Re: [PATCH v2] iio: chemical: ccs811: Add triggered buffer support

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 17 Aug 2017 14:34:29 +0300
Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com> wrote:

> A software trigger such as hrtimer can be used to capture the data
> that will be stored in the buffer.
> 
> Cc: Daniel Baluta <daniel.baluta@gmail.com>
> Cc: Alison Schofield <amsfield22@gmail.com>
> Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>

Looks good to me. Applied to the togreg branch of iio.git
and pushed out as testing for the autobuilders to play with it.

Thanks

Jonathan
> ---
> Changes in v2:
>   - Remove initialization of "shift" field with 0 in structure
>   - Remove taking the lock inside the trigger handler
>   - Replace devm_iio_triggered_buffer_setup with the non-devm*
>     function, in order to safely do the cleanup
>   - Add cleanup for triggered-buffer, inside remove function
>   - Put device in idle mode in case of error, in probe function
>   - Add error message, in case data can't be read, inside trigger handler
> 
>  drivers/iio/chemical/Kconfig  |  2 ++
>  drivers/iio/chemical/ccs811.c | 76 ++++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 73 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
> index 4d799b5..5cb5be7 100644
> --- a/drivers/iio/chemical/Kconfig
> +++ b/drivers/iio/chemical/Kconfig
> @@ -24,6 +24,8 @@ config ATLAS_PH_SENSOR
>  config CCS811
>  	tristate "AMS CCS811 VOC sensor"
>  	depends on I2C
> +    select IIO_BUFFER
> +    select IIO_TRIGGERED_BUFFER
>  	help
>  	  Say Y here to build I2C interface support for the AMS
>  	  CCS811 VOC (Volatile Organic Compounds) sensor
> diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c
> index 8dbb5ed..840a6cb 100644
> --- a/drivers/iio/chemical/ccs811.c
> +++ b/drivers/iio/chemical/ccs811.c
> @@ -21,6 +21,9 @@
>  #include <linux/delay.h>
>  #include <linux/i2c.h>
>  #include <linux/iio/iio.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
>  #include <linux/module.h>
> 
>  #define CCS811_STATUS		0x00
> @@ -76,25 +79,42 @@ struct ccs811_data {
>  	{
>  		.type = IIO_CURRENT,
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> -				      BIT(IIO_CHAN_INFO_SCALE)
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.scan_index = -1,
>  	}, {
>  		.type = IIO_VOLTAGE,
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> -				      BIT(IIO_CHAN_INFO_SCALE)
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.scan_index = -1,
>  	}, {
>  		.type = IIO_CONCENTRATION,
>  		.channel2 = IIO_MOD_CO2,
>  		.modified = 1,
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>  				      BIT(IIO_CHAN_INFO_OFFSET) |
> -				      BIT(IIO_CHAN_INFO_SCALE)
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.scan_index = 0,
> +		.scan_type = {
> +			.sign = 'u',
> +			.realbits = 16,
> +			.storagebits = 16,
> +			.endianness = IIO_BE,
> +		},
>  	}, {
>  		.type = IIO_CONCENTRATION,
>  		.channel2 = IIO_MOD_VOC,
>  		.modified = 1,
>  		.info_mask_separate =  BIT(IIO_CHAN_INFO_RAW) |
> -				       BIT(IIO_CHAN_INFO_SCALE)
> +				       BIT(IIO_CHAN_INFO_SCALE),
> +		.scan_index = 1,
> +		.scan_type = {
> +			.sign = 'u',
> +			.realbits = 16,
> +			.storagebits = 16,
> +			.endianness = IIO_BE,
> +		},
>  	},
> +	IIO_CHAN_SOFT_TIMESTAMP(2),
>  };
> 
>  /*
> @@ -253,6 +273,31 @@ static int ccs811_read_raw(struct iio_dev *indio_dev,
>  	.driver_module = THIS_MODULE,
>  };
> 
> +static irqreturn_t ccs811_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct ccs811_data *data = iio_priv(indio_dev);
> +	struct i2c_client *client = data->client;
> +	s16 buf[8]; /* s16 eCO2 + s16 TVOC + padding + 8 byte timestamp */
> +	int ret;
> +
> +	ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, 4,
> +					    (u8 *)&buf);
> +	if (ret != 4) {
> +		dev_err(&client->dev, "cannot read sensor data\n");
> +		goto err;
> +	}
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, buf,
> +					   iio_get_time_ns(indio_dev));
> +
> +err:
> +	iio_trigger_notify_done(indio_dev->trig);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static int ccs811_probe(struct i2c_client *client,
>  			const struct i2c_device_id *id)
>  {
> @@ -305,7 +350,27 @@ static int ccs811_probe(struct i2c_client *client,
>  	indio_dev->channels = ccs811_channels;
>  	indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);
> 
> -	return iio_device_register(indio_dev);
> +	ret = iio_triggered_buffer_setup(indio_dev, NULL,
> +					 ccs811_trigger_handler, NULL);
> +
> +	if (ret < 0) {
> +		dev_err(&client->dev, "triggered buffer setup failed\n");
> +		goto err_poweroff;
> +	}
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "unable to register iio device\n");
> +		goto err_buffer_cleanup;
> +	}
> +	return 0;
> +
> +err_buffer_cleanup:
> +	iio_triggered_buffer_cleanup(indio_dev);
> +err_poweroff:
> +	i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);
> +
> +	return ret;
>  }
> 
>  static int ccs811_remove(struct i2c_client *client)
> @@ -313,6 +378,7 @@ static int ccs811_remove(struct i2c_client *client)
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> 
>  	iio_device_unregister(indio_dev);
> +	iio_triggered_buffer_cleanup(indio_dev);
> 
>  	return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
>  					 CCS811_MODE_IDLE);
> --
> 1.9.1
> 
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