// SPDX-License-Identifier: GPL-2.0
// RTC driver for ChromeOS Embedded Controller.
//
// Copyright (C) 2017 Google, Inc.
// Author: Stephen Barber <[email protected]>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#define DRV_NAME "cros-ec-rtc"
#define SECS_PER_DAY (24 * 60 * 60)
/**
* 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)
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;
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)
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 = rtc_tm_to_time64(tm);
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 in %u seconds: %d\n",
alarm_offset, ret);
/*
* The EC code returns -EINVAL if the alarm time is too
* far in the future. Convert it to the expected error code.
*/
if (ret == -EINVAL)
ret = -ERANGE;
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_allocate_device(&pdev->dev);
if (IS_ERR(cros_ec_rtc->rtc))
return PTR_ERR(cros_ec_rtc->rtc);
cros_ec_rtc->rtc->ops = &cros_ec_rtc_ops;
cros_ec_rtc->rtc->range_max = U32_MAX;
/*
* The RTC on some older Chromebooks can only handle alarms less than
* 24 hours in the future. The only way to find out is to try to set an
* alarm further in the future. If that fails, assume that the RTC
* connected to the EC can only handle less than 24 hours of alarm
* window.
*/
ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, SECS_PER_DAY * 2);
if (ret == -EINVAL)
cros_ec_rtc->rtc->alarm_offset_max = SECS_PER_DAY - 1;
(void)cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
EC_RTC_ALARM_CLEAR);
ret = devm_rtc_register_device(cros_ec_rtc->rtc);
if (ret)
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 void 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");
}
static const struct platform_device_id cros_ec_rtc_id[] = {
{ DRV_NAME, 0 },
{}
};
MODULE_DEVICE_TABLE(platform, cros_ec_rtc_id);
static struct platform_driver cros_ec_rtc_driver = {
.probe = cros_ec_rtc_probe,
.remove_new = cros_ec_rtc_remove,
.driver = {
.name = DRV_NAME,
.pm = &cros_ec_rtc_pm_ops,
},
.id_table = cros_ec_rtc_id,
};
module_platform_driver(cros_ec_rtc_driver);
MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
MODULE_AUTHOR("Stephen Barber <[email protected]>");
MODULE_LICENSE("GPL v2");
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