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>
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_add - Start using a device clock for power management.
36 * @dev: Device whose clock is going to be used for power management.
37 * @con_id: Connection ID of the clock.
39 * Add the clock represented by @con_id to the list of clocks used for
40 * the power management of @dev.
42 int pm_clk_add(struct device *dev, const char *con_id)
44 struct pm_subsys_data *psd = dev_to_psd(dev);
45 struct pm_clock_entry *ce;
50 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
52 dev_err(dev, "Not enough memory for clock entry.\n");
57 ce->con_id = kstrdup(con_id, GFP_KERNEL);
60 "Not enough memory for clock connection ID.\n");
66 spin_lock_irq(&psd->lock);
67 list_add_tail(&ce->node, &psd->clock_list);
68 spin_unlock_irq(&psd->lock);
73 * __pm_clk_remove - Destroy PM clock entry.
74 * @ce: PM clock entry to destroy.
76 * This routine must be called under the spinlock protecting the PM list of
77 * clocks corresponding the the @ce's device.
79 static void __pm_clk_remove(struct pm_clock_entry *ce)
86 if (ce->status < PCE_STATUS_ERROR) {
87 if (ce->status == PCE_STATUS_ENABLED)
90 if (ce->status >= PCE_STATUS_ACQUIRED)
101 * pm_clk_remove - Stop using a device clock for power management.
102 * @dev: Device whose clock should not be used for PM any more.
103 * @con_id: Connection ID of the clock.
105 * Remove the clock represented by @con_id from the list of clocks used for
106 * the power management of @dev.
108 void pm_clk_remove(struct device *dev, const char *con_id)
110 struct pm_subsys_data *psd = dev_to_psd(dev);
111 struct pm_clock_entry *ce;
116 spin_lock_irq(&psd->lock);
118 list_for_each_entry(ce, &psd->clock_list, node) {
119 if (!con_id && !ce->con_id) {
122 } else if (!con_id || !ce->con_id) {
124 } else if (!strcmp(con_id, ce->con_id)) {
130 spin_unlock_irq(&psd->lock);
134 * pm_clk_init - Initialize a device's list of power management clocks.
135 * @dev: Device to initialize the list of PM clocks for.
137 * Initialize the lock and clock_list members of the device's pm_subsys_data
140 void pm_clk_init(struct device *dev)
142 struct pm_subsys_data *psd = dev_to_psd(dev);
144 INIT_LIST_HEAD(&psd->clock_list);
148 * pm_clk_create - Create and initialize a device's list of PM clocks.
149 * @dev: Device to create and initialize the list of PM clocks for.
151 * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
152 * members and make the @dev's power.subsys_data field point to it.
154 int pm_clk_create(struct device *dev)
156 int ret = dev_pm_get_subsys_data(dev);
157 return ret < 0 ? ret : 0;
161 * pm_clk_destroy - Destroy a device's list of power management clocks.
162 * @dev: Device to destroy the list of PM clocks for.
164 * Clear the @dev's power.subsys_data field, remove the list of clock entries
165 * from the struct pm_subsys_data object pointed to by it before and free
168 void pm_clk_destroy(struct device *dev)
170 struct pm_subsys_data *psd = dev_to_psd(dev);
171 struct pm_clock_entry *ce, *c;
176 spin_lock_irq(&psd->lock);
178 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
181 spin_unlock_irq(&psd->lock);
183 dev_pm_put_subsys_data(dev);
186 #endif /* CONFIG_PM */
188 #ifdef CONFIG_PM_RUNTIME
191 * pm_clk_acquire - Acquire a device clock.
192 * @dev: Device whose clock is to be acquired.
193 * @con_id: Connection ID of the clock.
195 static void pm_clk_acquire(struct device *dev,
196 struct pm_clock_entry *ce)
198 ce->clk = clk_get(dev, ce->con_id);
199 if (IS_ERR(ce->clk)) {
200 ce->status = PCE_STATUS_ERROR;
202 ce->status = PCE_STATUS_ACQUIRED;
203 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
208 * pm_clk_suspend - Disable clocks in a device's PM clock list.
209 * @dev: Device to disable the clocks for.
211 int pm_clk_suspend(struct device *dev)
213 struct pm_subsys_data *psd = dev_to_psd(dev);
214 struct pm_clock_entry *ce;
217 dev_dbg(dev, "%s()\n", __func__);
222 spin_lock_irqsave(&psd->lock, flags);
224 list_for_each_entry_reverse(ce, &psd->clock_list, node) {
225 if (ce->status == PCE_STATUS_NONE)
226 pm_clk_acquire(dev, ce);
228 if (ce->status < PCE_STATUS_ERROR) {
229 clk_disable(ce->clk);
230 ce->status = PCE_STATUS_ACQUIRED;
234 spin_unlock_irqrestore(&psd->lock, flags);
240 * pm_clk_resume - Enable clocks in a device's PM clock list.
241 * @dev: Device to enable the clocks for.
243 int pm_clk_resume(struct device *dev)
245 struct pm_subsys_data *psd = dev_to_psd(dev);
246 struct pm_clock_entry *ce;
249 dev_dbg(dev, "%s()\n", __func__);
254 spin_lock_irqsave(&psd->lock, flags);
256 list_for_each_entry(ce, &psd->clock_list, node) {
257 if (ce->status == PCE_STATUS_NONE)
258 pm_clk_acquire(dev, ce);
260 if (ce->status < PCE_STATUS_ERROR) {
262 ce->status = PCE_STATUS_ENABLED;
266 spin_unlock_irqrestore(&psd->lock, flags);
272 * pm_clk_notify - Notify routine for device addition and removal.
