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_runtime.h>
14 #include <linux/clk.h>
15 #include <linux/slab.h>
16 #include <linux/err.h>
21 struct list_head clock_list;
32 struct pm_clock_entry {
33 struct list_head node;
36 enum pce_status status;
39 static struct pm_clk_data *__to_pcd(struct device *dev)
41 return dev ? dev->power.subsys_data : NULL;
45 * pm_clk_add - Start using a device clock for power management.
46 * @dev: Device whose clock is going to be used for power management.
47 * @con_id: Connection ID of the clock.
49 * Add the clock represented by @con_id to the list of clocks used for
50 * the power management of @dev.
52 int pm_clk_add(struct device *dev, const char *con_id)
54 struct pm_clk_data *pcd = __to_pcd(dev);
55 struct pm_clock_entry *ce;
60 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
62 dev_err(dev, "Not enough memory for clock entry.\n");
67 ce->con_id = kstrdup(con_id, GFP_KERNEL);
70 "Not enough memory for clock connection ID.\n");
76 mutex_lock(&pcd->lock);
77 list_add_tail(&ce->node, &pcd->clock_list);
78 mutex_unlock(&pcd->lock);
83 * __pm_clk_remove - Destroy PM clock entry.
84 * @ce: PM clock entry to destroy.
86 * This routine must be called under the mutex protecting the PM list of clocks
87 * corresponding the the @ce's device.
89 static void __pm_clk_remove(struct pm_clock_entry *ce)
96 if (ce->status < PCE_STATUS_ERROR) {
97 if (ce->status == PCE_STATUS_ENABLED)
100 if (ce->status >= PCE_STATUS_ACQUIRED)
111 * pm_clk_remove - Stop using a device clock for power management.
112 * @dev: Device whose clock should not be used for PM any more.
113 * @con_id: Connection ID of the clock.
115 * Remove the clock represented by @con_id from the list of clocks used for
116 * the power management of @dev.
118 void pm_clk_remove(struct device *dev, const char *con_id)
120 struct pm_clk_data *pcd = __to_pcd(dev);
121 struct pm_clock_entry *ce;
126 mutex_lock(&pcd->lock);
128 list_for_each_entry(ce, &pcd->clock_list, node) {
129 if (!con_id && !ce->con_id) {
132 } else if (!con_id || !ce->con_id) {
134 } else if (!strcmp(con_id, ce->con_id)) {
140 mutex_unlock(&pcd->lock);
144 * pm_clk_init - Initialize a device's list of power management clocks.
145 * @dev: Device to initialize the list of PM clocks for.
147 * Allocate a struct pm_clk_data object, initialize its lock member and
148 * make the @dev's power.subsys_data field point to it.
150 int pm_clk_init(struct device *dev)
152 struct pm_clk_data *pcd;
154 pcd = kzalloc(sizeof(*pcd), GFP_KERNEL);
156 dev_err(dev, "Not enough memory for PM clock data.\n");
160 INIT_LIST_HEAD(&pcd->clock_list);
161 mutex_init(&pcd->lock);
162 dev->power.subsys_data = pcd;
167 * pm_clk_destroy - Destroy a device's list of power management clocks.
168 * @dev: Device to destroy the list of PM clocks for.
170 * Clear the @dev's power.subsys_data field, remove the list of clock entries
171 * from the struct pm_clk_data object pointed to by it before and free
174 void pm_clk_destroy(struct device *dev)
176 struct pm_clk_data *pcd = __to_pcd(dev);
177 struct pm_clock_entry *ce, *c;
182 dev->power.subsys_data = NULL;
184 mutex_lock(&pcd->lock);
186 list_for_each_entry_safe_reverse(ce, c, &pcd->clock_list, node)
189 mutex_unlock(&pcd->lock);
194 #endif /* CONFIG_PM */
196 #ifdef CONFIG_PM_RUNTIME
199 * pm_clk_acquire - Acquire a device clock.
200 * @dev: Device whose clock is to be acquired.
201 * @con_id: Connection ID of the clock.
203 static void pm_clk_acquire(struct device *dev,
204 struct pm_clock_entry *ce)
206 ce->clk = clk_get(dev, ce->con_id);
207 if (IS_ERR(ce->clk)) {
208 ce->status = PCE_STATUS_ERROR;
210 ce->status = PCE_STATUS_ACQUIRED;
211 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
216 * pm_clk_suspend - Disable clocks in a device's PM clock list.
217 * @dev: Device to disable the clocks for.
