Am 12.11.2016 um 15:19 schrieb Jonathan Cameron [off-list ref]:

On 12/11/16 14:04, Jonathan Cameron wrote:

quoted

On 11/11/16 19:02, H. Nikolaus Schaller wrote:

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The tsc2007 chip not only has a resistive touch screen controller but
also an external AUX adc imput which can be used for an ambient
light sensor, battery voltage monitoring or any general purpose.

Additionally it can measure the chip temperature.

This extension provides an iio interface for these adc channels.

Since it is not wasting much resources and is very straightforward,
we simply provide all other adc channels as optional iio interfaces
as weel. This can be used for debugging or special applications.

This patch also splits the tsc2007 driver in several source files:
tsc2007.h -- constants, structs and stubs
tsc2007_core.c -- functional parts of the original driver
tsc2007_iio.c -- the optional iio stuff

Makefile magic allows to conditionally link the iio
stuff if CONFIG_IIO=y in a way that it works with
CONFIG_TOUCHSCREEN_TSC2007=m.

I ran a quick build test and it blows up in a number of ways related to
the #ifdef CONFIG_IIO.

I'm not entirely sure why but
#if IS_ENABLED(CONFIG_IIO) works fine.

Ah, I'm being sleepy today.  It's because I'm building IIO as a module
and the symbol defined would therefore be CONFIG_IIO_MODULE.

The IS_ENABLED macro takes care of both cases.

Ah, yes. I wasn't aware that CONFIG_IIO is tristate at all.
We have it as "y" and therefore didn't notice.

I will collect this fix for V8.

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Otherwise looks good to me

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Signed-off-by: H. Nikolaus Schaller <redacted>

Reviewed-by: Jonathan Cameron <jic23@kernel.org>

Will add this as well.

Thanks for the detailled review!

BR,
Nikolaus