Re: [RFC v2 4/4] iio: chemical: add SGX VZ89x VOC sensor support

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Thinking this over do we needed a IIO_CHAN_INFO_PROCESSED_OFFSET to
signal that it needs to be after the (value - offset) * scale
calculation?

Thanks,

Matt

On Sun, Sep 6, 2015 at 9:20 PM, Matt Ranostay <mranostay@xxxxxxxxx> wrote:
> Also one thing to note here is calculation is ((value - 13) * scale))
> + offset versus the normal (value + offset) * scale.. Not sure the
> best way to handle this possibly could be..
>
> Thanks,
>
> Matt
>
> On Sun, Sep 6, 2015 at 8:13 PM, George McCollister
> <george.mccollister@xxxxxxxxx> wrote:
>>
>>
>> On Sun, Sep 6, 2015 at 9:39 PM, Matt Ranostay <mranostay@xxxxxxxxx> 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>
>>> ---
>>>  .../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/Makefile                      |   6 +
>>>  drivers/iio/chemical/vz89x.c                       | 236
>>> +++++++++++++++++++++
>>>  6 files changed, 275 insertions(+)
>>>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-chemical-vz89x
>>>  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.
>>> +
>>> +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.
>>> +
>>> +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.
>>> 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-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
>>>  obj-y += accel/
>>>  obj-y += adc/
>>>  obj-y += amplifiers/
>>> +obj-y += chemical/
>>>  obj-y += common/
>>>  obj-y += dac/
>>>  obj-y += gyro/
>>> diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
>>> new file mode 100644
>>> index 0000000..7292f2d
>>> --- /dev/null
>>> +++ b/drivers/iio/chemical/Makefile
>>> @@ -0,0 +1,6 @@
>>> +#
>>> +# Makefile for IIO chemical sensors
>>> +#
>>> +
>>> +# When adding new entries keep the list in alphabetical order
>>> +obj-$(CONFIG_VZ89X)            += vz89x.o
>>> diff --git a/drivers/iio/chemical/vz89x.c b/drivers/iio/chemical/vz89x.c
>>> new file mode 100644
>>> index 0000000..ac381cc
>>> --- /dev/null
>>> +++ b/drivers/iio/chemical/vz89x.c
>>> @@ -0,0 +1,236 @@
>>> +/*
>>> + * 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",
>>> +       },
>>> +       {
>>> +               .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_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] - 13;
>>
>> Magic numbers are unlucky.
>>
>>>
>>> +                       return IIO_VAL_INT_PLUS_MICRO;
>>> +               case VZ89X_VOC_SHORT_IDX:
>>> +                       *val = data->buffer[chan->address] - 13;
>>> +                       return IIO_VAL_INT;
>>> +               case VZ89X_VOC_TVOC_IDX:
>>> +                       *val = 0;
>>> +                       *val2 = data->buffer[chan->address] - 13;
>>> +                       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:
>>> +               *val = 0;
>>> +               *val2 = 400;
>>> +               return IIO_VAL_INT_PLUS_MICRO;
>>> +       }
>>> +
>>> +       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");
>>> --
>>> 1.9.1
>>>
>>> --
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>>
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