Re: [v4,1/1] hwmon: (nct7904) Add watchdog function

[Guenter Roeck]

On Tue, Mar 31, 2020 at 05:28:50AM +0000, yuechao.zhao@xxxxxxxxxxxxxxxx wrote:
> From: Yuechao Zhao <yuechao.zhao@xxxxxxxxxxxxxxxx>
> 
> implement watchdong functionality into the "hwmon/nct7904.c"

s/watchdong/watchdog/

No need to resend; I fixed it up.

> 
> Signed-off-by: Yuechao Zhao <yuechao.zhao@xxxxxxxxxxxxxxxx>

Applied to hwmon-next.

Thanks,
Guenter

> ---
> v4:
> - Set "wdt->timeout" to actual timeout
> - Modify nct7904_wdt_get_timeleft return value
> - Remove code 'i2c_set_clientdata(client, data)'
> 
> v3:
> - Delete useless message(noise).
> - Delete useless variable 'ret'.
> - Delete 'ping_timeout'.
> - Use 'wdt->timeout' as basis for setting the chip timeout
> - Implement a get_timeout function
> - Use devm_watchdog_register_device() instead of watchdog_register_device().
> - Use watchdog_stop_on_unregister() when driver remove.
> - Delete nct7904_remove() function.
> - Fix typos.
> 
> v2:
> - Modify dependency of NC7904 into "drivers/hwmon/Kconfig".
> ---
>  drivers/hwmon/Kconfig   |   6 ++-
>  drivers/hwmon/nct7904.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 141 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 05a3083..cd0ae82 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1340,10 +1340,12 @@ config SENSORS_NCT7802
>  
>  config SENSORS_NCT7904
>  	tristate "Nuvoton NCT7904"
> -	depends on I2C
> +	depends on I2C && WATCHDOG
> +	select WATCHDOG_CORE
>  	help
>  	  If you say yes here you get support for the Nuvoton NCT7904
> -	  hardware monitoring chip, including manual fan speed control.
> +	  hardware monitoring chip, including manual fan speed control
> +	  and support for the integrated watchdog.
>  
>  	  This driver can also be built as a module. If so, the module
>  	  will be called nct7904.
> diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
> index 1f5743d..571a649 100644
> --- a/drivers/hwmon/nct7904.c
> +++ b/drivers/hwmon/nct7904.c
> @@ -8,6 +8,9 @@
>   * Copyright (c) 2019 Advantech
>   * Author: Amy.Shih <amy.shih@xxxxxxxxxxxxxxxx>
>   *
> + * Copyright (c) 2020 Advantech
> + * Author: Yuechao Zhao <yuechao.zhao@xxxxxxxxxxxxxxxx>
> + *
>   * Supports the following chips:
>   *
>   * Chip        #vin  #fan  #pwm  #temp  #dts  chip ID
> @@ -20,6 +23,7 @@
>  #include <linux/i2c.h>
>  #include <linux/mutex.h>
>  #include <linux/hwmon.h>
> +#include <linux/watchdog.h>
>  
>  #define VENDOR_ID_REG		0x7A	/* Any bank */
>  #define NUVOTON_ID		0x50
> @@ -87,18 +91,42 @@
>  #define FANCTL1_FMR_REG		0x00	/* Bank 3; 1 reg per channel */
>  #define FANCTL1_OUT_REG		0x10	/* Bank 3; 1 reg per channel */
>  
> +#define WDT_LOCK_REG		0xE0	/* W/O Lock Watchdog Register */
> +#define WDT_EN_REG		0xE1	/* R/O Watchdog Enable Register */
> +#define WDT_STS_REG		0xE2	/* R/O Watchdog Status Register */
> +#define WDT_TIMER_REG		0xE3	/* R/W Watchdog Timer Register */
> +#define WDT_SOFT_EN		0x55	/* Enable soft watchdog timer */
> +#define WDT_SOFT_DIS		0xAA	/* Disable soft watchdog timer */
> +
>  #define VOLT_MONITOR_MODE	0x0
>  #define THERMAL_DIODE_MODE	0x1
>  #define THERMISTOR_MODE		0x3
>  
>  #define ENABLE_TSI	BIT(1)
>  
> +#define WATCHDOG_TIMEOUT	1	/* 1 minute default timeout */
> +
> +/*The timeout range is 1-255 minutes*/
> +#define MIN_TIMEOUT		(1 * 60)
> +#define MAX_TIMEOUT		(255 * 60)
> +
> +static int timeout = WATCHDOG_TIMEOUT;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in minutes. 1 <= timeout <= 255, default="
> +			__MODULE_STRING(WATCHODOG_TIMEOUT) ".");
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started once started (default="
> +			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
>  static const unsigned short normal_i2c[] = {
>  	0x2d, 0x2e, I2C_CLIENT_END
>  };
>  
>  struct nct7904_data {
>  	struct i2c_client *client;
> +	struct watchdog_device wdt;
>  	struct mutex bank_lock;
