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Commit 50c22cd1 authored by Matt Ranostay's avatar Matt Ranostay Committed by Guenter Roeck
Browse files

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: default avatarMatt Ranostay <mranostay@gmail.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 803decce

Documentation/hwmon/sht3x

+4 −0
Original line number Diff line number Diff line
@@ -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

drivers/hwmon/sht3x.c

+50 −0
Original line number Diff line number Diff line
@@ -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

};