hwmon: (tmp401) Add support for update_interval attribute
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/hwmon/tmp401.c b/drivers/hwmon/tmp401.c
index 0611462..fa6af51 100644
--- a/drivers/hwmon/tmp401.c
+++ b/drivers/hwmon/tmp401.c
@@ -127,6 +127,8 @@
unsigned long last_updated; /* in jiffies */
enum chips kind;
+ unsigned int update_interval; /* in milliseconds */
+
/* register values */
u8 status;
u8 config;
@@ -194,10 +196,13 @@
struct tmp401_data *data = i2c_get_clientdata(client);
struct tmp401_data *ret = data;
int val;
+ unsigned long next_update;
mutex_lock(&data->update_lock);
- if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+ next_update = data->last_updated +
+ msecs_to_jiffies(data->update_interval) + 1;
+ if (time_after(jiffies, next_update) || !data->valid) {
val = i2c_smbus_read_byte_data(client, TMP401_STATUS);
if (val < 0) {
ret = ERR_PTR(val);
@@ -372,6 +377,46 @@
return count;
}
+static ssize_t show_update_interval(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct tmp401_data *data = i2c_get_clientdata(client);
+
+ return sprintf(buf, "%u\n", data->update_interval);
+}
+
+static ssize_t set_update_interval(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct tmp401_data *data = i2c_get_clientdata(client);
+ unsigned long val;
+ int err, rate;
+
+ err = kstrtoul(buf, 10, &val);
+ if (err)
+ return err;
+
+ /*
+ * For valid rates, interval can be calculated as
+ * interval = (1 << (7 - rate)) * 125;
+ * Rounded rate is therefore
+ * rate = 7 - __fls(interval * 4 / (125 * 3));
+ * Use clamp_val() to avoid overflows, and to ensure valid input
+ * for __fls.
+ */
+ val = clamp_val(val, 125, 16000);
+ rate = 7 - __fls(val * 4 / (125 * 3));
+ mutex_lock(&data->update_lock);
+ i2c_smbus_write_byte_data(client, TMP401_CONVERSION_RATE_WRITE, rate);
+ data->update_interval = (1 << (7 - rate)) * 125;
+ mutex_unlock(&data->update_lock);
+
+ return count;
+}
+
static SENSOR_DEVICE_ATTR_2(temp1_input, S_IRUGO, show_temp, NULL, 0, 0);
static SENSOR_DEVICE_ATTR_2(temp1_min, S_IWUSR | S_IRUGO, show_temp,
store_temp, 1, 0);
@@ -405,6 +450,9 @@
static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_status, NULL,
TMP401_STATUS_REMOTE_CRIT);
+static DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR, show_update_interval,
+ set_update_interval);
+
static struct attribute *tmp401_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
@@ -425,6 +473,8 @@
&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
+ &dev_attr_update_interval.attr,
+
NULL
};
@@ -466,9 +516,11 @@
static void tmp401_init_client(struct i2c_client *client)
{
int config, config_orig;
+ struct tmp401_data *data = i2c_get_clientdata(client);
/* Set the conversion rate to 2 Hz */
i2c_smbus_write_byte_data(client, TMP401_CONVERSION_RATE_WRITE, 5);
+ data->update_interval = 500;
/* Start conversions (disable shutdown if necessary) */
config = i2c_smbus_read_byte_data(client, TMP401_CONFIG_READ);