watchdog: Add Nuvoton NCT6694 WDT support (f9d737a7) · Commits · git / linux-nf

MAINTAINERS

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		@@ -18089,6 +18089,7 @@ F: drivers/gpio/gpio-nct6694.c
		F: drivers/i2c/busses/i2c-nct6694.c
		F: drivers/mfd/nct6694.c
		F: drivers/net/can/usb/nct6694_canfd.c
		F: drivers/watchdog/nct6694_wdt.c
		F: include/linux/mfd/nct6694.h

		NUVOTON NCT7201 IIO DRIVER

drivers/watchdog/Kconfig

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		@@ -760,6 +760,17 @@ config MAX77620_WATCHDOG
		MAX77620 chips. To compile this driver as a module,
		choose M here: the module will be called max77620_wdt.

		config NCT6694_WATCHDOG
		tristate "Nuvoton NCT6694 watchdog support"
		depends on MFD_NCT6694
		select WATCHDOG_CORE
		help
		Say Y here to support Nuvoton NCT6694 watchdog timer
		functionality.

		This driver can also be built as a module. If so, the module
		will be called nct6694_wdt.

		config IMX2_WDT
		tristate "IMX2+ Watchdog"
		depends on ARCH_MXC \|\| ARCH_LAYERSCAPE \|\| COMPILE_TEST

drivers/watchdog/Makefile

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		@@ -235,6 +235,7 @@ obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
		obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
		obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
		obj-$(CONFIG_MAX77620_WATCHDOG) += max77620_wdt.o
		obj-$(CONFIG_NCT6694_WATCHDOG) += nct6694_wdt.o
		obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
		obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
		obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o

drivers/watchdog/nct6694_wdt.c

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* Nuvoton NCT6694 WDT driver based on USB interface.
		*
		* Copyright (C) 2025 Nuvoton Technology Corp.
		*/

		#include <linux/idr.h>
		#include <linux/kernel.h>
		#include <linux/mfd/nct6694.h>
		#include <linux/module.h>
		#include <linux/platform_device.h>
		#include <linux/slab.h>
		#include <linux/watchdog.h>

		#define DEVICE_NAME "nct6694-wdt"

		#define NCT6694_DEFAULT_TIMEOUT 10
		#define NCT6694_DEFAULT_PRETIMEOUT 0

		#define NCT6694_WDT_MAX_DEVS 2

		/*
		* USB command module type for NCT6694 WDT controller.
		* This defines the module type used for communication with the NCT6694
		* WDT controller over the USB interface.
		*/
		#define NCT6694_WDT_MOD 0x07

		/* Command 00h - WDT Setup */
		#define NCT6694_WDT_SETUP 0x00
		#define NCT6694_WDT_SETUP_SEL(idx) (idx ? 0x01 : 0x00)

		/* Command 01h - WDT Command */
		#define NCT6694_WDT_COMMAND 0x01
		#define NCT6694_WDT_COMMAND_SEL(idx) (idx ? 0x01 : 0x00)

		static unsigned int timeout[NCT6694_WDT_MAX_DEVS] = {
		[0 ... (NCT6694_WDT_MAX_DEVS - 1)] = NCT6694_DEFAULT_TIMEOUT
		};
		module_param_array(timeout, int, NULL, 0644);
		MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");

		static unsigned int pretimeout[NCT6694_WDT_MAX_DEVS] = {
		[0 ... (NCT6694_WDT_MAX_DEVS - 1)] = NCT6694_DEFAULT_PRETIMEOUT
		};
		module_param_array(pretimeout, int, NULL, 0644);
		MODULE_PARM_DESC(pretimeout, "Watchdog pre-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) ")");

		enum {
		NCT6694_ACTION_NONE = 0,
		NCT6694_ACTION_SIRQ,
		NCT6694_ACTION_GPO,
		};

		struct __packed nct6694_wdt_setup {
		__le32 pretimeout;
		__le32 timeout;
		u8 owner;
		u8 scratch;
		u8 control;
		u8 status;
		__le32 countdown;
		};

		struct __packed nct6694_wdt_cmd {
		__le32 wdt_cmd;
		__le32 reserved;
		};

