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hwmon: (sht3x) add humidity heater element control 

The enables control of the SHT31 sensors heating element that can turned
on to remove excess humidity.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: David Frey <david.frey@sensirion.com>
Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
steinar/wifi_calib_4_9_kernel
Matt Ranostay 2016-07-09 23:49:18 -07:00 committed by Guenter Roeck
parent 803deccec2
commit 50c22cd154
2 changed files with 54 additions and 0 deletions
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4
Documentation/hwmon/sht3x
View File

@ -67,6 +67,10 @@ temp1_alarm: alarm flag is set to 1 if the temperature is outside the
configured limits. Alarm only works in periodic measure mode
humidity1_alarm: alarm flag is set to 1 if the humidity is outside the
configured limits. Alarm only works in periodic measure mode
heater_enable: heater enable, heating element removes excess humidity from
sensor
0: turned off
1: turned on
update_interval: update interval, 0 for single shot, interval in msec
for periodic measurement. If the interval is not supported
by the sensor, the next faster interval is chosen

50
drivers/hwmon/sht3x.c
View File

@ -44,6 +44,10 @@ static const unsigned char sht3x_cmd_measure_nonblocking_lpm[] = { 0x24, 0x16 };
static const unsigned char sht3x_cmd_measure_periodic_mode[] = { 0xe0, 0x00 };
static const unsigned char sht3x_cmd_break[] = { 0x30, 0x93 };
/* commands for heater control */
static const unsigned char sht3x_cmd_heater_on[] = { 0x30, 0x6d };
static const unsigned char sht3x_cmd_heater_off[] = { 0x30, 0x66 };
/* other commands */
static const unsigned char sht3x_cmd_read_status_reg[] = { 0xf3, 0x2d };
static const unsigned char sht3x_cmd_clear_status_reg[] = { 0x30, 0x41 };
@ -507,6 +511,49 @@ static ssize_t humidity1_alarm_show(struct device *dev,
return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x08));
}
static ssize_t heater_enable_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
int ret;
ret = status_register_read(dev, attr, buffer,
SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
if (ret)
return ret;
return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x20));
}
static ssize_t heater_enable_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
struct sht3x_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int ret;
bool status;
ret = kstrtobool(buf, &status);
if (ret)
return ret;
mutex_lock(&data->i2c_lock);
if (status)
ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_on,
SHT3X_CMD_LENGTH);
else
ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_off,
SHT3X_CMD_LENGTH);
mutex_unlock(&data->i2c_lock);
return ret;
}
static ssize_t update_interval_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@ -612,6 +659,8 @@ static SENSOR_DEVICE_ATTR(humidity1_min_hyst, S_IRUGO | S_IWUSR,
static SENSOR_DEVICE_ATTR(temp1_alarm, S_IRUGO, temp1_alarm_show, NULL, 0);
static SENSOR_DEVICE_ATTR(humidity1_alarm, S_IRUGO, humidity1_alarm_show,
NULL, 0);
static SENSOR_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR,
heater_enable_show, heater_enable_store, 0);
static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
update_interval_show, update_interval_store, 0);
@ -628,6 +677,7 @@ static struct attribute *sht3x_attrs[] = {
&sensor_dev_attr_humidity1_min_hyst.dev_attr.attr,
&sensor_dev_attr_temp1_alarm.dev_attr.attr,
&sensor_dev_attr_humidity1_alarm.dev_attr.attr,
&sensor_dev_attr_heater_enable.dev_attr.attr,
&sensor_dev_attr_update_interval.dev_attr.attr,
NULL
};