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Subject[v4,1/1] hwmon: (nct7904) Add watchdog function
Date
From: Yuechao Zhao <yuechao.zhao@advantech.com.cn>

implement watchdong functionality into the "hwmon/nct7904.c"

Signed-off-by: Yuechao Zhao <yuechao.zhao@advantech.com.cn>
---
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@advantech.com.tw>
*
+ * Copyright (c) 2020 Advantech
+ * Author: Yuechao Zhao <yuechao.zhao@advantech.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 +917,95 @@ 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[] = {
--
1.8.3.1
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