hwmon: (adm1031) Allow setting update rate
Based on earlier work by Ira W. Snyder.
The adm1031 chip is capable of using a runtime configurable sampling rate,
using the fan filter register. Add support for reading and setting the
update rate via sysfs.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Ira W. Snyder <iws@ovro.caltech.edu>
diff --git a/drivers/hwmon/adm1031.c b/drivers/hwmon/adm1031.c
index 1644b92..15c1a96 100644
--- a/drivers/hwmon/adm1031.c
+++ b/drivers/hwmon/adm1031.c
@@ -36,6 +36,7 @@
#define ADM1031_REG_FAN_DIV(nr) (0x20 + (nr))
#define ADM1031_REG_PWM (0x22)
#define ADM1031_REG_FAN_MIN(nr) (0x10 + (nr))
+#define ADM1031_REG_FAN_FILTER (0x23)
#define ADM1031_REG_TEMP_OFFSET(nr) (0x0d + (nr))
#define ADM1031_REG_TEMP_MAX(nr) (0x14 + 4 * (nr))
@@ -61,6 +62,9 @@
#define ADM1031_CONF2_TACH2_ENABLE 0x08
#define ADM1031_CONF2_TEMP_ENABLE(chan) (0x10 << (chan))
+#define ADM1031_UPDATE_RATE_MASK 0x1c
+#define ADM1031_UPDATE_RATE_SHIFT 2
+
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2c, 0x2d, 0x2e, I2C_CLIENT_END };
@@ -75,6 +79,7 @@
int chip_type;
char valid; /* !=0 if following fields are valid */
unsigned long last_updated; /* In jiffies */
+ unsigned int update_rate; /* In milliseconds */
/* The chan_select_table contains the possible configurations for
* auto fan control.
*/
@@ -738,6 +743,57 @@
static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_alarm, NULL, 13);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 14);
+/* Update Rate */
+static const unsigned int update_rates[] = {
+ 16000, 8000, 4000, 2000, 1000, 500, 250, 125,
+};
+
+static ssize_t show_update_rate(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct adm1031_data *data = i2c_get_clientdata(client);
+
+ return sprintf(buf, "%u\n", data->update_rate);
+}
+
+static ssize_t set_update_rate(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct adm1031_data *data = i2c_get_clientdata(client);
+ unsigned long val;
+ int i, err;
+ u8 reg;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err)
+ return err;
+
+ /* find the nearest update rate from the table */
+ for (i = 0; i < ARRAY_SIZE(update_rates) - 1; i++) {
+ if (val >= update_rates[i])
+ break;
+ }
+ /* if not found, we point to the last entry (lowest update rate) */
+
+ /* set the new update rate while preserving other settings */
+ reg = adm1031_read_value(client, ADM1031_REG_FAN_FILTER);
+ reg &= ~ADM1031_UPDATE_RATE_MASK;
+ reg |= i << ADM1031_UPDATE_RATE_SHIFT;
+ adm1031_write_value(client, ADM1031_REG_FAN_FILTER, reg);
+
+ mutex_lock(&data->update_lock);
+ data->update_rate = update_rates[i];
+ mutex_unlock(&data->update_lock);
+
+ return count;
+}
+
+static DEVICE_ATTR(update_rate, S_IRUGO | S_IWUSR, show_update_rate,
+ set_update_rate);
+
static struct attribute *adm1031_attributes[] = {
&sensor_dev_attr_fan1_input.dev_attr.attr,
&sensor_dev_attr_fan1_div.dev_attr.attr,
@@ -774,6 +830,7 @@
&sensor_dev_attr_auto_fan1_min_pwm.dev_attr.attr,
+ &dev_attr_update_rate.attr,
&dev_attr_alarms.attr,
NULL
@@ -900,6 +957,7 @@
{
unsigned int read_val;
unsigned int mask;
+ int i;
struct adm1031_data *data = i2c_get_clientdata(client);
mask = (ADM1031_CONF2_PWM1_ENABLE | ADM1031_CONF2_TACH1_ENABLE);
@@ -919,18 +977,24 @@
ADM1031_CONF1_MONITOR_ENABLE);
}
+ /* Read the chip's update rate */
+ mask = ADM1031_UPDATE_RATE_MASK;
+ read_val = adm1031_read_value(client, ADM1031_REG_FAN_FILTER);
+ i = (read_val & mask) >> ADM1031_UPDATE_RATE_SHIFT;
+ data->update_rate = update_rates[i];
}
static struct adm1031_data *adm1031_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct adm1031_data *data = i2c_get_clientdata(client);
+ unsigned long next_update;
int chan;
mutex_lock(&data->update_lock);
- if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
- || !data->valid) {
+ next_update = data->last_updated + msecs_to_jiffies(data->update_rate);
+ if (time_after(jiffies, next_update) || !data->valid) {
dev_dbg(&client->dev, "Starting adm1031 update\n");
for (chan = 0;