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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/module.h>
9#include <linux/platform_data/cros_ec_commands.h>
10#include <linux/platform_data/cros_ec_proto.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 */
25struct 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
32static 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
59static 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. */
85static 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. */
104static 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 = rtc_tm_to_time64(tm);
110
111 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time);
112 if (ret < 0) {
113 dev_err(dev, "error setting time: %d\n", ret);
114 return ret;
115 }
116
117 return 0;
118}
119
120/* Read alarm time from RTC. */
121static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
122{
123 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
124 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
125 int ret;
126 u32 current_time, alarm_offset;
127
128 /*
129 * The EC host command for getting the alarm is relative (i.e. 5
130 * seconds from now) whereas rtc_wkalrm is absolute. Get the current
131 * RTC time first so we can calculate the relative time.
132 */
133 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
134 if (ret < 0) {
135 dev_err(dev, "error getting time: %d\n", ret);
136 return ret;
137 }
138
139 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset);
140 if (ret < 0) {
141 dev_err(dev, "error getting alarm: %d\n", ret);
142 return ret;
143 }
144
145 rtc_time64_to_tm(current_time + alarm_offset, &alrm->time);
146
147 return 0;
148}
149
150/* Set the EC's RTC alarm. */
151static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
152{
153 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
154 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
155 int ret;
156 time64_t alarm_time;
157 u32 current_time, alarm_offset;
158
159 /*
160 * The EC host command for setting the alarm is relative
161 * (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute.
162 * Get the current RTC time first so we can calculate the
163 * relative time.
164 */
165 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
166 if (ret < 0) {
167 dev_err(dev, "error getting time: %d\n", ret);
168 return ret;
169 }
170
171 alarm_time = rtc_tm_to_time64(&alrm->time);
172
173 if (alarm_time < 0 || alarm_time > U32_MAX)
174 return -EINVAL;
175
176 if (!alrm->enabled) {
177 /*
178 * If the alarm is being disabled, send an alarm
179 * clear command.
180 */
181 alarm_offset = EC_RTC_ALARM_CLEAR;
182 cros_ec_rtc->saved_alarm = (u32)alarm_time;
183 } else {
184 /* Don't set an alarm in the past. */
185 if ((u32)alarm_time <= current_time)
186 return -ETIME;
187
188 alarm_offset = (u32)alarm_time - current_time;
189 }
190
191 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset);
192 if (ret < 0) {
193 dev_err(dev, "error setting alarm: %d\n", ret);
194 return ret;
195 }
196
197 return 0;
198}
199
200static int cros_ec_rtc_alarm_irq_enable(struct device *dev,
201 unsigned int enabled)
202{
203 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
204 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
205 int ret;
206 u32 current_time, alarm_offset, alarm_value;
207
208 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
209 if (ret < 0) {
210 dev_err(dev, "error getting time: %d\n", ret);
211 return ret;
212 }
213
214 if (enabled) {
215 /* Restore saved alarm if it's still in the future. */
216 if (cros_ec_rtc->saved_alarm < current_time)
217 alarm_offset = EC_RTC_ALARM_CLEAR;
218 else
219 alarm_offset = cros_ec_rtc->saved_alarm - current_time;
220
221 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
222 alarm_offset);
223 if (ret < 0) {
224 dev_err(dev, "error restoring alarm: %d\n", ret);
225 return ret;
226 }
227 } else {
228 /* Disable alarm, saving the old alarm value. */
229 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM,
230 &alarm_offset);
231 if (ret < 0) {
232 dev_err(dev, "error saving alarm: %d\n", ret);
233 return ret;
234 }
235
236 alarm_value = current_time + alarm_offset;
237
238 /*
239 * If the current EC alarm is already past, we don't want
240 * to set an alarm when we go through the alarm irq enable
241 * path.
