--- /dev/null
+// 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");
projects / thirdparty / kernel / stable.git / commitdiff
