[PATCH v5 05/11] platform: cznic: turris-omnia-mcu: Add support for MCU watchdog

Marek Behún
2024-03-23T16:44:18Z

Add support for the watchdog mechanism provided by the MCU.

Signed-off-by: Marek Behún <kabel@kernel.org>
---
drivers/platform/cznic/Kconfig | 2 +
drivers/platform/cznic/Makefile | 1 +
.../platform/cznic/turris-omnia-mcu-base.c | 4 +
.../cznic/turris-omnia-mcu-watchdog.c | 122 ++++++++++++++++++
drivers/platform/cznic/turris-omnia-mcu.h | 24 ++++
5 files changed, 153 insertions(+)
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-watchdog.c

diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
index 0a752aa654fa..e2649cdecc38 100644
--- a/drivers/platform/cznic/Kconfig
+++ b/drivers/platform/cznic/Kconfig
@@ -20,6 +20,7 @@ config TURRIS_OMNIA_MCU
select GPIOLIB
select GPIOLIB_IRQCHIP
select RTC_CLASS
+ select WATCHDOG_CORE
help
Say Y here to add support for the features implemented by the
microcontroller on the CZ.NIC's Turris Omnia SOHO router.
@@ -27,6 +28,7 @@ config TURRIS_OMNIA_MCU
- board poweroff into true low power mode (with voltage regulators
disabled) and the ability to configure wake up from this mode (via
rtcwake)
+ - MCU watchdog
- GPIO pins
- to get front button press events (the front button can be
configured either to generate press events to the CPU or to change
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
index 6f1470d1f673..a43997a12d74 100644
--- a/drivers/platform/cznic/Makefile
+++ b/drivers/platform/cznic/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_TURRIS_OMNIA_MCU) += turris-omnia-mcu.o
turris-omnia-mcu-objs := turris-omnia-mcu-base.o
turris-omnia-mcu-objs += turris-omnia-mcu-gpio.o
turris-omnia-mcu-objs += turris-omnia-mcu-sys-off-wakeup.o
+turris-omnia-mcu-objs += turris-omnia-mcu-watchdog.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
index 6ab4494335ca..5a45834003cd 100644
--- a/drivers/platform/cznic/turris-omnia-mcu-base.c
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -331,6 +331,10 @@ static int omnia_mcu_probe(struct i2c_client *client)
if (err)
return err;

+ err = omnia_mcu_register_watchdog(mcu);
+ if (err)
+ return err;
+
return omnia_mcu_register_gpiochip(mcu);
}

diff --git a/drivers/platform/cznic/turris-omnia-mcu-watchdog.c b/drivers/platform/cznic/turris-omnia-mcu-watchdog.c
new file mode 100644
index 000000000000..94cdd6eea4c8
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-watchdog.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU watchdog driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#include <linux/moduleparam.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+#include <linux/watchdog.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, 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, 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, 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, CMD_SET_WDT_TIMEOUT,
+ timeout * 10);
+}
+
+static unsigned int omnia_wdt_get_timeleft(struct watchdog_device *wdt)
+{
+ struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+ int ret;
+
+ ret = omnia_cmd_read_u16(mcu->client, CMD_GET_WDT_TIMELEFT);
+ if (ret < 0) {
+ dev_err(&mcu->client->dev, "Cannot get watchdog timeleft: %d\n",
+ ret);
+ return 0;
+ }
+
+ return ret / 10;
+}
+
+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;
+ int ret;
+
+ if (!(mcu->features & 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 = 6553; /* 65535 deciseconds */
+
+ 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);
+
+ ret = omnia_cmd_read_u8(mcu->client, CMD_GET_WATCHDOG_STATE);
+ if (ret < 0)
+ return dev_err_probe(dev, ret,
+ "Cannot get MCU watchdog state\n");
+
+ if (ret)
+ set_bit(WDOG_HW_RUNNING, &mcu->wdt.status);
+
+ watchdog_set_nowayout(&mcu->wdt, nowayout);
+ watchdog_stop_on_reboot(&mcu->wdt);
+ ret = devm_watchdog_register_device(dev, &mcu->wdt);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Cannot register MCU watchdog\n");
+
+ return 0;
+}
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
index af9845d1c6d2..3e2c96079e64 100644
--- a/drivers/platform/cznic/turris-omnia-mcu.h
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -15,6 +15,7 @@
#include <linux/mutex.h>
#include <linux/rtc.h>
#include <linux/types.h>
+#include <linux/watchdog.h>
#include <linux/workqueue.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
@@ -42,6 +43,9 @@ struct omnia_mcu {
struct rtc_device *rtcdev;
u32 rtc_alarm;
bool front_button_poweron;
+
+ /* MCU watchdog */
+ struct watchdog_device wdt;
};

static inline int omnia_cmd_write(const struct i2c_client *client, void *cmd,
@@ -54,6 +58,25 @@ static inline int omnia_cmd_write(const struct i2c_client *client, void *cmd,
return ret < 0 ? ret : 0;
}

+static inline int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd,
+ u8 val)
+{
+ u8 buf[2] = { cmd, val };
+
+ return omnia_cmd_write(client, buf, sizeof(buf));
+}
+
+static inline int omnia_cmd_write_u16(const struct i2c_client *client, u8 cmd,
+ u16 val)
+{
+ u8 buf[3];
+
+ buf[0] = cmd;
+ put_unaligned_le16(val, &buf[1]);
+
+ return omnia_cmd_write(client, buf, sizeof(buf));
+}
+
static inline int omnia_cmd_write_u32(const struct i2c_client *client, u8 cmd,
u32 val)
{
@@ -148,5 +171,6 @@ extern const struct attribute_group omnia_mcu_poweroff_group;

int omnia_mcu_register_gpiochip(struct omnia_mcu *mcu);
int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu);
+int omnia_mcu_register_watchdog(struct omnia_mcu *mcu);

#endif /* __TURRIS_OMNIA_MCU_H */
--
2.43.2