1 // SPDX-License-Identifier: GPL-2.0
2 // RTC driver for ChromeOS Embedded Controller.
3 //
4 // Copyright (C) 2017 Google, Inc.
5 // Author: Stephen Barber <smbarber@chromium.org>
6
7 #include <linux/kernel.h>
8 #include <linux/mfd/cros_ec.h>
9 #include <linux/mfd/cros_ec_commands.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/rtc.h>
13 #include <linux/slab.h>
14
15 #define DRV_NAME "cros-ec-rtc"
16
17 /**
18 * struct cros_ec_rtc - Driver data for EC RTC
19 *
20 * @cros_ec: Pointer to EC device
21 * @rtc: Pointer to RTC device
22 * @notifier: Notifier info for responding to EC events
23 * @saved_alarm: Alarm to restore when interrupts are reenabled
24 */
25 struct cros_ec_rtc {
26 struct cros_ec_device *cros_ec;
27 struct rtc_device *rtc;
28 struct notifier_block notifier;
29 u32 saved_alarm;
30 };
31
cros_ec_rtc_get(struct cros_ec_device * cros_ec,u32 command,u32 * response)32 static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command,
33 u32 *response)
34 {
35 int ret;
36 struct {
37 struct cros_ec_command msg;
38 struct ec_response_rtc data;
39 } __packed msg;
40
41 memset(&msg, 0, sizeof(msg));
42 msg.msg.command = command;
43 msg.msg.insize = sizeof(msg.data);
44
45 ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
46 if (ret < 0) {
47 dev_err(cros_ec->dev,
48 "error getting %s from EC: %d\n",
49 command == EC_CMD_RTC_GET_VALUE ? "time" : "alarm",
50 ret);
51 return ret;
52 }
53
54 *response = msg.data.time;
55
56 return 0;
57 }
58
cros_ec_rtc_set(struct cros_ec_device * cros_ec,u32 command,u32 param)59 static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command,
60 u32 param)
61 {
62 int ret = 0;
63 struct {
64 struct cros_ec_command msg;
65 struct ec_response_rtc data;
66 } __packed msg;
67
68 memset(&msg, 0, sizeof(msg));
69 msg.msg.command = command;
70 msg.msg.outsize = sizeof(msg.data);
71 msg.data.time = param;
72
73 ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
74 if (ret < 0) {
75 dev_err(cros_ec->dev, "error setting %s on EC: %d\n",
76 command == EC_CMD_RTC_SET_VALUE ? "time" : "alarm",
77 ret);
78 return ret;
79 }
80
81 return 0;
82 }
83
84 /* Read the current time from the EC. */
cros_ec_rtc_read_time(struct device * dev,struct rtc_time * tm)85 static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm)
86 {
87 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
88 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
89 int ret;
90 u32 time;
91
92 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time);
93 if (ret) {
94 dev_err(dev, "error getting time: %d\n", ret);
95 return ret;
96 }
97
98 rtc_time64_to_tm(time, tm);
99
100 return 0;
101 }
102
103 /* Set the current EC time. */
cros_ec_rtc_set_time(struct device * dev,struct rtc_time * tm)104 static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm)
105 {
106 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
107 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
108 int ret;
109 time64_t time;
110
111 time = rtc_tm_to_time64(tm);
112 if (time < 0 || time > U32_MAX)
113 return -EINVAL;
114
115 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time);
116 if (ret < 0) {
117 dev_err(dev, "error setting time: %d\n", ret);
118 return ret;
119 }
120
121 return 0;
122 }
123
124 /* Read alarm time from RTC. */
cros_ec_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)125 static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
126 {
127 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
128 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
129 int ret;
130 u32 current_time, alarm_offset;
131
132 /*
133 * The EC host command for getting the alarm is relative (i.e. 5
134 * seconds from now) whereas rtc_wkalrm is absolute. Get the current
135 * RTC time first so we can calculate the relative time.
