On 10/09/15 07:30, Matt Ranostay wrote:
> Add support for VZ89X sensors VOC and CO2 reporting channels in
> percentage which can be converted to part per million.
>
> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
Coming along nicely. My main comment in here is that the chemical type
can easily enough be a modifier (except for the odd 'short' case)
Hence I think they should be.
> ---
> .../ABI/testing/sysfs-bus-iio-chemical-vz89x | 30 +++
> .../devicetree/bindings/i2c/trivial-devices.txt | 1 +
> drivers/iio/Kconfig | 1 +
> drivers/iio/Makefile | 1 +
> drivers/iio/chemical/Kconfig | 15 ++
> drivers/iio/chemical/Makefile | 6 +
> drivers/iio/chemical/vz89x.c | 245 +++++++++++++++++++++
> 7 files changed, 299 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-chemical-vz89x
> create mode 100644 drivers/iio/chemical/Kconfig
> create mode 100644 drivers/iio/chemical/Makefile
> create mode 100644 drivers/iio/chemical/vz89x.c
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-chemical-vz89x b/Documentation/ABI/testing/sysfs-bus-iio-chemical-vz89x
> new file mode 100644
> index 0000000..74f2a35
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-chemical-vz89x
> @@ -0,0 +1,30 @@
> +What: /sys/bus/iio/devices/iio:deviceX/in_concentration_CO2_raw
> +Date: September 2015
> +KernelVersion: 4.3
> +Contact: Matt Ranostay <mranostay@xxxxxxxxx>
> +Description:
> + Get the unscaled, and no offset applied CO2 gas percentage
> + value.
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_concentration_VOC_short_raw
> +Date: September 2015
> +KernelVersion: 4.3
> +Contact: Matt Ranostay <mranostay@xxxxxxxxx>
> +Description:
> + Get the raw calibration VOC value from the sensor.
> + This value has little application outside of calibration.
So is this something that people are likely to need direct access to?
Perhaps it is better placed in debugfs.
If not I'd be tempted to do this one with a modifier of IIO_MOD_VOC and
because it's a wierd bit of non standard abi use an extended name to
say what it is.
(comments about using modifiers later in review).
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_concentration_tVOC_raw
> +Date: September 2015
> +KernelVersion: 4.3
> +Contact: Matt Ranostay <mranostay@xxxxxxxxx>
> +Description:
> + Get the unscaled, and no offset applied total VOC gas
> + percentage value.
I'd imagine anyone would assume that an undecorated VOC would be the total
so I'd drop the t designation.
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_resistance_raw
> +Date: September 2015
> +KernelVersion: 4.3
> +Contact: Matt Ranostay <mranostay@xxxxxxxxx>
> +Description:
> + Get the unscaled sensor resistance value.
You've already documented this in the main ABI. Doesn't need to be here.
Actually if you add modifiers for C02 / VOC then they should be in the main
ABI docs rather than here. I'd imagine you'll just end up with the
'special' raw VOC reading in this doc.
> diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> index d77d412..a550216 100644
> --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> @@ -88,6 +88,7 @@ ricoh,rs5c372b I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> ricoh,rv5c386 I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> ricoh,rv5c387a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> samsung,24ad0xd1 S524AD0XF1 (128K/256K-bit Serial EEPROM for Low Power)
> +sgx,vz89x SGX Sensortech VZ89X Sensors
> sii,s35390a 2-wire CMOS real-time clock
> skyworks,sky81452 Skyworks SKY81452: Six-Channel White LED Driver with Touch Panel Bias Supply
> st-micro,24c256 i2c serial eeprom (24cxx)
> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index 4011eff..9664e9c 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -61,6 +61,7 @@ config IIO_CONSUMERS_PER_TRIGGER
> source "drivers/iio/accel/Kconfig"
> source "drivers/iio/adc/Kconfig"
> source "drivers/iio/amplifiers/Kconfig"
> +source "drivers/iio/chemical/Kconfig"
> source "drivers/iio/common/Kconfig"
> source "drivers/iio/dac/Kconfig"
> source "drivers/iio/frequency/Kconfig"
> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
> index 698afc2..2288684 100644
> --- a/drivers/iio/Makefile
> +++ b/drivers/iio/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
> obj-y += accel/
> obj-y += adc/
> obj-y += amplifiers/
> +obj-y += chemical/
> obj-y += common/
> obj-y += dac/
> obj-y += gyro/
> diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
> new file mode 100644
> index 0000000..8fb44e5
> --- /dev/null
> +++ b/drivers/iio/chemical/Kconfig
> @@ -0,0 +1,15 @@
> +#
> +# Chemical sensors
> +#
> +
> +menu "AQI VOC sensors"
As Peter picked up on, expand your acronyms to make life easy for readers.
I'm going to hazard a guess that at we'll end up with a more generic
menu name to cover the other types of related sensors but that can change
when it needs to.
> +
> +config VZ89X
> + tristate "SGX Sensortech MiCS VZ89X VOC sensor"
> + depends on I2C
> + help
> + Say Y here to build I2C interface support for the SGX
> + Sensortech MiCS VZ89X VOC (Volatile Organic Compounds)
> + sensors
> +
> +endmenu
> diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
> new file mode 100644
> index 0000000..7292f2d
> --- /dev/null
> +++ b/drivers/iio/chemical/Makefile
> @@ -0,0 +1,6 @@
> +#
> +# Makefile for IIO chemical sensors
> +#
> +
> +# When adding new entries keep the list in alphabetical order
> +obj-$(CONFIG_VZ89X) += vz89x.o
> diff --git a/drivers/iio/chemical/vz89x.c b/drivers/iio/chemical/vz89x.c
> new file mode 100644
> index 0000000..847f853
> --- /dev/null
> +++ b/drivers/iio/chemical/vz89x.c
> @@ -0,0 +1,245 @@
> +/*
> + * vz89x.c - Support for SGX Sensortech MiCS VZ89X VOC sensors
> + *
> + * Copyright (C) 2015 Matt Ranostay <mranostay@xxxxxxxxx>
> + *
> + * 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,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_OFFSET) |
> + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
> + .address = VZ89X_VOC_CO2_IDX,
> + .extend_name = "CO2",
I think that the gas types we are likely to seen sensors for are actually
relatively few in number so we should effectively enforce the ABI by
using modifiers for these.
IIO_MOD_CO2
IIO_MOD_VOC
and for the _short one that's wierd and likely to be device specific so
using an extended name on top of the VOC modifier is fine.
The other big reason for this is when you get a threshold sensor for these
(I'm sure one will be along at somepoint). The event codes do not encode
the extended name in anyway so both the C02 and VOC sensors would give
the same code. Use a modifier and it all becomes straight forward.
Note that adding modifiers also includes updating the bits in tools/iio
to understand the new modifiers.
> + },
> + {
> + .type = IIO_CONCENTRATION,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .address = VZ89X_VOC_SHORT_IDX,
> + .extend_name = "VOC_short",
> + },
> + {
> + .type = IIO_CONCENTRATION,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_OFFSET) |
> + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
> + .address = VZ89X_VOC_TVOC_IDX,
> + .extend_name = "tVOC",
> + },
> + {
> + .type = IIO_RESISTANCE,
> + .info_mask_separate =
> + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
> + .address = VZ89X_VOC_RESISTANCE_IDX,
> + },
> +};
> +
> +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;
> + }
> +
> + data->last_update = jiffies;
> +
> + return 0;
> +}
> +
> +static int vz89x_get_resistance_reading(struct vz89x_data *data)
> +{
> + u8 *buf = &data->buffer[VZ89X_VOC_TVOC_IDX];
> +
> + return buf[0] | ((u16)buf[1] << 8) | ((u32)buf[2] << 16);
> +}
> +
> +static int vz89x_get_channel_scale(struct iio_chan_spec const *chan,
> + int *val, int *val2)
> +{
> + switch (chan->address) {
> + case VZ89X_VOC_CO2_IDX:
> + *val = 1600;
> + *val2 = 229;
> + return IIO_VAL_FRACTIONAL;
> + case VZ89X_VOC_TVOC_IDX:
> + *val = 1000;
> + *val2 = 229;
> + return IIO_VAL_FRACTIONAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> +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:
> + *val = 0;
> + *val2 = data->buffer[chan->address];
> + return IIO_VAL_INT_PLUS_MICRO;
This is unusual for a raw reading. Normally you'd output it as
IIO_VAL_INT and take up the device by 1e6 in the scale factor.
(mainly because you can only output integer values via the buffered
interface - but it's become a convention in general).
I wouldn't guarantee all tools will cope with it otherwise.
> + case VZ89X_VOC_SHORT_IDX:
> + *val = data->buffer[chan->address];
> + return IIO_VAL_INT;
> + case VZ89X_VOC_TVOC_IDX:
> + *val = 0;
> + *val2 = data->buffer[chan->address];
Same is true for this one.
> + return IIO_VAL_INT_PLUS_NANO;
> + 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;
> + case IIO_CONCENTRATION:
> + return vz89x_get_channel_scale(chan, val, val2);
> + default:
> + return -EINVAL;
> + }
> + break;
> + case IIO_CHAN_INFO_OFFSET:
> + switch (chan->address) {
> + case VZ89X_VOC_CO2_IDX:
> + *val = 0;
> + *val2 = 44250;
> + return IIO_VAL_INT_PLUS_NANO;
> + case VZ89X_VOC_TVOC_IDX:
> + *val = 0;
> + *val2 = -13;
> + return IIO_VAL_INT_PLUS_NANO;
> + default:
> + return -EINVAL;
> + }
> + }
> +
> + return ret;
> +}
> +
> +static const struct iio_info vz89x_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = vz89x_read_raw,
> +};
> +
> +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@xxxxxxxxx>");
> +MODULE_DESCRIPTION("SGX Sensortech MiCS VZ89X VOC sensors");
> +MODULE_LICENSE("GPL v2");
>
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