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8ee4aee5 EBS |
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> | |
6f2a71a3 SB |
6 | |
7 | #include <linux/kernel.h> | |
6f2a71a3 | 8 | #include <linux/module.h> |
840d9f13 EBS |
9 | #include <linux/platform_data/cros_ec_commands.h> |
10 | #include <linux/platform_data/cros_ec_proto.h> | |
6f2a71a3 SB |
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 | ||
f27efee6 GR |
17 | #define SECS_PER_DAY (24 * 60 * 60) |
18 | ||
6f2a71a3 SB |
19 | /** |
20 | * struct cros_ec_rtc - Driver data for EC RTC | |
21 | * | |
22 | * @cros_ec: Pointer to EC device | |
23 | * @rtc: Pointer to RTC device | |
24 | * @notifier: Notifier info for responding to EC events | |
25 | * @saved_alarm: Alarm to restore when interrupts are reenabled | |
26 | */ | |
27 | struct cros_ec_rtc { | |
28 | struct cros_ec_device *cros_ec; | |
29 | struct rtc_device *rtc; | |
30 | struct notifier_block notifier; | |
31 | u32 saved_alarm; | |
32 | }; | |
33 | ||
34 | static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command, | |
35 | u32 *response) | |
36 | { | |
37 | int ret; | |
38 | struct { | |
39 | struct cros_ec_command msg; | |
40 | struct ec_response_rtc data; | |
41 | } __packed msg; | |
42 | ||
43 | memset(&msg, 0, sizeof(msg)); | |
44 | msg.msg.command = command; | |
45 | msg.msg.insize = sizeof(msg.data); | |
46 | ||
47 | ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg); | |
f27efee6 | 48 | if (ret < 0) |
6f2a71a3 | 49 | return ret; |
6f2a71a3 SB |
50 | |
51 | *response = msg.data.time; | |
52 | ||
53 | return 0; | |
54 | } | |
55 | ||
56 | static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command, | |
57 | u32 param) | |
58 | { | |
f27efee6 | 59 | int ret; |
6f2a71a3 SB |
60 | struct { |
61 | struct cros_ec_command msg; | |
62 | struct ec_response_rtc data; | |
63 | } __packed msg; | |
64 | ||
65 | memset(&msg, 0, sizeof(msg)); | |
66 | msg.msg.command = command; | |
67 | msg.msg.outsize = sizeof(msg.data); | |
68 | msg.data.time = param; | |
69 | ||
70 | ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg); | |
f27efee6 | 71 | if (ret < 0) |
6f2a71a3 | 72 | return ret; |
6f2a71a3 SB |
73 | return 0; |
74 | } | |
75 | ||
76 | /* Read the current time from the EC. */ | |
77 | static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
78 | { | |
79 | struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | |
80 | struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | |
81 | int ret; | |
82 | u32 time; | |
83 | ||
84 | ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time); | |
85 | if (ret) { | |
86 | dev_err(dev, "error getting time: %d\n", ret); | |
87 | return ret; | |
88 | } | |
89 | ||
90 | rtc_time64_to_tm(time, tm); | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | /* Set the current EC time. */ | |
96 | static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
97 | { | |
98 | struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | |
99 | struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | |
100 | int ret; | |
0e843137 | 101 | time64_t time = rtc_tm_to_time64(tm); |
6f2a71a3 SB |
102 | |
103 | ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time); | |
104 | if (ret < 0) { | |
105 | dev_err(dev, "error setting time: %d\n", ret); | |
106 | return ret; | |
107 | } | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
112 | /* Read alarm time from RTC. */ | |
113 | static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) | |
114 | { | |
115 | struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | |
116 | struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | |
117 | int ret; | |
118 | u32 current_time, alarm_offset; | |
119 | ||
120 | /* | |
121 | * The EC host command for getting the alarm is relative (i.e. 5 | |
122 | * seconds from now) whereas rtc_wkalrm is absolute. Get the current | |
123 | * RTC time first so we can calculate the relative time. | |
124 | */ | |
125 | ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); | |
126 | if (ret < 0) { | |
127 | dev_err(dev, "error getting time: %d\n", ret); | |
128 | return ret; | |
129 | } | |
130 | ||
131 | ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset); | |
132 | if (ret < 0) { | |
133 | dev_err(dev, "error getting alarm: %d\n", ret); | |
134 | return ret; | |
135 | } | |
136 | ||
137 | rtc_time64_to_tm(current_time + alarm_offset, &alrm->time); | |
138 | ||
139 | return 0; | |
140 | } | |
141 | ||
142 | /* Set the EC's RTC alarm. */ | |
143 | static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) | |
