1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright (C) 2021 ROHM Semiconductors
4 // regulator IRQ based event notification helpers
5 //
6 // Logic has been partially adapted from qcom-labibb driver.
7 //
8 // Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
9
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/interrupt.h>
13 #include <linux/kernel.h>
14 #include <linux/reboot.h>
15 #include <linux/regmap.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 #include <linux/regulator/driver.h>
19
20 #include "internal.h"
21
22 #define REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS 10000
23
24 struct regulator_irq {
25 struct regulator_irq_data rdata;
26 struct regulator_irq_desc desc;
27 int irq;
28 int retry_cnt;
29 struct delayed_work isr_work;
30 };
31
32 /*
33 * Should only be called from threaded handler to prevent potential deadlock
34 */
rdev_flag_err(struct regulator_dev * rdev,int err)35 static void rdev_flag_err(struct regulator_dev *rdev, int err)
36 {
37 spin_lock(&rdev->err_lock);
38 rdev->cached_err |= err;
39 spin_unlock(&rdev->err_lock);
40 }
41
rdev_clear_err(struct regulator_dev * rdev,int err)42 static void rdev_clear_err(struct regulator_dev *rdev, int err)
43 {
44 spin_lock(&rdev->err_lock);
45 rdev->cached_err &= ~err;
46 spin_unlock(&rdev->err_lock);
47 }
48
regulator_notifier_isr_work(struct work_struct * work)49 static void regulator_notifier_isr_work(struct work_struct *work)
50 {
51 struct regulator_irq *h;
52 struct regulator_irq_desc *d;
53 struct regulator_irq_data *rid;
54 int ret = 0;
55 int tmo, i;
56 int num_rdevs;
57
58 h = container_of(work, struct regulator_irq,
59 isr_work.work);
60 d = &h->desc;
61 rid = &h->rdata;
62 num_rdevs = rid->num_states;
63
64 reread:
65 if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
66 if (!d->die)
67 return hw_protection_shutdown("Regulator HW failure? - no IC recovery",
68 REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
69 ret = d->die(rid);
70 /*
71 * If the 'last resort' IC recovery failed we will have
72 * nothing else left to do...
73 */
74 if (ret)
75 return hw_protection_shutdown("Regulator HW failure. IC recovery failed",
76 REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
77
78 /*
79 * If h->die() was implemented we assume recovery has been
80 * attempted (probably regulator was shut down) and we
81 * just enable IRQ and bail-out.
82 */
83 goto enable_out;
84 }
85 if (d->renable) {
86 ret = d->renable(rid);
87
88 if (ret == REGULATOR_FAILED_RETRY) {
89 /* Driver could not get current status */
90 h->retry_cnt++;
91 if (!d->reread_ms)
92 goto reread;
93
94 tmo = d->reread_ms;
95 goto reschedule;
96 }
97
98 if (ret) {
99 /*
100 * IC status reading succeeded. update error info
101 * just in case the renable changed it.
102 */
103 for (i = 0; i < num_rdevs; i++) {
104 struct regulator_err_state *stat;
105 struct regulator_dev *rdev;
106
107 stat = &rid->states[i];
108 rdev = stat->rdev;
109 rdev_clear_err(rdev, (~stat->errors) &
110 stat->possible_errs);
111 }
112 h->retry_cnt++;
113 /*
114 * The IC indicated problem is still ON - no point in
115 * re-enabling the IRQ. Retry later.
116 */
117 tmo = d->irq_off_ms;
118 goto reschedule;
119 }
120 }
121
122 /*
123 * Either IC reported problem cleared or no status checker was provided.
124 * If problems are gone - good. If not - then the IRQ will fire again
125 * and we'll have a new nice loop. In any case we should clear error
126 * flags here and re-enable IRQs.
127 */
128 for (i = 0; i < num_rdevs; i++) {
129 struct regulator_err_state *stat;
130 struct regulator_dev *rdev;
131
132 stat = &rid->states[i];
133 rdev = stat->rdev;
134 rdev_clear_err(rdev, stat->possible_errs);
135 }
136
137 /*
138 * Things have been seemingly successful => zero retry-counter.