242 */
243 if (alarm_value < current_time)
244 cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR;
245 else
246 cros_ec_rtc->saved_alarm = alarm_value;
247
248 alarm_offset = EC_RTC_ALARM_CLEAR;
249 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
250 alarm_offset);
251 if (ret < 0) {
252 dev_err(dev, "error disabling alarm: %d\n", ret);
253 return ret;
254 }
255 }
256
257 return 0;
258}
259
260static int cros_ec_rtc_event(struct notifier_block *nb,
261 unsigned long queued_during_suspend,
262 void *_notify)
263{
264 struct cros_ec_rtc *cros_ec_rtc;
265 struct rtc_device *rtc;
266 struct cros_ec_device *cros_ec;
267 u32 host_event;
268
269 cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier);
270 rtc = cros_ec_rtc->rtc;
271 cros_ec = cros_ec_rtc->cros_ec;
272
273 host_event = cros_ec_get_host_event(cros_ec);
274 if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) {
275 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
276 return NOTIFY_OK;
277 } else {
278 return NOTIFY_DONE;
279 }
280}
281
282static const struct rtc_class_ops cros_ec_rtc_ops = {
283 .read_time = cros_ec_rtc_read_time,
284 .set_time = cros_ec_rtc_set_time,
285 .read_alarm = cros_ec_rtc_read_alarm,
286 .set_alarm = cros_ec_rtc_set_alarm,
287 .alarm_irq_enable = cros_ec_rtc_alarm_irq_enable,
288};
289
290#ifdef CONFIG_PM_SLEEP
291static int cros_ec_rtc_suspend(struct device *dev)
292{
293 struct platform_device *pdev = to_platform_device(dev);
294 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
295
296 if (device_may_wakeup(dev))
297 return enable_irq_wake(cros_ec_rtc->cros_ec->irq);
298
299 return 0;
300}
301
302static int cros_ec_rtc_resume(struct device *dev)
303{
304 struct platform_device *pdev = to_platform_device(dev);
305 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
306
307 if (device_may_wakeup(dev))
308 return disable_irq_wake(cros_ec_rtc->cros_ec->irq);
309
310 return 0;
311}
312#endif
313
314static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend,
315 cros_ec_rtc_resume);
316
317static int cros_ec_rtc_probe(struct platform_device *pdev)
318{
319 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
320 struct cros_ec_device *cros_ec = ec_dev->ec_dev;
321 struct cros_ec_rtc *cros_ec_rtc;
322 struct rtc_time tm;
323 int ret;
324
325 cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc),
326 GFP_KERNEL);
327 if (!cros_ec_rtc)
328 return -ENOMEM;
329
330 platform_set_drvdata(pdev, cros_ec_rtc);
331 cros_ec_rtc->cros_ec = cros_ec;
332
333 /* Get initial time */
334 ret = cros_ec_rtc_read_time(&pdev->dev, &tm);
335 if (ret) {
336 dev_err(&pdev->dev, "failed to read RTC time\n");
337 return ret;
338 }
339
340 ret = device_init_wakeup(&pdev->dev, 1);
341 if (ret) {
342 dev_err(&pdev->dev, "failed to initialize wakeup\n");
343 return ret;
344 }
345
346 cros_ec_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
347 if (IS_ERR(cros_ec_rtc->rtc))
348 return PTR_ERR(cros_ec_rtc->rtc);
349
350 cros_ec_rtc->rtc->ops = &cros_ec_rtc_ops;
351 cros_ec_rtc->rtc->range_max = U32_MAX;
352
353 ret = rtc_register_device(cros_ec_rtc->rtc);
354 if (ret)
355 return ret;
356
357 /* Get RTC events from the EC. */
358 cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event;
359 ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
360 &cros_ec_rtc->notifier);
361 if (ret) {
362 dev_err(&pdev->dev, "failed to register notifier\n");
363 return ret;
364 }
365
366 return 0;
367}
368
369static int cros_ec_rtc_remove(struct platform_device *pdev)
370{
371 struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev);
372 struct device *dev = &pdev->dev;
373 int ret;
374
375 ret = blocking_notifier_chain_unregister(
376 &cros_ec_rtc->cros_ec->event_notifier,
377 &cros_ec_rtc->notifier);
378 if (ret) {
379 dev_err(dev, "failed to unregister notifier\n");
380 return ret;
381 }
382
383 return 0;
384}
385
386static struct platform_driver cros_ec_rtc_driver = {
387 .probe = cros_ec_rtc_probe,
388 .remove = cros_ec_rtc_remove,
389 .driver = {
390 .name = DRV_NAME,
391 .pm = &cros_ec_rtc_pm_ops,
392 },
393};
394
395module_platform_driver(cros_ec_rtc_driver);
396
397MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
398MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>");
399MODULE_LICENSE("GPL v2");
400MODULE_ALIAS("platform:" DRV_NAME);