The ad7298 drivers buffer implementation uses the IIO kfifo buffer, so it needs
to select IIO_KFIFO_BUF. Otherwise (if no other driver selects the symbol) the
following linker error will occur:

drivers/built-in.o: In function `ad7298_register_ring_funcs_and_init':
	(.text+0x245cf2): undefined reference to `iio_kfifo_allocate'
drivers/built-in.o: In function `ad7298_register_ring_funcs_and_init':
	(.text+0x245d7d): undefined reference to `iio_kfifo_free'
drivers/built-in.o: In function `ad7298_ring_cleanup':
	(.text+0x245dcd): undefined reference to `iio_kfifo_free'

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reported-by: Randy Dunlap <redacted>

---
The patch is only required for 3.5-rc1+. Versions prior to 3.5-rc1 require a
different patch (IIO_SW_RING instead of IIO_KFIFO_BUF) which I'll send to stable
once this patch is in Linus' tree.
---
 drivers/staging/iio/adc/Kconfig |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
index 2490dd2..8f1b3af 100644
--- a/drivers/staging/iio/adc/Kconfig
+++ b/drivers/staging/iio/adc/Kconfig

@@ -13,6 +13,7 @@ config AD7291
 config AD7298
 	tristate "Analog Devices AD7298 ADC driver"
 	depends on SPI
+	select IIO_KFIFO_BUF if IIO_BUFFER
 	help
 	  Say yes here to build support for Analog Devices AD7298
 	  8 Channel ADC with temperature sensor.

-- 
1.7.10