144 | { | |
145 | struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | |
146 | struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | |
147 | int ret; | |
148 | time64_t alarm_time; | |
149 | u32 current_time, alarm_offset; | |
150 | ||
151 | /* | |
152 | * The EC host command for setting the alarm is relative | |
153 | * (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute. | |
154 | * Get the current RTC time first so we can calculate the | |
155 | * relative time. | |
156 | */ | |
157 | ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); | |
158 | if (ret < 0) { | |
159 | dev_err(dev, "error getting time: %d\n", ret); | |
160 | return ret; | |
161 | } | |
162 | ||
163 | alarm_time = rtc_tm_to_time64(&alrm->time); | |
164 | ||
165 | if (alarm_time < 0 || alarm_time > U32_MAX) | |
166 | return -EINVAL; | |
167 | ||
168 | if (!alrm->enabled) { | |
169 | /* | |
170 | * If the alarm is being disabled, send an alarm | |
171 | * clear command. | |
172 | */ | |
173 | alarm_offset = EC_RTC_ALARM_CLEAR; | |
174 | cros_ec_rtc->saved_alarm = (u32)alarm_time; | |
175 | } else { | |
176 | /* Don't set an alarm in the past. */ | |
72dd71f0 JC |
177 | if ((u32)alarm_time <= current_time) |
178 | return -ETIME; | |
179 | ||
180 | alarm_offset = (u32)alarm_time - current_time; | |
6f2a71a3 SB |
181 | } |
182 | ||
183 | ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset); | |
184 | if (ret < 0) { | |
f27efee6 GR |
185 | if (ret == -EINVAL && alarm_offset >= SECS_PER_DAY) { |
186 | /* | |
187 | * RTC chips on some older Chromebooks can only handle | |
188 | * alarms up to 24h in the future. Try to set an alarm | |
189 | * below that limit to avoid suspend failures. | |
190 | */ | |
191 | ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, | |
192 | SECS_PER_DAY - 1); | |
193 | } | |
194 | ||
195 | if (ret < 0) { | |
196 | dev_err(dev, "error setting alarm in %u seconds: %d\n", | |
197 | alarm_offset, ret); | |
198 | return ret; | |
199 | } | |
6f2a71a3 SB |
200 | } |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
205 | static int cros_ec_rtc_alarm_irq_enable(struct device *dev, | |
206 | unsigned int enabled) | |
207 | { | |
208 | struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | |
209 | struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | |
210 | int ret; | |
211 | u32 current_time, alarm_offset, alarm_value; | |
212 | ||
213 | ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); | |
214 | if (ret < 0) { | |
215 | dev_err(dev, "error getting time: %d\n", ret); | |
216 | return ret; | |
217 | } | |
218 | ||
219 | if (enabled) { | |
220 | /* Restore saved alarm if it's still in the future. */ | |
221 | if (cros_ec_rtc->saved_alarm < current_time) | |
222 | alarm_offset = EC_RTC_ALARM_CLEAR; | |
223 | else | |
224 | alarm_offset = cros_ec_rtc->saved_alarm - current_time; | |
225 | ||
226 | ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, | |
227 | alarm_offset); | |
228 | if (ret < 0) { | |
229 | dev_err(dev, "error restoring alarm: %d\n", ret); | |
230 | return ret; | |
231 | } | |
232 | } else { | |
233 | /* Disable alarm, saving the old alarm value. */ | |
234 | ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, | |
235 | &alarm_offset); | |
236 | if (ret < 0) { | |
237 | dev_err(dev, "error saving alarm: %d\n", ret); | |
238 | return ret; | |
239 | } | |
240 | ||
241 | alarm_value = current_time + alarm_offset; | |
242 | ||
243 | /* | |
244 | * If the current EC alarm is already past, we don't want | |
245 | * to set an alarm when we go through the alarm irq enable | |
246 | * path. | |
247 | */ | |
248 | if (alarm_value < current_time) | |
249 | cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR; | |
250 | else | |
251 | cros_ec_rtc->saved_alarm = alarm_value; | |
252 | ||
253 | alarm_offset = EC_RTC_ALARM_CLEAR; | |
254 | ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, | |
255 | alarm_offset); | |
256 | if (ret < 0) { | |
257 | dev_err(dev, "error disabling alarm: %d\n", ret); | |
258 | return ret; | |
259 | } | |
260 | } | |
261 | ||
262 | return 0; | |
263 | } | |
264 | ||
265 | static int cros_ec_rtc_event(struct notifier_block *nb, | |
266 | unsigned long queued_during_suspend, | |
267 | void *_notify) | |
268 | { | |
269 | struct cros_ec_rtc *cros_ec_rtc; | |
270 | struct rtc_device *rtc; | |
271 | struct cros_ec_device *cros_ec; | |
272 | u32 host_event; | |
273 | ||
274 | cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier); | |