		union __packed nct6694_wdt_msg {
		struct nct6694_wdt_setup setup;
		struct nct6694_wdt_cmd cmd;
		};

		struct nct6694_wdt_data {
		struct watchdog_device wdev;
		struct device *dev;
		struct nct6694 *nct6694;
		union nct6694_wdt_msg *msg;
		unsigned char wdev_idx;
		};

		static int nct6694_wdt_setting(struct watchdog_device *wdev,
		u32 timeout_val, u8 timeout_act,
		u32 pretimeout_val, u8 pretimeout_act)
		{
		struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
		struct nct6694_wdt_setup *setup = &data->msg->setup;
		const struct nct6694_cmd_header cmd_hd = {
		.mod = NCT6694_WDT_MOD,
		.cmd = NCT6694_WDT_SETUP,
		.sel = NCT6694_WDT_SETUP_SEL(data->wdev_idx),
		.len = cpu_to_le16(sizeof(*setup))
		};
		unsigned int timeout_fmt, pretimeout_fmt;

		if (pretimeout_val == 0)
		pretimeout_act = NCT6694_ACTION_NONE;

		timeout_fmt = (timeout_val * 1000) \| (timeout_act << 24);
		pretimeout_fmt = (pretimeout_val * 1000) \| (pretimeout_act << 24);

		memset(setup, 0, sizeof(*setup));
		setup->timeout = cpu_to_le32(timeout_fmt);
		setup->pretimeout = cpu_to_le32(pretimeout_fmt);

		return nct6694_write_msg(data->nct6694, &cmd_hd, setup);
		}

		static int nct6694_wdt_start(struct watchdog_device *wdev)
		{
		struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
		int ret;

		ret = nct6694_wdt_setting(wdev, wdev->timeout, NCT6694_ACTION_GPO,
		wdev->pretimeout, NCT6694_ACTION_GPO);
		if (ret)
		return ret;

		dev_dbg(data->dev, "Setting WDT(%d): timeout = %d, pretimeout = %d\n",
		data->wdev_idx, wdev->timeout, wdev->pretimeout);

		return ret;
		}

		static int nct6694_wdt_stop(struct watchdog_device *wdev)
		{
		struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
		struct nct6694_wdt_cmd *cmd = &data->msg->cmd;
		const struct nct6694_cmd_header cmd_hd = {
		.mod = NCT6694_WDT_MOD,
		.cmd = NCT6694_WDT_COMMAND,
		.sel = NCT6694_WDT_COMMAND_SEL(data->wdev_idx),
		.len = cpu_to_le16(sizeof(*cmd))
		};

		memcpy(&cmd->wdt_cmd, "WDTC", 4);
		cmd->reserved = 0;

		return nct6694_write_msg(data->nct6694, &cmd_hd, cmd);
		}

		static int nct6694_wdt_ping(struct watchdog_device *wdev)
		{
		struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
		struct nct6694_wdt_cmd *cmd = &data->msg->cmd;
		const struct nct6694_cmd_header cmd_hd = {
		.mod = NCT6694_WDT_MOD,
		.cmd = NCT6694_WDT_COMMAND,
		.sel = NCT6694_WDT_COMMAND_SEL(data->wdev_idx),
		.len = cpu_to_le16(sizeof(*cmd))
		};

		memcpy(&cmd->wdt_cmd, "WDTS", 4);
		cmd->reserved = 0;

		return nct6694_write_msg(data->nct6694, &cmd_hd, cmd);
		}

		static int nct6694_wdt_set_timeout(struct watchdog_device *wdev,
		unsigned int new_timeout)
		{
		int ret;

		ret = nct6694_wdt_setting(wdev, new_timeout, NCT6694_ACTION_GPO,
		wdev->pretimeout, NCT6694_ACTION_GPO);
		if (ret)
		return ret;

		wdev->timeout = new_timeout;

		return 0;
		}

		static int nct6694_wdt_set_pretimeout(struct watchdog_device *wdev,
		unsigned int new_pretimeout)
		{
		int ret;

