Re: [PATCH v3] rtc: rtc-ds1374: wdt: Use watchdog core for watchdog part

From: Guenter Roeck
Date: Mon Jul 06 2020 - 18:09:22 EST

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In reply to: Johnson CH Chen (陳昭勳): "[PATCH v3] rtc: rtc-ds1374: wdt: Use watchdog core for watchdog part"
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On Mon, Jul 06, 2020 at 07:24:25AM +0000, Johnson CH Chen (ïïïLïï) wrote:
> Let ds1374 watchdog use watchdog core functions. It also includes
> improving watchdog timer setting and nowayout, and just uses ioctl()
> of watchdog core.
>
> Signed-off-by: Johnson Chen <johnsonch.chen@xxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>

This should be dropped. Yes, the test robot reported a problem with
an earlier version of this patch, but it did not report a problem with
_this_ version of the patch.

>
> v2->v3:
> - Fix a problem reported by WATCHDOG_CORE if WATCHDOG
> - Remove save_client
> - Let wdt_margin be 0 for watchdog_init_timeout()
> - Use dev_info() rather than pr_info()
> - Avoid more strings in this driver
>
> v1->v2:
> - Use ds1374_wdt_settimeout() before registering the watchdog
> - Remove watchdog_unregister_device() because devm_watchdog_register_device() is used
> - Remove ds1374_wdt_ping()
> - TIMER_MARGIN_MAX to 4095 for 24-bit value
> - Keep wdt_margin
> - Fix coding styles
> ---

Change log should be here, after "---"

> drivers/rtc/Kconfig | 1 +
> drivers/rtc/rtc-ds1374.c | 253 ++++++++++-----------------------------
> 2 files changed, 61 insertions(+), 193 deletions(-)
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index b54d87d45c89..c25d51f35f0c 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -282,6 +282,7 @@ config RTC_DRV_DS1374
> config RTC_DRV_DS1374_WDT
> bool "Dallas/Maxim DS1374 watchdog timer"
> depends on RTC_DRV_DS1374
> + select WATCHDOG_CORE if WATCHDOG
> help
> If you say Y here you will get support for the
> watchdog timer in the Dallas Semiconductor DS1374
> diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c
> index 9c51a12cf70f..e86e381e52a0 100644
> --- a/drivers/rtc/rtc-ds1374.c
> +++ b/drivers/rtc/rtc-ds1374.c
> @@ -46,6 +46,7 @@
> #define DS1374_REG_WDALM2 0x06
> #define DS1374_REG_CR 0x07 /* Control */
> #define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
> +#define DS1374_REG_CR_WDSTR 0x08 /* 1=INT, 0=RST */
> #define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
> #define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
> #define DS1374_REG_SR 0x08 /* Status */
> @@ -71,7 +72,9 @@ struct ds1374 {
> struct i2c_client *client;
> struct rtc_device *rtc;
> struct work_struct work;
> -
> +#ifdef CONFIG_RTC_DRV_DS1374_WDT
> + struct watchdog_device wdt;
> +#endif
> /* The mutex protects alarm operations, and prevents a race
> * between the enable_irq() in the workqueue and the free_irq()
> * in the remove function.
> @@ -369,237 +372,99 @@ static const struct rtc_class_ops ds1374_rtc_ops = {
> *
> *****************************************************************************
> */
> -static struct i2c_client *save_client;
> /* Default margin */
> -#define WD_TIMO 131762
> +#define TIMER_MARGIN_DEFAULT 32
> +#define TIMER_MARGIN_MIN 1
> +#define TIMER_MARGIN_MAX 4095 /* 24-bit value */
>
> #define DRV_NAME "DS1374 Watchdog"
>
> -static int wdt_margin = WD_TIMO;
> -static unsigned long wdt_is_open;
> +static int wdt_margin;
> module_param(wdt_margin, int, 0);
> MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
>
> +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 const struct watchdog_info ds1374_wdt_info = {
> .identity = "DS1374 WTD",
> .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
> WDIOF_MAGICCLOSE,
> };
>
> -static int ds1374_wdt_settimeout(unsigned int timeout)
> +static int ds1374_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
> {
> - int ret = -ENOIOCTLCMD;
> - int cr;
> + int ret, cr;
> + struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
> + struct i2c_client *client = ds1374->client;
>
> - ret = cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
> - if (ret < 0)
> - goto out;
> + wdt->timeout = timeout;
> +
> + cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
> + if (cr < 0)
> + return cr;
>
> /* Disable any existing watchdog/alarm before setting the new one */
> cr &= ~DS1374_REG_CR_WACE;
>
> - ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
> + ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
> if (ret < 0)
> - goto out;
> + return ret;
>
> /* Set new watchdog time */
> - ret = ds1374_write_rtc(save_client, timeout, DS1374_REG_WDALM0, 3);
> + timeout = timeout * 4096;
> + ret = ds1374_write_rtc(client, timeout, DS1374_REG_WDALM0, 3);
> if (ret) {
> - pr_info("couldn't set new watchdog time\n");
> - goto out;
> + dev_info(&client->dev, "couldn't set new watchdog time\n");

This should be dev_err(). Note though that I would suggest to drop the message -
there are other errors for which there is no error message, and I don't see
why this one would be more important or relevant.

