Date:	Wed, 14 Jan 2015 17:19:47 +0100
From:	Karol Wrona <k.wrona@...sung.com>
To:	Jonathan Cameron <jic23@...nel.org>, linux-iio@...r.kernel.org,
	Hartmut Knaack <knaack.h@....de>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Peter Meerwald <pmeerw@...erw.net>,
	linux-kernel@...r.kernel.org
Cc:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Karol Wrona <wrona.vy@...il.com>
Subject: Re: iio: Move buffer registration to the core

Please, ignore that. This one was sent by accident.


On 01/14/2015 05:09 PM, Karol Wrona wrote:
> From: Lars-Peter Clausen <lars@...afoo.de>
> 
> Originally device and buffer registration were kept as separate operations
> in IIO to allow to register two distinct sets of channels for buffered and
> non-buffered operations. This has since already been further restricted and
> the channel set registered for the buffer needs to be a subset of the
> channel set registered for the device. Additionally the possibility to not
> have a raw (or processed) attribute for a channel which was registered for
> the device was added a while ago. This means it is possible to not register
> any device level attributes for a channel even if it is registered for the
> device. Also if a channel's scan_index is set to -1 and the channel is
> registered for the buffer it is ignored.
> 
> So in summary it means it is possible to register the same channel array for
> both the device and the buffer yet still end up with distinctive sets of
> channels for both of them. This makes the argument for having to have to
> manually register the channels for both the device and the buffer invalid.
> Considering that the vast majority of all drivers want to register the same
> set of channels for both the buffer and the device it makes sense to move
> the buffer registration into the core to avoid some boiler-plate code in the
> device driver setup path.
> 
> Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>
> Signed-off-by: Jonathan Cameron <jic23@...nel.org>
> 
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index b730864..d550ac7 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -264,16 +264,8 @@ static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
>  	indio_dev->setup_ops = setup_ops;
>  	indio_dev->modes |= INDIO_BUFFER_HARDWARE;
>  
> -	ret = iio_buffer_register(indio_dev,
> -				  indio_dev->channels,
> -				  indio_dev->num_channels);
> -	if (ret)
> -		goto error_free_irq;
> -
>  	return 0;
>  
> -error_free_irq:
> -	free_irq(irq, indio_dev);
>  error_kfifo_free:
>  	iio_kfifo_free(indio_dev->buffer);
>  	return ret;
> @@ -285,7 +277,6 @@ static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
>  
>  	free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
>  	iio_kfifo_free(indio_dev->buffer);
> -	iio_buffer_unregister(indio_dev);
>  }
>  
>  
> diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
> index 5f0ea77..3598835 100644
> --- a/drivers/iio/iio_core.h
> +++ b/drivers/iio/iio_core.h
> @@ -48,6 +48,8 @@ unsigned int iio_buffer_poll(struct file *filp,
>  ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
>  				      size_t n, loff_t *f_ps);
>  
> +int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev);
> +void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev);
>  
>  #define iio_buffer_poll_addr (&iio_buffer_poll)
>  #define iio_buffer_read_first_n_outer_addr (&iio_buffer_read_first_n_outer)
> @@ -60,6 +62,13 @@ void iio_buffer_wakeup_poll(struct iio_dev *indio_dev);
>  #define iio_buffer_poll_addr NULL
>  #define iio_buffer_read_first_n_outer_addr NULL
>  
> +static inline int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
> +{
> +	return 0;
> +}
> +
> +static inline void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev) {}
> +
>  static inline void iio_disable_all_buffers(struct iio_dev *indio_dev) {}
