Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
watchdog: Add Nuvoton NCT6694 WDT support
This driver supports Watchdog timer functionality for NCT6694 MFD
device based on USB interface.
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ming Yu <a0282524688@gmail.com>
Link: https://lore.kernel.org/r/20250912091952.1169369-6-a0282524688@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
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MAINTAINERS
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MAINTAINERS
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drivers/watchdog/Kconfig
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drivers/watchdog/Kconfig
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MAX77620 chips. To compile this driver as a module,
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choose M here: the module will be called max77620_wdt.
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config NCT6694_WATCHDOG
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tristate "Nuvoton NCT6694 watchdog support"
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depends on MFD_NCT6694
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select WATCHDOG_CORE
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help
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Say Y here to support Nuvoton NCT6694 watchdog timer
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functionality.
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This driver can also be built as a module. If so, the module
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will be called nct6694_wdt.
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config IMX2_WDT
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tristate "IMX2+ Watchdog"
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depends on ARCH_MXC || ARCH_LAYERSCAPE || COMPILE_TEST
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drivers/watchdog/Makefile
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drivers/watchdog/Makefile
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obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
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obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
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obj-$(CONFIG_MAX77620_WATCHDOG) += max77620_wdt.o
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obj-$(CONFIG_NCT6694_WATCHDOG) += nct6694_wdt.o
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obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
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obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
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obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
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drivers/watchdog/nct6694_wdt.c
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drivers/watchdog/nct6694_wdt.c
···
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Nuvoton NCT6694 WDT driver based on USB interface.
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*
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* Copyright (C) 2025 Nuvoton Technology Corp.
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*/
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#include <linux/idr.h>
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#include <linux/kernel.h>
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#include <linux/mfd/nct6694.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/watchdog.h>
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#define DEVICE_NAME "nct6694-wdt"
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#define NCT6694_DEFAULT_TIMEOUT 10
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#define NCT6694_DEFAULT_PRETIMEOUT 0
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#define NCT6694_WDT_MAX_DEVS 2
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/*
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* USB command module type for NCT6694 WDT controller.
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* This defines the module type used for communication with the NCT6694
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* WDT controller over the USB interface.
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*/
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#define NCT6694_WDT_MOD 0x07
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/* Command 00h - WDT Setup */
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#define NCT6694_WDT_SETUP 0x00
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#define NCT6694_WDT_SETUP_SEL(idx) (idx ? 0x01 : 0x00)
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/* Command 01h - WDT Command */
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#define NCT6694_WDT_COMMAND 0x01
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#define NCT6694_WDT_COMMAND_SEL(idx) (idx ? 0x01 : 0x00)
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static unsigned int timeout[NCT6694_WDT_MAX_DEVS] = {
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[0 ... (NCT6694_WDT_MAX_DEVS - 1)] = NCT6694_DEFAULT_TIMEOUT
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};
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module_param_array(timeout, int, NULL, 0644);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
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static unsigned int pretimeout[NCT6694_WDT_MAX_DEVS] = {
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[0 ... (NCT6694_WDT_MAX_DEVS - 1)] = NCT6694_DEFAULT_PRETIMEOUT
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};
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module_param_array(pretimeout, int, NULL, 0644);
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MODULE_PARM_DESC(pretimeout, "Watchdog pre-timeout in seconds");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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enum {
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NCT6694_ACTION_NONE = 0,
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NCT6694_ACTION_SIRQ,
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NCT6694_ACTION_GPO,
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};
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struct __packed nct6694_wdt_setup {
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__le32 pretimeout;
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__le32 timeout;
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u8 owner;
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u8 scratch;
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u8 control;
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u8 status;
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__le32 countdown;
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};
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struct __packed nct6694_wdt_cmd {
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__le32 wdt_cmd;
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__le32 reserved;
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};
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union __packed nct6694_wdt_msg {