273 * @nb: Notifier block object this function is a member of.
274 * @action: Operation being carried out by the caller.
275 * @data: Device the routine is being run for.
277 * For this function to work, @nb must be a member of an object of type
278 * struct pm_clk_notifier_block containing all of the requisite data.
279 * Specifically, the pm_domain member of that object is copied to the device's
280 * pm_domain field and its con_ids member is used to populate the device's list
281 * of PM clocks, depending on @action.
283 * If the device's pm_domain field is already populated with a value different
284 * from the one stored in the struct pm_clk_notifier_block object, the function
287 static int pm_clk_notify(struct notifier_block *nb,
288 unsigned long action, void *data)
290 struct pm_clk_notifier_block *clknb;
291 struct device *dev = data;
295 dev_dbg(dev, "%s() %ld\n", __func__, action);
297 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
300 case BUS_NOTIFY_ADD_DEVICE:
304 error = pm_clk_create(dev);
308 dev->pm_domain = clknb->pm_domain;
309 if (clknb->con_ids[0]) {
310 for (con_id = clknb->con_ids; *con_id; con_id++)
311 pm_clk_add(dev, *con_id);
313 pm_clk_add(dev, NULL);
317 case BUS_NOTIFY_DEL_DEVICE:
318 if (dev->pm_domain != clknb->pm_domain)
321 dev->pm_domain = NULL;
329 #else /* !CONFIG_PM_RUNTIME */
334 * pm_clk_suspend - Disable clocks in a device's PM clock list.
335 * @dev: Device to disable the clocks for.
337 int pm_clk_suspend(struct device *dev)
339 struct pm_subsys_data *psd = dev_to_psd(dev);
340 struct pm_clock_entry *ce;
343 dev_dbg(dev, "%s()\n", __func__);
345 /* If there is no driver, the clocks are already disabled. */
346 if (!psd || !dev->driver)
349 spin_lock_irqsave(&psd->lock, flags);
351 list_for_each_entry_reverse(ce, &psd->clock_list, node)
352 clk_disable(ce->clk);
354 spin_unlock_irqrestore(&psd->lock, flags);
360 * pm_clk_resume - Enable clocks in a device's PM clock list.
361 * @dev: Device to enable the clocks for.
363 int pm_clk_resume(struct device *dev)
365 struct pm_subsys_data *psd = dev_to_psd(dev);
366 struct pm_clock_entry *ce;
369 dev_dbg(dev, "%s()\n", __func__);
371 /* If there is no driver, the clocks should remain disabled. */
372 if (!psd || !dev->driver)
375 spin_lock_irqsave(&psd->lock, flags);
377 list_for_each_entry(ce, &psd->clock_list, node)
380 spin_unlock_irqrestore(&psd->lock, flags);
385 #endif /* CONFIG_PM */
388 * enable_clock - Enable a device clock.
389 * @dev: Device whose clock is to be enabled.
390 * @con_id: Connection ID of the clock.
392 static void enable_clock(struct device *dev, const char *con_id)
396 clk = clk_get(dev, con_id);
400 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
405 * disable_clock - Disable a device clock.
406 * @dev: Device whose clock is to be disabled.
407 * @con_id: Connection ID of the clock.
409 static void disable_clock(struct device *dev, const char *con_id)
413 clk = clk_get(dev, con_id);
417 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
422 * pm_clk_notify - Notify routine for device addition and removal.
423 * @nb: Notifier block object this function is a member of.
424 * @action: Operation being carried out by the caller.
425 * @data: Device the routine is being run for.
427 * For this function to work, @nb must be a member of an object of type
428 * struct pm_clk_notifier_block containing all of the requisite data.
429 * Specifically, the con_ids member of that object is used to enable or disable
430 * the device's clocks, depending on @action.
432 static int pm_clk_notify(struct notifier_block *nb,
433 unsigned long action, void *data)
435 struct pm_clk_notifier_block *clknb;
436 struct device *dev = data;
439 dev_dbg(dev, "%s() %ld\n", __func__, action);
441 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
444 case BUS_NOTIFY_BIND_DRIVER:
445 if (clknb->con_ids[0]) {
446 for (con_id = clknb->con_ids; *con_id; con_id++)
447 enable_clock(dev, *con_id);
449 enable_clock(dev, NULL);
452 case BUS_NOTIFY_UNBOUND_DRIVER:
453 if (clknb->con_ids[0]) {
454 for (con_id = clknb->con_ids; *con_id; con_id++)
455 disable_clock(dev, *con_id);
457 disable_clock(dev, NULL);
465 #endif /* !CONFIG_PM_RUNTIME */
468 * pm_clk_add_notifier - Add bus type notifier for power management clocks.
469 * @bus: Bus type to add the notifier to.
470 * @clknb: Notifier to be added to the given bus type.
472 * The nb member of @clknb is not expected to be initialized and its
473 * notifier_call member will be replaced with pm_clk_notify(). However,
474 * the remaining members of @clknb should be populated prior to calling this
477 void pm_clk_add_notifier(struct bus_type *bus,
478 struct pm_clk_notifier_block *clknb)
483 clknb->nb.notifier_call = pm_clk_notify;
484 bus_register_notifier(bus, &clknb->nb);