1 // SPDX-License-Identifier: GPL-2.0
2 // RTC driver for ChromeOS Embedded Controller.
4 // Copyright (C) 2017 Google, Inc.
5 // Author: Stephen Barber <smbarber@chromium.org>
7 #include <linux/kernel.h>
8 #include <linux/mfd/cros_ec.h>
9 #include <linux/module.h>
10 #include <linux/platform_data/cros_ec_commands.h>
11 #include <linux/platform_data/cros_ec_proto.h>
12 #include <linux/platform_device.h>
13 #include <linux/rtc.h>
14 #include <linux/slab.h>
16 #define DRV_NAME "cros-ec-rtc"
19 * struct cros_ec_rtc - Driver data for EC RTC
21 * @cros_ec: Pointer to EC device
22 * @rtc: Pointer to RTC device
23 * @notifier: Notifier info for responding to EC events
24 * @saved_alarm: Alarm to restore when interrupts are reenabled
27 struct cros_ec_device *cros_ec;
28 struct rtc_device *rtc;
29 struct notifier_block notifier;
33 static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command,
38 struct cros_ec_command msg;
39 struct ec_response_rtc data;
42 memset(&msg, 0, sizeof(msg));
43 msg.msg.command = command;
44 msg.msg.insize = sizeof(msg.data);
46 ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
49 "error getting %s from EC: %d\n",
50 command == EC_CMD_RTC_GET_VALUE ? "time" : "alarm",
55 *response = msg.data.time;
60 static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command,
65 struct cros_ec_command msg;
66 struct ec_response_rtc data;
69 memset(&msg, 0, sizeof(msg));
70 msg.msg.command = command;
71 msg.msg.outsize = sizeof(msg.data);
72 msg.data.time = param;
74 ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
76 dev_err(cros_ec->dev, "error setting %s on EC: %d\n",
77 command == EC_CMD_RTC_SET_VALUE ? "time" : "alarm",
85 /* Read the current time from the EC. */
86 static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm)
88 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
89 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
93 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time);
95 dev_err(dev, "error getting time: %d\n", ret);
99 rtc_time64_to_tm(time, tm);
104 /* Set the current EC time. */
105 static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm)
107 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
108 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
110 time64_t time = rtc_tm_to_time64(tm);
112 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time);
114 dev_err(dev, "error setting time: %d\n", ret);
121 /* Read alarm time from RTC. */
122 static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
124 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
125 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
127 u32 current_time, alarm_offset;
130 * The EC host command for getting the alarm is relative (i.e. 5
131 * seconds from now) whereas rtc_wkalrm is absolute. Get the current
132 * RTC time first so we can calculate the relative time.
134 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
136 dev_err(dev, "error getting time: %d\n", ret);
140 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset);
142 dev_err(dev, "error getting alarm: %d\n", ret);
146 rtc_time64_to_tm(current_time + alarm_offset, &alrm->time);
151 /* Set the EC's RTC alarm. */
152 static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
154 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
155 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
158 u32 current_time, alarm_offset;
161 * The EC host command for setting the alarm is relative
162 * (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute.