>  static inline void iio_buffer_wakeup_poll(struct iio_dev *indio_dev) {}
>  
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index f667e4e..8bb3e64 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -385,14 +385,16 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
>  
>  static const char * const iio_scan_elements_group_name = "scan_elements";
>  
> -int iio_buffer_register(struct iio_dev *indio_dev,
> -			const struct iio_chan_spec *channels,
> -			int num_channels)
> +int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
>  {
>  	struct iio_dev_attr *p;
>  	struct attribute **attr;
>  	struct iio_buffer *buffer = indio_dev->buffer;
>  	int ret, i, attrn, attrcount, attrcount_orig = 0;
> +	const struct iio_chan_spec *channels;
> +
> +	if (!buffer)
> +		return 0;
>  
>  	if (buffer->attrs)
>  		indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
> @@ -404,9 +406,10 @@ int iio_buffer_register(struct iio_dev *indio_dev,
>  	}
>  	attrcount = attrcount_orig;
>  	INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
> +	channels = indio_dev->channels;
>  	if (channels) {
>  		/* new magic */
> -		for (i = 0; i < num_channels; i++) {
> +		for (i = 0; i < indio_dev->num_channels; i++) {
>  			if (channels[i].scan_index < 0)
>  				continue;
>  
> @@ -463,15 +466,16 @@ error_cleanup_dynamic:
>  
>  	return ret;
>  }
> -EXPORT_SYMBOL(iio_buffer_register);
>  
> -void iio_buffer_unregister(struct iio_dev *indio_dev)
> +void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
>  {
> +	if (!indio_dev->buffer)
> +		return;
> +
>  	kfree(indio_dev->buffer->scan_mask);
>  	kfree(indio_dev->buffer->scan_el_group.attrs);
>  	iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
>  }
> -EXPORT_SYMBOL(iio_buffer_unregister);
>  
>  ssize_t iio_buffer_read_length(struct device *dev,
>  			       struct device_attribute *attr,
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 45bb3a4..ee442ee 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1158,11 +1158,19 @@ int iio_device_register(struct iio_dev *indio_dev)
>  			"Failed to register debugfs interfaces\n");
>  		return ret;
>  	}
> +
> +	ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
> +	if (ret) {
> +		dev_err(indio_dev->dev.parent,
> +			"Failed to create buffer sysfs interfaces\n");
> +		goto error_unreg_debugfs;
> +	}
> +
>  	ret = iio_device_register_sysfs(indio_dev);
>  	if (ret) {
>  		dev_err(indio_dev->dev.parent,
>  			"Failed to register sysfs interfaces\n");
> -		goto error_unreg_debugfs;
> +		goto error_buffer_free_sysfs;
>  	}
>  	ret = iio_device_register_eventset(indio_dev);
>  	if (ret) {
> @@ -1195,6 +1203,8 @@ error_unreg_eventset:
>  	iio_device_unregister_eventset(indio_dev);
>  error_free_sysfs:
>  	iio_device_unregister_sysfs(indio_dev);
> +error_buffer_free_sysfs:
> +	iio_buffer_free_sysfs_and_mask(indio_dev);
>  error_unreg_debugfs:
>  	iio_device_unregister_debugfs(indio_dev);
>  	return ret;
> @@ -1223,6 +1233,8 @@ void iio_device_unregister(struct iio_dev *indio_dev)
>  	iio_buffer_wakeup_poll(indio_dev);
>  
>  	mutex_unlock(&indio_dev->info_exist_lock);
> +
> +	iio_buffer_free_sysfs_and_mask(indio_dev);
>  }
>  EXPORT_SYMBOL(iio_device_unregister);
>  
> diff --git a/drivers/iio/industrialio-triggered-buffer.c b/drivers/iio/industrialio-triggered-buffer.c
> index d6f54930..61a5d04 100644
> --- a/drivers/iio/industrialio-triggered-buffer.c
> +++ b/drivers/iio/industrialio-triggered-buffer.c
> @@ -32,7 +32,7 @@ static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
>   *
>   * This function combines some common tasks which will normally be performed
>   * when setting up a triggered buffer. It will allocate the buffer and the
> - * pollfunc, as well as register the buffer with the IIO core.
> + * pollfunc.
