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1/*
2 * drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks
3 *
4 * Copyright (c) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
5 *
6 * This file is released under the GPLv2.
7 */
8
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/device.h>
12#include <linux/io.h>
13#include <linux/pm.h>
14#include <linux/pm_clock.h>
15#include <linux/clk.h>
16#include <linux/slab.h>
17#include <linux/err.h>
18
19#ifdef CONFIG_PM
20
21enum pce_status {
22 PCE_STATUS_NONE = 0,
23 PCE_STATUS_ACQUIRED,
24 PCE_STATUS_ENABLED,
25 PCE_STATUS_ERROR,
26};
27
28struct pm_clock_entry {
29 struct list_head node;
30 char *con_id;
31 struct clk *clk;
32 enum pce_status status;
33};
34
35/**
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.
39 */
40static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
41{
42 ce->clk = clk_get(dev, ce->con_id);
43 if (IS_ERR(ce->clk)) {
44 ce->status = PCE_STATUS_ERROR;
45 } else {
46 ce->status = PCE_STATUS_ACQUIRED;
47 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
48 }
49}
50
51/**
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.
55 *
56 * Add the clock represented by @con_id to the list of clocks used for
57 * the power management of @dev.
58 */
59int pm_clk_add(struct device *dev, const char *con_id)
60{
61 struct pm_subsys_data *psd = dev_to_psd(dev);
62 struct pm_clock_entry *ce;
63
64 if (!psd)
65 return -EINVAL;
66
67 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
68 if (!ce) {
69 dev_err(dev, "Not enough memory for clock entry.\n");
70 return -ENOMEM;
71 }
72
73 if (con_id) {
74 ce->con_id = kstrdup(con_id, GFP_KERNEL);
75 if (!ce->con_id) {
76 dev_err(dev,
77 "Not enough memory for clock connection ID.\n");
78 kfree(ce);
79 return -ENOMEM;
80 }
81 }
82
83 pm_clk_acquire(dev, ce);
84
85 spin_lock_irq(&psd->lock);
86 list_add_tail(&ce->node, &psd->clock_list);
87 spin_unlock_irq(&psd->lock);
88 return 0;
89}
90
91/**
92 * __pm_clk_remove - Destroy PM clock entry.
93 * @ce: PM clock entry to destroy.
94 */
95static void __pm_clk_remove(struct pm_clock_entry *ce)
96{
97 if (!ce)
98 return;
99
100 if (ce->status < PCE_STATUS_ERROR) {
101 if (ce->status == PCE_STATUS_ENABLED)
102 clk_disable(ce->clk);
103
104 if (ce->status >= PCE_STATUS_ACQUIRED)
105 clk_put(ce->clk);
106 }
107
108 kfree(ce->con_id);
109 kfree(ce);
110}
111
112/**
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.
116 *
117 * Remove the clock represented by @con_id from the list of clocks used for
118 * the power management of @dev.
119 */
120void pm_clk_remove(struct device *dev, const char *con_id)
121{
122 struct pm_subsys_data *psd = dev_to_psd(dev);
123 struct pm_clock_entry *ce;
124
125 if (!psd)
126 return;
127
128 spin_lock_irq(&psd->lock);
129
130 list_for_each_entry(ce, &psd->clock_list, node) {
131 if (!con_id && !ce->con_id)
132 goto remove;
133 else if (!con_id || !ce->con_id)
134 continue;
135 else if (!strcmp(con_id, ce->con_id))
136 goto remove;
137 }
138
139 spin_unlock_irq(&psd->lock);
140 return;
141
142 remove:
143 list_del(&ce->node);
144 spin_unlock_irq(&psd->lock);
145
146 __pm_clk_remove(ce);
147}
148
149/**
150 * pm_clk_init - Initialize a device's list of power management clocks.
151 * @dev: Device to initialize the list of PM clocks for.
