linux-kernel - Re: [PATCH v3 2/3] input: touchscreen: ad7879: fix default x/y axis assignment

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Date:	Wed, 3 Feb 2016 08:41:42 +0100
From:	Michael Hennerich <michael.hennerich@...log.com>
To:	Stefan Agner <stefan@...er.ch>, <dmitry.torokhov@...il.com>,
	<robh+dt@...nel.org>
CC:	<mark.rutland@....com>, <ijc+devicetree@...lion.org.uk>,
	<galak@...eaurora.org>, <realmz6@...il.com>, <broonie@...nel.org>,
	<jic23@...nel.org>, <linux-input@...r.kernel.org>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 2/3] input: touchscreen: ad7879: fix default x/y axis
 assignment

On 02/03/2016 12:20 AM, Stefan Agner wrote:
> The X/Y position measurements read from the controller are interpreted
> wrong. The first measurement X+ contains the Y position, and the second
> measurement Y+ the X position (see also Table 11 Register Table in the
> data sheet).
>
> The problem is already known and a swap option has been introduced:
> commit 6680884a4420 ("Input: ad7879 - add option to correct xy axis")
>
> However, the meaning of the new boolean is inverted since the underlying
> values are already swapped. Let ts->swap_xy set to true actually be the
> swapped configuration of the two axis.
>
> Signed-off-by: Stefan Agner <stefan@...er.ch>

Acked-by: Michael Hennerich <michael.hennerich@...log.com>

> ---
> Changes since v2:
> - (none)
> Changes since v1:
> - Keep axis swapped by default when using platform data
>
>   drivers/input/touchscreen/ad7879.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/input/touchscreen/ad7879.c b/drivers/input/touchscreen/ad7879.c
> index 93b8ea2..abd0220 100644
> --- a/drivers/input/touchscreen/ad7879.c
> +++ b/drivers/input/touchscreen/ad7879.c
> @@ -94,8 +94,8 @@
>   #define AD7879_TEMP_BIT			(1<<1)
>
>   enum {
> -	AD7879_SEQ_XPOS  = 0,
> -	AD7879_SEQ_YPOS  = 1,
> +	AD7879_SEQ_YPOS  = 0,
> +	AD7879_SEQ_XPOS  = 1,
>   	AD7879_SEQ_Z1    = 2,
>   	AD7879_SEQ_Z2    = 3,
>   	AD7879_NR_SENSE  = 4,
> @@ -517,7 +517,9 @@ struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
>   	ts->dev = dev;
>   	ts->input = input_dev;
>   	ts->irq = irq;
> -	ts->swap_xy = pdata->swap_xy;
> +
> +	/* Use swapped axis by default (backward compatibility) */
> +	ts->swap_xy = !pdata->swap_xy;
>
>   	setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);
>
>


-- 
Greetings,
Michael

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