136 */
137 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
138 if (ret < 0) {
139 dev_err(dev, "error getting time: %d\n", ret);
140 return ret;
141 }
142
143 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset);
144 if (ret < 0) {
145 dev_err(dev, "error getting alarm: %d\n", ret);
146 return ret;
147 }
148
149 rtc_time64_to_tm(current_time + alarm_offset, &alrm->time);
150
151 return 0;
152 }
153
154 /* Set the EC's RTC alarm. */
cros_ec_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)155 static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
156 {
157 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
158 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
159 int ret;
160 time64_t alarm_time;
161 u32 current_time, alarm_offset;
162
163 /*
164 * The EC host command for setting the alarm is relative
165 * (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute.
166 * Get the current RTC time first so we can calculate the
167 * relative time.
168 */
169 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
170 if (ret < 0) {
171 dev_err(dev, "error getting time: %d\n", ret);
172 return ret;
173 }
174
175 alarm_time = rtc_tm_to_time64(&alrm->time);
176
177 if (alarm_time < 0 || alarm_time > U32_MAX)
178 return -EINVAL;
179
180 if (!alrm->enabled) {
181 /*
182 * If the alarm is being disabled, send an alarm
183 * clear command.
184 */
185 alarm_offset = EC_RTC_ALARM_CLEAR;
186 cros_ec_rtc->saved_alarm = (u32)alarm_time;
187 } else {
188 /* Don't set an alarm in the past. */
189 if ((u32)alarm_time <= current_time)
190 return -ETIME;
191
192 alarm_offset = (u32)alarm_time - current_time;
193 }
194
195 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset);
196 if (ret < 0) {
197 dev_err(dev, "error setting alarm: %d\n", ret);
198 return ret;
199 }
200
201 return 0;
202 }
203
cros_ec_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)204 static int cros_ec_rtc_alarm_irq_enable(struct device *dev,
205 unsigned int enabled)
206 {
207 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
208 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
209 int ret;
210 u32 current_time, alarm_offset, alarm_value;
211
212 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
213 if (ret < 0) {
214 dev_err(dev, "error getting time: %d\n", ret);
215 return ret;
216 }
217
218 if (enabled) {
219 /* Restore saved alarm if it's still in the future. */
220 if (cros_ec_rtc->saved_alarm < current_time)
221 alarm_offset = EC_RTC_ALARM_CLEAR;
222 else
223 alarm_offset = cros_ec_rtc->saved_alarm - current_time;
224
225 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
226 alarm_offset);
227 if (ret < 0) {
228 dev_err(dev, "error restoring alarm: %d\n", ret);
229 return ret;
230 }
231 } else {
232 /* Disable alarm, saving the old alarm value. */
233 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM,
234 &alarm_offset);
235 if (ret < 0) {
236 dev_err(dev, "error saving alarm: %d\n", ret);
237 return ret;
238 }
239
240 alarm_value = current_time + alarm_offset;
241
242 /*
243 * If the current EC alarm is already past, we don't want
244 * to set an alarm when we go through the alarm irq enable
245 * path.