163 * Get the current RTC time first so we can calculate the
166 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
168 dev_err(dev, "error getting time: %d\n", ret);
172 alarm_time = rtc_tm_to_time64(&alrm->time);
174 if (alarm_time < 0 || alarm_time > U32_MAX)
177 if (!alrm->enabled) {
179 * If the alarm is being disabled, send an alarm
182 alarm_offset = EC_RTC_ALARM_CLEAR;
183 cros_ec_rtc->saved_alarm = (u32)alarm_time;
185 /* Don't set an alarm in the past. */
186 if ((u32)alarm_time <= current_time)
189 alarm_offset = (u32)alarm_time - current_time;
192 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset);
194 dev_err(dev, "error setting alarm: %d\n", ret);
201 static int cros_ec_rtc_alarm_irq_enable(struct device *dev,
202 unsigned int enabled)
204 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
205 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
207 u32 current_time, alarm_offset, alarm_value;
209 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
211 dev_err(dev, "error getting time: %d\n", ret);
216 /* Restore saved alarm if it's still in the future. */
217 if (cros_ec_rtc->saved_alarm < current_time)
218 alarm_offset = EC_RTC_ALARM_CLEAR;
220 alarm_offset = cros_ec_rtc->saved_alarm - current_time;
222 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
225 dev_err(dev, "error restoring alarm: %d\n", ret);
229 /* Disable alarm, saving the old alarm value. */
230 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM,
233 dev_err(dev, "error saving alarm: %d\n", ret);
237 alarm_value = current_time + alarm_offset;
240 * If the current EC alarm is already past, we don't want
241 * to set an alarm when we go through the alarm irq enable
244 if (alarm_value < current_time)
245 cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR;
247 cros_ec_rtc->saved_alarm = alarm_value;
249 alarm_offset = EC_RTC_ALARM_CLEAR;
250 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
253 dev_err(dev, "error disabling alarm: %d\n", ret);
261 static int cros_ec_rtc_event(struct notifier_block *nb,
262 unsigned long queued_during_suspend,
265 struct cros_ec_rtc *cros_ec_rtc;
266 struct rtc_device *rtc;
267 struct cros_ec_device *cros_ec;
270 cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier);
271 rtc = cros_ec_rtc->rtc;
272 cros_ec = cros_ec_rtc->cros_ec;
274 host_event = cros_ec_get_host_event(cros_ec);
275 if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) {
276 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
283 static const struct rtc_class_ops cros_ec_rtc_ops = {
284 .read_time = cros_ec_rtc_read_time,
285 .set_time = cros_ec_rtc_set_time,
286 .read_alarm = cros_ec_rtc_read_alarm,
287 .set_alarm = cros_ec_rtc_set_alarm,
288 .alarm_irq_enable = cros_ec_rtc_alarm_irq_enable,
291 #ifdef CONFIG_PM_SLEEP
292 static int cros_ec_rtc_suspend(struct device *dev)
294 struct platform_device *pdev = to_platform_device(dev);
295 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
297 if (device_may_wakeup(dev))
298 return enable_irq_wake(cros_ec_rtc->cros_ec->irq);
303 static int cros_ec_rtc_resume(struct device *dev)
305 struct platform_device *pdev = to_platform_device(dev);
306 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
308 if (device_may_wakeup(dev))
309 return disable_irq_wake(cros_ec_rtc->cros_ec->irq);
315 static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend,
318 static int cros_ec_rtc_probe(struct platform_device *pdev)
320 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
321 struct cros_ec_device *cros_ec = ec_dev->ec_dev;
322 struct cros_ec_rtc *cros_ec_rtc;
326 cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc),
331 platform_set_drvdata(pdev, cros_ec_rtc);
332 cros_ec_rtc->cros_ec = cros_ec;
334 /* Get initial time */
335 ret = cros_ec_rtc_read_time(&pdev->dev, &tm);
337 dev_err(&pdev->dev, "failed to read RTC time\n");
341 ret = device_init_wakeup(&pdev->dev, 1);
343 dev_err(&pdev->dev, "failed to initialize wakeup\n");
347 cros_ec_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
348 if (IS_ERR(cros_ec_rtc->rtc))
349 return PTR_ERR(cros_ec_rtc->rtc);
351 cros_ec_rtc->rtc->ops = &cros_ec_rtc_ops;
352 cros_ec_rtc->rtc->range_max = U32_MAX;
354 ret = rtc_register_device(cros_ec_rtc->rtc);
358 /* Get RTC events from the EC. */
359 cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event;
360 ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
361 &cros_ec_rtc->notifier);
363 dev_err(&pdev->dev, "failed to register notifier\n");
370 static int cros_ec_rtc_remove(struct platform_device *pdev)
372 struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev);
373 struct device *dev = &pdev->dev;
376 ret = blocking_notifier_chain_unregister(
377 &cros_ec_rtc->cros_ec->event_notifier,
378 &cros_ec_rtc->notifier);
380 dev_err(dev, "failed to unregister notifier\n");
387 static struct platform_driver cros_ec_rtc_driver = {
388 .probe = cros_ec_rtc_probe,
389 .remove = cros_ec_rtc_remove,
392 .pm = &cros_ec_rtc_pm_ops,
396 module_platform_driver(cros_ec_rtc_driver);
398 MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
399 MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>");
400 MODULE_LICENSE("GPL v2");
401 MODULE_ALIAS("platform:" DRV_NAME);