From 50c22cd154e5f7d13072d98ef3e2baba3c074734 Mon Sep 17 00:00:00 2001 From: Matt Ranostay Date: Sat, 9 Jul 2016 23:49:18 -0700 Subject: 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 Cc: David Frey Signed-off-by: Matt Ranostay Signed-off-by: Guenter Roeck diff --git a/Documentation/hwmon/sht3x b/Documentation/hwmon/sht3x index f5aa633..b0d8818 100644 --- a/Documentation/hwmon/sht3x +++ b/Documentation/hwmon/sht3x @@ -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 diff --git a/drivers/hwmon/sht3x.c b/drivers/hwmon/sht3x.c index 707a3f8..b73a488 100644 --- a/drivers/hwmon/sht3x.c +++ b/drivers/hwmon/sht3x.c @@ -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 }; -- cgit v0.10.2