139 */
140 h->retry_cnt = 0;
141
142 enable_out:
143 enable_irq(h->irq);
144
145 return;
146
147 reschedule:
148 if (!d->high_prio)
149 mod_delayed_work(system_wq, &h->isr_work,
150 msecs_to_jiffies(tmo));
151 else
152 mod_delayed_work(system_highpri_wq, &h->isr_work,
153 msecs_to_jiffies(tmo));
154 }
155
regulator_notifier_isr(int irq,void * data)156 static irqreturn_t regulator_notifier_isr(int irq, void *data)
157 {
158 struct regulator_irq *h = data;
159 struct regulator_irq_desc *d;
160 struct regulator_irq_data *rid;
161 unsigned long rdev_map = 0;
162 int num_rdevs;
163 int ret, i;
164
165 d = &h->desc;
166 rid = &h->rdata;
167 num_rdevs = rid->num_states;
168
169 if (d->fatal_cnt)
170 h->retry_cnt++;
171
172 /*
173 * we spare a few cycles by not clearing statuses prior to this call.
174 * The IC driver must initialize the status buffers for rdevs
175 * which it indicates having active events via rdev_map.
176 *
177 * Maybe we should just to be on a safer side(?)
178 */
179 ret = d->map_event(irq, rid, &rdev_map);
180
181 /*
182 * If status reading fails (which is unlikely) we don't ack/disable
183 * IRQ but just increase fail count and retry when IRQ fires again.
184 * If retry_count exceeds the given safety limit we call IC specific die
185 * handler which can try disabling regulator(s).
186 *
187 * If no die handler is given we will just power-off as a last resort.
188 *
189 * We could try disabling all associated rdevs - but we might shoot
190 * ourselves in the head and leave the problematic regulator enabled. So
191 * if IC has no die-handler populated we just assume the regulator
192 * can't be disabled.
193 */
194 if (unlikely(ret == REGULATOR_FAILED_RETRY))
195 goto fail_out;
196
197 h->retry_cnt = 0;
198 /*
199 * Let's not disable IRQ if there were no status bits for us. We'd
200 * better leave spurious IRQ handling to genirq
201 */
202 if (ret || !rdev_map)
203 return IRQ_NONE;
204
205 /*
206 * Some events are bogus if the regulator is disabled. Skip such events
207 * if all relevant regulators are disabled
208 */
209 if (d->skip_off) {
210 for_each_set_bit(i, &rdev_map, num_rdevs) {
211 struct regulator_dev *rdev;
212 const struct regulator_ops *ops;
213
214 rdev = rid->states[i].rdev;
215 ops = rdev->desc->ops;
216
217 /*
218 * If any of the flagged regulators is enabled we do
219 * handle this
220 */
221 if (ops->is_enabled(rdev))
222 break;
223 }
224 if (i == num_rdevs)
225 return IRQ_NONE;
226 }
227
228 /* Disable IRQ if HW keeps line asserted */
229 if (d->irq_off_ms)
230 disable_irq_nosync(irq);
231
232 /*
233 * IRQ seems to be for us. Let's fire correct notifiers / store error
234 * flags
235 */
236 for_each_set_bit(i, &rdev_map, num_rdevs) {
237 struct regulator_err_state *stat;
238 struct regulator_dev *rdev;
239
240 stat = &rid->states[i];
241 rdev = stat->rdev;
242
243 rdev_dbg(rdev, "Sending regulator notification EVT 0x%lx\n",
244 stat->notifs);
245
246 regulator_notifier_call_chain(rdev, stat->notifs, NULL);
247 rdev_flag_err(rdev, stat->errors);
248 }
249
250 if (d->irq_off_ms) {
251 if (!d->high_prio)
252 schedule_delayed_work(&h->isr_work,
253 msecs_to_jiffies(d->irq_off_ms));
254 else
255 mod_delayed_work(system_highpri_wq,
256 &h->isr_work,
257 msecs_to_jiffies(d->irq_off_ms));
258 }
259
260 return IRQ_HANDLED;
261
262 fail_out:
263 if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
264 /* If we have no recovery, just try shut down straight away */
265 if (!d->die) {
266 hw_protection_shutdown("Regulator failure. Retry count exceeded",
267 REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
268 } else {
269 ret = d->die(rid);
270 /* If die() failed shut down as a last attempt to save the HW */
271 if (ret)
272 hw_protection_shutdown("Regulator failure. Recovery failed",
273 REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
274 }
275 }
276
277 return IRQ_NONE;
278 }
279
init_rdev_state(struct device * dev,struct regulator_irq * h,struct regulator_dev ** rdev,int common_err,int * rdev_err,int rdev_amount)280 static int init_rdev_state(struct device *dev, struct regulator_irq *h,
281 struct regulator_dev **rdev, int common_err,
282 int *rdev_err, int rdev_amount)
283 {
284 int i;
285
286 h->rdata.states = devm_kzalloc(dev, sizeof(*h->rdata.states) *
287 rdev_amount, GFP_KERNEL);
288 if (!h->rdata.states)
289 return -ENOMEM;
290
291 h->rdata.num_states = rdev_amount;
292 h->rdata.data = h->desc.data;
293
294 for (i = 0; i < rdev_amount; i++) {
295 h->rdata.states[i].possible_errs = common_err;
296 if (rdev_err)
297 h->rdata.states[i].possible_errs |= *rdev_err++;
298 h->rdata.states[i].rdev = *rdev++;
299 }
300
301 return 0;
302 }
303
init_rdev_errors(struct regulator_irq * h)304 static void init_rdev_errors(struct regulator_irq *h)
305 {
306 int i;
307
308 for (i = 0; i < h->rdata.num_states; i++)
309 if (h->rdata.states[i].possible_errs)
310 h->rdata.states[i].rdev->use_cached_err = true;
311 }
312
313 /**
314 * regulator_irq_helper - register IRQ based regulator event/error notifier
315 *
316 * @dev: device providing the IRQs
317 * @d: IRQ helper descriptor.