>   *
>   * Before calling this function the indio_dev structure should already be
>   * completely initialized, but not yet registered. In practice this means that
> @@ -78,16 +78,8 @@ int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
>  	/* Flag that polled ring buffering is possible */
>  	indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
>  
> -	ret = iio_buffer_register(indio_dev,
> -				  indio_dev->channels,
> -				  indio_dev->num_channels);
> -	if (ret)
> -		goto error_dealloc_pollfunc;
> -
>  	return 0;
>  
> -error_dealloc_pollfunc:
> -	iio_dealloc_pollfunc(indio_dev->pollfunc);
>  error_kfifo_free:
>  	iio_kfifo_free(indio_dev->buffer);
>  error_ret:
> @@ -101,7 +93,6 @@ EXPORT_SYMBOL(iio_triggered_buffer_setup);
>   */
>  void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
>  {
> -	iio_buffer_unregister(indio_dev);
>  	iio_dealloc_pollfunc(indio_dev->pollfunc);
>  	iio_kfifo_free(indio_dev->buffer);
>  }
> diff --git a/drivers/staging/iio/accel/lis3l02dq_core.c b/drivers/staging/iio/accel/lis3l02dq_core.c
> index f5e145c..b78c9c5 100644
> --- a/drivers/staging/iio/accel/lis3l02dq_core.c
> +++ b/drivers/staging/iio/accel/lis3l02dq_core.c
> @@ -716,14 +716,6 @@ static int lis3l02dq_probe(struct spi_device *spi)
>  	if (ret)
>  		return ret;
>  
> -	ret = iio_buffer_register(indio_dev,
> -				  lis3l02dq_channels,
> -				  ARRAY_SIZE(lis3l02dq_channels));
> -	if (ret) {
> -		dev_err(&spi->dev, "failed to initialize the buffer\n");
> -		goto error_unreg_buffer_funcs;
> -	}
> -
>  	if (spi->irq) {
>  		ret = request_threaded_irq(st->us->irq,
>  					   &lis3l02dq_th,
> @@ -732,7 +724,7 @@ static int lis3l02dq_probe(struct spi_device *spi)
>  					   "lis3l02dq",
>  					   indio_dev);
>  		if (ret)
> -			goto error_uninitialize_buffer;
> +			goto error_unreg_buffer_funcs;
>  
>  		ret = lis3l02dq_probe_trigger(indio_dev);
>  		if (ret)
> @@ -756,8 +748,6 @@ error_remove_trigger:
>  error_free_interrupt:
>  	if (spi->irq)
>  		free_irq(st->us->irq, indio_dev);
> -error_uninitialize_buffer:
> -	iio_buffer_unregister(indio_dev);
>  error_unreg_buffer_funcs:
>  	lis3l02dq_unconfigure_buffer(indio_dev);
>  	return ret;
> @@ -804,7 +794,6 @@ static int lis3l02dq_remove(struct spi_device *spi)
>  		free_irq(st->us->irq, indio_dev);
>  
>  	lis3l02dq_remove_trigger(indio_dev);
> -	iio_buffer_unregister(indio_dev);
>  	lis3l02dq_unconfigure_buffer(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/staging/iio/accel/sca3000_core.c b/drivers/staging/iio/accel/sca3000_core.c
> index aef8c91..9cd04c7 100644
> --- a/drivers/staging/iio/accel/sca3000_core.c
> +++ b/drivers/staging/iio/accel/sca3000_core.c
> @@ -1156,11 +1156,6 @@ static int sca3000_probe(struct spi_device *spi)
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = iio_buffer_register(indio_dev, indio_dev->channels,
> -				  indio_dev->num_channels);
> -	if (ret < 0)
> -		goto error_unregister_dev;
> -
>  	if (spi->irq) {
>  		ret = request_threaded_irq(spi->irq,
>  					   NULL,
> @@ -1169,7 +1164,7 @@ static int sca3000_probe(struct spi_device *spi)
>  					   "sca3000",
>  					   indio_dev);
>  		if (ret)
> -			goto error_unregister_ring;
> +			goto error_unregister_dev;
>  	}
>  	sca3000_register_ring_funcs(indio_dev);
>  	ret = sca3000_clean_setup(st);
> @@ -1180,8 +1175,6 @@ static int sca3000_probe(struct spi_device *spi)
>  error_free_irq:
>  	if (spi->irq)
>  		free_irq(spi->irq, indio_dev);
> -error_unregister_ring:
> -	iio_buffer_unregister(indio_dev);
>  error_unregister_dev:
>  	iio_device_unregister(indio_dev);
>  	return ret;
> @@ -1215,7 +1208,6 @@ static int sca3000_remove(struct spi_device *spi)
>  	if (spi->irq)
>  		free_irq(spi->irq, indio_dev);
>  	iio_device_unregister(indio_dev);
> -	iio_buffer_unregister(indio_dev);
>  	sca3000_unconfigure_ring(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/staging/iio/iio_simple_dummy_buffer.c b/drivers/staging/iio/iio_simple_dummy_buffer.c
> index 35d60d5..a2d72c1 100644
> --- a/drivers/staging/iio/iio_simple_dummy_buffer.c
> +++ b/drivers/staging/iio/iio_simple_dummy_buffer.c
> @@ -172,15 +172,8 @@ int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
>  	 */
>  	indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
>  
> -	ret = iio_buffer_register(indio_dev, indio_dev->channels,
> -				  indio_dev->num_channels);
> -	if (ret)
> -		goto error_dealloc_pollfunc;
> -
>  	return 0;
>  
> -error_dealloc_pollfunc:
> -	iio_dealloc_pollfunc(indio_dev->pollfunc);
>  error_free_buffer:
>  	iio_kfifo_free(indio_dev->buffer);
>  error_ret:
> @@ -194,7 +187,6 @@ error_ret:
>   */
>  void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
>  {
> -	iio_buffer_unregister(indio_dev);
>  	iio_dealloc_pollfunc(indio_dev->pollfunc);
>  	iio_kfifo_free(indio_dev->buffer);
>  }
> diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
> index aa6a368..c50b138 100644
> --- a/drivers/staging/iio/impedance-analyzer/ad5933.c
> +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
> @@ -752,23 +752,16 @@ static int ad5933_probe(struct i2c_client *client,
>  	if (ret)
>  		goto error_disable_reg;
>  
> -	ret = iio_buffer_register(indio_dev, ad5933_channels,
> -		ARRAY_SIZE(ad5933_channels));
> -	if (ret)
> -		goto error_unreg_ring;
> -
>  	ret = ad5933_setup(st);
>  	if (ret)
> -		goto error_uninitialize_ring;
> +		goto error_unreg_ring;
>  
>  	ret = iio_device_register(indio_dev);
>  	if (ret)
> -		goto error_uninitialize_ring;
> +		goto error_unreg_ring;
>  
>  	return 0;
>  
> -error_uninitialize_ring:
> -	iio_buffer_unregister(indio_dev);
>  error_unreg_ring:
>  	iio_kfifo_free(indio_dev->buffer);
>  error_disable_reg:
> @@ -784,7 +777,6 @@ static int ad5933_remove(struct i2c_client *client)
>  	struct ad5933_state *st = iio_priv(indio_dev);
>  
>  	iio_device_unregister(indio_dev);
> -	iio_buffer_unregister(indio_dev);
>  	iio_kfifo_free(indio_dev->buffer);
>  	if (!IS_ERR(st->reg))
>  		regulator_disable(st->reg);
> diff --git a/drivers/staging/iio/meter/ade7758.h b/drivers/staging/iio/meter/ade7758.h
> index 0731820..762d7dc 100644
> --- a/drivers/staging/iio/meter/ade7758.h
> +++ b/drivers/staging/iio/meter/ade7758.h
> @@ -146,7 +146,6 @@ ssize_t ade7758_read_data_from_ring(struct device *dev,
>  int ade7758_configure_ring(struct iio_dev *indio_dev);
>  void ade7758_unconfigure_ring(struct iio_dev *indio_dev);
>  
> -void ade7758_uninitialize_ring(struct iio_dev *indio_dev);
>  int ade7758_set_irq(struct device *dev, bool enable);
>  
>  int ade7758_spi_write_reg_8(struct device *dev,
> diff --git a/drivers/staging/iio/meter/ade7758_core.c b/drivers/staging/iio/meter/ade7758_core.c
> index abc6006..6e8b011 100644
> --- a/drivers/staging/iio/meter/ade7758_core.c
> +++ b/drivers/staging/iio/meter/ade7758_core.c
