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hwmon: (lm75) Prepare to support per-chip resolution and sample time

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Prepare the lm75 driver to support per-chip resolution and sample
time. For now we only make the code generic enough to support it, but
we still use the same, unchanged resolution (9-bit) and sample time
(1.5 s) for all chips.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Jean Delvare 2013-05-04 14:49:36 +02:00 committed by Jean Delvare
parent 8a5c5cc617
commit 87d0621ae2
1 changed files with 26 additions and 5 deletions
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31
drivers/hwmon/lm75.c
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@ -71,9 +71,12 @@ struct lm75_data {
struct device *hwmon_dev;
struct mutex update_lock;
u8 orig_conf;
u8 resolution; /* In bits, between 9 and 12 */
u8 resolution_limits;
char valid; /* !=0 if registers are valid */
unsigned long last_updated; /* In jiffies */
u16 temp[3]; /* Register values,
unsigned long sample_time; /* In jiffies */
s16 temp[3]; /* Register values,
0 = input
1 = max
2 = hyst */
@ -93,12 +96,15 @@ static ssize_t show_temp(struct device *dev, struct device_attribute *da,
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct lm75_data *data = lm75_update_device(dev);
long temp;
if (IS_ERR(data))
return PTR_ERR(data);
return sprintf(buf, "%d\n",
LM75_TEMP_FROM_REG(data->temp[attr->index]));
temp = ((data->temp[attr->index] >> (16 - data->resolution)) * 1000)
>> (data->resolution - 8);
return sprintf(buf, "%ld\n", temp);
}
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
@ -110,13 +116,25 @@ static ssize_t set_temp(struct device *dev, struct device_attribute *da,
int nr = attr->index;
long temp;
int error;
u8 resolution;
error = kstrtol(buf, 10, &temp);
if (error)
return error;
/*
* Resolution of limit registers is assumed to be the same as the
* temperature input register resolution unless given explicitly.
*/
if (attr->index && data->resolution_limits)
resolution = data->resolution_limits;
else
resolution = data->resolution;
mutex_lock(&data->update_lock);
data->temp[nr] = LM75_TEMP_TO_REG(temp);
temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
data->temp[nr] = DIV_ROUND_CLOSEST(temp << (resolution - 8),
1000) << (16 - resolution);
lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
mutex_unlock(&data->update_lock);
return count;
@ -190,6 +208,9 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
break;
}
data->resolution = 9;
data->sample_time = HZ + HZ / 2;
/* configure as specified */
status = lm75_read_value(client, LM75_REG_CONF);
if (status < 0) {
@ -427,7 +448,7 @@ static struct lm75_data *lm75_update_device(struct device *dev)
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
if (time_after(jiffies, data->last_updated + data->sample_time)
|| !data->valid) {
int i;
dev_dbg(&client->dev, "Starting lm75 update\n");