Re: [PATCH v1 5/9] watchdog: Add Nuvoton NCT6694 WDT support

Ming Yu
2024-10-28T09:49:39Z

Dear Guenter,

Thank you for your comments,
I will remove the unnecessary logs in the next patch.

Guenter Roeck <linux@roeck-us.net> 於 2024年10月24日 週四 下午11:33寫道：
>
> On 10/24/24 01:59, Ming Yu wrote:
> > This driver supports Watchdog timer functionality for NCT6694 MFD
> > device based on USB interface.
> >
> > Signed-off-by: Ming Yu <tmyu0@nuvoton.com>
> > ---
> > MAINTAINERS | 1 +
> > drivers/watchdog/Kconfig | 11 ++
> > drivers/watchdog/Makefile | 1 +
> > drivers/watchdog/nct6694_wdt.c | 329 +++++++++++++++++++++++++++++++++
> > 4 files changed, 342 insertions(+)
> > create mode 100644 drivers/watchdog/nct6694_wdt.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index eccd5e795daa..63387c0d4ab6 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -16442,6 +16442,7 @@ F: drivers/gpio/gpio-nct6694.c
> > F: drivers/i2c/busses/i2c-nct6694.c
> > F: drivers/mfd/nct6694.c
> > F: drivers/net/can/nct6694_canfd.c
> > +F: drivers/watchdog/nct6694_wdt.c
> > F: include/linux/mfd/nct6694.h
> >
> > NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 684b9fe84fff..bc9d63d69204 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -739,6 +739,17 @@ 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
> > + If you say yes to this option, support will be included for Nuvoton
> > + NCT6694, a USB device to watchdog timer.
> > +
> > + 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
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index ab6f2b41e38e..453ceacd43ab 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -231,6 +231,7 @@ 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
> > diff --git a/drivers/watchdog/nct6694_wdt.c b/drivers/watchdog/nct6694_wdt.c
> > new file mode 100644
> > index 000000000000..68e2926ec504
> > --- /dev/null
> > +++ b/drivers/watchdog/nct6694_wdt.c
> > @@ -0,0 +1,329 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Nuvoton NCT6694 WDT driver based on USB interface.
> > + *
> > + * Copyright (C) 2024 Nuvoton Technology Corp.
> > + */
> > +
> > +#include <linux/watchdog.h>
> > +#include <linux/slab.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/mfd/nct6694.h>
> > +
> > +#define DRVNAME "nct6694-wdt"
> > +
> > +#define WATCHDOG_TIMEOUT 10
> > +#define WATCHDOG_PRETIMEOUT 0
> > +
> > +/* Host interface */
> > +#define REQUEST_WDT_MOD 0x07
> > +
> > +/* Message Channel*/
> > +/* Command 00h */
> > +#define REQUEST_WDT_CMD0_LEN 0x0F
> > +#define REQUEST_WDT_CMD0_OFFSET(idx) (idx ? 0x0100 : 0x0000) /* OFFSET = SEL|CMD */
> > +#define WDT_PRETIMEOUT_IDX 0x00
> > +#define WDT_PRETIMEOUT_LEN 0x04 /* PRETIMEOUT(3byte) | ACT(1byte) */
> > +#define WDT_TIMEOUT_IDX 0x04
> > +#define WDT_TIMEOUT_LEN 0x04 /* TIMEOUT(3byte) | ACT(1byte) */
> > +#define WDT_COUNTDOWN_IDX 0x0C
> > +#define WDT_COUNTDOWN_LEN 0x03
> > +
> > +#define WDT_PRETIMEOUT_ACT BIT(1)
> > +#define WDT_TIMEOUT_ACT BIT(1)
> > +
> > +/* Command 01h */
> > +#define REQUEST_WDT_CMD1_LEN 0x04
> > +#define REQUEST_WDT_CMD1_OFFSET(idx) (idx ? 0x0101 : 0x0001) /* OFFSET = SEL|CMD */
> > +#define WDT_CMD_IDX 0x00
> > +#define WDT_CMD_LEN 0x04
> > +
> > +static unsigned int timeout;
> > +module_param(timeout, int, 0);
> > +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
> > +
> > +static unsigned int pretimeout;
> > +module_param(pretimeout, int, 0);
> > +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) ")");
> > +
> > +struct nct6694_wdt_data {
> > + struct nct6694 *nct6694;
> > + struct watchdog_device wdev;
> > + unsigned int wdev_idx;
> > +};
> > +
> > +static inline void set_buf32(void *buf, u32 u32_val)
> > +{
> > + u8 *p = (u8 *)buf;
> > +
> > + p[0] = u32_val & 0xFF;
> > + p[1] = (u32_val >> 8) & 0xFF;
> > + p[2] = (u32_val >> 16) & 0xFF;
> > + p[3] = (u32_val >> 24) & 0xFF;
> > +}
> > +
> > +static int nct6694_wdt_start(struct watchdog_device *wdev)
> > +{
> > + struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
> > +
> > + pr_debug("%s: WDT(%d) Start\n", __func__, data->wdev_idx);
> > +
> > + return 0;
> > +}
> > +
> > +static int nct6694_wdt_stop(struct watchdog_device *wdev)
> > +{
> > + struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
> > + struct nct6694 *nct6694 = data->nct6694;
> > + unsigned char buf[REQUEST_WDT_CMD1_LEN] = {'W', 'D', 'T', 'C'};
> > + int ret;
> > +
> > + pr_debug("%s: WDT(%d) Close\n", __func__, data->wdev_idx);
> > + ret = nct6694_write_msg(nct6694, REQUEST_WDT_MOD,
> > + REQUEST_WDT_CMD1_OFFSET(data->wdev_idx),
> > + REQUEST_WDT_CMD1_LEN, buf);
> > + if (ret)
> > + pr_err("%s: Failed to start WDT device!\n", __func__);
>
> Please refrain from logging noise. Besides, the message is wrong:
> the watchdog is stopped here, not started.
>
> Also, all messages should use dev_, not pr_ functions.

