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/init.h>
10 #include <linux/kernel.h>
11 #include <linux/device.h>
14 #include <linux/pm_clock.h>
15 #include <linux/clk.h>
16 #include <linux/slab.h>
17 #include <linux/err.h>
28 struct pm_clock_entry {
29 struct list_head node;
32 enum pce_status status;
36 * pm_clk_acquire - Acquire a device clock.
37 * @dev: Device whose clock is to be acquired.
38 * @ce: PM clock entry corresponding to the clock.
40 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
42 ce->clk = clk_get(dev, ce->con_id);
43 if (IS_ERR(ce->clk)) {
44 ce->status = PCE_STATUS_ERROR;
47 ce->status = PCE_STATUS_ACQUIRED;
48 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
53 * pm_clk_add - Start using a device clock for power management.
54 * @dev: Device whose clock is going to be used for power management.
55 * @con_id: Connection ID of the clock.
57 * Add the clock represented by @con_id to the list of clocks used for
58 * the power management of @dev.
60 int pm_clk_add(struct device *dev, const char *con_id)
62 struct pm_subsys_data *psd = dev_to_psd(dev);
63 struct pm_clock_entry *ce;
68 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
70 dev_err(dev, "Not enough memory for clock entry.\n");
75 ce->con_id = kstrdup(con_id, GFP_KERNEL);
78 "Not enough memory for clock connection ID.\n");
84 pm_clk_acquire(dev, ce);
86 spin_lock_irq(&psd->lock);
87 list_add_tail(&ce->node, &psd->clock_list);
88 spin_unlock_irq(&psd->lock);
93 * __pm_clk_remove - Destroy PM clock entry.
94 * @ce: PM clock entry to destroy.
96 static void __pm_clk_remove(struct pm_clock_entry *ce)
101 if (ce->status < PCE_STATUS_ERROR) {
102 if (ce->status == PCE_STATUS_ENABLED)
103 clk_disable(ce->clk);
105 if (ce->status >= PCE_STATUS_ACQUIRED) {
106 clk_unprepare(ce->clk);
116 * pm_clk_remove - Stop using a device clock for power management.
117 * @dev: Device whose clock should not be used for PM any more.
118 * @con_id: Connection ID of the clock.
120 * Remove the clock represented by @con_id from the list of clocks used for
121 * the power management of @dev.
123 void pm_clk_remove(struct device *dev, const char *con_id)
125 struct pm_subsys_data *psd = dev_to_psd(dev);
126 struct pm_clock_entry *ce;
131 spin_lock_irq(&psd->lock);
133 list_for_each_entry(ce, &psd->clock_list, node) {
134 if (!con_id && !ce->con_id)
136 else if (!con_id || !ce->con_id)
138 else if (!strcmp(con_id, ce->con_id))
142 spin_unlock_irq(&psd->lock);
147 spin_unlock_irq(&psd->lock);
153 * pm_clk_init - Initialize a device's list of power management clocks.
154 * @dev: Device to initialize the list of PM clocks for.
156 * Initialize the lock and clock_list members of the device's pm_subsys_data
159 void pm_clk_init(struct device *dev)
161 struct pm_subsys_data *psd = dev_to_psd(dev);
163 INIT_LIST_HEAD(&psd->clock_list);
167 * pm_clk_create - Create and initialize a device's list of PM clocks.
168 * @dev: Device to create and initialize the list of PM clocks for.
170 * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
171 * members and make the @dev's power.subsys_data field point to it.
173 int pm_clk_create(struct device *dev)
175 return dev_pm_get_subsys_data(dev);
179 * pm_clk_destroy - Destroy a device's list of power management clocks.
180 * @dev: Device to destroy the list of PM clocks for.
182 * Clear the @dev's power.subsys_data field, remove the list of clock entries
183 * from the struct pm_subsys_data object pointed to by it before and free
186 void pm_clk_destroy(struct device *dev)
188 struct pm_subsys_data *psd = dev_to_psd(dev);
189 struct pm_clock_entry *ce, *c;
190 struct list_head list;
195 INIT_LIST_HEAD(&list);
197 spin_lock_irq(&psd->lock);
199 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
200 list_move(&ce->node, &list);
202 spin_unlock_irq(&psd->lock);
204 dev_pm_put_subsys_data(dev);
206 list_for_each_entry_safe_reverse(ce, c, &list, node) {
212 #endif /* CONFIG_PM */
214 #ifdef CONFIG_PM_RUNTIME
217 * pm_clk_suspend - Disable clocks in a device's PM clock list.
218 * @dev: Device to disable the clocks for.
220 int pm_clk_suspend(struct device *dev)
222 struct pm_subsys_data *psd = dev_to_psd(dev);
223 struct pm_clock_entry *ce;
226 dev_dbg(dev, "%s()\n", __func__);
231 spin_lock_irqsave(&psd->lock, flags);
233 list_for_each_entry_reverse(ce, &psd->clock_list, node) {
234 if (ce->status < PCE_STATUS_ERROR) {
235 if (ce->status == PCE_STATUS_ENABLED)
236 clk_disable(ce->clk);
237 ce->status = PCE_STATUS_ACQUIRED;
241 spin_unlock_irqrestore(&psd->lock, flags);
247 * pm_clk_resume - Enable clocks in a device's PM clock list.
248 * @dev: Device to enable the clocks for.