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struct nct6694_wdt_setup setup;
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struct nct6694_wdt_cmd cmd;
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};
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struct nct6694_wdt_data {
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struct watchdog_device wdev;
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struct device *dev;
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struct nct6694 *nct6694;
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union nct6694_wdt_msg *msg;
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unsigned char wdev_idx;
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};
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static int nct6694_wdt_setting(struct watchdog_device *wdev,
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u32 timeout_val, u8 timeout_act,
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u32 pretimeout_val, u8 pretimeout_act)
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{
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struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
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struct nct6694_wdt_setup *setup = &data->msg->setup;
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const struct nct6694_cmd_header cmd_hd = {
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.mod = NCT6694_WDT_MOD,
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.cmd = NCT6694_WDT_SETUP,
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.sel = NCT6694_WDT_SETUP_SEL(data->wdev_idx),
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.len = cpu_to_le16(sizeof(*setup))
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};
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unsigned int timeout_fmt, pretimeout_fmt;
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if (pretimeout_val == 0)
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pretimeout_act = NCT6694_ACTION_NONE;
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timeout_fmt = (timeout_val * 1000) | (timeout_act << 24);
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pretimeout_fmt = (pretimeout_val * 1000) | (pretimeout_act << 24);
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memset(setup, 0, sizeof(*setup));
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setup->timeout = cpu_to_le32(timeout_fmt);
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setup->pretimeout = cpu_to_le32(pretimeout_fmt);
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return nct6694_write_msg(data->nct6694, &cmd_hd, setup);
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}
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static int nct6694_wdt_start(struct watchdog_device *wdev)
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{
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struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
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int ret;
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ret = nct6694_wdt_setting(wdev, wdev->timeout, NCT6694_ACTION_GPO,
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wdev->pretimeout, NCT6694_ACTION_GPO);
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if (ret)
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return ret;
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dev_dbg(data->dev, "Setting WDT(%d): timeout = %d, pretimeout = %d\n",
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data->wdev_idx, wdev->timeout, wdev->pretimeout);
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return ret;
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}
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static int nct6694_wdt_stop(struct watchdog_device *wdev)
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{
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struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
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struct nct6694_wdt_cmd *cmd = &data->msg->cmd;
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const struct nct6694_cmd_header cmd_hd = {
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.mod = NCT6694_WDT_MOD,
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.cmd = NCT6694_WDT_COMMAND,
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.sel = NCT6694_WDT_COMMAND_SEL(data->wdev_idx),
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.len = cpu_to_le16(sizeof(*cmd))
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};
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memcpy(&cmd->wdt_cmd, "WDTC", 4);
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cmd->reserved = 0;
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return nct6694_write_msg(data->nct6694, &cmd_hd, cmd);
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}
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static int nct6694_wdt_ping(struct watchdog_device *wdev)
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{
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struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
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struct nct6694_wdt_cmd *cmd = &data->msg->cmd;
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const struct nct6694_cmd_header cmd_hd = {
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.mod = NCT6694_WDT_MOD,
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.cmd = NCT6694_WDT_COMMAND,
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.sel = NCT6694_WDT_COMMAND_SEL(data->wdev_idx),
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.len = cpu_to_le16(sizeof(*cmd))
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};
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memcpy(&cmd->wdt_cmd, "WDTS", 4);
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cmd->reserved = 0;
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return nct6694_write_msg(data->nct6694, &cmd_hd, cmd);
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}
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static int nct6694_wdt_set_timeout(struct watchdog_device *wdev,
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unsigned int new_timeout)
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{
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int ret;
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ret = nct6694_wdt_setting(wdev, new_timeout, NCT6694_ACTION_GPO,
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wdev->pretimeout, NCT6694_ACTION_GPO);
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if (ret)
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return ret;
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wdev->timeout = new_timeout;
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return 0;
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}
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static int nct6694_wdt_set_pretimeout(struct watchdog_device *wdev,
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unsigned int new_pretimeout)
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{
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int ret;
