Re: [PATCH v3 2/3] iio: chemical: sgp30: Support Sensirion SGP30/SGPC3 sensors

From: Jonathan Cameron
Date: Sat Dec 22 2018 - 11:56:41 EST

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On Tue, 18 Dec 2018 18:44:40 +0100
Tomasz Duszynski <tduszyns@xxxxxxxxx> wrote:

> On Mon, Dec 17, 2018 at 11:59:36AM +0000, Jonathan Cameron wrote:
> > On Sun, 16 Dec 2018 17:38:18 +0100
> > Andreas Brauchli <a.brauchli@xxxxxxxxxxxxxxx> wrote:
> >
> > > On Sun, 2018-12-16 at 13:34 +0000, Jonathan Cameron wrote:
> > > > On Thu, 13 Dec 2018 15:43:23 +0100
> > > > Andreas Brauchli <a.brauchli@xxxxxxxxxxxxxxx> wrote:
> > > >
> > > > > Support Sensirion SGP30 and SGPC3 multi-pixel I2C gas sensors
> > > > >
> > > > > Supported Features:
> > > > >
> > > > > * Indoor Air Quality (IAQ) concentrations for
> > > > > - tVOC (in_concentration_voc_input)
> > > > > - CO2eq (in_concentration_co2_input) - SGP30 only
> > > > >
> > > > > IAQ concentrations are periodically read out by a background
> > > > > thread
> > > > > to allow the sensor to maintain its internal baseline.
> > > > >
> > > > > * Gas concentration signals
> > > > > - Ethanol (in_concentration_ethanol_raw)
> > > > > - H2 (in_concentration_h2_raw) - SGP30 only
> > > > >
> > > > > https://www.sensirion.com/file/datasheet_sgp30
> > > > > https://www.sensirion.com/file/datasheet_sgpc3
> > > > >
> > > > > Signed-off-by: Andreas Brauchli <andreas.brauchli@xxxxxxxxxxxxx>
> > > >
> > > > Why do we provide endianness info given we don't provide the buffered
> > > > interface? It's only used when we do.
> > >
> > > Makes sense but I wasn't aware of it. The initial submission came with
> > > buffering, so it probably wasn't spotted in v2.
> > >
> > > >
> > > > Some over the top line wrapping as well. However as that's it
> > > > I'll just clean up whilst applying. If I've missed something odd
> > > > around the endian thing shout!
> > >
> > > No that's it, thanks a lot.
> > >
> > > >
> > > > Jonathan
> > > >
> > > > > ---
> > > > > drivers/iio/chemical/Kconfig | 13 +
> > > > > drivers/iio/chemical/Makefile | 1 +
> > > > > drivers/iio/chemical/sgp30.c | 603
> > > > > ++++++++++++++++++++++++++++++++++
> > > > > 3 files changed, 617 insertions(+)
> > > > > create mode 100644 drivers/iio/chemical/sgp30.c
> > > > >
> > > > > diff --git a/drivers/iio/chemical/Kconfig
> > > > > b/drivers/iio/chemical/Kconfig
> > > > > index b8e005be4f87..b0c912be94a9 100644
> > > > > --- a/drivers/iio/chemical/Kconfig
> > > > > +++ b/drivers/iio/chemical/Kconfig
> > > > > @@ -61,6 +61,19 @@ config IAQCORE
> > > > > iAQ-Core Continuous/Pulsed VOC (Volatile Organic Compounds)
> > > > > sensors
> > > > >
> > > > > +config SENSIRION_SGP30
> > >
> > > I noticed that in Tomasz's SPS30 patch it's just SPS30, so for
> > > consistency's sake I'm fine with dropping the branding. Up to you.
> >
> > We've never had any hard rules on this, at least partly because a lot
> > of drivers came from other subsystems in the early days.
> >
> > We probably should have a rule though. SGP30 for example is generic
> > enough that it might well be reused by someone else.
> >
>
> Wondering how likely is this? These days some popular sensors have their
> clones. Interestingly enough, they are sold as genuine i.e
> without vendor/sensor name changes. On the other hand there are very
> same ICs manufactured by different companies but still with
> different names.
>
> > Anyone have any strong opinions on this? If not I think I'll start
> > encouraging prefixing with manufacturer of first supported device.
> >
>
> What about sticking to what we have now and adding prefix when we do
> have naming collision? Just my 2 cents.
