linux/drivers/platform/cznic/turris-omnia-mcu-watchdog.c
Marek Behún ab89fb5fb9
platform: cznic: turris-omnia-mcu: Add support for MCU watchdog
Add support for the watchdog mechanism provided by the MCU.

Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Link: https://lore.kernel.org/r/20240701113010.16447-6-kabel@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-07-01 15:46:37 +02:00

131 lines
3.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* CZ.NIC's Turris Omnia MCU watchdog driver
*
* 2024 by Marek Behún <kabel@kernel.org>
*/
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/units.h>
#include <linux/watchdog.h>
#include <linux/turris-omnia-mcu-interface.h>
#include "turris-omnia-mcu.h"
#define WATCHDOG_TIMEOUT 120
static unsigned int timeout;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static int omnia_wdt_start(struct watchdog_device *wdt)
{
struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
return omnia_cmd_write_u8(mcu->client, OMNIA_CMD_SET_WATCHDOG_STATE, 1);
}
static int omnia_wdt_stop(struct watchdog_device *wdt)
{
struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
return omnia_cmd_write_u8(mcu->client, OMNIA_CMD_SET_WATCHDOG_STATE, 0);
}
static int omnia_wdt_ping(struct watchdog_device *wdt)
{
struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
return omnia_cmd_write_u8(mcu->client, OMNIA_CMD_SET_WATCHDOG_STATE, 1);
}
static int omnia_wdt_set_timeout(struct watchdog_device *wdt,
unsigned int timeout)
{
struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
return omnia_cmd_write_u16(mcu->client, OMNIA_CMD_SET_WDT_TIMEOUT,
timeout * DECI);
}
static unsigned int omnia_wdt_get_timeleft(struct watchdog_device *wdt)
{
struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
u16 timeleft;
int err;
err = omnia_cmd_read_u16(mcu->client, OMNIA_CMD_GET_WDT_TIMELEFT,
&timeleft);
if (err) {
dev_err(&mcu->client->dev, "Cannot get watchdog timeleft: %d\n",
err);
return 0;
}
return timeleft / DECI;
}
static const struct watchdog_info omnia_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "Turris Omnia MCU Watchdog",
};
static const struct watchdog_ops omnia_wdt_ops = {
.owner = THIS_MODULE,
.start = omnia_wdt_start,
.stop = omnia_wdt_stop,
.ping = omnia_wdt_ping,
.set_timeout = omnia_wdt_set_timeout,
.get_timeleft = omnia_wdt_get_timeleft,
};
int omnia_mcu_register_watchdog(struct omnia_mcu *mcu)
{
struct device *dev = &mcu->client->dev;
u8 state;
int err;
if (!(mcu->features & OMNIA_FEAT_WDT_PING))
return 0;
mcu->wdt.info = &omnia_wdt_info;
mcu->wdt.ops = &omnia_wdt_ops;
mcu->wdt.parent = dev;
mcu->wdt.min_timeout = 1;
mcu->wdt.max_timeout = 65535 / DECI;
mcu->wdt.timeout = WATCHDOG_TIMEOUT;
watchdog_init_timeout(&mcu->wdt, timeout, dev);
watchdog_set_drvdata(&mcu->wdt, mcu);
omnia_wdt_set_timeout(&mcu->wdt, mcu->wdt.timeout);
err = omnia_cmd_read_u8(mcu->client, OMNIA_CMD_GET_WATCHDOG_STATE,
&state);
if (err)
return dev_err_probe(dev, err,
"Cannot get MCU watchdog state\n");
if (state)
set_bit(WDOG_HW_RUNNING, &mcu->wdt.status);
watchdog_set_nowayout(&mcu->wdt, nowayout);
watchdog_stop_on_reboot(&mcu->wdt);
err = devm_watchdog_register_device(dev, &mcu->wdt);
if (err)
return dev_err_probe(dev, err,
"Cannot register MCU watchdog\n");
return 0;
}