Re: [RFC v4 1/3] iio: buffer-callback: allow getting underlying iio_dev

[Jonathan Cameron <jic23@kernel.org>]

On 20/08/16 04:17, Matt Ranostay wrote:
> Add iio_channel_cb_get_iio_dev function to allow getting the
> underlying iio_dev. This is useful for setting the trigger of the
> consumer ADC device.
> 
> Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Clearly going to be a necessary bit of infrastructure.

Applied to the togreg branch of iio.git - initially pushed out as
testing for the autobuilders to play with it.

Thanks,

Jonathan
> ---
>  drivers/iio/buffer/industrialio-buffer-cb.c | 24 ++++++++++++++----------
>  include/linux/iio/consumer.h                | 12 ++++++++++++
>  2 files changed, 26 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/iio/buffer/industrialio-buffer-cb.c b/drivers/iio/buffer/industrialio-buffer-cb.c
> index 323079c3ccce..b8f550e47d3d 100644
> --- a/drivers/iio/buffer/industrialio-buffer-cb.c
> +++ b/drivers/iio/buffer/industrialio-buffer-cb.c
> @@ -18,6 +18,7 @@ struct iio_cb_buffer {
>  	int (*cb)(const void *data, void *private);
>  	void *private;
>  	struct iio_channel *channels;
> +	struct iio_dev *indio_dev;
>  };
>  
>  static struct iio_cb_buffer *buffer_to_cb_buffer(struct iio_buffer *buffer)
> @@ -52,7 +53,6 @@ struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
>  {
>  	int ret;
>  	struct iio_cb_buffer *cb_buff;
> -	struct iio_dev *indio_dev;
>  	struct iio_channel *chan;
>  
>  	cb_buff = kzalloc(sizeof(*cb_buff), GFP_KERNEL);
> @@ -72,17 +72,17 @@ struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
>  		goto error_free_cb_buff;
>  	}
>  
> -	indio_dev = cb_buff->channels[0].indio_dev;
> +	cb_buff->indio_dev = cb_buff->channels[0].indio_dev;
>  	cb_buff->buffer.scan_mask
> -		= kcalloc(BITS_TO_LONGS(indio_dev->masklength), sizeof(long),
> -			  GFP_KERNEL);
> +		= kcalloc(BITS_TO_LONGS(cb_buff->indio_dev->masklength),
> +			  sizeof(long), GFP_KERNEL);
>  	if (cb_buff->buffer.scan_mask == NULL) {
>  		ret = -ENOMEM;
>  		goto error_release_channels;
>  	}
>  	chan = &cb_buff->channels[0];
>  	while (chan->indio_dev) {
> -		if (chan->indio_dev != indio_dev) {
> +		if (chan->indio_dev != cb_buff->indio_dev) {
>  			ret = -EINVAL;
>  			goto error_free_scan_mask;
>  		}
> @@ -105,17 +105,14 @@ EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);
>  
>  int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
>  {
> -	return iio_update_buffers(cb_buff->channels[0].indio_dev,
> -				  &cb_buff->buffer,
> +	return iio_update_buffers(cb_buff->indio_dev, &cb_buff->buffer,
>  				  NULL);
>  }
>  EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);
>  
>  void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
>  {
> -	iio_update_buffers(cb_buff->channels[0].indio_dev,
> -			   NULL,
> -			   &cb_buff->buffer);
> +	iio_update_buffers(cb_buff->indio_dev, NULL, &cb_buff->buffer);
>  }
>  EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);
>  
> @@ -133,6 +130,13 @@ struct iio_channel
>  }
>  EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);
>  
> +struct iio_dev
> +*iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer)
> +{
> +	return cb_buffer->indio_dev;
> +}
> +EXPORT_SYMBOL_GPL(iio_channel_cb_get_iio_dev);
> +
>  MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
>  MODULE_DESCRIPTION("Industrial I/O callback buffer");
>  MODULE_LICENSE("GPL");
> diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
> index 3d672f72e7ec..9edccfba1ffb 100644
> --- a/include/linux/iio/consumer.h
> +++ b/include/linux/iio/consumer.h
> @@ -165,6 +165,18 @@ struct iio_channel
>  *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
>  
>  /**
> + * iio_channel_cb_get_iio_dev() - get access to the underlying device.
> + * @cb_buffer:		The callback buffer from whom we want the device
> + *			information.
> + *
> + * This function allows one to obtain information about the device.
> + * The primary aim is to allow drivers that are consuming a device to query
> + * things like current trigger.
> + */
> +struct iio_dev
> +*iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer);
> +
> +/**
>   * iio_read_channel_raw() - read from a given channel
>   * @chan:		The channel being queried.
>   * @val:		Value read back.
>