[PATCH 4.19 45/91] Input: resistive-adc-touch - fix kconfig dependency on IIO_BUFFER

[Greg Kroah-Hartman]

From: Necip Fazil Yildiran <fazilyildiran@xxxxxxxxx>

[ Upstream commit 676650d007e06fddcf3fe38238251d71bd179641 ]

When TOUCHSCREEN_ADC is enabled and IIO_BUFFER is disabled, it results
in the following Kbuild warning:

WARNING: unmet direct dependencies detected for IIO_BUFFER_CB
  Depends on [n]: IIO [=y] && IIO_BUFFER [=n]
  Selected by [y]:
  - TOUCHSCREEN_ADC [=y] && !UML && INPUT [=y] && INPUT_TOUCHSCREEN [=y] && IIO [=y]

The reason is that TOUCHSCREEN_ADC selects IIO_BUFFER_CB without depending
on or selecting IIO_BUFFER while IIO_BUFFER_CB depends on IIO_BUFFER. This
can also fail building the kernel.

Honor the kconfig dependency to remove unmet direct dependency warnings
and avoid any potential build failures.

Fixes: aa132ffb6b0a ("input: touchscreen: resistive-adc-touch: add generic resistive ADC touchscreen")
Signed-off-by: Necip Fazil Yildiran <fazilyildiran@xxxxxxxxx>
Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20201102221504.541279-1-fazilyildiran@xxxxxxxxx
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/input/touchscreen/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 2a80675cfd947..de400d76df55a 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -95,6 +95,7 @@ config TOUCHSCREEN_AD7879_SPI
 config TOUCHSCREEN_ADC
 	tristate "Generic ADC based resistive touchscreen"
 	depends on IIO
+	select IIO_BUFFER
 	select IIO_BUFFER_CB
 	help
 	  Say Y here if you want to use the generic ADC
-- 
2.27.0