246 */
247 if (alarm_value < current_time)
248 cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR;
249 else
250 cros_ec_rtc->saved_alarm = alarm_value;
251
252 alarm_offset = EC_RTC_ALARM_CLEAR;
253 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
254 alarm_offset);
255 if (ret < 0) {
256 dev_err(dev, "error disabling alarm: %d\n", ret);
257 return ret;
258 }
259 }
260
261 return 0;
262 }
263
cros_ec_rtc_event(struct notifier_block * nb,unsigned long queued_during_suspend,void * _notify)264 static int cros_ec_rtc_event(struct notifier_block *nb,
265 unsigned long queued_during_suspend,
266 void *_notify)
267 {
268 struct cros_ec_rtc *cros_ec_rtc;
269 struct rtc_device *rtc;
270 struct cros_ec_device *cros_ec;
271 u32 host_event;
272
273 cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier);
274 rtc = cros_ec_rtc->rtc;
275 cros_ec = cros_ec_rtc->cros_ec;
276
277 host_event = cros_ec_get_host_event(cros_ec);
278 if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) {
279 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
280 return NOTIFY_OK;
281 } else {
282 return NOTIFY_DONE;
283 }
284 }
285
286 static const struct rtc_class_ops cros_ec_rtc_ops = {
287 .read_time = cros_ec_rtc_read_time,
288 .set_time = cros_ec_rtc_set_time,
289 .read_alarm = cros_ec_rtc_read_alarm,
290 .set_alarm = cros_ec_rtc_set_alarm,
291 .alarm_irq_enable = cros_ec_rtc_alarm_irq_enable,
292 };
293
294 #ifdef CONFIG_PM_SLEEP
cros_ec_rtc_suspend(struct device * dev)295 static int cros_ec_rtc_suspend(struct device *dev)
296 {
297 struct platform_device *pdev = to_platform_device(dev);
298 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
299
300 if (device_may_wakeup(dev))
301 return enable_irq_wake(cros_ec_rtc->cros_ec->irq);
302
303 return 0;
304 }
305
cros_ec_rtc_resume(struct device * dev)306 static int cros_ec_rtc_resume(struct device *dev)
307 {
308 struct platform_device *pdev = to_platform_device(dev);
309 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
310
311 if (device_may_wakeup(dev))
312 return disable_irq_wake(cros_ec_rtc->cros_ec->irq);
313
314 return 0;
315 }
316 #endif
317
318 static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend,
319 cros_ec_rtc_resume);
320
cros_ec_rtc_probe(struct platform_device * pdev)321 static int cros_ec_rtc_probe(struct platform_device *pdev)
322 {
323 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
324 struct cros_ec_device *cros_ec = ec_dev->ec_dev;
325 struct cros_ec_rtc *cros_ec_rtc;
326 struct rtc_time tm;
327 int ret;
328
329 cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc),
330 GFP_KERNEL);
331 if (!cros_ec_rtc)
332 return -ENOMEM;
333
334 platform_set_drvdata(pdev, cros_ec_rtc);
335 cros_ec_rtc->cros_ec = cros_ec;
336
337 /* Get initial time */
338 ret = cros_ec_rtc_read_time(&pdev->dev, &tm);
339 if (ret) {
340 dev_err(&pdev->dev, "failed to read RTC time\n");
341 return ret;
342 }
343
344 ret = device_init_wakeup(&pdev->dev, 1);
345 if (ret) {
346 dev_err(&pdev->dev, "failed to initialize wakeup\n");
347 return ret;
348 }
349
350 cros_ec_rtc->rtc = devm_rtc_device_register(&pdev->dev, DRV_NAME,
351 &cros_ec_rtc_ops,
352 THIS_MODULE);
353 if (IS_ERR(cros_ec_rtc->rtc)) {
354 ret = PTR_ERR(cros_ec_rtc->rtc);
355 dev_err(&pdev->dev, "failed to register rtc device\n");
356 return ret;
357 }
358
359 /* Get RTC events from the EC. */
360 cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event;
361 ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
362 &cros_ec_rtc->notifier);
363 if (ret) {
364 dev_err(&pdev->dev, "failed to register notifier\n");
365 return ret;
366 }
367
368 return 0;
369 }
370
cros_ec_rtc_remove(struct platform_device * pdev)371 static int cros_ec_rtc_remove(struct platform_device *pdev)
372 {
373 struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev);
374 struct device *dev = &pdev->dev;
375 int ret;
376
377 ret = blocking_notifier_chain_unregister(
378 &cros_ec_rtc->cros_ec->event_notifier,
379 &cros_ec_rtc->notifier);
380 if (ret) {
381 dev_err(dev, "failed to unregister notifier\n");
382 return ret;
383 }
384
385 return 0;
386 }
387
388 static struct platform_driver cros_ec_rtc_driver = {
389 .probe = cros_ec_rtc_probe,
390 .remove = cros_ec_rtc_remove,
391 .driver = {
392 .name = DRV_NAME,
393 .pm = &cros_ec_rtc_pm_ops,
394 },
395 };
396
397 module_platform_driver(cros_ec_rtc_driver);
398
399 MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
400 MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>");
401 MODULE_LICENSE("GPL v2");
402 MODULE_ALIAS("platform:" DRV_NAME);
403