Subject: Re: [PATCH] staging: iio: ad7476: fix !CONFIG_IIO_RING_BUFFER build issue reported by Randy Dunlap

From: Jonathan Cameron <[email-masked]>
Date: Thu, 14 Oct 2010 11:22:48 +0100

On 10/14/10 09:17, [email-masked] wrote:
> From: Michael Hennerich <[email-masked]>
> 
> Fix function function decalration
> Enable CONFIG_IIO_RING_BUFFER for the ad7476 driver
> 
> Signed-off-by: Michael Hennerich <[email-masked]>
> ---
>  drivers/staging/iio/adc/Kconfig  |    3 +++
>  drivers/staging/iio/adc/ad7476.h |    4 +---
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
> index 81a7d45..acb6767 100644
> --- a/drivers/staging/iio/adc/Kconfig
> +++ b/drivers/staging/iio/adc/Kconfig
> @@ -50,6 +50,9 @@ config AD799X_RING_BUFFER
>  config AD7476
>  	tristate "Analog Devices AD7475/6/7/8 AD7466/7/8 and AD7495 ADC driver"
>  	depends on SPI
> +	select IIO_RING_BUFFER	
> +	select IIO_SW_RING
> +	select IIO_TRIGGER 	
>  	help
>  	  Say yes here to build support for Analog Devices
>  	  AD7475, AD7476, AD7477, AD7478, AD7466, AD7467, AD7468, AD7495
> diff --git a/drivers/staging/iio/adc/ad7476.h b/drivers/staging/iio/adc/ad7476.h
> index 6e4a85b..b51b49e 100644
> --- a/drivers/staging/iio/adc/ad7476.h
> +++ b/drivers/staging/iio/adc/ad7476.h
> @@ -59,9 +59,7 @@ int ad7476_scan_from_ring(struct ad7476_state *st);
>  int ad7476_register_ring_funcs_and_init(struct iio_dev *indio_dev);
>  void ad7476_ring_cleanup(struct iio_dev *indio_dev);
>  #else /* CONFIG_IIO_RING_BUFFER */

If you are selecting the ring buffer (which is fine), then why do you need
anything to be in this else?  The buffer will always be there.

Maybe I'm missing something?
> -static inline ssize_t ad7476_scan_from_ring(struct device *dev,
> -					     struct device_attribute *attr,
> -					     char *buf)
> +static inline int ad7476_scan_from_ring(struct ad7476_state *st)
>  {
>  	return 0;
>  }