--- /dev/null
+/*
+ * 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");
projects / deliverable / linux.git / commitdiff
