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@xxxxxxxxxxxx>
---
drivers/hwmon/lm75.c | 31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)
--- linux-3.9-rc2.orig/drivers/hwmon/lm75.c 2013-03-12 13:37:45.206041683 +0100
+++ linux-3.9-rc2/drivers/hwmon/lm75.c 2013-03-12 13:58:09.676334428 +0100
@@ -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 *
{
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 *d
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, co
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_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");
--
Jean Delvare
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