>
Agreed in the sense that it's not worth changing existing drivers unless
we have a reason to..

But if the question is raised for what is preferred, I think adding a vendor
is good. There have been clashes with i2c devices in the past where the
binding without vendor was insufficient to distinguish the part.

Not sure what it was, but I remember the discussion being one of the motivations
to add vendor prefixes to the look up for i2c devices.

Jonathan

> > Jonathan
> >
> > >
> > > > > + tristate "Sensirion SGPxx gas sensors"
> > > > > + depends on I2C
> > > > > + select CRC8
> > > > > + help
> > > > > + Say Y here to build I2C interface support for the following
> > > > > + Sensirion SGP gas sensors:
> > > > > + * SGP30 gas sensor
> > > > > + * SGPC3 low power gas sensor
> > > > > +
> > > > > + To compile this driver as module, choose M here: the
> > > > > + module will be called sgp30.
> > > > > +
> > > > > 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 2f4c4ba4d781..61e83944db1a 100644
> > > > > --- a/drivers/iio/chemical/Makefile
> > > > > +++ b/drivers/iio/chemical/Makefile
> > > > > @@ -9,4 +9,5 @@ obj-$(CONFIG_BME680_I2C) += bme680_i2c.o
> > > > > obj-$(CONFIG_BME680_SPI) += bme680_spi.o
> > > > > obj-$(CONFIG_CCS811) += ccs811.o
> > > > > obj-$(CONFIG_IAQCORE) += ams-iaq-core.o
> > > > > +obj-$(CONFIG_SENSIRION_SGP30) += sgp30.o
> > > > > obj-$(CONFIG_VZ89X) += vz89x.o
> > > > > diff --git a/drivers/iio/chemical/sgp30.c
> > > > > b/drivers/iio/chemical/sgp30.c
> > > > > new file mode 100644
> > > > > index 000000000000..90eb4cbb18cf
> > > > > --- /dev/null
> > > > > +++ b/drivers/iio/chemical/sgp30.c
> > > > > @@ -0,0 +1,603 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +/*
> > > > > + * sgp30.c - Support for Sensirion SGP Gas Sensors
> > > > > + *
> > > > > + * Copyright (C) 2018 Andreas Brauchli <
> > > > > andreas.brauchli@xxxxxxxxxxxxx>
> > > > > + *
> > > > > + * I2C slave address: 0x58
> > > > > + *
> > > > > + * Datasheets:
> > > > > + * https://www.sensirion.com/file/datasheet_sgp30
> > > > > + * https://www.sensirion.com/file/datasheet_sgpc3
> > > > > + *
> > > > > + * TODO:
> > > > > + * - baseline support
> > > > > + * - humidity compensation
> > > > > + * - power mode switching (SGPC3)
> > > > > + */
> > > > > +
> > > > > +#include <linux/crc8.h>
> > > > > +#include <linux/delay.h>
> > > > > +#include <linux/kthread.h>
> > > > > +#include <linux/module.h>
> > > > > +#include <linux/mutex.h>
> > > > > +#include <linux/i2c.h>
> > > > > +#include <linux/of_device.h>
> > > > > +#include <linux/iio/iio.h>
> > > > > +#include <linux/iio/sysfs.h>
> > > > > +
> > > > > +#define SGP_WORD_LEN 2
> > > > > +#define SGP_CRC8_POLYNOMIAL 0x31
> > > > > +#define SGP_CRC8_INIT 0xff
> > > > > +#define SGP_CRC8_LEN 1
> > > > > +#define SGP_CMD(cmd_word) cpu_to_be16(cmd_word)
> > > > > +#define SGP_CMD_DURATION_US 12000
> > > > > +#define SGP_MEASUREMENT_DURATION_US 50000
> > > > > +#define SGP_CMD_LEN SGP_WORD_LEN
> > > > > +#define SGP_CMD_MAX_BUF_SIZE (SGP_CMD_LEN +
> > > > > 2 * SGP_WORD_LEN)
> > > > > +#define SGP_MEASUREMENT_LEN 2
> > > > > +#define SGP30_MEASURE_INTERVAL_HZ 1
> > > > > +#define SGPC3_MEASURE_INTERVAL_HZ 2
> > > > > +#define SGP_VERS_PRODUCT(data) ((((data)->feature_set) &
> > > > > 0xf000) >> 12)
> > > > > +#define SGP_VERS_RESERVED(data) ((((data)->feature_set) &
> > > > > 0x0800) >> 11)
> > > > > +#define SGP_VERS_GEN(data) ((((data)->feature_set) & 0x0600) >> 9)
> > > > > +#define SGP_VERS_ENG_BIT(data) ((((data)->feature_set) &
