linux-kernel - Re: [RESEND PATCH 2/2] Input: mt6779-keypad

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Message-ID: <YoHfUYmq49V5Bygd@google.com>
Date:   Sun, 15 May 2022 22:21:21 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Mattijs Korpershoek <mkorpershoek@...libre.com>
Cc:     Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Kevin Hilman <khilman@...libre.com>,
        Fabien Parent <fparent@...libre.com>,
        linux-input@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH 2/2] Input: mt6779-keypad - implement row/column
 selection

On Fri, May 13, 2022 at 05:18:45PM +0200, Mattijs Korpershoek wrote:
> The MediaTek keypad has a total of 6 input rows and 6 input columns.
> By default, rows/columns 0-2 are enabled.
> 
> This is controlled by the KP_SEL register:
> - bits[9:4]   control row selection
> - bits[15:10] control column selection
> 
> Each bit enables the corresponding row/column number (e.g KP_SEL[4]
> enables ROW0)
> 
> Depending on how the keypad is wired, this may result in wrong readings
> of the keypad state.
> 
> Program the KP_SEL register to limit the key detection to n_rows,
> n_cols we retrieve from the device tree.
> 
> Signed-off-by: Mattijs Korpershoek <mkorpershoek@...libre.com>
> ---
>  drivers/input/keyboard/mt6779-keypad.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/input/keyboard/mt6779-keypad.c b/drivers/input/keyboard/mt6779-keypad.c
> index 23360de20da5..653dfc619696 100644
> --- a/drivers/input/keyboard/mt6779-keypad.c
> +++ b/drivers/input/keyboard/mt6779-keypad.c
> @@ -17,6 +17,11 @@
>  #define MTK_KPD_DEBOUNCE	0x0018
>  #define MTK_KPD_DEBOUNCE_MASK	GENMASK(13, 0)
>  #define MTK_KPD_DEBOUNCE_MAX_MS	256
> +#define MTK_KPD_SEL		0x0020
> +#define MTK_KPD_SEL_COL	GENMASK(15, 10)
> +#define MTK_KPD_SEL_ROW	GENMASK(9, 4)
> +#define MTK_KPD_SEL_COLMASK(c)	(MTK_KPD_SEL_COL >> (6 - (c)))

Would it be clearer to say

#define MTK_KPD_SEL_COLMASK(c)	GENMASK((c) + 3, 4)

?

Thanks.

-- 
Dmitry