--- /dev/null
+/*
+ * vz89x.c - Support for SGX Sensortech MiCS VZ89X 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>
+#include <linux/iio/sysfs.h>
+
+#define VZ89X_REG_MEASUREMENT 0x09
+#define VZ89X_REG_MEASUREMENT_SIZE 6
+
+#define VZ89X_VOC_CO2_IDX 0
+#define VZ89X_VOC_SHORT_IDX 1
+#define VZ89X_VOC_TVOC_IDX 2
+#define VZ89X_VOC_RESISTANCE_IDX 3
+
+struct vz89x_data {
+ struct i2c_client *client;
+ struct mutex lock;
+ unsigned long last_update;
+
+ u8 buffer[VZ89X_REG_MEASUREMENT_SIZE];
+};
+
+static const struct iio_chan_spec vz89x_channels[] = {
+ {
+ .type = IIO_CONCENTRATION,
+ .channel2 = IIO_MOD_CO2,
+ .modified = 1,
+ .info_mask_separate =
+ BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
+ .address = VZ89X_VOC_CO2_IDX,
+ },
+ {
+ .type = IIO_CONCENTRATION,
+ .channel2 = IIO_MOD_VOC,
+ .modified = 1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .address = VZ89X_VOC_SHORT_IDX,
+ .extend_name = "short",
+ },
+ {
+ .type = IIO_CONCENTRATION,
+ .channel2 = IIO_MOD_VOC,
+ .modified = 1,
+ .info_mask_separate =
+ BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
+ .address = VZ89X_VOC_TVOC_IDX,
+ },
+ {
+ .type = IIO_RESISTANCE,
+ .info_mask_separate =
+ BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+ .address = VZ89X_VOC_RESISTANCE_IDX,
+ },
+};
+
+static IIO_CONST_ATTR(in_concentration_co2_scale, "0.00000698689");
+static IIO_CONST_ATTR(in_concentration_voc_scale, "0.00000000436681223");
+
+static struct attribute *vz89x_attributes[] = {
+ &iio_const_attr_in_concentration_co2_scale.dev_attr.attr,
+ &iio_const_attr_in_concentration_voc_scale.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group vz89x_attrs_group = {
+ .attrs = vz89x_attributes,
+};
+
+/*
+ * Chipset sometime updates in the middle of a reading causing it to reset the
+ * data pointer, and causing invalid reading of previous data.
+ * We can check for this by reading MSB of the resistance reading that is
+ * always zero, and by also confirming the VOC_short isn't zero.
+ */
+
+static int vz89x_measurement_is_valid(struct vz89x_data *data)
+{
+ if (data->buffer[VZ89X_VOC_SHORT_IDX] == 0)
+ return 1;
+
+ return !!(data->buffer[VZ89X_REG_MEASUREMENT_SIZE - 1] > 0);
+}
+
+static int vz89x_get_measurement(struct vz89x_data *data)
+{
+ int ret;
+ int i;
+
+ /* sensor can only be polled once a second max per datasheet */
+ if (!time_after(jiffies, data->last_update + HZ))
+ return 0;
+
+ ret = i2c_smbus_write_word_data(data->client,
+ VZ89X_REG_MEASUREMENT, 0);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < VZ89X_REG_MEASUREMENT_SIZE; i++) {
+ ret = i2c_smbus_read_byte(data->client);
+ if (ret < 0)
+ return ret;
+ data->buffer[i] = ret;
+ }
+
+ ret = vz89x_measurement_is_valid(data);
+ if (ret)
+ return -EAGAIN;
+
+ data->last_update = jiffies;
+
+ return 0;
+}
+
+static int vz89x_get_resistance_reading(struct vz89x_data *data)
+{
+ u8 *buf = &data->buffer[VZ89X_VOC_RESISTANCE_IDX];
+
+ return buf[0] | (buf[1] << 8);
+}
+
+static int vz89x_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct vz89x_data *data = iio_priv(indio_dev);
+ int ret = -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&data->lock);
+ ret = vz89x_get_measurement(data);
+ mutex_unlock(&data->lock);
+
+ if (ret)
+ return ret;
+
+ switch (chan->address) {
+ case VZ89X_VOC_CO2_IDX:
+ case VZ89X_VOC_SHORT_IDX:
+ case VZ89X_VOC_TVOC_IDX:
+ *val = data->buffer[chan->address];
+ return IIO_VAL_INT;
+ case VZ89X_VOC_RESISTANCE_IDX:
+ *val = vz89x_get_resistance_reading(data);
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ break;
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_RESISTANCE:
+ *val = 10;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ break;
+ case IIO_CHAN_INFO_OFFSET:
+ switch (chan->address) {
+ case VZ89X_VOC_CO2_IDX:
+ *val = 44;
+ *val2 = 250000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case VZ89X_VOC_TVOC_IDX:
+ *val = -13;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ return ret;
+}
+
+static const struct iio_info vz89x_info = {
+ .attrs = &vz89x_attrs_group,
+ .read_raw = vz89x_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int vz89x_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct vz89x_data *data;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_BYTE))
+ return -ENODEV;
+
+ 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;
+ data->last_update = jiffies - HZ;
+ mutex_init(&data->lock);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &vz89x_info,
+ indio_dev->name = dev_name(&client->dev);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ indio_dev->channels = vz89x_channels;
+ indio_dev->num_channels = ARRAY_SIZE(vz89x_channels);
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id vz89x_id[] = {
+ { "vz89x", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, vz89x_id);
+
+static const struct of_device_id vz89x_dt_ids[] = {
+ { .compatible = "sgx,vz89x" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, vz89x_dt_ids);
+
+static struct i2c_driver vz89x_driver = {
+ .driver = {
+ .name = "vz89x",
+ .of_match_table = of_match_ptr(vz89x_dt_ids),
+ },
+ .probe = vz89x_probe,
+ .id_table = vz89x_id,
+};
+module_i2c_driver(vz89x_driver);
+
+MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
+MODULE_DESCRIPTION("SGX Sensortech MiCS VZ89X VOC sensors");
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff