diff options
Diffstat (limited to 'drivers/iio/chemical/ags02ma.c')
| -rw-r--r-- | drivers/iio/chemical/ags02ma.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/drivers/iio/chemical/ags02ma.c b/drivers/iio/chemical/ags02ma.c new file mode 100644 index 0000000000..8fcd809465 --- /dev/null +++ b/drivers/iio/chemical/ags02ma.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2023 Anshul Dalal <anshulusr@gmail.com> + * + * Driver for Aosong AGS02MA + * + * Datasheet: + * https://asairsensors.com/wp-content/uploads/2021/09/AGS02MA.pdf + * Product Page: + * http://www.aosong.com/m/en/products-33.html + */ + +#include <linux/crc8.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/module.h> + +#include <linux/iio/iio.h> + +#define AGS02MA_TVOC_READ_REG 0x00 +#define AGS02MA_VERSION_REG 0x11 + +#define AGS02MA_VERSION_PROCESSING_DELAY 30 +#define AGS02MA_TVOC_READ_PROCESSING_DELAY 1500 + +#define AGS02MA_CRC8_INIT 0xff +#define AGS02MA_CRC8_POLYNOMIAL 0x31 + +DECLARE_CRC8_TABLE(ags02ma_crc8_table); + +struct ags02ma_data { + struct i2c_client *client; +}; + +struct ags02ma_reading { + __be32 data; + u8 crc; +} __packed; + +static int ags02ma_register_read(struct i2c_client *client, u8 reg, u16 delay, + u32 *val) +{ + int ret; + u8 crc; + struct ags02ma_reading read_buffer; + + ret = i2c_master_send(client, ®, sizeof(reg)); + if (ret < 0) { + dev_err(&client->dev, + "Failed to send data to register 0x%x: %d", reg, ret); + return ret; + } + + /* Processing Delay, Check Table 7.7 in the datasheet */ + msleep_interruptible(delay); + + ret = i2c_master_recv(client, (u8 *)&read_buffer, sizeof(read_buffer)); + if (ret < 0) { + dev_err(&client->dev, + "Failed to receive from register 0x%x: %d", reg, ret); + return ret; + } + + crc = crc8(ags02ma_crc8_table, (u8 *)&read_buffer.data, + sizeof(read_buffer.data), AGS02MA_CRC8_INIT); + if (crc != read_buffer.crc) { + dev_err(&client->dev, "CRC error\n"); + return -EIO; + } + + *val = be32_to_cpu(read_buffer.data); + return 0; +} + +static int ags02ma_read_raw(struct iio_dev *iio_device, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + int ret; + struct ags02ma_data *data = iio_priv(iio_device); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = ags02ma_register_read(data->client, AGS02MA_TVOC_READ_REG, + AGS02MA_TVOC_READ_PROCESSING_DELAY, + val); + if (ret < 0) + return ret; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + /* The sensor reads data as ppb */ + *val = 0; + *val2 = 100; + return IIO_VAL_INT_PLUS_NANO; + default: + return -EINVAL; + } +} + +static const struct iio_info ags02ma_info = { + .read_raw = ags02ma_read_raw, +}; + +static const struct iio_chan_spec ags02ma_channel = { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_VOC, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), +}; + +static int ags02ma_probe(struct i2c_client *client) +{ + int ret; + struct ags02ma_data *data; + struct iio_dev *indio_dev; + u32 version; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + crc8_populate_msb(ags02ma_crc8_table, AGS02MA_CRC8_POLYNOMIAL); + + ret = ags02ma_register_read(client, AGS02MA_VERSION_REG, + AGS02MA_VERSION_PROCESSING_DELAY, &version); + if (ret < 0) + return dev_err_probe(&client->dev, ret, + "Failed to read device version\n"); + dev_dbg(&client->dev, "Aosong AGS02MA, Version: 0x%x", version); + + data = iio_priv(indio_dev); + data->client = client; + indio_dev->info = &ags02ma_info; + indio_dev->channels = &ags02ma_channel; + indio_dev->num_channels = 1; + indio_dev->name = "ags02ma"; + + return devm_iio_device_register(&client->dev, indio_dev); +} + +static const struct i2c_device_id ags02ma_id_table[] = { + { "ags02ma" }, + { /* Sentinel */ } +}; +MODULE_DEVICE_TABLE(i2c, ags02ma_id_table); + +static const struct of_device_id ags02ma_of_table[] = { + { .compatible = "aosong,ags02ma" }, + { /* Sentinel */ } +}; +MODULE_DEVICE_TABLE(of, ags02ma_of_table); + +static struct i2c_driver ags02ma_driver = { + .driver = { + .name = "ags02ma", + .of_match_table = ags02ma_of_table, + }, + .id_table = ags02ma_id_table, + .probe = ags02ma_probe, +}; +module_i2c_driver(ags02ma_driver); + +MODULE_AUTHOR("Anshul Dalal <anshulusr@gmail.com>"); +MODULE_DESCRIPTION("Aosong AGS02MA TVOC Driver"); +MODULE_LICENSE("GPL"); |