152 *
153 * Initialize the lock and clock_list members of the device's pm_subsys_data
154 * object.
155 */
156void pm_clk_init(struct device *dev)
157{
158 struct pm_subsys_data *psd = dev_to_psd(dev);
159 if (psd)
160 INIT_LIST_HEAD(&psd->clock_list);
161}
162
163/**
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.
166 *
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.
169 */
170int pm_clk_create(struct device *dev)
171{
172 int ret = dev_pm_get_subsys_data(dev);
173 return ret < 0 ? ret : 0;
174}
175
176/**
177 * pm_clk_destroy - Destroy a device's list of power management clocks.
178 * @dev: Device to destroy the list of PM clocks for.
179 *
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
182 * that object.
183 */
184void pm_clk_destroy(struct device *dev)
185{
186 struct pm_subsys_data *psd = dev_to_psd(dev);
187 struct pm_clock_entry *ce, *c;
188 struct list_head list;
189
190 if (!psd)
191 return;
192
193 INIT_LIST_HEAD(&list);
194
195 spin_lock_irq(&psd->lock);
196
197 list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
198 list_move(&ce->node, &list);
199
200 spin_unlock_irq(&psd->lock);
201
202 dev_pm_put_subsys_data(dev);
203
204 list_for_each_entry_safe_reverse(ce, c, &list, node) {
205 list_del(&ce->node);
206 __pm_clk_remove(ce);
207 }
208}
209
210#endif /* CONFIG_PM */
211
212#ifdef CONFIG_PM_RUNTIME
213
214/**
215 * pm_clk_suspend - Disable clocks in a device's PM clock list.
216 * @dev: Device to disable the clocks for.
217 */
218int pm_clk_suspend(struct device *dev)
219{
220 struct pm_subsys_data *psd = dev_to_psd(dev);
221 struct pm_clock_entry *ce;
222 unsigned long flags;
223
224 dev_dbg(dev, "%s()\n", __func__);
225
226 if (!psd)
227 return 0;
228
229 spin_lock_irqsave(&psd->lock, flags);
230
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;
236 }
237 }
238
239 spin_unlock_irqrestore(&psd->lock, flags);
240
241 return 0;
242}
243
244/**
245 * pm_clk_resume - Enable clocks in a device's PM clock list.
246 * @dev: Device to enable the clocks for.
247 */
248int pm_clk_resume(struct device *dev)
249{
250 struct pm_subsys_data *psd = dev_to_psd(dev);
251 struct pm_clock_entry *ce;
252 unsigned long flags;
253
254 dev_dbg(dev, "%s()\n", __func__);
255
256 if (!psd)
257 return 0;
258
259 spin_lock_irqsave(&psd->lock, flags);
260
261 list_for_each_entry(ce, &psd->clock_list, node) {
262 if (ce->status < PCE_STATUS_ERROR) {
263 clk_enable(ce->clk);
264 ce->status = PCE_STATUS_ENABLED;
265 }
266 }
267
268 spin_unlock_irqrestore(&psd->lock, flags);
269
270 return 0;
271}
272
273/**
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.
278 *
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.
284 *
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
287 * does nothing.
288 */
289static int pm_clk_notify(struct notifier_block *nb,
290 unsigned long action, void *data)
291{
292 struct pm_clk_notifier_block *clknb;
293 struct device *dev = data;
294 char **con_id;
295 int error;
296
297 dev_dbg(dev, "%s() %ld\n", __func__, action);
298
299 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
300
301 switch (action) {
302 case BUS_NOTIFY_ADD_DEVICE:
303 if (dev->pm_domain)
304 break;
305
306 error = pm_clk_create(dev);
307 if (error)
308 break;
309
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);
314 } else {
315 pm_clk_add(dev, NULL);
316 }
317
318 break;
319 case BUS_NOTIFY_DEL_DEVICE:
320 if (dev->pm_domain != clknb->pm_domain)
321 break;
322
323 dev->pm_domain = NULL;
324 pm_clk_destroy(dev);
325 break;
326 }
327
328 return 0;
329}
330
331#else /* !CONFIG_PM_RUNTIME */
332
333#ifdef CONFIG_PM
334
335/**
336 * pm_clk_suspend - Disable clocks in a device's PM clock list.
