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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>
hifive-unleashed-5.1
Guenter Roeck 2013-03-28 02:03:10 -07:00
parent 8eb6d90fec
commit 0846e30dd4
1 changed files with 53 additions and 1 deletions
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54
drivers/hwmon/tmp401.c
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@ -127,6 +127,8 @@ struct tmp401_data {
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 @@ static struct tmp401_data *tmp401_update_device(struct device *dev)
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 @@ static ssize_t reset_temp_history(struct device *dev,
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_max_alarm, S_IRUGO, show_status, NULL,
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 @@ static struct attribute *tmp401_attributes[] = {
&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 const struct attribute_group tmp411_group = {
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);