> > > > > 0x0100) >> 8)
> > > > > +#define SGP_VERS_MAJOR(data) ((((data)->feature_set) &
> > > > > 0x00e0) >> 5)
> > > > > +#define SGP_VERS_MINOR(data) (((data)->feature_set) &
> > > > > 0x001f)
> > > > > +
> > > > > +DECLARE_CRC8_TABLE(sgp_crc8_table);
> > > > > +
> > > > > +enum sgp_product_id {
> > > > > + SGP30 = 0,
> > > > > + SGPC3,
> > > > > +};
> > > > > +
> > > > > +enum sgp30_channel_idx {
> > > > > + SGP30_IAQ_TVOC_IDX = 0,
> > > > > + SGP30_IAQ_CO2EQ_IDX,
> > > > > + SGP30_SIG_ETOH_IDX,
> > > > > + SGP30_SIG_H2_IDX,
> > > > > +};
> > > > > +
> > > > > +enum sgpc3_channel_idx {
> > > > > + SGPC3_IAQ_TVOC_IDX = 10,
> > > > > + SGPC3_SIG_ETOH_IDX,
> > > > > +};
> > > > > +
> > > > > +enum sgp_cmd {
> > > > > + SGP_CMD_IAQ_INIT = SGP_CMD(0x2003),
> > > > > + SGP_CMD_IAQ_MEASURE = SGP_CMD(0x2008),
> > > > > + SGP_CMD_GET_FEATURE_SET = SGP_CMD(0x202f),
> > > > > + SGP_CMD_GET_SERIAL_ID = SGP_CMD(0x3682),
> > > > > +
> > > > > + SGP30_CMD_MEASURE_SIGNAL = SGP_CMD(0x2050),
> > > > > +
> > > > > + SGPC3_CMD_MEASURE_RAW = SGP_CMD(0x2046),
> > > > > +};
> > > > > +
> > > > > +struct sgp_version {
> > > > > + u8 major;
> > > > > + u8 minor;
> > > > > +};
> > > > > +
> > > > > +struct sgp_crc_word {
> > > > > + __be16 value;
> > > > > + u8 crc8;
> > > > > +} __attribute__((__packed__));
> > > > > +
> > > > > +union sgp_reading {
> > > > > + u8 start;
> > > > > + struct sgp_crc_word raw_words[4];
> > > > > +};
> > > > > +
> > > > > +enum _iaq_buffer_state {
> > > > > + IAQ_BUFFER_EMPTY = 0,
> > > > > + IAQ_BUFFER_DEFAULT_VALS,
> > > > > + IAQ_BUFFER_VALID,
> > > > > +};
> > > > > +
> > > > > +struct sgp_data {
> > > > > + struct i2c_client *client;
> > > > > + struct task_struct *iaq_thread;
> > > > > + struct mutex data_lock;
> > > > > + unsigned long iaq_init_start_jiffies;
> > > > > + unsigned long iaq_defval_skip_jiffies;
> > > > > + u16 product_id;
> > > > > + u16 feature_set;
> > > > > + unsigned long measure_interval_jiffies;
> > > > > + enum sgp_cmd iaq_init_cmd;
> > > > > + enum sgp_cmd measure_iaq_cmd;
> > > > > + enum sgp_cmd measure_gas_signals_cmd;
> > > > > + union sgp_reading buffer;
> > > > > + union sgp_reading iaq_buffer;
> > > > > + enum _iaq_buffer_state iaq_buffer_state;
> > > > > +};
> > > > > +
> > > > > +struct sgp_device {
> > > > > + const struct iio_chan_spec *channels;
> > > > > + int num_channels;
> > > > > +};
> > > > > +
> > > > > +static const struct sgp_version supported_versions_sgp30[] = {
> > > > > + {
> > > > > + .major = 1,
> > > > > + .minor = 0,
> > > > > + },
> > > > > +};
> > > > > +
> > > > > +static const struct sgp_version supported_versions_sgpc3[] = {
> > > > > + {
> > > > > + .major = 0,
> > > > > + .minor = 4,
> > > > > + },
> > > > > +};
> > > > > +
> > > > > +static const struct iio_chan_spec sgp30_channels[] = {
> > > > > + {
> > > > > + .type = IIO_CONCENTRATION,
> > > > > + .channel2 = IIO_MOD_VOC,
> > > > > + .modified = 1,
> > > > > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> > > > > + .address = SGP30_IAQ_TVOC_IDX,
> > > > > + },
> > > > > + {
> > > > > + .type = IIO_CONCENTRATION,
> > > > > + .channel2 = IIO_MOD_CO2,
> > > > > + .modified = 1,
> > > > > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> > > > > + .address = SGP30_IAQ_CO2EQ_IDX,
> > > > > + },
> > > > > + {
> > > > > + .type = IIO_CONCENTRATION,
> > > > > + .channel2 = IIO_MOD_ETHANOL,
> > > > > + .modified = 1,
> > > > > + .info_mask_separate =
> > > > > + BIT(IIO_CHAN_INFO_RAW),
> > > >
> > > > Definitely looks like it'll fit in under 80 chars.