[Ming] Okay! I will change it.

>
> > +
> > + return ret;
> > +}
> > +
> > +static int nct6694_wdt_ping(struct watchdog_device *wdev)
> > +{
> > + struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
> > + struct nct6694 *nct6694 = data->nct6694;
> > + unsigned char buf[REQUEST_WDT_CMD1_LEN] = {'W', 'D', 'T', 'S'};
> > + int ret;
> > +
> > + pr_debug("%s: WDT(%d) Ping\n", __func__, data->wdev_idx);
> > + ret = nct6694_write_msg(nct6694, REQUEST_WDT_MOD,
> > + REQUEST_WDT_CMD1_OFFSET(data->wdev_idx),
> > + REQUEST_WDT_CMD1_LEN, buf);
> > + if (ret)
> > + pr_err("%s: Failed to ping WDT device!\n", __func__);
>
> Same as above and everywhere else.
>
> > +
> > + return ret;
> > +}
> > +
> > +static int nct6694_wdt_set_timeout(struct watchdog_device *wdev,
> > + unsigned int timeout)
> > +{
> > + struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
> > + struct nct6694 *nct6694 = data->nct6694;
> > + unsigned int timeout_fmt, pretimeout_fmt;
> > + unsigned char buf[REQUEST_WDT_CMD0_LEN];
> > + int ret;
> > +
> > + if (timeout < wdev->pretimeout) {
> > + pr_err("%s: 'timeout' must be greater than 'pre timeout'!\n",
> > + __func__);
> > + return -EINVAL;
>
> the driver is supposed to adjust pretimeout in this case. And please,
> again, refrain from logging noise.

[Ming] Excuse me, is any recommendation about pretimeout value?