219 int pm_clk_suspend(struct device *dev)
221 struct pm_clk_data *pcd = __to_pcd(dev);
222 struct pm_clock_entry *ce;
224 dev_dbg(dev, "%s()\n", __func__);
229 mutex_lock(&pcd->lock);
231 list_for_each_entry_reverse(ce, &pcd->clock_list, node) {
232 if (ce->status == PCE_STATUS_NONE)
233 pm_clk_acquire(dev, ce);
235 if (ce->status < PCE_STATUS_ERROR) {
236 clk_disable(ce->clk);
237 ce->status = PCE_STATUS_ACQUIRED;
241 mutex_unlock(&pcd->lock);
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_clk_data *pcd = __to_pcd(dev);
253 struct pm_clock_entry *ce;
255 dev_dbg(dev, "%s()\n", __func__);
260 mutex_lock(&pcd->lock);
262 list_for_each_entry(ce, &pcd->clock_list, node) {
263 if (ce->status == PCE_STATUS_NONE)
264 pm_clk_acquire(dev, ce);
266 if (ce->status < PCE_STATUS_ERROR) {
268 ce->status = PCE_STATUS_ENABLED;
272 mutex_unlock(&pcd->lock);
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_init(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_clk_data *pcd = __to_pcd(dev);
346 struct pm_clock_entry *ce;
348 dev_dbg(dev, "%s()\n", __func__);
350 /* If there is no driver, the clocks are already disabled. */
351 if (!pcd || !dev->driver)
354 mutex_lock(&pcd->lock);
356 list_for_each_entry_reverse(ce, &pcd->clock_list, node)
357 clk_disable(ce->clk);
359 mutex_unlock(&pcd->lock);
365 * pm_clk_resume - Enable clocks in a device's PM clock list.
366 * @dev: Device to enable the clocks for.
368 int pm_clk_resume(struct device *dev)
370 struct pm_clk_data *pcd = __to_pcd(dev);
371 struct pm_clock_entry *ce;
373 dev_dbg(dev, "%s()\n", __func__);
375 /* If there is no driver, the clocks should remain disabled. */
376 if (!pcd || !dev->driver)
379 mutex_lock(&pcd->lock);
381 list_for_each_entry(ce, &pcd->clock_list, node)
384 mutex_unlock(&pcd->lock);
389 #endif /* CONFIG_PM */
392 * enable_clock - Enable a device clock.
393 * @dev: Device whose clock is to be enabled.
394 * @con_id: Connection ID of the clock.
396 static void enable_clock(struct device *dev, const char *con_id)
400 clk = clk_get(dev, con_id);
404 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
409 * disable_clock - Disable a device clock.
410 * @dev: Device whose clock is to be disabled.
411 * @con_id: Connection ID of the clock.
413 static void disable_clock(struct device *dev, const char *con_id)
417 clk = clk_get(dev, con_id);
421 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
426 * pm_clk_notify - Notify routine for device addition and removal.
427 * @nb: Notifier block object this function is a member of.
428 * @action: Operation being carried out by the caller.
429 * @data: Device the routine is being run for.
431 * For this function to work, @nb must be a member of an object of type
432 * struct pm_clk_notifier_block containing all of the requisite data.
433 * Specifically, the con_ids member of that object is used to enable or disable
434 * the device's clocks, depending on @action.
436 static int pm_clk_notify(struct notifier_block *nb,
437 unsigned long action, void *data)
439 struct pm_clk_notifier_block *clknb;
440 struct device *dev = data;
443 dev_dbg(dev, "%s() %ld\n", __func__, action);
445 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
448 case BUS_NOTIFY_BIND_DRIVER:
449 if (clknb->con_ids[0]) {
450 for (con_id = clknb->con_ids; *con_id; con_id++)
451 enable_clock(dev, *con_id);
453 enable_clock(dev, NULL);
456 case BUS_NOTIFY_UNBOUND_DRIVER:
457 if (clknb->con_ids[0]) {
458 for (con_id = clknb->con_ids; *con_id; con_id++)
459 disable_clock(dev, *con_id);
461 disable_clock(dev, NULL);
469 #endif /* !CONFIG_PM_RUNTIME */
472 * pm_clk_add_notifier - Add bus type notifier for power management clocks.
473 * @bus: Bus type to add the notifier to.
474 * @clknb: Notifier to be added to the given bus type.
476 * The nb member of @clknb is not expected to be initialized and its
477 * notifier_call member will be replaced with pm_clk_notify(). However,
478 * the remaining members of @clknb should be populated prior to calling this
481 void pm_clk_add_notifier(struct bus_type *bus,
482 struct pm_clk_notifier_block *clknb)
487 clknb->nb.notifier_call = pm_clk_notify;
488 bus_register_notifier(bus, &clknb->nb);