> > > >
> > > > > + .address = SGP30_SIG_ETOH_IDX,
> > > > > + .scan_type = {
> > > > > + .endianness = IIO_BE,
> > > > > + },
> > > > > + },
> > > > > + {
> > > > > + .type = IIO_CONCENTRATION,
> > > > > + .channel2 = IIO_MOD_H2,
> > > > > + .modified = 1,
> > > > > + .info_mask_separate =
> > > > > + BIT(IIO_CHAN_INFO_RAW),
> > > >
> > > > Same here on length.
> > > >
> > > > > + .address = SGP30_SIG_H2_IDX,
> > > > > + .scan_type = {
> > > > > + .endianness = IIO_BE,
> > > > > + },
> > > > > + },
> > > > > +};
> > > > > +
> > > > > +static const struct iio_chan_spec sgpc3_channels[] = {
> > > > > + {
> > > > > + .type = IIO_CONCENTRATION,
> > > > > + .channel2 = IIO_MOD_VOC,
> > > > > + .modified = 1,
> > > > > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> > > > > + .address = SGPC3_IAQ_TVOC_IDX,
> > > > > + },
> > > > > + {
> > > > > + .type = IIO_CONCENTRATION,
> > > > > + .channel2 = IIO_MOD_ETHANOL,
> > > > > + .modified = 1,
> > > > > + .info_mask_separate =
> > > > > + BIT(IIO_CHAN_INFO_RAW),
> > > >
> > > > And another on length.
> > > > > + .address = SGPC3_SIG_ETOH_IDX,
> > > > > + .scan_type = {
> > > > > + .endianness = IIO_BE,
> > > > > + },
> > > > > + },
> > > > > +};
> > > > > +
> > > > > +static const struct sgp_device sgp_devices[] = {
> > > > > + [SGP30] = {
> > > > > + .channels = sgp30_channels,
> > > > > + .num_channels = ARRAY_SIZE(sgp30_channels),
> > > > > + },
> > > > > + [SGPC3] = {
> > > > > + .channels = sgpc3_channels,
> > > > > + .num_channels = ARRAY_SIZE(sgpc3_channels),
> > > > > + },
> > > > > +};
> > > > > +
> > > > > +/**
> > > > > + * sgp_verify_buffer() - verify the checksums of the data buffer
> > > > > words
> > > > > + *
> > > > > + * @data: SGP data
> > > > > + * @buf: Raw data buffer
> > > > > + * @word_count: Num data words stored in the buffer, excluding CRC
> > > > > bytes
> > > > > + *
> > > > > + * Return: 0 on success, negative error otherwise.
> > > > > + */
> > > > > +static int sgp_verify_buffer(const struct sgp_data *data,
> > > > > + union sgp_reading *buf, size_t word_count)
> > > > > +{
> > > > > + size_t size = word_count * (SGP_WORD_LEN + SGP_CRC8_LEN);
> > > > > + int i;
> > > > > + u8 crc;
> > > > > + u8 *data_buf = &buf->start;
> > > > > +
> > > > > + for (i = 0; i < size; i += SGP_WORD_LEN + SGP_CRC8_LEN) {
> > > > > + crc = crc8(sgp_crc8_table, &data_buf[i], SGP_WORD_LEN,
> > > > > + SGP_CRC8_INIT);
> > > > > + if (crc != data_buf[i + SGP_WORD_LEN]) {
> > > > > + dev_err(&data->client->dev, "CRC error\n");
> > > > > + return -EIO;
> > > > > + }
> > > > > + }
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * sgp_read_cmd() - reads data from sensor after issuing a command
> > > > > + * The caller must hold data->data_lock for the duration of the
> > > > > call.