> + return ret;
> }
>
> /* Enable watchdog timer */
> cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
> + cr &= ~DS1374_REG_CR_WDSTR;/* for RST PIN */
> cr &= ~DS1374_REG_CR_AIE;
>
> - ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
> + ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
> if (ret < 0)
> - goto out;
> + return ret;
>
> return 0;
> -out:
> - return ret;
> }
>
> -
> /*
> * Reload the watchdog timer. (ie, pat the watchdog)
> */
> -static void ds1374_wdt_ping(void)
> +static int ds1374_wdt_start(struct watchdog_device *wdt)
> {
> u32 val;
> - int ret = 0;
> + struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
>
> - ret = ds1374_read_rtc(save_client, &val, DS1374_REG_WDALM0, 3);
> - if (ret)
> - pr_info("WD TICK FAIL!!!!!!!!!! %i\n", ret);
> + return ds1374_read_rtc(ds1374->client, &val, DS1374_REG_WDALM0, 3);
> }
>
> -static void ds1374_wdt_disable(void)
> +static int ds1374_wdt_stop(struct watchdog_device *wdt)
> {
> int cr;
> + struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
> + struct i2c_client *client = ds1374->client;

Nit: Reverse christmas tree looks a bit better.

+ struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
+ struct i2c_client *client = ds1374->client;
int cr;

>
> - cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
> + cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);

Missing error check:

if (cr < 0)
return cr;