> > + }
> > +
> > + timeout_fmt = timeout * 1000 | (WDT_TIMEOUT_ACT << 24);
> > + pretimeout_fmt = wdev->pretimeout * 1000 | (WDT_PRETIMEOUT_ACT << 24);
> > + set_buf32(&buf[WDT_TIMEOUT_IDX], le32_to_cpu(timeout_fmt));
> > + set_buf32(&buf[WDT_PRETIMEOUT_IDX], le32_to_cpu(pretimeout_fmt));
> > +
> > + ret = nct6694_write_msg(nct6694, REQUEST_WDT_MOD,
> > + REQUEST_WDT_CMD0_OFFSET(data->wdev_idx),
> > + REQUEST_WDT_CMD0_LEN, buf);
> > + if (ret) {
> > + pr_err("%s: Don't write the setup command in Start stage!\n",
> > + __func__);
> > + return ret;
> > + }
> > +
> > + wdev->timeout = timeout;
> > +
> > + return 0;
> > +}
> > +
> > +static int nct6694_wdt_set_pretimeout(struct watchdog_device *wdev,
> > + unsigned int pretimeout)
> > +{
> > + struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
> > + struct nct6694 *nct6694 = data->nct6694;
> > + unsigned int timeout_fmt, pretimeout_fmt;
> > + unsigned char buf[REQUEST_WDT_CMD0_LEN];
> > + int ret;
> > +
> > + if (pretimeout > wdev->timeout) {
> > + pr_err("%s: 'pre timeout' must be less than 'timeout'!\n",
> > + __func__);
> > + return -EINVAL;
>
> Already checked by the watchdog core.

[Ming] I understand. I will remove it.

>
> > + }
> > + timeout_fmt = wdev->timeout * 1000 | (WDT_TIMEOUT_ACT << 24);
> > + pretimeout_fmt = pretimeout * 1000 | (WDT_PRETIMEOUT_ACT << 24);
> > + set_buf32(&buf[WDT_TIMEOUT_IDX], le32_to_cpu(timeout_fmt));
> > + set_buf32(&buf[WDT_PRETIMEOUT_IDX], le32_to_cpu(pretimeout_fmt));
> > +
> > + ret = nct6694_write_msg(nct6694, REQUEST_WDT_MOD,
> > + REQUEST_WDT_CMD0_OFFSET(data->wdev_idx),
> > + REQUEST_WDT_CMD0_LEN, buf);
> > + if (ret) {
> > + pr_err("%s: Don't write the setup command in Start stage!\n", __func__);
>
> Besides it being noise, I don't even understand what this message is
> supposed to mean, and neither would anyone else.
>
> > + return ret;
> > + }
> > +
> > + wdev->pretimeout = 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 *nct6694 = data->nct6694;
> > + unsigned char buf[WDT_COUNTDOWN_LEN];
> > + unsigned int timeleft_ms;
> > + int ret;
> > +
> > + ret = nct6694_read_msg(nct6694, REQUEST_WDT_MOD,
> > + REQUEST_WDT_CMD0_OFFSET(data->wdev_idx),
> > + REQUEST_WDT_CMD0_LEN, WDT_COUNTDOWN_IDX,
> > + WDT_COUNTDOWN_LEN, buf);
> > + if (ret)
> > + pr_err("%s: Failed to get WDT device!\n", __func__);
> > +
> > + timeleft_ms = ((buf[2] << 16) | (buf[1] << 8) | buf[0]) & 0xFFFFFF;
>
> If the above command failed this will be a random number.

[Ming] Okay! I will update error handling about return value.

>
> > +
> > + return timeleft_ms / 1000;
> > +}
> > +
> > +static int nct6694_wdt_setup(struct watchdog_device *wdev)
> > +{
> > + struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
> > + struct nct6694 *nct6694 = data->nct6694;
> > + unsigned char buf[REQUEST_WDT_CMD0_LEN] = {0};
> > + unsigned int timeout_fmt, pretimeout_fmt;
> > + int ret;
> > +
> > + if (timeout)
> > + wdev->timeout = timeout;
> > +
> Already set.
>
> > + if (pretimeout) {
> > + wdev->pretimeout = pretimeout;
>
> Pretimeout is already set in the probe function. Do it completely there.
>
> > + pretimeout_fmt = wdev->pretimeout * 1000 | (WDT_PRETIMEOUT_ACT << 24);
> > + } else {
> > + pretimeout_fmt = 0;
> > + }
> > +
> > + timeout_fmt = wdev->timeout * 1000 | (WDT_TIMEOUT_ACT << 24);
> > + set_buf32(&buf[WDT_TIMEOUT_IDX], le32_to_cpu(timeout_fmt));
> > + set_buf32(&buf[WDT_PRETIMEOUT_IDX], le32_to_cpu(pretimeout_fmt));
> > +
> > + ret = nct6694_write_msg(nct6694, REQUEST_WDT_MOD,
> > + REQUEST_WDT_CMD0_OFFSET(data->wdev_idx),
> > + REQUEST_WDT_CMD0_LEN, buf);
>
>
> This seems pretty pointless at this time. Why not do it in the watchdog
> start function ?

