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Date: Sat, 5 Sep 2015 09:45:45 +0200 (CEST)
From: Peter Meerwald <pmeerw@...erw.net>
To: Matt Ranostay <mranostay@...il.com>
cc: jic23@...nel.org, lars@...afoo.de, linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [RFC v1 4/4] iio: chemical: add SGX VZ89x VOC sensor support
> Add support for VZ89X sensors VOC and CO2 reporting channels in
> ppm/ppb units.
comments below
link to datasheet?
> Signed-off-by: Matt Ranostay <mranostay@...il.com>
> ---
> .../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 | 237 +++++++++++++++++++++
> 5 files changed, 246 insertions(+)
> create mode 100644 drivers/iio/chemical/Makefile
> create mode 100644 drivers/iio/chemical/vz89x.c
>
> 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..a596a22
> --- /dev/null
> +++ b/drivers/iio/chemical/vz89x.c
> @@ -0,0 +1,237 @@
> +/*
> + * vz89x.c - Support for SGX Sensortech MiCS VZ89X VOC sensors
> + *
> + * Copyright (C) 2015 Matt Ranostay <mranostay@...il.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_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_PPM,
> + .modified = 1,
> + .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) | BIT(IIO_CHAN_INFO_SCALE),
> + .address = VZ89X_VOC_SHORT_IDX,
> + .extend_name = "VOC_short",
> + },
> + {
> + .type = IIO_CONCENTRATION,
> + .channel2 = IIO_MOD_PPB,
> + .modified = 1,
> + .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_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);
could a block transfer be used?
> + if (ret < 0)
> + return ret;
> + }
> +
> + data->last_update = jiffies;
> +
> + return 0;
> +}
> +
> +static int vz89x_get_resistance_reading(struct vz89x_data *data,
> + struct iio_chan_spec const *chan)
> +{
> + u8 *buf = &data->buffer[chan->address];
I think only VZ89X_RESISTANCE_IDX as chan->address makes sense here?
> +
> + return buf[0] | ((u16)buf[1] << 8) | ((u16)buf[2] << 16);
why cast to u16? no cast is neccessary
> +}
> +
> +static int vz89x_get_channel_scale(struct iio_chan_spec const *chan,
> + int *val, int *val2)
> +{
> + int ret = -EINVAL;
> +
> + switch (chan->address) {
> + case VZ89X_VOC_CO2_IDX:
> + *val = 1600;
> + *val2 = 229;
> + ret = IIO_VAL_FRACTIONAL;
return directly and save the break, no init of ret
> + break;
> + case VZ89X_VOC_SHORT_IDX:
> + *val = 0;
> + ret = IIO_VAL_INT;
> + break;
> + case VZ89X_VOC_TVOC_IDX:
> + *val = 1000;
> + *val2 = 229;
> + ret = IIO_VAL_FRACTIONAL;
default
> + }
> +
> + return ret;
> +}
> +
> +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);
> +
> + if (chan->type == IIO_RESISTANCE)
> + *val = vz89x_get_resistance_reading(data, chan);
chan argument is not needed
> + else
> + *val = data->buffer[chan->address] - 13;
maybe have this block after checking ret, operating on invalid data isn't
well behaved :)
what is 13? could this be incorporated in _OFFSET?
> +
> + if (!ret)
> + ret = IIO_VAL_INT;
> +
> + mutex_unlock(&data->lock);
> + break;
> + case IIO_CHAN_INFO_SCALE:
> + switch (chan->type) {
> + case IIO_RESISTANCE:
> + *val = 10;
> + ret = IIO_VAL_INT;
> + break;
> + case IIO_CONCENTRATION:
> + ret = vz89x_get_channel_scale(chan, val, val2);
> + break;
> + default:
> + ret = -EINVAL;
> + }
> + break;
> + case IIO_CHAN_INFO_OFFSET:
> + *val = 400;
> + ret = IIO_VAL_INT;
> + break;
> + }
> +
> + 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@...il.com>");
> +MODULE_DESCRIPTION("SGX Sensortech MiCS VZ89X VOC sensors");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald
+43-664-2444418 (mobile)
--
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