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;
46 ce->status = PCE_STATUS_ACQUIRED;
47 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
52 * pm_clk_add - Start using a device clock for power management.
53 * @dev: Device whose clock is going to be used for power management.
54 * @con_id: Connection ID of the clock.
56 * Add the clock represented by @con_id to the list of clocks used for
57 * the power management of @dev.
59 int pm_clk_add(struct device *dev, const char *con_id)
61 struct pm_subsys_data *psd = dev_to_psd(dev);
62 struct pm_clock_entry *ce;
67 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
69 dev_err(dev, "Not enough memory for clock entry.\n");
74 ce->con_id = kstrdup(con_id, GFP_KERNEL);
77 "Not enough memory for clock connection ID.\n");
83 pm_clk_acquire(dev, ce);
85 spin_lock_irq(&psd->lock);
86 list_add_tail(&ce->node, &psd->clock_list);
87 spin_unlock_irq(&psd->lock);
92 * __pm_clk_remove - Destroy PM clock entry.
93 * @ce: PM clock entry to destroy.
95 static void __pm_clk_remove(struct pm_clock_entry *ce)
100 if (ce->status < PCE_STATUS_ERROR) {
101 if (ce->status == PCE_STATUS_ENABLED)
102 clk_disable(ce->clk);
104 if (ce->status >= PCE_STATUS_ACQUIRED)
113 * pm_clk_remove - Stop using a device clock for power management.
114 * @dev: Device whose clock should not be used for PM any more.
115 * @con_id: Connection ID of the clock.
117 * Remove the clock represented by @con_id from the list of clocks used for
118 * the power management of @dev.
120 void pm_clk_remove(struct device *dev, const char *con_id)
122 struct pm_subsys_data *psd = dev_to_psd(dev);
123 struct pm_clock_entry *ce;
128 spin_lock_irq(&psd->lock);
130 list_for_each_entry(ce, &psd->clock_list, node) {
131 if (!con_id && !ce->con_id)
133 else if (!con_id || !ce->con_id)
135 else if (!strcmp(con_id, ce->con_id))
139 spin_unlock_irq(&psd->lock);
144 spin_unlock_irq(&psd->lock);
150 * pm_clk_init - Initialize a device's list of power management clocks.
151 * @dev: Device to initialize the list of PM clocks for.
153 * Initialize the lock and clock_list members of the device's pm_subsys_data
156 void pm_clk_init(struct device *dev)
158 struct pm_subsys_data *psd = dev_to_psd(dev);
160 INIT_LIST_HEAD(&psd->clock_list);
164 * pm_clk_create - Create and initialize a device's list of PM clocks.
165 * @dev: Device to create and initialize the list of PM clocks for.
167 * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
168 * members and make the @dev's power.subsys_data field point to it.
170 int pm_clk_create(struct device *dev)
172 int ret = dev_pm_get_subsys_data(dev);
173 return ret < 0 ? ret : 0;
177 * pm_clk_destroy - Destroy a device's list of power management clocks.
178 * @dev: Device to destroy the list of PM clocks for.
180 * Clear the @dev's power.subsys_data field, remove the list of clock entries
181 * from the struct pm_subsys_data object pointed to by it before and free
184 void pm_clk_destroy(struct device *dev)
186 struct pm_subsys_data *psd = dev_to_psd(dev);
187 struct pm_clock_entry *ce, *c;
188 struct list_head list;
193 INIT_LIST_HEAD(&list);
195 spin_lock_irq(&psd->lock);
197 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
198 list_move(&ce->node, &list);
200 spin_unlock_irq(&psd->lock);
202 dev_pm_put_subsys_data(dev);
204 list_for_each_entry_safe_reverse(ce, c, &list, node) {
210 #endif /* CONFIG_PM */
212 #ifdef CONFIG_PM_RUNTIME
215 * pm_clk_suspend - Disable clocks in a device's PM clock list.
216 * @dev: Device to disable the clocks for.
218 int pm_clk_suspend(struct device *dev)
220 struct pm_subsys_data *psd = dev_to_psd(dev);
221 struct pm_clock_entry *ce;
224 dev_dbg(dev, "%s()\n", __func__);
229 spin_lock_irqsave(&psd->lock, flags);
231 list_for_each_entry_reverse(ce, &psd->clock_list, node) {
232 if (ce->status < PCE_STATUS_ERROR) {
233 if (ce->status == PCE_STATUS_ENABLED)
234 clk_disable(ce->clk);
235 ce->status = PCE_STATUS_ACQUIRED;
239 spin_unlock_irqrestore(&psd->lock, flags);
245 * pm_clk_resume - Enable clocks in a device's PM clock list.
246 * @dev: Device to enable the clocks for.
248 int pm_clk_resume(struct device *dev)
250 struct pm_subsys_data *psd = dev_to_psd(dev);
251 struct pm_clock_entry *ce;
254 dev_dbg(dev, "%s()\n", __func__);
259 spin_lock_irqsave(&psd->lock, flags);
261 list_for_each_entry(ce, &psd->clock_list, node) {
262 if (ce->status < PCE_STATUS_ERROR) {
264 ce->status = PCE_STATUS_ENABLED;
268 spin_unlock_irqrestore(&psd->lock, flags);
274 * pm_clk_notify - Notify routine for device addition and removal.
