// SPDX-License-Identifier: GPL-2.0
/*
* CZ.NIC's Turris Omnia MCU system off and RTC wakeup driver
*
* This is not a true RTC driver (in the sense that it does not provide a
* real-time clock), rather the MCU implements a wakeup from powered off state
* at a specified time relative to MCU boot, and we expose this feature via RTC
* alarm, so that it can be used via the rtcwake command, which is the standard
* Linux command for this.
*
* 2024 by Marek Behún <[email protected]>
*/
#include <linux/crc32.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/kstrtox.h>
#include <linux/reboot.h>
#include <linux/rtc.h>
#include <linux/sysfs.h>
#include <linux/types.h>
#include <linux/turris-omnia-mcu-interface.h>
#include "turris-omnia-mcu.h"
static int omnia_get_uptime_wakeup(const struct i2c_client *client, u32 *uptime,
u32 *wakeup)
{
__le32 reply[2];
int err;
err = omnia_cmd_read(client, OMNIA_CMD_GET_UPTIME_AND_WAKEUP, reply,
sizeof(reply));
if (err)
return err;
if (uptime)
*uptime = le32_to_cpu(reply[0]);
if (wakeup)
*wakeup = le32_to_cpu(reply[1]);
return 0;
}
static int omnia_read_time(struct device *dev, struct rtc_time *tm)
{
u32 uptime;
int err;
err = omnia_get_uptime_wakeup(to_i2c_client(dev), &uptime, NULL);
if (err)
return err;
rtc_time64_to_tm(uptime, tm);
return 0;
}
static int omnia_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct i2c_client *client = to_i2c_client(dev);
struct omnia_mcu *mcu = i2c_get_clientdata(client);
u32 wakeup;
int err;
err = omnia_get_uptime_wakeup(client, NULL, &wakeup);
if (err)
return err;
alrm->enabled = !!wakeup;
rtc_time64_to_tm(wakeup ?: mcu->rtc_alarm, &alrm->time);
return 0;
}
static int omnia_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct i2c_client *client = to_i2c_client(dev);
struct omnia_mcu *mcu = i2c_get_clientdata(client);
mcu->rtc_alarm = rtc_tm_to_time64(&alrm->time);
if (alrm->enabled)
return omnia_cmd_write_u32(client, OMNIA_CMD_SET_WAKEUP,
mcu->rtc_alarm);
return 0;
}
static int omnia_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct omnia_mcu *mcu = i2c_get_clientdata(client);
return omnia_cmd_write_u32(client, OMNIA_CMD_SET_WAKEUP,
enabled ? mcu->rtc_alarm : 0);
}
static const struct rtc_class_ops omnia_rtc_ops = {
.read_time = omnia_read_time,
.read_alarm = omnia_read_alarm,
.set_alarm = omnia_set_alarm,
.alarm_irq_enable = omnia_alarm_irq_enable,
};
static int omnia_power_off(struct sys_off_data *data)
{
struct omnia_mcu *mcu = data->cb_data;
__be32 tmp;
u8 cmd[9];
u16 arg;
int err;
if (mcu->front_button_poweron)
arg = OMNIA_CMD_POWER_OFF_POWERON_BUTTON;
else
arg = 0;
cmd[0] = OMNIA_CMD_POWER_OFF;
put_unaligned_le16(OMNIA_CMD_POWER_OFF_MAGIC, &cmd[1]);
put_unaligned_le16(arg, &cmd[3]);
/*
* Although all values from and to MCU are passed in little-endian, the
* MCU's CRC unit uses big-endian CRC32 polynomial (0x04c11db7), so we
* need to use crc32_be() here.
*/
tmp = cpu_to_be32(get_unaligned_le32(&cmd[1]));
put_unaligned_le32(crc32_be(~0, (void *)&tmp, sizeof(tmp)), &cmd[5]);
err = omnia_cmd_write(mcu->client, cmd, sizeof(cmd));
if (err)
dev_err(&mcu->client->dev,
"Unable to send the poweroff command: %d\n", err);
return NOTIFY_DONE;
}
static int omnia_restart(struct sys_off_data *data)
{
struct omnia_mcu *mcu = data->cb_data;
u8 cmd[3];
int err;
cmd[0] = OMNIA_CMD_GENERAL_CONTROL;
if (reboot_mode == REBOOT_HARD)
cmd[1] = cmd[2] = OMNIA_CTL_HARD_RST;
else
cmd[1] = cmd[2] = OMNIA_CTL_LIGHT_RST;
err = omnia_cmd_write(mcu->client, cmd, sizeof(cmd));
if (err)
dev_err(&mcu->client->dev,
"Unable to send the restart command: %d\n", err);
/*
* MCU needs a little bit to process the I2C command, otherwise it will
* do a light reset based on SOC SYSRES_OUT pin.
*/
mdelay(1);
return NOTIFY_DONE;
}
static ssize_t front_button_poweron_show(struct device *dev,
struct device_attribute *a, char *buf)
{
struct omnia_mcu *mcu = dev_get_drvdata(dev);
return sysfs_emit(buf, "%d\n", mcu->front_button_poweron);
}
static ssize_t front_button_poweron_store(struct device *dev,
struct device_attribute *a,
const char *buf, size_t count)
{
struct omnia_mcu *mcu = dev_get_drvdata(dev);
bool val;
int err;
err = kstrtobool(buf, &val);
if (err)
return err;
mcu->front_button_poweron = val;
return count;
}
static DEVICE_ATTR_RW(front_button_poweron);
static struct attribute *omnia_mcu_poweroff_attrs[] = {
&dev_attr_front_button_poweron.attr,
NULL
};
static umode_t poweroff_attrs_visible(struct kobject *kobj, struct attribute *a,
int n)
{
struct device *dev = kobj_to_dev(kobj);
struct omnia_mcu *mcu = dev_get_drvdata(dev);
if (mcu->features & OMNIA_FEAT_POWEROFF_WAKEUP)
return a->mode;
return 0;
}
const struct attribute_group omnia_mcu_poweroff_group = {
.attrs = omnia_mcu_poweroff_attrs,
.is_visible = poweroff_attrs_visible,
};
int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu)
{
struct device *dev = &mcu->client->dev;
int err;
/* MCU restart is always available */
err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART,
SYS_OFF_PRIO_FIRMWARE,
omnia_restart, mcu);
if (err)
return dev_err_probe(dev, err,
"Cannot register system restart handler\n");
/*
* Poweroff and wakeup are available only if POWEROFF_WAKEUP feature is
* present.
*/
if (!(mcu->features & OMNIA_FEAT_POWEROFF_WAKEUP))
return 0;
err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_POWER_OFF,
SYS_OFF_PRIO_FIRMWARE,
omnia_power_off, mcu);
if (err)
return dev_err_probe(dev, err,
"Cannot register system power off handler\n");
mcu->rtcdev = devm_rtc_allocate_device(dev);
if (IS_ERR(mcu->rtcdev))
return dev_err_probe(dev, PTR_ERR(mcu->rtcdev),
"Cannot allocate RTC device\n");
mcu->rtcdev->ops = &omnia_rtc_ops;
mcu->rtcdev->range_max = U32_MAX;
set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, mcu->rtcdev->features);
err = devm_rtc_register_device(mcu->rtcdev);
if (err)
return dev_err_probe(dev, err, "Cannot register RTC device\n");
mcu->front_button_poweron = true;
return 0;
}
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