> > > > > + * @data: SGP data
> > > > > + * @cmd: SGP Command to issue
> > > > > + * @buf: Raw data buffer to use
> > > > > + * @word_count: Num words to read, excluding CRC bytes
> > > > > + *
> > > > > + * Return: 0 on success, negative error otherwise.
> > > > > + */
> > > > > +static int sgp_read_cmd(struct sgp_data *data, enum sgp_cmd cmd,
> > > > > + union sgp_reading *buf, size_t word_count,
> > > > > + unsigned long duration_us)
> > > > > +{
> > > > > + int ret;
> > > > > + struct i2c_client *client = data->client;
> > > > > + size_t size = word_count * (SGP_WORD_LEN + SGP_CRC8_LEN);
> > > > > + u8 *data_buf;
> > > > > +
> > > > > + ret = i2c_master_send(client, (const char *)&cmd, SGP_CMD_LEN);
> > > > > + if (ret != SGP_CMD_LEN)
> > > > > + return -EIO;
> > > > > + usleep_range(duration_us, duration_us + 1000);
> > > > > +
> > > > > + if (word_count == 0)
> > > > > + return 0;
> > > > > +
> > > > > + data_buf = &buf->start;
> > > > > + ret = i2c_master_recv(client, data_buf, size);
> > > > > + if (ret < 0)
> > > > > + return ret;
> > > > > + if (ret != size)
> > > > > + return -EIO;
> > > > > +
> > > > > + return sgp_verify_buffer(data, buf, word_count);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * sgp_measure_iaq() - measure and retrieve IAQ values from sensor
> > > > > + * The caller must hold data->data_lock for the duration of the
> > > > > call.
> > > > > + * @data: SGP data
> > > > > + *
> > > > > + * Return: 0 on success, -EBUSY on default values, negative
> > > > > error
> > > > > + * otherwise.
> > > > > + */
> > > > > +
> > > > > +static int sgp_measure_iaq(struct sgp_data *data)
> > > > > +{
> > > > > + int ret;
> > > > > + /* data contains default values */
> > > > > + bool default_vals = !time_after(jiffies, data-
> > > > > >iaq_init_start_jiffies +
> > > > > + data-
> > > > > >iaq_defval_skip_jiffies);
> > > > > +
> > > > > + ret = sgp_read_cmd(data, data->measure_iaq_cmd, &data-
> > > > > >iaq_buffer,
> > > > > + SGP_MEASUREMENT_LEN,
> > > > > SGP_MEASUREMENT_DURATION_US);
> > > > > + if (ret < 0)
> > > > > + return ret;
> > > > > +
> > > > > + data->iaq_buffer_state = IAQ_BUFFER_DEFAULT_VALS;
> > > > > +
> > > > > + if (default_vals)
> > > > > + return -EBUSY;
> > > > > +
> > > > > + data->iaq_buffer_state = IAQ_BUFFER_VALID;
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > +static void sgp_iaq_thread_sleep_until(const struct sgp_data
> > > > > *data,
> > > > > + unsigned long sleep_jiffies)
> > > > > +{
> > > > > + const long IAQ_POLL = 50000;
> > > > > +
> > > > > + while (!time_after(jiffies, sleep_jiffies)) {
> > > > > + usleep_range(IAQ_POLL, IAQ_POLL + 10000);
> > > > > + if (kthread_should_stop() || data-
> > > > > >iaq_init_start_jiffies == 0)
> > > > > + return;
> > > > > + }
> > > > > +}
> > > > > +
> > > > > +static int sgp_iaq_threadfn(void *p)
> > > > > +{
> > > > > + struct sgp_data *data = (struct sgp_data *)p;
> > > > > + unsigned long next_update_jiffies;
> > > > > + int ret;
> > > > > +
> > > > > + while (!kthread_should_stop()) {
> > > > > + mutex_lock(&data->data_lock);
> > > > > + if (data->iaq_init_start_jiffies == 0) {
> > > > > + ret = sgp_read_cmd(data, data->iaq_init_cmd,
> > > > > NULL, 0,
> > > > > + SGP_CMD_DURATION_US);
> > > > > + if (ret < 0)
