diff options
Diffstat (limited to 'drivers/hwmon/aht10.c')
| -rw-r--r-- | drivers/hwmon/aht10.c | 192 |
1 files changed, 116 insertions, 76 deletions
diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c index 2d9770cb4401..007befdba977 100644 --- a/drivers/hwmon/aht10.c +++ b/drivers/hwmon/aht10.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0-only /* - * aht10.c - Linux hwmon driver for AHT10 Temperature and Humidity sensor + * aht10.c - Linux hwmon driver for AHT10/AHT20 Temperature and Humidity sensors * Copyright (C) 2020 Johannes Cornelis Draaijer */ @@ -10,9 +10,13 @@ #include <linux/i2c.h> #include <linux/ktime.h> #include <linux/module.h> +#include <linux/crc8.h> #define AHT10_MEAS_SIZE 6 +#define AHT20_MEAS_SIZE 7 +#define AHT20_CRC8_POLY 0x31 + /* * Poll intervals (in milliseconds) */ @@ -33,6 +37,8 @@ #define AHT10_CMD_MEAS 0b10101100 #define AHT10_CMD_RST 0b10111010 +#define DHT20_CMD_INIT 0x71 + /* * Flags in the answer byte/command */ @@ -44,11 +50,19 @@ #define AHT10_MAX_POLL_INTERVAL_LEN 30 +enum aht10_variant { aht10, aht20, dht20}; + +static const struct i2c_device_id aht10_id[] = { + { "aht10", aht10 }, + { "aht20", aht20 }, + { "dht20", dht20 }, + { }, +}; +MODULE_DEVICE_TABLE(i2c, aht10_id); + /** - * struct aht10_data - All the data required to operate an AHT10 chip - * @client: the i2c client associated with the AHT10 - * @lock: a mutex that is used to prevent parallel access to the - * i2c client + * struct aht10_data - All the data required to operate an AHT10/AHT20 chip + * @client: the i2c client associated with the AHT10/AHT20 * @min_poll_interval: the minimum poll interval * While the poll rate limit is not 100% necessary, * the datasheet recommends that a measurement @@ -56,42 +70,42 @@ * the chip from warming up due to the heat it generates. * If it's unwanted, it can be ignored setting it to * it to 0. Default value is 2000 ms - * @previous_poll_time: the previous time that the AHT10 + * @previous_poll_time: the previous time that the AHT10/AHT20 * was polled * @temperature: the latest temperature value received from - * the AHT10 + * the AHT10/AHT20 * @humidity: the latest humidity value received from the - * AHT10 + * AHT10/AHT20 + * @crc8: crc8 support flag + * @meas_size: measurements data size + * @init_cmd: Initialization command */ struct aht10_data { struct i2c_client *client; - /* - * Prevent simultaneous access to the i2c - * client and previous_poll_time - */ - struct mutex lock; ktime_t min_poll_interval; ktime_t previous_poll_time; int temperature; int humidity; + bool crc8; + unsigned int meas_size; + u8 init_cmd; }; -/** - * aht10_init() - Initialize an AHT10 chip - * @client: the i2c client associated with the AHT10 - * @data: the data associated with this AHT10 chip - * Return: 0 if succesfull, 1 if not +/* + * aht10_init() - Initialize an AHT10/AHT20 chip + * @data: the data associated with this AHT10/AHT20 chip + * Return: 0 if successful, 1 if not */ static int aht10_init(struct aht10_data *data) { - const u8 cmd_init[] = {AHT10_CMD_INIT, AHT10_CAL_ENABLED | AHT10_MODE_CYC, + const u8 cmd_init[] = {data->init_cmd, AHT10_CAL_ENABLED | AHT10_MODE_CYC, 0x00}; int res; u8 status; struct i2c_client *client = data->client; - res = i2c_master_send(client, cmd_init, 3); + res = i2c_master_send(client, cmd_init, sizeof(cmd_init)); if (res < 0) return res; @@ -108,7 +122,7 @@ static int aht10_init(struct aht10_data *data) return 0; } -/** +/* * aht10_polltime_expired() - check if the minimum poll interval has * expired * @data: the data containing the time to compare @@ -122,59 +136,74 @@ static int aht10_polltime_expired(struct aht10_data *data) return ktime_after(difference, data->min_poll_interval); } -/** - * aht10_read_values() - read and parse the raw data from the AHT10 - * @aht10_data: the struct aht10_data to use for the lock - * Return: 0 if succesfull, 1 if not +DECLARE_CRC8_TABLE(crc8_table); + +/* + * crc8_check() - check crc of the sensor's measurements + * @raw_data: data frame received from sensor(including crc as the last byte) + * @count: size of the data frame + * Return: 0 if successful, 1 if not + */ +static int crc8_check(u8 *raw_data, int count) +{ + /* + * crc calculated on the whole frame(including crc byte) should yield + * zero in case of correctly received bytes + */ + return crc8(crc8_table, raw_data, count, CRC8_INIT_VALUE); +} + +/* + * aht10_read_values() - read and parse the raw data from the AHT10/AHT20 + * @data: the struct aht10_data to use for the lock + * Return: 0 if successful, 1 if not */ static int aht10_read_values(struct aht10_data *data) { const u8 cmd_meas[] = {AHT10_CMD_MEAS, 0x33, 0x00}; u32 temp, hum; int res; - u8 raw_data[AHT10_MEAS_SIZE]; + u8 