[Ming] Yes, I will remove it and do it in the start callback in the next patch.

>
> > + if (ret)
> > + return ret;
> > +
> > + pr_info("Setting WDT(%d): timeout = %d, pretimeout = %d\n",
> > + data->wdev_idx, wdev->timeout, wdev->pretimeout);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct watchdog_info nct6694_wdt_info = {
> > + .options = WDIOF_SETTIMEOUT |
> > + WDIOF_KEEPALIVEPING |
> > + WDIOF_MAGICCLOSE |
> > + WDIOF_PRETIMEOUT,
> > + .identity = DRVNAME,
> > +};
> > +
> > +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 int nct6694_wdt_probe(struct platform_device *pdev)
> > +{
> > + const struct mfd_cell *cell = mfd_get_cell(pdev);
> > + struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
> > + struct nct6694_wdt_data *data;
> > + struct watchdog_device *wdev;
> > + int ret;
> > +
> > + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> > + if (!data)
> > + return -ENOMEM;
> > +
> > + data->nct6694 = nct6694;
> > + data->wdev_idx = cell->id;
> > +
> > + wdev = &data->wdev;
> > + wdev->info = &nct6694_wdt_info;
> > + wdev->ops = &nct6694_wdt_ops;
> > + wdev->timeout = WATCHDOG_TIMEOUT;
> > + wdev->pretimeout = WATCHDOG_PRETIMEOUT;
> > + wdev->min_timeout = 1;
> > + wdev->max_timeout = 255;
> > +
> > + platform_set_drvdata(pdev, data);
> > +
> > + /* Register watchdog timer device to WDT framework */
> > + watchdog_set_drvdata(&data->wdev, data);
> > + watchdog_init_timeout(&data->wdev, timeout, &pdev->dev);
> > + watchdog_set_nowayout(&data->wdev, nowayout);
> > + watchdog_stop_on_reboot(&data->wdev);
> > +
> > + ret = devm_watchdog_register_device(&pdev->dev, &data->wdev);
> > + if (ret) {
> > + dev_err(&pdev->dev, "%s: Failed to register watchdog device: %d\n",
> > + __func__, ret);
> > + return ret;
> > + }
> > +
> > + ret = nct6694_wdt_setup(&data->wdev);
>
> This is too late. It needs to be done before registering the watchdog.
>
> > + if (ret) {
> > + dev_err(&pdev->dev, "Failed to setup WDT device!\n");
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver nct6694_wdt_driver = {
> > + .driver = {
> > + .name = DRVNAME,
> > + },
> > + .probe = nct6694_wdt_probe,
> > +};
> > +
> > +static int __init nct6694_init(void)
> > +{
> > + int err;
> > +
> > + err = platform_driver_register(&nct6694_wdt_driver);
> > + if (!err) {
> > + if (err)
> > + platform_driver_unregister(&nct6694_wdt_driver);
> > + }
> > +
> > + return err;
> > +}
> > +subsys_initcall(nct6694_init);
> > +
> > +static void __exit nct6694_exit(void)
> > +{
> > + platform_driver_unregister(&nct6694_wdt_driver);
> > +}
> > +module_exit(nct6694_exit);
> > +
> > +MODULE_DESCRIPTION("USB-WDT driver for NCT6694");
> > +MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
> > +MODULE_LICENSE("GPL");
>

Best regards,
Ming