drivers/hwmon/aht10.c

1 // SPDX-License-Identifier: GPL-2.0-only
4  * aht10.c - Linux hwmon driver for AHT10/AHT20 Temperature and Humidity sensors
61  *   struct aht10_data - All the data required to operate an AHT10/AHT20 chip
76  *   @humidity: the latest humidity value received from the
92 	int humidity;  member
98  * aht10_init() - Initialize an AHT10/AHT20 chip
108 	struct i2c_client *client = data->client;  in aht10_init()
119 		return -ENODATA;  in aht10_init()
122 		return -EBUSY;  in aht10_init()
128  * aht10_polltime_expired() - check if the minimum poll interval has
136 	ktime_t difference = ktime_sub(current_time, data->previous_poll_time);  in aht10_polltime_expired()
138 	return ktime_after(difference, data->min_poll_interval);  in aht10_polltime_expired()
144  * crc8_check() - check crc of the sensor's measurements
145  * @raw_data: data frame received from sensor(including crc as the last byte)
159  * aht10_read_values() - read and parse the raw data from the AHT10/AHT20
169 	struct i2c_client *client = data->client;  in aht10_read_values()
171 	mutex_lock(&data->lock);  in aht10_read_values()
173 		mutex_unlock(&data->lock);  in aht10_read_values()
179 		mutex_unlock(&data->lock);  in aht10_read_values()
185 	res = i2c_master_recv(client, raw_data, data->meas_size);  in aht10_read_values()
186 	if (res != data->meas_size) {  in aht10_read_values()
187 		mutex_unlock(&data->lock);  in aht10_read_values()
189 			return -ENODATA;  in aht10_read_values()
193 	if (data->crc8 && crc8_check(raw_data, data->meas_size)) {  in aht10_read_values()
194 		mutex_unlock(&data->lock);  in aht10_read_values()
195 		return -EIO;  in aht10_read_values()
209 	data->temperature = (int)temp - 50000;  in aht10_read_values()
210 	data->humidity = hum;  in aht10_read_values()
211 	data->previous_poll_time = ktime_get_boottime();  in aht10_read_values()
213 	mutex_unlock(&data->lock);  in aht10_read_values()
218  * aht10_interval_write() - store the given minimum poll interval.
219  * Return: 0 on success, -EINVAL if a value lower than the
225 	data->min_poll_interval = ms_to_ktime(clamp_val(val, 2000, LONG_MAX));  in aht10_interval_write()
230  * aht10_interval_read() - read the minimum poll interval
236 	*val = ktime_to_ms(data->min_poll_interval);  in aht10_interval_read()
241  * aht10_temperature1_read() - read the temperature in millidegrees
251 	*val = data->temperature;  in aht10_temperature1_read()
256  * aht10_humidity1_read() - read the relative humidity in millipercent
266 	*val = data->humidity;  in aht10_humidity1_read()
297 		return -EOPNOTSUPP;  in aht10_hwmon_read()
310 		return -EOPNOTSUPP;  in aht10_hwmon_write()
317 	HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT),
335 	struct device *device = &client->dev;  in aht10_probe()
340 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))  in aht10_probe()
341 		return -ENOENT;  in aht10_probe()
345 		return -ENOMEM;  in aht10_probe()
347 	data->min_poll_interval = ms_to_ktime(AHT10_DEFAULT_MIN_POLL_INTERVAL);  in aht10_probe()
348 	data->client = client;  in aht10_probe()
352 		data->meas_size = AHT20_MEAS_SIZE;  in aht10_probe()
353 		data->crc8 = true;  in aht10_probe()
357 		data->meas_size = AHT10_MEAS_SIZE;  in aht10_probe()
361 	mutex_init(&data->lock);  in aht10_probe()
372 							 client->name,  in aht10_probe()
391 MODULE_DESCRIPTION("AHT10/AHT20 Temperature and Humidity sensor driver");