>  	int bank_sel;
>  	u32 fanin_mask;
> @@ -889,6 +917,95 @@ static int nct7904_detect(struct i2c_client *client,
>  	.info = nct7904_info,
>  };
>  
> +/*
> + * Watchdog Function
> + */
> +static int nct7904_wdt_start(struct watchdog_device *wdt)
> +{
> +	struct nct7904_data *data = watchdog_get_drvdata(wdt);
> +
> +	/* Enable soft watchdog timer */
> +	return nct7904_write_reg(data, BANK_0, WDT_LOCK_REG, WDT_SOFT_EN);
> +}
> +
> +static int nct7904_wdt_stop(struct watchdog_device *wdt)
> +{
> +	struct nct7904_data *data = watchdog_get_drvdata(wdt);
> +
> +	return nct7904_write_reg(data, BANK_0, WDT_LOCK_REG, WDT_SOFT_DIS);
> +}
> +
> +static int nct7904_wdt_set_timeout(struct watchdog_device *wdt,
> +				   unsigned int timeout)
> +{
> +	struct nct7904_data *data = watchdog_get_drvdata(wdt);
> +	/*
> +	 * The NCT7904 is very special in watchdog function.
> +	 * Its minimum unit is minutes. And wdt->timeout needs
> +	 * to match the actual timeout selected. So, this needs
> +	 * to be: wdt->timeout = timeout / 60 * 60.
> +	 * For example, if the user configures a timeout of
> +	 * 119 seconds, the actual timeout will be 60 seconds.
> +	 * So, wdt->timeout must then be set to 60 seconds.
> +	 */
> +	wdt->timeout = timeout / 60 * 60;
> +
> +	return nct7904_write_reg(data, BANK_0, WDT_TIMER_REG,
> +				 wdt->timeout / 60);
> +}
> +
> +static int nct7904_wdt_ping(struct watchdog_device *wdt)
> +{
> +	/*
> +	 * Note:
> +	 * NCT7904 does not support refreshing WDT_TIMER_REG register when
> +	 * the watchdog is active. Please disable watchdog before feeding
> +	 * the watchdog and enable it again.
> +	 */
> +	struct nct7904_data *data = watchdog_get_drvdata(wdt);
> +	int ret;
> +
> +	/* Disable soft watchdog timer */
> +	ret = nct7904_write_reg(data, BANK_0, WDT_LOCK_REG, WDT_SOFT_DIS);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* feed watchdog */
> +	ret = nct7904_write_reg(data, BANK_0, WDT_TIMER_REG, wdt->timeout / 60);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Enable soft watchdog timer */
> +	return nct7904_write_reg(data, BANK_0, WDT_TIMER_REG, WDT_SOFT_EN);
> +}
> +
> +static unsigned int nct7904_wdt_get_timeleft(struct watchdog_device *wdt)
> +{
> +	struct nct7904_data *data = watchdog_get_drvdata(wdt);
> +	int ret;
> +
> +	ret = nct7904_read_reg(data, BANK_0, WDT_TIMER_REG);
> +	if (ret < 0)
> +		return 0;
> +
> +	return ret * 60;
> +}
> +
> +static const struct watchdog_info nct7904_wdt_info = {
> +	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
> +				WDIOF_MAGICCLOSE,
> +	.identity	= "nct7904 watchdog",
> +};
> +
> +static const struct watchdog_ops nct7904_wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= nct7904_wdt_start,
> +	.stop		= nct7904_wdt_stop,
> +	.ping		= nct7904_wdt_ping,
> +	.set_timeout	= nct7904_wdt_set_timeout,
> +	.get_timeleft	= nct7904_wdt_get_timeleft,
> +};
> +
>  static int nct7904_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
> @@ -1012,7 +1129,26 @@ static int nct7904_probe(struct i2c_client *client,
>  	hwmon_dev =
>  		devm_hwmon_device_register_with_info(dev, client->name, data,
>  						     &nct7904_chip_info, NULL);
> -	return PTR_ERR_OR_ZERO(hwmon_dev);
> +	ret = PTR_ERR_OR_ZERO(hwmon_dev);
> +	if (ret)
> +		return ret;
> +
> +	/* Watchdog initialization */
> +	data->wdt.ops = &nct7904_wdt_ops;
> +	data->wdt.info = &nct7904_wdt_info;
> +
> +	data->wdt.timeout = timeout * 60; /* in seconds */
> +	data->wdt.min_timeout = MIN_TIMEOUT;
> +	data->wdt.max_timeout = MAX_TIMEOUT;
> +	data->wdt.parent = &client->dev;
> +
> +	watchdog_init_timeout(&data->wdt, timeout * 60, &client->dev);
> +	watchdog_set_nowayout(&data->wdt, nowayout);
> +	watchdog_set_drvdata(&data->wdt, data);
> +
> +	watchdog_stop_on_unregister(&data->wdt);
> +
> +	return devm_watchdog_register_device(dev, &data->wdt);
>  }
>  
>  static const struct i2c_device_id nct7904_id[] = {