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ret = nct6694_wdt_setting(wdev, wdev->timeout, NCT6694_ACTION_GPO,
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new_pretimeout, NCT6694_ACTION_GPO);
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if (ret)
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return ret;
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wdev->pretimeout = new_pretimeout;
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return 0;
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}
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static unsigned int nct6694_wdt_get_time(struct watchdog_device *wdev)
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{
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struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
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struct nct6694_wdt_setup *setup = &data->msg->setup;
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const struct nct6694_cmd_header cmd_hd = {
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.mod = NCT6694_WDT_MOD,
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.cmd = NCT6694_WDT_SETUP,
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.sel = NCT6694_WDT_SETUP_SEL(data->wdev_idx),
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.len = cpu_to_le16(sizeof(*setup))
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};
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unsigned int timeleft_ms;
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int ret;
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ret = nct6694_read_msg(data->nct6694, &cmd_hd, setup);
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if (ret)
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return 0;
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timeleft_ms = le32_to_cpu(setup->countdown);
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return timeleft_ms / 1000;
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}
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static const struct watchdog_info nct6694_wdt_info = {
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE |
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WDIOF_PRETIMEOUT,
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.identity = DEVICE_NAME,
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};
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static const struct watchdog_ops nct6694_wdt_ops = {
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.owner = THIS_MODULE,
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.start = nct6694_wdt_start,
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.stop = nct6694_wdt_stop,
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.set_timeout = nct6694_wdt_set_timeout,
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.set_pretimeout = nct6694_wdt_set_pretimeout,
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.get_timeleft = nct6694_wdt_get_time,
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.ping = nct6694_wdt_ping,
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};
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static void nct6694_wdt_ida_free(void *d)
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{
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struct nct6694_wdt_data *data = d;
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struct nct6694 *nct6694 = data->nct6694;
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ida_free(&nct6694->wdt_ida, data->wdev_idx);
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}
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static int nct6694_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct nct6694 *nct6694 = dev_get_drvdata(dev->parent);
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struct nct6694_wdt_data *data;
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struct watchdog_device *wdev;
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int ret;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->msg = devm_kzalloc(dev, sizeof(union nct6694_wdt_msg),
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GFP_KERNEL);
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if (!data->msg)
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return -ENOMEM;
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data->dev = dev;
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data->nct6694 = nct6694;
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ret = ida_alloc(&nct6694->wdt_ida, GFP_KERNEL);
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if (ret < 0)
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return ret;
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data->wdev_idx = ret;
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ret = devm_add_action_or_reset(dev, nct6694_wdt_ida_free, data);
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if (ret)
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return ret;
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wdev = &data->wdev;
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wdev->info = &nct6694_wdt_info;
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wdev->ops = &nct6694_wdt_ops;
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wdev->timeout = timeout[data->wdev_idx];
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wdev->pretimeout = pretimeout[data->wdev_idx];
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if (timeout[data->wdev_idx] < pretimeout[data->wdev_idx]) {
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dev_warn(data->dev, "pretimeout < timeout. Setting to zero\n");
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wdev->pretimeout = 0;
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}
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wdev->min_timeout = 1;
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wdev->max_timeout = 255;
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platform_set_drvdata(pdev, data);
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watchdog_set_drvdata(&data->wdev, data);
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watchdog_set_nowayout(&data->wdev, nowayout);
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watchdog_stop_on_reboot(&data->wdev);
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return devm_watchdog_register_device(dev, &data->wdev);
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}
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static struct platform_driver nct6694_wdt_driver = {
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.driver = {
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.name = DEVICE_NAME,
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},
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.probe = nct6694_wdt_probe,
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};
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module_platform_driver(nct6694_wdt_driver);
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MODULE_DESCRIPTION("USB-WDT driver for NCT6694");
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MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:nct6694-wdt");