> > > > > + goto unlock_sleep_continue;
> > > > > + data->iaq_init_start_jiffies = jiffies;
> > > > > + }
> > > > > +
> > > > > + ret = sgp_measure_iaq(data);
> > > > > + if (ret && ret != -EBUSY) {
> > > > > + dev_warn(&data->client->dev,
> > > > > + "IAQ measurement error [%d]\n", ret);
> > > > > + }
> > > > > +unlock_sleep_continue:
> > > > > + next_update_jiffies = jiffies + data-
> > > > > >measure_interval_jiffies;
> > > > > + mutex_unlock(&data->data_lock);
> > > > > + sgp_iaq_thread_sleep_until(data, next_update_jiffies);
> > > > > + }
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > +static int sgp_read_raw(struct iio_dev *indio_dev,
> > > > > + struct iio_chan_spec const *chan, int *val,
> > > > > + int *val2, long mask)
> > > > > +{
> > > > > + struct sgp_data *data = iio_priv(indio_dev);
> > > > > + struct sgp_crc_word *words;
> > > > > + int ret;
> > > > > +
> > > > > + switch (mask) {
> > > > > + case IIO_CHAN_INFO_PROCESSED:
> > > > > + mutex_lock(&data->data_lock);
> > > > > + if (data->iaq_buffer_state != IAQ_BUFFER_VALID) {
> > > > > + mutex_unlock(&data->data_lock);
> > > > > + return -EBUSY;
> > > > > + }
> > > > > + words = data->iaq_buffer.raw_words;
> > > > > + switch (chan->address) {
> > > > > + case SGP30_IAQ_TVOC_IDX:
> > > > > + case SGPC3_IAQ_TVOC_IDX:
> > > > > + *val = 0;
> > > > > + *val2 = be16_to_cpu(words[1].value);
> > > > > + ret = IIO_VAL_INT_PLUS_NANO;
> > > > > + break;
> > > > > + case SGP30_IAQ_CO2EQ_IDX:
> > > > > + *val = 0;
> > > > > + *val2 = be16_to_cpu(words[0].value);
> > > > > + ret = IIO_VAL_INT_PLUS_MICRO;
> > > > > + break;
> > > > > + default:
> > > > > + ret = -EINVAL;
> > > > > + break;
> > > > > + }
> > > > > + mutex_unlock(&data->data_lock);
> > > > > + break;
> > > > > + case IIO_CHAN_INFO_RAW:
> > > > > + mutex_lock(&data->data_lock);
> > > > > + if (chan->address == SGPC3_SIG_ETOH_IDX) {
> > > > > + if (data->iaq_buffer_state == IAQ_BUFFER_EMPTY)
> > > > > + ret = -EBUSY;
> > > > > + else
> > > > > + ret = 0;
> > > > > + words = data->iaq_buffer.raw_words;
> > > > > + } else {
> > > > > + ret = sgp_read_cmd(data, data-
> > > > > >measure_gas_signals_cmd,
> > > > > + &data->buffer,
> > > > > SGP_MEASUREMENT_LEN,
> > > > > + SGP_MEASUREMENT_DURATION_US)
> > > > > ;
> > > > > + words = data->buffer.raw_words;
> > > > > + }
> > > > > + if (ret) {
> > > > > + mutex_unlock(&data->data_lock);
> > > > > + return ret;
> > > > > + }
> > > > > +
> > > > > + switch (chan->address) {
> > > > > + case SGP30_SIG_ETOH_IDX:
> > > > > + *val = be16_to_cpu(words[1].value);
> > > > > + ret = IIO_VAL_INT;
> > > > > + break;
> > > > > + case SGPC3_SIG_ETOH_IDX:
> > > > > + case SGP30_SIG_H2_IDX:
> > > > > + *val = be16_to_cpu(words[0].value);
> > > > > + ret = IIO_VAL_INT;
> > > > > + break;
> > > > > + default:
> > > > > + ret = -EINVAL;
> > > > > + break;
> > > > > + }
> > > > > + mutex_unlock(&data->data_lock);
> > > > > + break;
> > > > > + default:
> > > > > + return -EINVAL;
> > > > > + }
> > > > > +
> > > > > + return ret;
> > > > > +}
> > > > > +
> > > > > +static int sgp_check_compat(struct sgp_data *data,
> > > > > + unsigned int product_id)
> > > > > +{
> > > > > + const struct sgp_version *supported_versions;
> > > > > + u16 ix, num_fs;
> > > > > + u16 product, generation, major, minor;