> /* Disable watchdog timer */
> cr &= ~DS1374_REG_CR_WACE;
>
> - i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
> + return i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
> }
>
> -/*
> - * Watchdog device is opened, and watchdog starts running.
> - */
> -static int ds1374_wdt_open(struct inode *inode, struct file *file)
> -{
> - struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
> -
> - if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
> - mutex_lock(&ds1374->mutex);
> - if (test_and_set_bit(0, &wdt_is_open)) {
> - mutex_unlock(&ds1374->mutex);
> - return -EBUSY;
> - }
> - /*
> - * Activate
> - */
> - wdt_is_open = 1;
> - mutex_unlock(&ds1374->mutex);
> - return stream_open(inode, file);
> - }
> - return -ENODEV;
> -}
> -
> -/*
> - * Close the watchdog device.
> - */
> -static int ds1374_wdt_release(struct inode *inode, struct file *file)
> -{
> - if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
> - clear_bit(0, &wdt_is_open);
> -
> - return 0;
> -}
> -
> -/*
> - * Pat the watchdog whenever device is written to.
> - */
> -static ssize_t ds1374_wdt_write(struct file *file, const char __user *data,
> - size_t len, loff_t *ppos)
> -{
> - if (len) {
> - ds1374_wdt_ping();
> - return 1;
> - }
> - return 0;
> -}
> -
> -static ssize_t ds1374_wdt_read(struct file *file, char __user *data,
> - size_t len, loff_t *ppos)
> -{
> - return 0;
> -}
> -
> -/*
> - * Handle commands from user-space.
> - */
> -static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd,
> - unsigned long arg)
> -{
> - int new_margin, options;
> -
> - switch (cmd) {
> - case WDIOC_GETSUPPORT:
> - return copy_to_user((struct watchdog_info __user *)arg,
> - &ds1374_wdt_info, sizeof(ds1374_wdt_info)) ? -EFAULT : 0;
> -
> - case WDIOC_GETSTATUS:
> - case WDIOC_GETBOOTSTATUS:
> - return put_user(0, (int __user *)arg);
> - case WDIOC_KEEPALIVE:
> - ds1374_wdt_ping();
> - return 0;
> - case WDIOC_SETTIMEOUT:
> - if (get_user(new_margin, (int __user *)arg))
> - return -EFAULT;
> -
> - /* the hardware's tick rate is 4096 Hz, so
> - * the counter value needs to be scaled accordingly
> - */
> - new_margin <<= 12;
> - if (new_margin < 1 || new_margin > 16777216)
> - return -EINVAL;
> -
> - wdt_margin = new_margin;
> - ds1374_wdt_settimeout(new_margin);
> - ds1374_wdt_ping();
> - /* fallthrough */
> - case WDIOC_GETTIMEOUT:
> - /* when returning ... inverse is true */
> - return put_user((wdt_margin >> 12), (int __user *)arg);
> - case WDIOC_SETOPTIONS:
> - if (copy_from_user(&options, (int __user *)arg, sizeof(int)))
> - return -EFAULT;
> -
> - if (options & WDIOS_DISABLECARD) {
> - pr_info("disable watchdog\n");
> - ds1374_wdt_disable();
> - return 0;
> - }
> -
> - if (options & WDIOS_ENABLECARD) {
> - pr_info("enable watchdog\n");
> - ds1374_wdt_settimeout(wdt_margin);
> - ds1374_wdt_ping();
> - return 0;
> - }
> - return -EINVAL;
> - }
> - return -ENOTTY;
> -}
> -
> -static long ds1374_wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
> - unsigned long arg)
> -{
> - int ret;
> - struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
> -
> - mutex_lock(&ds1374->mutex);
> - ret = ds1374_wdt_ioctl(file, cmd, arg);
> - mutex_unlock(&ds1374->mutex);
> -
> - return ret;
> -}
> -
> -static int ds1374_wdt_notify_sys(struct notifier_block *this,
> - unsigned long code, void *unused)
> -{
> - if (code == SYS_DOWN || code == SYS_HALT)
> - /* Disable Watchdog */
> - ds1374_wdt_disable();
> - return NOTIFY_DONE;
> -}
> -
> -static const struct file_operations ds1374_wdt_fops = {
> - .owner = THIS_MODULE,
> - .read = ds1374_wdt_read,
> - .unlocked_ioctl = ds1374_wdt_unlocked_ioctl,
> - .compat_ioctl = compat_ptr_ioctl,
> - .write = ds1374_wdt_write,
> - .open = ds1374_wdt_open,
> - .release = ds1374_wdt_release,
> - .llseek = no_llseek,
> +static const struct watchdog_ops ds1374_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = ds1374_wdt_start,
> + .stop = ds1374_wdt_stop,
> + .set_timeout = ds1374_wdt_settimeout,
> };
>
> -static struct miscdevice ds1374_miscdev = {
> - .minor = WATCHDOG_MINOR,
> - .name = "watchdog",
> - .fops = &ds1374_wdt_fops,
> -};
> -
> -static struct notifier_block ds1374_wdt_notifier = {
> - .notifier_call = ds1374_wdt_notify_sys,
> -};
>
> #endif /*CONFIG_RTC_DRV_DS1374_WDT*/
> /*
> @@ -652,16 +517,23 @@ static int ds1374_probe(struct i2c_client *client,
> return ret;
>
> #ifdef CONFIG_RTC_DRV_DS1374_WDT
> - save_client = client;
> - ret = misc_register(&ds1374_miscdev);
> + ds1374->wdt.info = &ds1374_wdt_info;
> + ds1374->wdt.ops = &ds1374_wdt_ops;
> + ds1374->wdt.timeout = TIMER_MARGIN_DEFAULT;
> + ds1374->wdt.min_timeout = TIMER_MARGIN_MIN;
> + ds1374->wdt.max_timeout = TIMER_MARGIN_MAX;
> +
> + watchdog_init_timeout(&ds1374->wdt, wdt_margin, &client->dev);
> + watchdog_set_nowayout(&ds1374->wdt, nowayout);
> + watchdog_stop_on_reboot(&ds1374->wdt);
> + watchdog_stop_on_unregister(&ds1374->wdt);
> + watchdog_set_drvdata(&ds1374->wdt, ds1374);
> + ds1374_wdt_settimeout(&ds1374->wdt, ds1374->wdt.timeout);
> +
> +

Drop 2nd empty line.

> + ret = devm_watchdog_register_device(&client->dev, &ds1374->wdt);
> if (ret)
> return ret;
> - ret = register_reboot_notifier(&ds1374_wdt_notifier);
> - if (ret) {
> - misc_deregister(&ds1374_miscdev);
> - return ret;
> - }
> - ds1374_wdt_settimeout(131072);
> #endif
>
> return 0;
> @@ -670,11 +542,6 @@ static int ds1374_probe(struct i2c_client *client,
> static int ds1374_remove(struct i2c_client *client)
> {
> struct ds1374 *ds1374 = i2c_get_clientdata(client);
> -#ifdef CONFIG_RTC_DRV_DS1374_WDT
> - misc_deregister(&ds1374_miscdev);
> - ds1374_miscdev.parent = NULL;
> - unregister_reboot_notifier(&ds1374_wdt_notifier);
> -#endif
>
> if (client->irq > 0) {
> mutex_lock(&ds1374->mutex);

Next message: Chu Lin: "[PATCH v2 0/1] hwmon:max6697: Allow max6581 to create tempX_offset"
Previous message: Wei Yang: "Re: [RESEND Patch v2 0/4] mm/mremap: cleanup move_page_tables() a little"
In reply to: Johnson CH Chen (陳昭勳): "[PATCH v3] rtc: rtc-ds1374: wdt: Use watchdog core for watchdog part"
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