| // SPDX-License-Identifier: GPL-2.0 | 
 | // RTC driver for ChromeOS Embedded Controller. | 
 | // | 
 | // Copyright (C) 2017 Google, Inc. | 
 | // Author: Stephen Barber <smbarber@chromium.org> | 
 |  | 
 | #include <linux/kernel.h> | 
 | #include <linux/mfd/cros_ec.h> | 
 | #include <linux/mfd/cros_ec_commands.h> | 
 | #include <linux/module.h> | 
 | #include <linux/platform_device.h> | 
 | #include <linux/rtc.h> | 
 | #include <linux/slab.h> | 
 |  | 
 | #define DRV_NAME	"cros-ec-rtc" | 
 |  | 
 | /** | 
 |  * struct cros_ec_rtc - Driver data for EC RTC | 
 |  * | 
 |  * @cros_ec: Pointer to EC device | 
 |  * @rtc: Pointer to RTC device | 
 |  * @notifier: Notifier info for responding to EC events | 
 |  * @saved_alarm: Alarm to restore when interrupts are reenabled | 
 |  */ | 
 | struct cros_ec_rtc { | 
 | 	struct cros_ec_device *cros_ec; | 
 | 	struct rtc_device *rtc; | 
 | 	struct notifier_block notifier; | 
 | 	u32 saved_alarm; | 
 | }; | 
 |  | 
 | static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command, | 
 | 			   u32 *response) | 
 | { | 
 | 	int ret; | 
 | 	struct { | 
 | 		struct cros_ec_command msg; | 
 | 		struct ec_response_rtc data; | 
 | 	} __packed msg; | 
 |  | 
 | 	memset(&msg, 0, sizeof(msg)); | 
 | 	msg.msg.command = command; | 
 | 	msg.msg.insize = sizeof(msg.data); | 
 |  | 
 | 	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg); | 
 | 	if (ret < 0) { | 
 | 		dev_err(cros_ec->dev, | 
 | 			"error getting %s from EC: %d\n", | 
 | 			command == EC_CMD_RTC_GET_VALUE ? "time" : "alarm", | 
 | 			ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	*response = msg.data.time; | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command, | 
 | 			   u32 param) | 
 | { | 
 | 	int ret = 0; | 
 | 	struct { | 
 | 		struct cros_ec_command msg; | 
 | 		struct ec_response_rtc data; | 
 | 	} __packed msg; | 
 |  | 
 | 	memset(&msg, 0, sizeof(msg)); | 
 | 	msg.msg.command = command; | 
 | 	msg.msg.outsize = sizeof(msg.data); | 
 | 	msg.data.time = param; | 
 |  | 
 | 	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg); | 
 | 	if (ret < 0) { | 
 | 		dev_err(cros_ec->dev, "error setting %s on EC: %d\n", | 
 | 			command == EC_CMD_RTC_SET_VALUE ? "time" : "alarm", | 
 | 			ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | /* Read the current time from the EC. */ | 
 | static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm) | 
 | { | 
 | 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | 
 | 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | 
 | 	int ret; | 
 | 	u32 time; | 
 |  | 
 | 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time); | 
 | 	if (ret) { | 
 | 		dev_err(dev, "error getting time: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	rtc_time64_to_tm(time, tm); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | /* Set the current EC time. */ | 
 | static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm) | 
 | { | 
 | 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | 
 | 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | 
 | 	int ret; | 
 | 	time64_t time; | 
 |  | 
 | 	time = rtc_tm_to_time64(tm); | 
 | 	if (time < 0 || time > U32_MAX) | 
 | 		return -EINVAL; | 
 |  | 
 | 	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time); | 
 | 	if (ret < 0) { | 
 | 		dev_err(dev, "error setting time: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | /* Read alarm time from RTC. */ | 
 | static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) | 
 | { | 
 | 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | 
 | 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | 
 | 	int ret; | 
 | 	u32 current_time, alarm_offset; | 
 |  | 
 | 	/* | 
 | 	 * The EC host command for getting the alarm is relative (i.e. 5 | 
 | 	 * seconds from now) whereas rtc_wkalrm is absolute. Get the current | 
 | 	 * RTC time first so we can calculate the relative time. | 
 | 	 */ | 
 | 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); | 
 | 	if (ret < 0) { | 
