diff options
Diffstat (limited to 'drivers/iio/chemical/ams-iaq-core.c')
| -rw-r--r-- | drivers/iio/chemical/ams-iaq-core.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/iio/chemical/ams-iaq-core.c b/drivers/iio/chemical/ams-iaq-core.c new file mode 100644 index 000000000000..41a8e6f2e31d --- /dev/null +++ b/drivers/iio/chemical/ams-iaq-core.c @@ -0,0 +1,200 @@ +/* + * ams-iaq-core.c - Support for AMS iAQ-Core VOC sensors + * + * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/init.h> +#include <linux/i2c.h> +#include <linux/iio/iio.h> + +#define AMS_IAQCORE_DATA_SIZE 9 + +#define AMS_IAQCORE_VOC_CO2_IDX 0 +#define AMS_IAQCORE_VOC_RESISTANCE_IDX 1 +#define AMS_IAQCORE_VOC_TVOC_IDX 2 + +struct ams_iaqcore_reading { + __be16 co2_ppm; + u8 status; + __be32 resistance; + __be16 voc_ppb; +} __attribute__((__packed__)); + +struct ams_iaqcore_data { + struct i2c_client *client; + struct mutex lock; + unsigned long last_update; + + struct ams_iaqcore_reading buffer; +}; + +static const struct iio_chan_spec ams_iaqcore_channels[] = { + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_CO2, + .modified = 1, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .address = AMS_IAQCORE_VOC_CO2_IDX, + }, + { + .type = IIO_RESISTANCE, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .address = AMS_IAQCORE_VOC_RESISTANCE_IDX, + }, + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_VOC, + .modified = 1, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .address = AMS_IAQCORE_VOC_TVOC_IDX, + }, +}; + +static int ams_iaqcore_read_measurement(struct ams_iaqcore_data *data) +{ + struct i2c_client *client = data->client; + int ret; + + struct i2c_msg msg = { + .addr = client->addr, + .flags = client->flags | I2C_M_RD, + .len = AMS_IAQCORE_DATA_SIZE, + .buf = (char *) &data->buffer, + }; + + ret = i2c_transfer(client->adapter, &msg, 1); + + return (ret == AMS_IAQCORE_DATA_SIZE) ? 0 : ret; +} + +static int ams_iaqcore_get_measurement(struct ams_iaqcore_data *data) +{ + int ret; + + /* sensor can only be polled once a second max per datasheet */ + if (!time_after(jiffies, data->last_update + HZ)) + return 0; + + ret = ams_iaqcore_read_measurement(data); + if (ret < 0) + return ret; + + data->last_update = jiffies; + + return 0; +} + +static int ams_iaqcore_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + struct ams_iaqcore_data *data = iio_priv(indio_dev); + int ret; + + if (mask != IIO_CHAN_INFO_PROCESSED) + return -EINVAL; + + mutex_lock(&data->lock); + ret = ams_iaqcore_get_measurement(data); + + if (ret) + goto err_out; + + switch (chan->address) { + case AMS_IAQCORE_VOC_CO2_IDX: + *val = 0; + *val2 = be16_to_cpu(data->buffer.co2_ppm); + ret = IIO_VAL_INT_PLUS_MICRO; + break; + case AMS_IAQCORE_VOC_RESISTANCE_IDX: + *val = be32_to_cpu(data->buffer.resistance); + ret = IIO_VAL_INT; + break; + case AMS_IAQCORE_VOC_TVOC_IDX: + *val = 0; + *val2 = be16_to_cpu(data->buffer.voc_ppb); + ret = IIO_VAL_INT_PLUS_NANO; + break; + default: + ret = -EINVAL; + } + +err_out: + mutex_unlock(&data->lock); + + return ret; +} + +static const struct iio_info ams_iaqcore_info = { + .read_raw = ams_iaqcore_read_raw, + .driver_module = THIS_MODULE, +}; + +static int ams_iaqcore_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct iio_dev *indio_dev; + struct ams_iaqcore_data *data; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + + /* so initial reading will complete */ + data->last_update = jiffies - HZ; + mutex_init(&data->lock); + + indio_dev->dev.parent = &client->dev; + indio_dev->info = &ams_iaqcore_info, + indio_dev->name = dev_name(&client->dev); + indio_dev->modes = INDIO_DIRECT_MODE; + + indio_dev->channels = ams_iaqcore_channels; + indio_dev->num_channels = ARRAY_SIZE(ams_iaqcore_channels); + + return devm_iio_device_register(&client->dev, indio_dev); +} + +static const struct i2c_device_id ams_iaqcore_id[] = { + { "ams-iaq-core", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ams_iaqcore_id); + +static const struct of_device_id ams_iaqcore_dt_ids[] = { + { .compatible = "ams,iaq-core" }, + { } +}; +MODULE_DEVICE_TABLE(of, ams_iaqcore_dt_ids); + +static struct i2c_driver ams_iaqcore_driver = { + .driver = { + .name = "ams-iaq-core", + .of_match_table = of_match_ptr(ams_iaqcore_dt_ids), + }, + .probe = ams_iaqcore_probe, + .id_table = ams_iaqcore_id, +}; +module_i2c_driver(ams_iaqcore_driver); + +MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); +MODULE_DESCRIPTION("AMS iAQ-Core VOC sensors"); +MODULE_LICENSE("GPL v2"); |