> @@ -885,23 +885,15 @@ static int ade7758_probe(struct spi_device *spi)
>  	if (ret)
>  		goto error_free_tx;
>  
> -	ret = iio_buffer_register(indio_dev,
> -				  &ade7758_channels[0],
> -				  ARRAY_SIZE(ade7758_channels));
> -	if (ret) {
> -		dev_err(&spi->dev, "failed to initialize the ring\n");
> -		goto error_unreg_ring_funcs;
> -	}
> -
>  	/* Get the device into a sane initial state */
>  	ret = ade7758_initial_setup(indio_dev);
>  	if (ret)
> -		goto error_uninitialize_ring;
> +		goto error_unreg_ring_funcs;
>  
>  	if (spi->irq) {
>  		ret = ade7758_probe_trigger(indio_dev);
>  		if (ret)
> -			goto error_uninitialize_ring;
> +			goto error_unreg_ring_funcs;
>  	}
>  
>  	ret = iio_device_register(indio_dev);
> @@ -913,8 +905,6 @@ static int ade7758_probe(struct spi_device *spi)
>  error_remove_trigger:
>  	if (spi->irq)
>  		ade7758_remove_trigger(indio_dev);
> -error_uninitialize_ring:
> -	ade7758_uninitialize_ring(indio_dev);
>  error_unreg_ring_funcs:
>  	ade7758_unconfigure_ring(indio_dev);
>  error_free_tx:
> @@ -932,7 +922,6 @@ static int ade7758_remove(struct spi_device *spi)
>  	iio_device_unregister(indio_dev);
>  	ade7758_stop_device(&indio_dev->dev);
>  	ade7758_remove_trigger(indio_dev);
> -	ade7758_uninitialize_ring(indio_dev);
>  	ade7758_unconfigure_ring(indio_dev);
>  	kfree(st->tx);
>  	kfree(st->rx);
> diff --git a/drivers/staging/iio/meter/ade7758_ring.c b/drivers/staging/iio/meter/ade7758_ring.c
> index c0accf8..27c3ed6 100644
> --- a/drivers/staging/iio/meter/ade7758_ring.c
> +++ b/drivers/staging/iio/meter/ade7758_ring.c
> @@ -181,8 +181,3 @@ error_iio_kfifo_free:
>  	iio_kfifo_free(indio_dev->buffer);
>  	return ret;
>  }
> -
> -void ade7758_uninitialize_ring(struct iio_dev *indio_dev)
> -{
> -	iio_buffer_unregister(indio_dev);
> -}
> diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
> index 8c8ce61..b0e006c 100644
> --- a/include/linux/iio/buffer.h
> +++ b/include/linux/iio/buffer.h
> @@ -151,22 +151,6 @@ static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev,
>  int iio_update_demux(struct iio_dev *indio_dev);
>  
>  /**
> - * iio_buffer_register() - register the buffer with IIO core
> - * @indio_dev:		device with the buffer to be registered
> - * @channels:		the channel descriptions used to construct buffer
> - * @num_channels:	the number of channels
> - **/
> -int iio_buffer_register(struct iio_dev *indio_dev,
> -			const struct iio_chan_spec *channels,
> -			int num_channels);
> -
> -/**
> - * iio_buffer_unregister() - unregister the buffer from IIO core
> - * @indio_dev:		the device with the buffer to be unregistered
> - **/
> -void iio_buffer_unregister(struct iio_dev *indio_dev);
> -
> -/**
>   * iio_buffer_read_length() - attr func to get number of datums in the buffer
>   **/
>  ssize_t iio_buffer_read_length(struct device *dev,
> @@ -223,16 +207,6 @@ static inline void iio_device_attach_buffer(struct iio_dev *indio_dev,
>  
>  #else /* CONFIG_IIO_BUFFER */
>  
> -static inline int iio_buffer_register(struct iio_dev *indio_dev,
> -					   const struct iio_chan_spec *channels,
> -					   int num_channels)
> -{
> -	return 0;
> -}
> -
> -static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
> -{}
> -
>  static inline void iio_buffer_get(struct iio_buffer *buffer) {}
>  static inline void iio_buffer_put(struct iio_buffer *buffer) {}
>  
> 

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