250 int pm_clk_resume(struct device *dev)
252 struct pm_subsys_data *psd = dev_to_psd(dev);
253 struct pm_clock_entry *ce;
257 dev_dbg(dev, "%s()\n", __func__);
262 spin_lock_irqsave(&psd->lock, flags);
264 list_for_each_entry(ce, &psd->clock_list, node) {
265 if (ce->status < PCE_STATUS_ERROR) {
266 ret = clk_enable(ce->clk);
268 ce->status = PCE_STATUS_ENABLED;
272 spin_unlock_irqrestore(&psd->lock, flags);
278 * pm_clk_notify - Notify routine for device addition and removal.
279 * @nb: Notifier block object this function is a member of.
280 * @action: Operation being carried out by the caller.
281 * @data: Device the routine is being run for.
283 * For this function to work, @nb must be a member of an object of type
284 * struct pm_clk_notifier_block containing all of the requisite data.
285 * Specifically, the pm_domain member of that object is copied to the device's
286 * pm_domain field and its con_ids member is used to populate the device's list
287 * of PM clocks, depending on @action.
289 * If the device's pm_domain field is already populated with a value different
290 * from the one stored in the struct pm_clk_notifier_block object, the function
293 static int pm_clk_notify(struct notifier_block *nb,
294 unsigned long action, void *data)
296 struct pm_clk_notifier_block *clknb;
297 struct device *dev = data;
301 dev_dbg(dev, "%s() %ld\n", __func__, action);
303 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
306 case BUS_NOTIFY_ADD_DEVICE:
310 error = pm_clk_create(dev);
314 dev->pm_domain = clknb->pm_domain;
315 if (clknb->con_ids[0]) {
316 for (con_id = clknb->con_ids; *con_id; con_id++)
317 pm_clk_add(dev, *con_id);
319 pm_clk_add(dev, NULL);
323 case BUS_NOTIFY_DEL_DEVICE:
324 if (dev->pm_domain != clknb->pm_domain)
327 dev->pm_domain = NULL;
335 #else /* !CONFIG_PM_RUNTIME */
340 * pm_clk_suspend - Disable clocks in a device's PM clock list.
341 * @dev: Device to disable the clocks for.
343 int pm_clk_suspend(struct device *dev)
345 struct pm_subsys_data *psd = dev_to_psd(dev);
346 struct pm_clock_entry *ce;
349 dev_dbg(dev, "%s()\n", __func__);
351 /* If there is no driver, the clocks are already disabled. */
352 if (!psd || !dev->driver)
355 spin_lock_irqsave(&psd->lock, flags);
357 list_for_each_entry_reverse(ce, &psd->clock_list, node)
358 clk_disable(ce->clk);
360 spin_unlock_irqrestore(&psd->lock, flags);
366 * pm_clk_resume - Enable clocks in a device's PM clock list.
367 * @dev: Device to enable the clocks for.
369 int pm_clk_resume(struct device *dev)
371 struct pm_subsys_data *psd = dev_to_psd(dev);
372 struct pm_clock_entry *ce;
375 dev_dbg(dev, "%s()\n", __func__);
377 /* If there is no driver, the clocks should remain disabled. */
378 if (!psd || !dev->driver)
381 spin_lock_irqsave(&psd->lock, flags);
383 list_for_each_entry(ce, &psd->clock_list, node)
386 spin_unlock_irqrestore(&psd->lock, flags);
391 #endif /* CONFIG_PM */
394 * enable_clock - Enable a device clock.
395 * @dev: Device whose clock is to be enabled.
396 * @con_id: Connection ID of the clock.
398 static void enable_clock(struct device *dev, const char *con_id)
402 clk = clk_get(dev, con_id);
404 clk_prepare_enable(clk);
406 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
411 * disable_clock - Disable a device clock.
412 * @dev: Device whose clock is to be disabled.
413 * @con_id: Connection ID of the clock.
415 static void disable_clock(struct device *dev, const char *con_id)
419 clk = clk_get(dev, con_id);
421 clk_disable_unprepare(clk);
423 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
428 * pm_clk_notify - Notify routine for device addition and removal.
429 * @nb: Notifier block object this function is a member of.
430 * @action: Operation being carried out by the caller.
431 * @data: Device the routine is being run for.
433 * For this function to work, @nb must be a member of an object of type
434 * struct pm_clk_notifier_block containing all of the requisite data.
435 * Specifically, the con_ids member of that object is used to enable or disable
436 * the device's clocks, depending on @action.
438 static int pm_clk_notify(struct notifier_block *nb,
439 unsigned long action, void *data)
441 struct pm_clk_notifier_block *clknb;
442 struct device *dev = data;
445 dev_dbg(dev, "%s() %ld\n", __func__, action);
447 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
450 case BUS_NOTIFY_BIND_DRIVER:
451 if (clknb->con_ids[0]) {
452 for (con_id = clknb->con_ids; *con_id; con_id++)
453 enable_clock(dev, *con_id);
455 enable_clock(dev, NULL);
458 case BUS_NOTIFY_UNBOUND_DRIVER:
459 if (clknb->con_ids[0]) {
460 for (con_id = clknb->con_ids; *con_id; con_id++)
461 disable_clock(dev, *con_id);
463 disable_clock(dev, NULL);
471 #endif /* !CONFIG_PM_RUNTIME */
474 * pm_clk_add_notifier - Add bus type notifier for power management clocks.
475 * @bus: Bus type to add the notifier to.
476 * @clknb: Notifier to be added to the given bus type.
478 * The nb member of @clknb is not expected to be initialized and its
479 * notifier_call member will be replaced with pm_clk_notify(). However,
480 * the remaining members of @clknb should be populated prior to calling this
483 void pm_clk_add_notifier(struct bus_type *bus,
484 struct pm_clk_notifier_block *clknb)
489 clknb->nb.notifier_call = pm_clk_notify;
490 bus_register_notifier(bus, &clknb->nb);