318 * @irq: IRQ used to inform events/errors to be notified.
319 * @irq_flags: Extra IRQ flags to be OR'ed with the default
320 * IRQF_ONESHOT when requesting the (threaded) irq.
321 * @common_errs: Errors which can be flagged by this IRQ for all rdevs.
322 * When IRQ is re-enabled these errors will be cleared
323 * from all associated regulators
324 * @per_rdev_errs: Optional error flag array describing errors specific
325 * for only some of the regulators. These errors will be
326 * or'ed with common errors. If this is given the array
327 * should contain rdev_amount flags. Can be set to NULL
328 * if there is no regulator specific error flags for this
329 * IRQ.
330 * @rdev: Array of pointers to regulators associated with this
331 * IRQ.
332 * @rdev_amount: Amount of regulators associated with this IRQ.
333 *
334 * Return: handle to irq_helper or an ERR_PTR() encoded error code.
335 */
regulator_irq_helper(struct device * dev,const struct regulator_irq_desc * d,int irq,int irq_flags,int common_errs,int * per_rdev_errs,struct regulator_dev ** rdev,int rdev_amount)336 void *regulator_irq_helper(struct device *dev,
337 const struct regulator_irq_desc *d, int irq,
338 int irq_flags, int common_errs, int *per_rdev_errs,
339 struct regulator_dev **rdev, int rdev_amount)
340 {
341 struct regulator_irq *h;
342 int ret;
343
344 if (!rdev_amount || !d || !d->map_event || !d->name)
345 return ERR_PTR(-EINVAL);
346
347 h = devm_kzalloc(dev, sizeof(*h), GFP_KERNEL);
348 if (!h)
349 return ERR_PTR(-ENOMEM);
350
351 h->irq = irq;
352 h->desc = *d;
353
354 ret = init_rdev_state(dev, h, rdev, common_errs, per_rdev_errs,
355 rdev_amount);
356 if (ret)
357 return ERR_PTR(ret);
358
359 init_rdev_errors(h);
360
361 if (h->desc.irq_off_ms)
362 INIT_DELAYED_WORK(&h->isr_work, regulator_notifier_isr_work);
363
364 ret = request_threaded_irq(h->irq, NULL, regulator_notifier_isr,
365 IRQF_ONESHOT | irq_flags, h->desc.name, h);
366 if (ret) {
367 dev_err(dev, "Failed to request IRQ %d\n", irq);
368
369 return ERR_PTR(ret);
370 }
371
372 return h;
373 }
374 EXPORT_SYMBOL_GPL(regulator_irq_helper);
375
376 /**
377 * regulator_irq_helper_cancel - drop IRQ based regulator event/error notifier
378 *
379 * @handle: Pointer to handle returned by a successful call to
380 * regulator_irq_helper(). Will be NULLed upon return.
381 *
382 * The associated IRQ is released and work is cancelled when the function
383 * returns.
384 */
regulator_irq_helper_cancel(void ** handle)385 void regulator_irq_helper_cancel(void **handle)
386 {
387 if (handle && *handle) {
388 struct regulator_irq *h = *handle;
389
390 free_irq(h->irq, h);
391 if (h->desc.irq_off_ms)
392 cancel_delayed_work_sync(&h->isr_work);
393
394 h = NULL;
395 }
396 }
397 EXPORT_SYMBOL_GPL(regulator_irq_helper_cancel);
398