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Date:   Tue, 3 Nov 2020 10:58:17 +0000
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     Necip Fazil Yildiran <fazilyildiran@gmail.com>
CC:     <dmitry.torokhov@gmail.com>, <eugen.hristev@microchip.com>,
        <linux-input@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <paul@pgazz.com>, <jeho@cs.utexas.edu>
Subject: Re: [PATCH] Input: touchscreen: fix kconfig dependency bug for
 TOUCHSCREEN_ADC
Message-ID: <20201103105817.00005a7f@Huawei.com>
In-Reply-To: <20201102221504.541279-1-fazilyildiran@gmail.com>
References: <20201102221504.541279-1-fazilyildiran@gmail.com>
Organization: Huawei Technologies Research and Development (UK) Ltd.
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On Tue, 3 Nov 2020 01:15:05 +0300
Necip Fazil Yildiran <fazilyildiran@gmail.com> wrote:

> 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")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=209881
> Signed-off-by: Necip Fazil Yildiran <fazilyildiran@gmail.com>

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/input/touchscreen/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index f012fe746df0..cc18f54ea887 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -96,6 +96,7 @@ 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