Re: [PATCH v4 05/10] staging:iio:adc:ad7298: Use new triggered buffer setup helper function

[Jonathan Cameron <jic23@cam.ac.uk>]

On 6/18/2012 12:44 PM, Lars-Peter Clausen wrote:
> Use the new triggered buffer setup helper function to allocate and register
> buffer and pollfunc.
>
> The previous code was not passing the temperature channel to iio_buffer_register
> since the temperature channel can not be used in buffered mode. With the new
> helper functions it is not possible to do this, instead the scan index for the
> temperature channel is set to -1 which will cause iio_buffer_register to ignore
> the channel. (Also While we are at it also assign the symbolic constant instead
> of the raw value to the channel address for the temperature channel).
>
> Also as part of the conversion drop scan_timestamp being enabled by default,
> since it is a left over of an earlier cleanup.
>
> Signed-off-by: Lars-Peter Clausen<lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
> ---
> Changes since v3:
> 	* Set temperature channel scan index to -1 so it can not be used in buffered
> 	  mode. This is the same behaviour as without this patch.
> ---
>   drivers/staging/iio/adc/Kconfig       |    2 +-
>   drivers/staging/iio/adc/ad7298.h      |    5 +++
>   drivers/staging/iio/adc/ad7298_core.c |   15 +++-----
>   drivers/staging/iio/adc/ad7298_ring.c |   64 ++++++---------------------------
>   4 files changed, 20 insertions(+), 66 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
> index 7cdf421..bb6fffd 100644
> --- a/drivers/staging/iio/adc/Kconfig
> +++ b/drivers/staging/iio/adc/Kconfig
> @@ -13,7 +13,7 @@ config AD7291
>   config AD7298
>   	tristate "Analog Devices AD7298 ADC driver"
>   	depends on SPI
> -	select IIO_KFIFO_BUF if IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER if IIO_BUFFER
>   	help
>   	  Say yes here to build support for Analog Devices AD7298
>   	  8 Channel ADC with temperature sensor.
> diff --git a/drivers/staging/iio/adc/ad7298.h b/drivers/staging/iio/adc/ad7298.h
> index 5051a7e..18f2787 100644
> --- a/drivers/staging/iio/adc/ad7298.h
> +++ b/drivers/staging/iio/adc/ad7298.h
> @@ -55,6 +55,8 @@ struct ad7298_state {
>   #ifdef CONFIG_IIO_BUFFER
>   int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev);
>   void ad7298_ring_cleanup(struct iio_dev *indio_dev);
> +int ad7298_update_scan_mode(struct iio_dev *indio_dev,
> +	const unsigned long *active_scan_mask);
>   #else /* CONFIG_IIO_BUFFER */
>
>   static inline int
> @@ -66,5 +68,8 @@ ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev)
>   static inline void ad7298_ring_cleanup(struct iio_dev *indio_dev)
>   {
>   }
> +
> +#define ad7298_update_scan_mode NULL
> +
>   #endif /* CONFIG_IIO_BUFFER */
>   #endif /* IIO_ADC_AD7298_H_ */
> diff --git a/drivers/staging/iio/adc/ad7298_core.c b/drivers/staging/iio/adc/ad7298_core.c
> index c90f2b3..6141f4a 100644
> --- a/drivers/staging/iio/adc/ad7298_core.c
> +++ b/drivers/staging/iio/adc/ad7298_core.c
> @@ -45,8 +45,8 @@ static struct iio_chan_spec ad7298_channels[] = {
>   		.channel = 0,
>   		.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
>   		IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
> -		.address = 9,
> -		.scan_index = AD7298_CH_TEMP,
> +		.address = AD7298_CH_TEMP,
> +		.scan_index = -1,
>   		.scan_type = {
>   			.sign = 's',
>   			.realbits = 32,
> @@ -171,6 +171,7 @@ static int ad7298_read_raw(struct iio_dev *indio_dev,
>
>   static const struct iio_info ad7298_info = {
>   	.read_raw =&ad7298_read_raw,
> +	.update_scan_mode = ad7298_update_scan_mode,
>   	.driver_module = THIS_MODULE,
>   };
>
> @@ -231,19 +232,12 @@ static int __devinit ad7298_probe(struct spi_device *spi)
>   	if (ret)
>   		goto error_disable_reg;
>
> -	ret = iio_buffer_register(indio_dev,
> -				&ad7298_channels[1], /* skip temp0 */
> -				  ARRAY_SIZE(ad7298_channels) - 1);