> > > > > +
> > > > > + /* driver does not match product */
> > > > > + generation = SGP_VERS_GEN(data);
> > > > > + if (generation != 0) {
> > > > > + dev_err(&data->client->dev,
> > > > > + "incompatible product generation %d != 0",
> > > > > generation);
> > > > > + return -ENODEV;
> > > > > + }
> > > > > +
> > > > > + product = SGP_VERS_PRODUCT(data);
> > > > > + if (product != product_id) {
> > > > > + dev_err(&data->client->dev,
> > > > > + "sensor reports a different product:
> > > > > 0x%04hx\n",
> > > > > + product);
> > > > > + return -ENODEV;
> > > > > + }
> > > > > +
> > > > > + if (SGP_VERS_RESERVED(data))
> > > > > + dev_warn(&data->client->dev, "reserved bit is set\n");
> > > > > +
> > > > > + /* engineering samples are not supported: no interface
> > > > > guarantees */
> > > > > + if (SGP_VERS_ENG_BIT(data))
> > > > > + return -ENODEV;
> > > > > +
> > > > > + switch (product) {
> > > > > + case SGP30:
> > > > > + supported_versions = supported_versions_sgp30;
> > > > > + num_fs = ARRAY_SIZE(supported_versions_sgp30);
> > > > > + break;
> > > > > + case SGPC3:
> > > > > + supported_versions = supported_versions_sgpc3;
> > > > > + num_fs = ARRAY_SIZE(supported_versions_sgpc3);
> > > > > + break;
> > > > > + default:
> > > > > + return -ENODEV;
> > > > > + }
> > > > > +
> > > > > + major = SGP_VERS_MAJOR(data);
> > > > > + minor = SGP_VERS_MINOR(data);
> > > > > + for (ix = 0; ix < num_fs; ix++) {
> > > > > + if (major == supported_versions[ix].major &&
> > > > > + minor >= supported_versions[ix].minor)
> > > > > + return 0;
> > > > > + }
> > > > > + dev_err(&data->client->dev, "unsupported sgp version: %d.%d\n",
> > > > > + major, minor);
> > > > > +
> > > > > + return -ENODEV;
> > > > > +}
> > > > > +
> > > > > +static void sgp_init(struct sgp_data *data)
> > > > > +{
> > > > > + data->iaq_init_cmd = SGP_CMD_IAQ_INIT;
> > > > > + data->iaq_init_start_jiffies = 0;
> > > > > + data->iaq_buffer_state = IAQ_BUFFER_EMPTY;
> > > > > + switch (SGP_VERS_PRODUCT(data)) {
> > > > > + case SGP30:
> > > > > + data->measure_interval_jiffies =
> > > > > SGP30_MEASURE_INTERVAL_HZ * HZ;
> > > > > + data->measure_iaq_cmd = SGP_CMD_IAQ_MEASURE;
> > > > > + data->measure_gas_signals_cmd =
> > > > > SGP30_CMD_MEASURE_SIGNAL;
> > > > > + data->product_id = SGP30;
> > > > > + data->iaq_defval_skip_jiffies = 15 * HZ;
> > > > > + break;
> > > > > + case SGPC3:
> > > > > + data->measure_interval_jiffies =
> > > > > SGPC3_MEASURE_INTERVAL_HZ * HZ;
> > > > > + data->measure_iaq_cmd = SGPC3_CMD_MEASURE_RAW;
> > > > > + data->measure_gas_signals_cmd = SGPC3_CMD_MEASURE_RAW;
> > > > > + data->product_id = SGPC3;
> > > > > + data->iaq_defval_skip_jiffies =
> > > > > + 43 * data->measure_interval_jiffies;
> > > > > + break;
> > > > > + };
> > > > > +}
> > > > > +
> > > > > +static const struct iio_info sgp_info = {
> > > > > + .read_raw = sgp_read_raw,
> > > > > +};
> > > > > +
> > > > > +static const struct of_device_id sgp_dt_ids[] = {
> > > > > + { .compatible = "sensirion,sgp30", .data = (void *)SGP30 },
> > > > > + { .compatible = "sensirion,sgpc3", .data = (void *)SGPC3 },
> > > > > + { }
> > > > > +};
> > > > > +
> > > > > +static int sgp_probe(struct i2c_client *client,
> > > > > + const struct i2c_device_id *id)
> > > > > +{