337 * @dev: Device to disable the clocks for.
338 */
339int pm_clk_suspend(struct device *dev)
340{
341 struct pm_subsys_data *psd = dev_to_psd(dev);
342 struct pm_clock_entry *ce;
343 unsigned long flags;
344
345 dev_dbg(dev, "%s()\n", __func__);
346
347 /* If there is no driver, the clocks are already disabled. */
348 if (!psd || !dev->driver)
349 return 0;
350
351 spin_lock_irqsave(&psd->lock, flags);
352
353 list_for_each_entry_reverse(ce, &psd->clock_list, node)
354 clk_disable(ce->clk);
355
356 spin_unlock_irqrestore(&psd->lock, flags);
357
358 return 0;
359}
360
361/**
362 * pm_clk_resume - Enable clocks in a device's PM clock list.
363 * @dev: Device to enable the clocks for.
364 */
365int pm_clk_resume(struct device *dev)
366{
367 struct pm_subsys_data *psd = dev_to_psd(dev);
368 struct pm_clock_entry *ce;
369 unsigned long flags;
370
371 dev_dbg(dev, "%s()\n", __func__);
372
373 /* If there is no driver, the clocks should remain disabled. */
374 if (!psd || !dev->driver)
375 return 0;
376
377 spin_lock_irqsave(&psd->lock, flags);
378
379 list_for_each_entry(ce, &psd->clock_list, node)
380 clk_enable(ce->clk);
381
382 spin_unlock_irqrestore(&psd->lock, flags);
383
384 return 0;
385}
386
387#endif /* CONFIG_PM */
388
389/**
390 * enable_clock - Enable a device clock.
391 * @dev: Device whose clock is to be enabled.
392 * @con_id: Connection ID of the clock.
393 */
394static void enable_clock(struct device *dev, const char *con_id)
395{
396 struct clk *clk;
397
398 clk = clk_get(dev, con_id);
399 if (!IS_ERR(clk)) {
400 clk_enable(clk);
401 clk_put(clk);
402 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
403 }
404}
405
406/**
407 * disable_clock - Disable a device clock.
408 * @dev: Device whose clock is to be disabled.
409 * @con_id: Connection ID of the clock.
410 */
411static void disable_clock(struct device *dev, const char *con_id)
412{
413 struct clk *clk;
414
415 clk = clk_get(dev, con_id);
416 if (!IS_ERR(clk)) {
417 clk_disable(clk);
418 clk_put(clk);
419 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
420 }
421}
422
423/**
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.
428 *
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.
433 */
434static int pm_clk_notify(struct notifier_block *nb,
435 unsigned long action, void *data)
436{
437 struct pm_clk_notifier_block *clknb;
438 struct device *dev = data;
439 char **con_id;
440
441 dev_dbg(dev, "%s() %ld\n", __func__, action);
442
443 clknb = container_of(nb, struct pm_clk_notifier_block, nb);
444
445 switch (action) {
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);
450 } else {
451 enable_clock(dev, NULL);
452 }
453 break;
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);
458 } else {
459 disable_clock(dev, NULL);
460 }
461 break;
462 }
463
464 return 0;
465}
466
467#endif /* !CONFIG_PM_RUNTIME */
468
469/**
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.
473 *
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
477 * routine.
478 */
479void pm_clk_add_notifier(struct bus_type *bus,
480 struct pm_clk_notifier_block *clknb)
481{
482 if (!bus || !clknb)
483 return;
484
485 clknb->nb.notifier_call = pm_clk_notify;
486 bus_register_notifier(bus, &clknb->nb);
487}