raw_data[AHT20_MEAS_SIZE]; struct i2c_client *client = data->client; - mutex_lock(&data->lock); - if (aht10_polltime_expired(data)) { - res = i2c_master_send(client, cmd_meas, sizeof(cmd_meas)); - if (res < 0) { - mutex_unlock(&data->lock); - return res; - } - - usleep_range(AHT10_MEAS_DELAY, - AHT10_MEAS_DELAY + AHT10_DELAY_EXTRA); - - res = i2c_master_recv(client, raw_data, AHT10_MEAS_SIZE); - if (res != AHT10_MEAS_SIZE) { - mutex_unlock(&data->lock); - if (res >= 0) - return -ENODATA; - else - return res; - } - - hum = ((u32)raw_data[1] << 12u) | - ((u32)raw_data[2] << 4u) | - ((raw_data[3] & 0xF0u) >> 4u); - - temp = ((u32)(raw_data[3] & 0x0Fu) << 16u) | - ((u32)raw_data[4] << 8u) | - raw_data[5]; - - temp = ((temp * 625) >> 15u) * 10; - hum = ((hum * 625) >> 16u) * 10; - - data->temperature = (int)temp - 50000; - data->humidity = hum; - data->previous_poll_time = ktime_get_boottime(); + if (!aht10_polltime_expired(data)) + return 0; + + res = i2c_master_send(client, cmd_meas, sizeof(cmd_meas)); + if (res < 0) + return res; + + usleep_range(AHT10_MEAS_DELAY, AHT10_MEAS_DELAY + AHT10_DELAY_EXTRA); + + res = i2c_master_recv(client, raw_data, data->meas_size); + if (res != data->meas_size) { + if (res >= 0) + return -ENODATA; + return res; } - mutex_unlock(&data->lock); + + if (data->crc8 && crc8_check(raw_data, data->meas_size)) + return -EIO; + + hum = ((u32)raw_data[1] << 12u) | + ((u32)raw_data[2] << 4u) | + ((raw_data[3] & 0xF0u) >> 4u); + + temp = ((u32)(raw_data[3] & 0x0Fu) << 16u) | + ((u32)raw_data[4] << 8u) | + raw_data[5]; + + temp = ((temp * 625) >> 15u) * 10; + hum = ((hum * 625) >> 16u) * 10; + + data->temperature = (int)temp - 50000; + data->humidity = hum; + data->previous_poll_time = ktime_get_boottime(); + return 0; } -/** +/* * aht10_interval_write() - store the given minimum poll interval. * Return: 0 on success, -EINVAL if a value lower than the * AHT10_MIN_POLL_INTERVAL is given @@ -186,7 +215,7 @@ static ssize_t aht10_interval_write(struct aht10_data *data, return 0; } -/** +/* * aht10_interval_read() - read the minimum poll interval * in milliseconds */ @@ -197,7 +226,7 @@ static ssize_t aht10_interval_read(struct aht10_data *data, return 0; } -/** +/* * aht10_temperature1_read() - read the temperature in millidegrees */ static int aht10_temperature1_read(struct aht10_data *data, long *val) @@ -212,7 +241,7 @@ static int aht10_temperature1_read(struct aht10_data *data, long *val) return 0; } -/** +/* * aht10_humidity1_read() - read the relative humidity in millipercent */ static int aht10_humidity1_read(struct aht10_data *data, long *val) @@ -271,7 +300,7 @@ static int aht10_hwmon_write(struct device *dev, enum hwmon_sensor_types type, } } -static const struct hwmon_channel_info *aht10_info[] = { +static const struct hwmon_channel_info * const aht10_info[] = { HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL), HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT), HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT), @@ -289,9 +318,9 @@ static const struct hwmon_chip_info aht10_chip_info = { .info = aht10_info, }; -static int aht10_probe(struct i2c_client *client, - const struct i2c_device_id *aht10_id) +static int aht10_probe(struct i2c_client *client) { + enum aht10_variant variant = (uintptr_t)i2c_get_match_data(client); struct device *device = &client->dev; struct device *hwmon_dev; struct aht10_data *data; @@ -307,7 +336,24 @@ static int aht10_probe(struct i2c_client *client, data->min_poll_interval = ms_to_ktime(AHT10_DEFAULT_MIN_POLL_INTERVAL); data->client = client; - mutex_init(&data->lock); + switch (variant) { + case aht20: + data->meas_size = AHT20_MEAS_SIZE; + data->crc8 = true; + crc8_populate_msb(crc8_table, AHT20_CRC8_POLY); + data->init_cmd = AHT10_CMD_INIT; + break; + case dht20: + data->meas_size = AHT20_MEAS_SIZE; + data->crc8 = true; + crc8_populate_msb(crc8_table, AHT20_CRC8_POLY); + data->init_cmd = DHT20_CMD_INIT; + break; + default: + data->meas_size = AHT10_MEAS_SIZE; + data->init_cmd = AHT10_CMD_INIT; + break; + } res = aht10_init(data); if (res < 0) @@ -326,12 +372,6 @@ static int aht10_probe(struct i2c_client *client, return PTR_ERR_OR_ZERO(hwmon_dev); } -static const struct i2c_device_id aht10_id[] = { - { "aht10", 0 }, - { }, -}; -MODULE_DEVICE_TABLE(i2c, aht10_id); - static struct i2c_driver aht10_driver = { .driver = { .name = "aht10", @@ -343,6 +383,6 @@ static struct i2c_driver aht10_driver = { module_i2c_driver(aht10_driver); MODULE_AUTHOR("Johannes Cornelis Draaijer <jcdra1@gmail.com>"); -MODULE_DESCRIPTION("AHT10 Temperature and Humidity sensor driver"); +MODULE_DESCRIPTION("AHT10/AHT20 Temperature and Humidity sensor driver"); MODULE_VERSION("1.0"); MODULE_LICENSE("GPL v2"); |