> > > > > + struct iio_dev *indio_dev;
> > > > > + struct sgp_data *data;
> > > > > + const struct of_device_id *of_id;
> > > > > + unsigned long product_id;
> > > > > + int ret;
> > > > > +
> > > > > + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> > > > > + if (!indio_dev)
> > > > > + return -ENOMEM;
> > > > > +
> > > > > + of_id = of_match_device(sgp_dt_ids, &client->dev);
> > > > > + if (of_id)
> > > > > + product_id = (unsigned long)of_id->data;
> > > > > + else
> > > > > + product_id = id->driver_data;
> > > > > +
> > > > > + data = iio_priv(indio_dev);
> > > > > + i2c_set_clientdata(client, indio_dev);
> > > > > + data->client = client;
> > > > > + crc8_populate_msb(sgp_crc8_table, SGP_CRC8_POLYNOMIAL);
> > > > > + mutex_init(&data->data_lock);
> > > > > +
> > > > > + /* get feature set version and write it to client data */
> > > > > + ret = sgp_read_cmd(data, SGP_CMD_GET_FEATURE_SET, &data-
> > > > > >buffer, 1,
> > > > > + SGP_CMD_DURATION_US);
> > > > > + if (ret < 0)
> > > > > + return ret;
> > > > > +
> > > > > + data->feature_set = be16_to_cpu(data-
> > > > > >buffer.raw_words[0].value);
> > > > > +
> > > > > + ret = sgp_check_compat(data, product_id);
> > > > > + if (ret)
> > > > > + return ret;
> > > > > +
> > > > > + indio_dev->dev.parent = &client->dev;
> > > > > + indio_dev->info = &sgp_info;
> > > > > + indio_dev->name = id->name;
> > > > > + indio_dev->modes = INDIO_DIRECT_MODE;
> > > > > + indio_dev->channels = sgp_devices[product_id].channels;
> > > > > + indio_dev->num_channels = sgp_devices[product_id].num_channels;
> > > > > +
> > > > > + sgp_init(data);
> > > > > +
> > > > > + ret = devm_iio_device_register(&client->dev, indio_dev);
> > > > > + if (ret) {
> > > > > + dev_err(&client->dev, "failed to register iio
> > > > > device\n");
> > > > > + return ret;
> > > > > + }
> > > > > +
> > > > > + data->iaq_thread = kthread_run(sgp_iaq_threadfn, data,
> > > > > + "%s-iaq", data->client->name);
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > +static int sgp_remove(struct i2c_client *client)
> > > > > +{
> > > > > + struct iio_dev *indio_dev = i2c_get_clientdata(client);
> > > > > + struct sgp_data *data = iio_priv(indio_dev);
> > > > > +
> > > > > + if (data->iaq_thread)
> > > > > + kthread_stop(data->iaq_thread);
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > +static const struct i2c_device_id sgp_id[] = {
> > > > > + { "sgp30", SGP30 },
> > > > > + { "sgpc3", SGPC3 },
> > > > > + { }
> > > > > +};
> > > > > +
> > > > > +MODULE_DEVICE_TABLE(i2c, sgp_id);
> > > > > +MODULE_DEVICE_TABLE(of, sgp_dt_ids);
> > > > > +
> > > > > +static struct i2c_driver sgp_driver = {
> > > > > + .driver = {
> > > > > + .name = "sgp30",
> > > > > + .of_match_table = of_match_ptr(sgp_dt_ids),
> > > > > + },
> > > > > + .probe = sgp_probe,
> > > > > + .remove = sgp_remove,
> > > > > + .id_table = sgp_id,
> > > > > +};
> > > > > +module_i2c_driver(sgp_driver);
> > > > > +
> > > > > +MODULE_AUTHOR("Andreas Brauchli <andreas.brauchli@xxxxxxxxxxxxx>")
> > > > > ;
> > > > > +MODULE_AUTHOR("Pascal Sachs <pascal.sachs@xxxxxxxxxxxxx>");
> > > > > +MODULE_DESCRIPTION("Sensirion SGP gas sensors");
> > > > > +MODULE_LICENSE("GPL v2");
> > > >
> > > >
> > >
> >
> >

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