 | 		dev_err(dev, "error getting time: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset); | 
 | 	if (ret < 0) { | 
 | 		dev_err(dev, "error getting alarm: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	rtc_time64_to_tm(current_time + alarm_offset, &alrm->time); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | /* Set the EC's RTC alarm. */ | 
 | static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) | 
 | { | 
 | 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | 
 | 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | 
 | 	int ret; | 
 | 	time64_t alarm_time; | 
 | 	u32 current_time, alarm_offset; | 
 |  | 
 | 	/* | 
 | 	 * The EC host command for setting the alarm is relative | 
 | 	 * (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute. | 
 | 	 * Get the current RTC time first so we can calculate the | 
 | 	 * relative time. | 
 | 	 */ | 
 | 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); | 
 | 	if (ret < 0) { | 
 | 		dev_err(dev, "error getting time: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	alarm_time = rtc_tm_to_time64(&alrm->time); | 
 |  | 
 | 	if (alarm_time < 0 || alarm_time > U32_MAX) | 
 | 		return -EINVAL; | 
 |  | 
 | 	if (!alrm->enabled) { | 
 | 		/* | 
 | 		 * If the alarm is being disabled, send an alarm | 
 | 		 * clear command. | 
 | 		 */ | 
 | 		alarm_offset = EC_RTC_ALARM_CLEAR; | 
 | 		cros_ec_rtc->saved_alarm = (u32)alarm_time; | 
 | 	} else { | 
 | 		/* Don't set an alarm in the past. */ | 
 | 		if ((u32)alarm_time <= current_time) | 
 | 			return -ETIME; | 
 |  | 
 | 		alarm_offset = (u32)alarm_time - current_time; | 
 | 	} | 
 |  | 
 | 	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset); | 
 | 	if (ret < 0) { | 
 | 		dev_err(dev, "error setting alarm: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int cros_ec_rtc_alarm_irq_enable(struct device *dev, | 
 | 					unsigned int enabled) | 
 | { | 
 | 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); | 
 | 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; | 
 | 	int ret; | 
 | 	u32 current_time, alarm_offset, alarm_value; | 
 |  | 
 | 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); | 
 | 	if (ret < 0) { | 
 | 		dev_err(dev, "error getting time: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	if (enabled) { | 
 | 		/* Restore saved alarm if it's still in the future. */ | 
 | 		if (cros_ec_rtc->saved_alarm < current_time) | 
 | 			alarm_offset = EC_RTC_ALARM_CLEAR; | 
 | 		else | 
 | 			alarm_offset = cros_ec_rtc->saved_alarm - current_time; | 
 |  | 
 | 		ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, | 
 | 				      alarm_offset); | 
 | 		if (ret < 0) { | 
 | 			dev_err(dev, "error restoring alarm: %d\n", ret); | 
 | 			return ret; | 
 | 		} | 
 | 	} else { | 
 | 		/* Disable alarm, saving the old alarm value. */ | 
 | 		ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, | 
 | 				      &alarm_offset); | 
 | 		if (ret < 0) { | 
 | 			dev_err(dev, "error saving alarm: %d\n", ret); | 
 | 			return ret; | 
 | 		} | 
 |  | 
 | 		alarm_value = current_time + alarm_offset; | 
 |  | 
 | 		/* | 
 | 		 * If the current EC alarm is already past, we don't want | 
 | 		 * to set an alarm when we go through the alarm irq enable | 
 | 		 * path. | 
 | 		 */ | 
 | 		if (alarm_value < current_time) | 
 | 			cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR; | 
 | 		else | 
 | 			cros_ec_rtc->saved_alarm = alarm_value; | 
 |  | 
 | 		alarm_offset = EC_RTC_ALARM_CLEAR; | 
 | 		ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, | 
 | 				      alarm_offset); | 
 | 		if (ret < 0) { | 
 | 			dev_err(dev, "error disabling alarm: %d\n", ret); | 
 | 			return ret; | 
 | 		} | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int cros_ec_rtc_event(struct notifier_block *nb, | 
 | 			     unsigned long queued_during_suspend, | 
 | 			     void *_notify) | 
 | { | 
 | 	struct cros_ec_rtc *cros_ec_rtc; | 
 | 	struct rtc_device *rtc; | 
 | 	struct cros_ec_device *cros_ec; | 
 | 	u32 host_event; | 
 |  | 
 | 	cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier); | 