275 | rtc = cros_ec_rtc->rtc; | |
276 | cros_ec = cros_ec_rtc->cros_ec; | |
277 | ||
278 | host_event = cros_ec_get_host_event(cros_ec); | |
279 | if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) { | |
280 | rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF); | |
281 | return NOTIFY_OK; | |
282 | } else { | |
283 | return NOTIFY_DONE; | |
284 | } | |
285 | } | |
286 | ||
287 | static const struct rtc_class_ops cros_ec_rtc_ops = { | |
288 | .read_time = cros_ec_rtc_read_time, | |
289 | .set_time = cros_ec_rtc_set_time, | |
290 | .read_alarm = cros_ec_rtc_read_alarm, | |
291 | .set_alarm = cros_ec_rtc_set_alarm, | |
292 | .alarm_irq_enable = cros_ec_rtc_alarm_irq_enable, | |
293 | }; | |
294 | ||
295 | #ifdef CONFIG_PM_SLEEP | |
296 | static int cros_ec_rtc_suspend(struct device *dev) | |
297 | { | |
298 | struct platform_device *pdev = to_platform_device(dev); | |
299 | struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev); | |
300 | ||
301 | if (device_may_wakeup(dev)) | |
d6752e18 | 302 | return enable_irq_wake(cros_ec_rtc->cros_ec->irq); |
6f2a71a3 SB |
303 | |
304 | return 0; | |
305 | } | |
306 | ||
307 | static int cros_ec_rtc_resume(struct device *dev) | |
308 | { | |
309 | struct platform_device *pdev = to_platform_device(dev); | |
310 | struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev); | |
311 | ||
312 | if (device_may_wakeup(dev)) | |
d6752e18 | 313 | return disable_irq_wake(cros_ec_rtc->cros_ec->irq); |
6f2a71a3 SB |
314 | |
315 | return 0; | |
316 | } | |
317 | #endif | |
318 | ||
319 | static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend, | |
320 | cros_ec_rtc_resume); | |
321 | ||
322 | static int cros_ec_rtc_probe(struct platform_device *pdev) | |
323 | { | |
324 | struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent); | |
325 | struct cros_ec_device *cros_ec = ec_dev->ec_dev; | |
326 | struct cros_ec_rtc *cros_ec_rtc; | |
327 | struct rtc_time tm; | |
328 | int ret; | |
329 | ||
330 | cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc), | |
331 | GFP_KERNEL); | |
332 | if (!cros_ec_rtc) | |
333 | return -ENOMEM; | |
334 | ||
335 | platform_set_drvdata(pdev, cros_ec_rtc); | |
336 | cros_ec_rtc->cros_ec = cros_ec; | |
337 | ||
338 | /* Get initial time */ | |
339 | ret = cros_ec_rtc_read_time(&pdev->dev, &tm); | |
340 | if (ret) { | |
341 | dev_err(&pdev->dev, "failed to read RTC time\n"); | |
342 | return ret; | |
343 | } | |
344 | ||
345 | ret = device_init_wakeup(&pdev->dev, 1); | |
346 | if (ret) { | |
347 | dev_err(&pdev->dev, "failed to initialize wakeup\n"); | |
348 | return ret; | |
349 | } | |
350 | ||
0e843137 | 351 | cros_ec_rtc->rtc = devm_rtc_allocate_device(&pdev->dev); |
4fc0d13f AB |
352 | if (IS_ERR(cros_ec_rtc->rtc)) |
353 | return PTR_ERR(cros_ec_rtc->rtc); | |
6f2a71a3 | 354 | |
0e843137 AB |
355 | cros_ec_rtc->rtc->ops = &cros_ec_rtc_ops; |
356 | cros_ec_rtc->rtc->range_max = U32_MAX; | |
357 | ||
fdcfd854 | 358 | ret = devm_rtc_register_device(cros_ec_rtc->rtc); |
0e843137 AB |
359 | if (ret) |
360 | return ret; | |
361 | ||
6f2a71a3 SB |
362 | /* Get RTC events from the EC. */ |
363 | cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event; | |
364 | ret = blocking_notifier_chain_register(&cros_ec->event_notifier, | |
365 | &cros_ec_rtc->notifier); | |
366 | if (ret) { | |
367 | dev_err(&pdev->dev, "failed to register notifier\n"); | |
368 | return ret; | |
369 | } | |
370 | ||
371 | return 0; | |
372 | } | |
373 | ||
374 | static int cros_ec_rtc_remove(struct platform_device *pdev) | |
375 | { | |
376 | struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev); | |
377 | struct device *dev = &pdev->dev; | |
378 | int ret; | |
379 | ||
380 | ret = blocking_notifier_chain_unregister( | |
381 | &cros_ec_rtc->cros_ec->event_notifier, | |
382 | &cros_ec_rtc->notifier); | |
5c9f4144 | 383 | if (ret) |
6f2a71a3 | 384 | dev_err(dev, "failed to unregister notifier\n"); |
6f2a71a3 SB |
385 | |
386 | return 0; | |
387 | } | |
388 | ||
389 | static struct platform_driver cros_ec_rtc_driver = { | |
390 | .probe = cros_ec_rtc_probe, | |
391 | .remove = cros_ec_rtc_remove, | |
392 | .driver = { | |
393 | .name = DRV_NAME, | |
394 | .pm = &cros_ec_rtc_pm_ops, | |
395 | }, | |
396 | }; | |
397 | ||
398 | module_platform_driver(cros_ec_rtc_driver); | |
399 | ||
400 | MODULE_DESCRIPTION("RTC driver for Chrome OS ECs"); | |
401 | MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>"); | |
e6988d23 | 402 | MODULE_LICENSE("GPL v2"); |
6f2a71a3 | 403 | MODULE_ALIAS("platform:" DRV_NAME); |