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Message-ID: <1cd1e048-71b2-b3e9-e22a-d0aae7129072@roeck-us.net>
Date: Mon, 30 Mar 2020 08:32:17 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: yuechao.zhao@...antech.com.cn, 345351830@...com
Cc: Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org,
linux-kernel@...r.kernel.org, amy.shih@...antech.com.tw,
oakley.ding@...antech.com.tw, jia.sui@...antech.com.cn,
shengkui.leng@...antech.com.cn
Subject: Re: [v3,1/1] hwmon: (nct7904) Add watchdog function
On 3/30/20 2:59 AM, yuechao.zhao@...antech.com.cn wrote:
> From: Yuechao Zhao <yuechao.zhao@...antech.com.cn>
>
> implement watchdong functionality into the "hwmon/nct7904.c"
>
> Signed-off-by: Yuechao Zhao <yuechao.zhao@...antech.com.cn>
> ---
> v2:
> - Modify dependency of NC7904 into "drivers/hwmon/Kconfig".
>
> 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.
> ---
> drivers/hwmon/Kconfig | 6 ++-
> drivers/hwmon/nct7904.c | 132 +++++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 135 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..13ac880 100644
> --- a/drivers/hwmon/nct7904.c
> +++ b/drivers/hwmon/nct7904.c
> @@ -8,6 +8,9 @@
> * Copyright (c) 2019 Advantech
> * Author: Amy.Shih <amy.shih@...antech.com.tw>
> *
> + * Copyright (c) 2020 Advantech
> + * Author: Yuechao Zhao <yuechao.zhao@...antech.com.cn>
> + *
> * 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 +917,87 @@ 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);
> +
> + wdt->timeout = timeout;
wdt->timeout needs to match the actual timeout selected.
For example, if the user configures a timeout of 119 seconds,
the actual timeout will be 60 seconds. wdt->timeout must then
be set to 60 seconds. So this needs to be
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 (unsigned int)ret;
The returned value is the time left in minutes, thus
return ret * 60;
The typecast is unnecessary.
> +}
> +
> +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 +1121,28 @@ 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);
> +
> + i2c_set_clientdata(client, data);
Unless I am missing something, this is not needed.
> +
> + return devm_watchdog_register_device(dev, &data->wdt);
> }
>
> static const struct i2c_device_id nct7904_id[] = {
>
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