 | 	rtc = cros_ec_rtc->rtc; | 
 | 	cros_ec = cros_ec_rtc->cros_ec; | 
 |  | 
 | 	host_event = cros_ec_get_host_event(cros_ec); | 
 | 	if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) { | 
 | 		rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF); | 
 | 		return NOTIFY_OK; | 
 | 	} else { | 
 | 		return NOTIFY_DONE; | 
 | 	} | 
 | } | 
 |  | 
 | static const struct rtc_class_ops cros_ec_rtc_ops = { | 
 | 	.read_time = cros_ec_rtc_read_time, | 
 | 	.set_time = cros_ec_rtc_set_time, | 
 | 	.read_alarm = cros_ec_rtc_read_alarm, | 
 | 	.set_alarm = cros_ec_rtc_set_alarm, | 
 | 	.alarm_irq_enable = cros_ec_rtc_alarm_irq_enable, | 
 | }; | 
 |  | 
 | #ifdef CONFIG_PM_SLEEP | 
 | static int cros_ec_rtc_suspend(struct device *dev) | 
 | { | 
 | 	struct platform_device *pdev = to_platform_device(dev); | 
 | 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev); | 
 |  | 
 | 	if (device_may_wakeup(dev)) | 
 | 		return enable_irq_wake(cros_ec_rtc->cros_ec->irq); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int cros_ec_rtc_resume(struct device *dev) | 
 | { | 
 | 	struct platform_device *pdev = to_platform_device(dev); | 
 | 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev); | 
 |  | 
 | 	if (device_may_wakeup(dev)) | 
 | 		return disable_irq_wake(cros_ec_rtc->cros_ec->irq); | 
 |  | 
 | 	return 0; | 
 | } | 
 | #endif | 
 |  | 
 | static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend, | 
 | 			 cros_ec_rtc_resume); | 
 |  | 
 | static int cros_ec_rtc_probe(struct platform_device *pdev) | 
 | { | 
 | 	struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent); | 
 | 	struct cros_ec_device *cros_ec = ec_dev->ec_dev; | 
 | 	struct cros_ec_rtc *cros_ec_rtc; | 
 | 	struct rtc_time tm; | 
 | 	int ret; | 
 |  | 
 | 	cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc), | 
 | 				   GFP_KERNEL); | 
 | 	if (!cros_ec_rtc) | 
 | 		return -ENOMEM; | 
 |  | 
 | 	platform_set_drvdata(pdev, cros_ec_rtc); | 
 | 	cros_ec_rtc->cros_ec = cros_ec; | 
 |  | 
 | 	/* Get initial time */ | 
 | 	ret = cros_ec_rtc_read_time(&pdev->dev, &tm); | 
 | 	if (ret) { | 
 | 		dev_err(&pdev->dev, "failed to read RTC time\n"); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	ret = device_init_wakeup(&pdev->dev, 1); | 
 | 	if (ret) { | 
 | 		dev_err(&pdev->dev, "failed to initialize wakeup\n"); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	cros_ec_rtc->rtc = devm_rtc_device_register(&pdev->dev, DRV_NAME, | 
 | 						    &cros_ec_rtc_ops, | 
 | 						    THIS_MODULE); | 
 | 	if (IS_ERR(cros_ec_rtc->rtc)) { | 
 | 		ret = PTR_ERR(cros_ec_rtc->rtc); | 
 | 		dev_err(&pdev->dev, "failed to register rtc device\n"); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	/* Get RTC events from the EC. */ | 
 | 	cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event; | 
 | 	ret = blocking_notifier_chain_register(&cros_ec->event_notifier, | 
 | 					       &cros_ec_rtc->notifier); | 
 | 	if (ret) { | 
 | 		dev_err(&pdev->dev, "failed to register notifier\n"); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int cros_ec_rtc_remove(struct platform_device *pdev) | 
 | { | 
 | 	struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev); | 
 | 	struct device *dev = &pdev->dev; | 
 | 	int ret; | 
 |  | 
 | 	ret = blocking_notifier_chain_unregister( | 
 | 				&cros_ec_rtc->cros_ec->event_notifier, | 
 | 				&cros_ec_rtc->notifier); | 
 | 	if (ret) { | 
 | 		dev_err(dev, "failed to unregister notifier\n"); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static struct platform_driver cros_ec_rtc_driver = { | 
 | 	.probe = cros_ec_rtc_probe, | 
 | 	.remove = cros_ec_rtc_remove, | 
 | 	.driver = { | 
 | 		.name = DRV_NAME, | 
 | 		.pm = &cros_ec_rtc_pm_ops, | 
 | 	}, | 
 | }; | 
 |  | 
 | module_platform_driver(cros_ec_rtc_driver); | 
 |  | 
 | MODULE_DESCRIPTION("RTC driver for Chrome OS ECs"); | 
 | MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>"); | 
 | MODULE_LICENSE("GPL v2"); | 
 | MODULE_ALIAS("platform:" DRV_NAME); |