275 * @nb: Notifier block object this function is a member of.
276 * @action: Operation being carried out by the caller.
277 * @data: Device the routine is being run for.
279 * For this function to work, @nb must be a member of an object of type
280 * struct pm_clk_notifier_block containing all of the requisite data.
281 * Specifically, the pm_domain member of that object is copied to the device's
282 * pm_domain field and its con_ids member is used to populate the device's list
283 * of PM clocks, depending on @action.
285 * If the device's pm_domain field is already populated with a value different
286 * from the one stored in the struct pm_clk_notifier_block object, the function
289 static int pm_clk_notify(struct notifier_block *nb,
290 unsigned long action, void *data)
292 struct pm_clk_notifier_block *clknb;
293 struct device *dev = data;
297 dev_dbg(dev, "%s() %ld\n", __func__, action);
299 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
302 case BUS_NOTIFY_ADD_DEVICE:
306 error = pm_clk_create(dev);
310 dev->pm_domain = clknb->pm_domain;
311 if (clknb->con_ids[0]) {
312 for (con_id = clknb->con_ids; *con_id; con_id++)
313 pm_clk_add(dev, *con_id);
315 pm_clk_add(dev, NULL);
319 case BUS_NOTIFY_DEL_DEVICE:
320 if (dev->pm_domain != clknb->pm_domain)
323 dev->pm_domain = NULL;
331 #else /* !CONFIG_PM_RUNTIME */
336 * pm_clk_suspend - Disable clocks in a device's PM clock list.
337 * @dev: Device to disable the clocks for.
339 int pm_clk_suspend(struct device *dev)
341 struct pm_subsys_data *psd = dev_to_psd(dev);
342 struct pm_clock_entry *ce;
345 dev_dbg(dev, "%s()\n", __func__);
347 /* If there is no driver, the clocks are already disabled. */
348 if (!psd || !dev->driver)
351 spin_lock_irqsave(&psd->lock, flags);
353 list_for_each_entry_reverse(ce, &psd->clock_list, node)
354 clk_disable(ce->clk);
356 spin_unlock_irqrestore(&psd->lock, flags);
362 * pm_clk_resume - Enable clocks in a device's PM clock list.
363 * @dev: Device to enable the clocks for.
365 int pm_clk_resume(struct device *dev)
367 struct pm_subsys_data *psd = dev_to_psd(dev);
368 struct pm_clock_entry *ce;
371 dev_dbg(dev, "%s()\n", __func__);
373 /* If there is no driver, the clocks should remain disabled. */
374 if (!psd || !dev->driver)
377 spin_lock_irqsave(&psd->lock, flags);
379 list_for_each_entry(ce, &psd->clock_list, node)
382 spin_unlock_irqrestore(&psd->lock, flags);
387 #endif /* CONFIG_PM */
390 * enable_clock - Enable a device clock.
391 * @dev: Device whose clock is to be enabled.
392 * @con_id: Connection ID of the clock.
394 static void enable_clock(struct device *dev, const char *con_id)
398 clk = clk_get(dev, con_id);
402 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
407 * disable_clock - Disable a device clock.
408 * @dev: Device whose clock is to be disabled.
409 * @con_id: Connection ID of the clock.
411 static void disable_clock(struct device *dev, const char *con_id)
415 clk = clk_get(dev, con_id);
419 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
424 * pm_clk_notify - Notify routine for device addition and removal.
425 * @nb: Notifier block object this function is a member of.
426 * @action: Operation being carried out by the caller.
427 * @data: Device the routine is being run for.
429 * For this function to work, @nb must be a member of an object of type
430 * struct pm_clk_notifier_block containing all of the requisite data.
431 * Specifically, the con_ids member of that object is used to enable or disable
432 * the device's clocks, depending on @action.
434 static int pm_clk_notify(struct notifier_block *nb,
435 unsigned long action, void *data)
437 struct pm_clk_notifier_block *clknb;
438 struct device *dev = data;
441 dev_dbg(dev, "%s() %ld\n", __func__, action);
443 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
446 case BUS_NOTIFY_BIND_DRIVER:
447 if (clknb->con_ids[0]) {
448 for (con_id = clknb->con_ids; *con_id; con_id++)
449 enable_clock(dev, *con_id);
451 enable_clock(dev, NULL);
454 case BUS_NOTIFY_UNBOUND_DRIVER:
455 if (clknb->con_ids[0]) {
456 for (con_id = clknb->con_ids; *con_id; con_id++)
457 disable_clock(dev, *con_id);
459 disable_clock(dev, NULL);
467 #endif /* !CONFIG_PM_RUNTIME */
470 * pm_clk_add_notifier - Add bus type notifier for power management clocks.
471 * @bus: Bus type to add the notifier to.
472 * @clknb: Notifier to be added to the given bus type.
474 * The nb member of @clknb is not expected to be initialized and its
475 * notifier_call member will be replaced with pm_clk_notify(). However,
476 * the remaining members of @clknb should be populated prior to calling this
479 void pm_clk_add_notifier(struct bus_type *bus,
480 struct pm_clk_notifier_block *clknb)
485 clknb->nb.notifier_call = pm_clk_notify;
486 bus_register_notifier(bus, &clknb->nb);