iio: chemical: add AMS iAQ-core support

Add support for AMS iAQ-core continuous and pulsed VOC sensors.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

4 files changed, 210 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
index c50cf13c852e..f6fec952d683 100644
--- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
+++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
@@ -20,6 +20,7 @@ adi,adt7476		+/-1C TDM Extended Temp Range I.C
 adi,adt7490             +/-1C TDM Extended Temp Range I.C
 adi,adxl345             Three-Axis Digital Accelerometer
 adi,adxl346             Three-Axis Digital Accelerometer (backward-compatibility value "adi,adxl345" must be listed too)
+ams,iaq-core            AMS iAQ-Core VOC Sensor
 at,24c08                i2c serial eeprom  (24cxx)
 atmel,24c00             i2c serial eeprom  (24cxx)
 atmel,24c01             i2c serial eeprom  (24cxx)
diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 3061b7299f0f..f16de61be46d 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -4,6 +4,14 @@
 
 menu "Chemical Sensors"
 
+config IAQCORE
+        tristate "AMS iAQ-Core VOC sensors"
+        depends on I2C
+        help
+          Say Y here to build I2C interface support for the AMS
+          iAQ-Core Continuous/Pulsed VOC (Volatile Organic Compounds)
+          sensors
+
 config VZ89X
         tristate "SGX Sensortech MiCS VZ89X VOC sensor"
         depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index 7292f2ded587..167861fadfab 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -3,4 +3,5 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_IAQCORE)           += ams-iaq-core.o
 obj-$(CONFIG_VZ89X)             += vz89x.o
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");