		ret = nct6694_wdt_setting(wdev, wdev->timeout, NCT6694_ACTION_GPO,
		new_pretimeout, NCT6694_ACTION_GPO);
		if (ret)
		return ret;

		wdev->pretimeout = new_pretimeout;

		return 0;
		}

		static unsigned int nct6694_wdt_get_time(struct watchdog_device *wdev)
		{
		struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
		struct nct6694_wdt_setup *setup = &data->msg->setup;
		const struct nct6694_cmd_header cmd_hd = {
		.mod = NCT6694_WDT_MOD,
		.cmd = NCT6694_WDT_SETUP,
		.sel = NCT6694_WDT_SETUP_SEL(data->wdev_idx),
		.len = cpu_to_le16(sizeof(*setup))
		};
		unsigned int timeleft_ms;
		int ret;

		ret = nct6694_read_msg(data->nct6694, &cmd_hd, setup);
		if (ret)
		return 0;

		timeleft_ms = le32_to_cpu(setup->countdown);

		return timeleft_ms / 1000;
		}

		static const struct watchdog_info nct6694_wdt_info = {
		.options = WDIOF_SETTIMEOUT \|
		WDIOF_KEEPALIVEPING \|
		WDIOF_MAGICCLOSE \|
		WDIOF_PRETIMEOUT,
		.identity = DEVICE_NAME,
		};

		static const struct watchdog_ops nct6694_wdt_ops = {
		.owner = THIS_MODULE,
		.start = nct6694_wdt_start,
		.stop = nct6694_wdt_stop,
		.set_timeout = nct6694_wdt_set_timeout,
		.set_pretimeout = nct6694_wdt_set_pretimeout,
		.get_timeleft = nct6694_wdt_get_time,
		.ping = nct6694_wdt_ping,
		};

		static void nct6694_wdt_ida_free(void *d)
		{
		struct nct6694_wdt_data *data = d;
		struct nct6694 *nct6694 = data->nct6694;

		ida_free(&nct6694->wdt_ida, data->wdev_idx);
		}

		static int nct6694_wdt_probe(struct platform_device *pdev)
		{
		struct device *dev = &pdev->dev;
		struct nct6694 *nct6694 = dev_get_drvdata(dev->parent);
		struct nct6694_wdt_data *data;
		struct watchdog_device *wdev;
		int ret;

		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
		if (!data)
		return -ENOMEM;

		data->msg = devm_kzalloc(dev, sizeof(union nct6694_wdt_msg),
		GFP_KERNEL);
		if (!data->msg)
		return -ENOMEM;

		data->dev = dev;
		data->nct6694 = nct6694;

		ret = ida_alloc(&nct6694->wdt_ida, GFP_KERNEL);
		if (ret < 0)
		return ret;
		data->wdev_idx = ret;

		ret = devm_add_action_or_reset(dev, nct6694_wdt_ida_free, data);
		if (ret)
		return ret;

		wdev = &data->wdev;
		wdev->info = &nct6694_wdt_info;
		wdev->ops = &nct6694_wdt_ops;
		wdev->timeout = timeout[data->wdev_idx];
		wdev->pretimeout = pretimeout[data->wdev_idx];
		if (timeout[data->wdev_idx] < pretimeout[data->wdev_idx]) {
		dev_warn(data->dev, "pretimeout < timeout. Setting to zero\n");
		wdev->pretimeout = 0;
		}

		wdev->min_timeout = 1;
		wdev->max_timeout = 255;

		platform_set_drvdata(pdev, data);

		watchdog_set_drvdata(&data->wdev, data);
		watchdog_set_nowayout(&data->wdev, nowayout);
		watchdog_stop_on_reboot(&data->wdev);

		return devm_watchdog_register_device(dev, &data->wdev);
		}

		static struct platform_driver nct6694_wdt_driver = {
		.driver = {
		.name = DEVICE_NAME,
		},
		.probe = nct6694_wdt_probe,
		};

		module_platform_driver(nct6694_wdt_driver);

		MODULE_DESCRIPTION("USB-WDT driver for NCT6694");
		MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
		MODULE_LICENSE("GPL");
		MODULE_ALIAS("platform:nct6694-wdt");