - Notify routine for device addition and removal.
314 * @nb: Notifier block object this function is a member of.
315 * @action: Operation being carried out by the caller.
316 * @data: Device the routine is being run for.
318 * For this function to work, @nb must be a member of an object of type
319 * struct pm_clk_notifier_block containing all of the requisite data.
320 * Specifically, the pm_domain member of that object is copied to the device's
321 * pm_domain field and its con_ids member is used to populate the device's list
322 * of PM clocks, depending on @action.
324 * If the device's pm_domain field is already populated with a value different
325 * from the one stored in the struct pm_clk_notifier_block object, the function
328 static int pm_clk_notify(struct notifier_block *nb,
329 unsigned long action, void *data)
331 struct pm_clk_notifier_block *clknb;
332 struct device *dev = data;
336 dev_dbg(dev, "%s() %ld\n", __func__, action);
338 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
341 case BUS_NOTIFY_ADD_DEVICE:
345 error = pm_clk_create(dev);
349 dev->pm_domain = clknb->pm_domain;
350 if (clknb->con_ids[0]) {
351 for (con_id = clknb->con_ids; *con_id; con_id++)
352 pm_clk_add(dev, *con_id);
354 pm_clk_add(dev, NULL);
358 case BUS_NOTIFY_DEL_DEVICE:
359 if (dev->pm_domain != clknb->pm_domain)
362 dev->pm_domain = NULL;
370 int pm_clk_runtime_suspend(struct device *dev)
374 dev_dbg(dev, "%s\n", __func__);
376 ret = pm_generic_runtime_suspend(dev);
378 dev_err(dev, "failed to suspend device\n");
382 ret = pm_clk_suspend(dev);
384 dev_err(dev, "failed to suspend clock\n");
385 pm_generic_runtime_resume(dev);
392 int pm_clk_runtime_resume(struct device *dev)
396 dev_dbg(dev, "%s\n", __func__);
398 ret = pm_clk_resume(dev);
400 dev_err(dev, "failed to resume clock\n");
404 return pm_generic_runtime_resume(dev);
407 #else /* !CONFIG_PM */
410 * enable_clock - Enable a device clock.
411 * @dev: Device whose clock is to be enabled.
412 * @con_id: Connection ID of the clock.
414 static void enable_clock(struct device *dev, const char *con_id)
418 clk = clk_get(dev, con_id);
420 clk_prepare_enable(clk);
422 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
427 * disable_clock - Disable a device clock.
428 * @dev: Device whose clock is to be disabled.
429 * @con_id: Connection ID of the clock.
431 static void disable_clock(struct device *dev, const char *con_id)
435 clk = clk_get(dev, con_id);
437 clk_disable_unprepare(clk);
439 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
444 * pm_clk_notify - Notify routine for device addition and removal.
445 * @nb: Notifier block object this function is a member of.
446 * @action: Operation being carried out by the caller.
447 * @data: Device the routine is being run for.
449 * For this function to work, @nb must be a member of an object of type
450 * struct pm_clk_notifier_block containing all of the requisite data.
451 * Specifically, the con_ids member of that object is used to enable or disable
452 * the device's clocks, depending on @action.
454 static int pm_clk_notify(struct notifier_block *nb,
455 unsigned long action, void *data)
457 struct pm_clk_notifier_block *clknb;
458 struct device *dev = data;
461 dev_dbg(dev, "%s() %ld\n", __func__, action);
463 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
466 case BUS_NOTIFY_BIND_DRIVER:
467 if (clknb->con_ids[0]) {
468 for (con_id = clknb->con_ids; *con_id; con_id++)
469 enable_clock(dev, *con_id);
471 enable_clock(dev, NULL);
474 case BUS_NOTIFY_UNBOUND_DRIVER:
475 if (clknb->con_ids[0]) {
476 for (con_id = clknb->con_ids; *con_id; con_id++)
477 disable_clock(dev, *con_id);
479 disable_clock(dev, NULL);
487 #endif /* !CONFIG_PM */
490 * pm_clk_add_notifier - Add bus type notifier for power management clocks.
491 * @bus: Bus type to add the notifier to.
492 * @clknb: Notifier to be added to the given bus type.
494 * The nb member of @clknb is not expected to be initialized and its
495 * notifier_call member will be replaced with pm_clk_notify(). However,
496 * the remaining members of @clknb should be populated prior to calling this
499 void pm_clk_add_notifier(struct bus_type *bus,
500 struct pm_clk_notifier_block *clknb)
505 clknb->nb.notifier_call = pm_clk_notify;
506 bus_register_notifier(bus, &clknb->nb);