> -	if (ret)
> -		goto error_cleanup_ring;
>   	ret = iio_device_register(indio_dev);
>   	if (ret)
> -		goto error_unregister_ring;
> +		goto error_cleanup_ring;
>
>   	return 0;
>
> -error_unregister_ring:
> -	iio_buffer_unregister(indio_dev);
>   error_cleanup_ring:
>   	ad7298_ring_cleanup(indio_dev);
>   error_disable_reg:
> @@ -263,7 +257,6 @@ static int __devexit ad7298_remove(struct spi_device *spi)
>   	struct ad7298_state *st = iio_priv(indio_dev);
>
>   	iio_device_unregister(indio_dev);
> -	iio_buffer_unregister(indio_dev);
>   	ad7298_ring_cleanup(indio_dev);
>   	if (!IS_ERR(st->reg)) {
>   		regulator_disable(st->reg);
> diff --git a/drivers/staging/iio/adc/ad7298_ring.c b/drivers/staging/iio/adc/ad7298_ring.c
> index 908a3e5..cd3e9cb 100644
> --- a/drivers/staging/iio/adc/ad7298_ring.c
> +++ b/drivers/staging/iio/adc/ad7298_ring.c
> @@ -13,37 +13,29 @@
>
>   #include<linux/iio/iio.h>
>   #include<linux/iio/buffer.h>
> -#include<linux/iio/kfifo_buf.h>
>   #include<linux/iio/trigger_consumer.h>
> +#include<linux/iio/triggered_buffer.h>
>
>   #include "ad7298.h"
>
>   /**
> - * ad7298_ring_preenable() setup the parameters of the ring before enabling
> - *
> - * The complex nature of the setting of the number of bytes per datum is due
> - * to this driver currently ensuring that the timestamp is stored at an 8
> - * byte boundary.
> + * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask
>    **/
> -static int ad7298_ring_preenable(struct iio_dev *indio_dev)
> +int ad7298_update_scan_mode(struct iio_dev *indio_dev,
> +	const unsigned long *active_scan_mask)
>   {
>   	struct ad7298_state *st = iio_priv(indio_dev);
>   	int i, m;
>   	unsigned short command;
> -	int scan_count, ret;
> -
> -	ret = iio_sw_buffer_preenable(indio_dev);
> -	if (ret<  0)
> -		return ret;
> +	int scan_count;
>
>   	/* Now compute overall size */
> -	scan_count = bitmap_weight(indio_dev->active_scan_mask,
> -				   indio_dev->masklength);
> +	scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength);
>
>   	command = AD7298_WRITE | st->ext_ref;
>
>   	for (i = 0, m = AD7298_CH(0); i<  AD7298_MAX_CHAN; i++, m>>= 1)
> -		if (test_bit(i, indio_dev->active_scan_mask))
> +		if (test_bit(i, active_scan_mask))
>   			command |= m;
>
>   	st->tx_buf[0] = cpu_to_be16(command);
> @@ -108,49 +100,13 @@ static irqreturn_t ad7298_trigger_handler(int irq, void *p)
>   	return IRQ_HANDLED;
>   }
>
> -static const struct iio_buffer_setup_ops ad7298_ring_setup_ops = {
> -	.preenable =&ad7298_ring_preenable,
> -	.postenable =&iio_triggered_buffer_postenable,
> -	.predisable =&iio_triggered_buffer_predisable,
> -};
> -
>   int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev)
>   {
> -	int ret;
> -
> -	indio_dev->buffer = iio_kfifo_allocate(indio_dev);
> -	if (!indio_dev->buffer) {
> -		ret = -ENOMEM;
> -		goto error_ret;
> -	}
> -	indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
> -						&ad7298_trigger_handler,
> -						 IRQF_ONESHOT,
> -						 indio_dev,
> -						 "ad7298_consumer%d",
> -						 indio_dev->id);
> -
> -	if (indio_dev->pollfunc == NULL) {
> -		ret = -ENOMEM;
> -		goto error_deallocate_kfifo;
> -	}
> -
> -	/* Ring buffer functions - here trigger setup related */
> -	indio_dev->setup_ops =&ad7298_ring_setup_ops;
> -	indio_dev->buffer->scan_timestamp = true;
> -
> -	/* Flag that polled ring buffering is possible */
> -	indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
> -	return 0;
> -
> -error_deallocate_kfifo:
> -	iio_kfifo_free(indio_dev->buffer);
> -error_ret:
> -	return ret;
> +	return iio_triggered_buffer_setup(indio_dev, NULL,
> +			&ad7298_trigger_handler, NULL);
>   }
>
>   void ad7298_ring_cleanup(struct iio_dev *indio_dev)
>   {
> -	iio_dealloc_pollfunc(indio_dev->pollfunc);
> -	iio_kfifo_free(indio_dev->buffer);
> +	iio_triggered_buffer_cleanup(indio_dev);
>   }