diff options
Diffstat (limited to 'drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c')
| -rw-r--r-- | drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c b/drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c new file mode 100644 index 000000000000..0e8ab15b6037 --- /dev/null +++ b/drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c @@ -0,0 +1,260 @@ +// 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 <kabel@kernel.org> + */ + +#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; +} |