linux-kernel - Re: [PATCH] Input: tsc2007 - switch to using input_set

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Date:   Sat, 18 Feb 2017 15:58:39 +0100
From:   "H. Nikolaus Schaller" <hns@...delico.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     linux-input@...r.kernel.org, Jonathan Cameron <jic23@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Sebastian Reichel <sre@...nel.org>
Subject: Re: [PATCH] Input: tsc2007 - switch to using input_set_capability()

Hi Dmitry,

> Am 17.02.2017 um 23:56 schrieb Dmitry Torokhov <dmitry.torokhov@...il.com>:
> 
> Do not manipulate evbit/keybit directly, use helper for that.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
> drivers/input/touchscreen/tsc2007_core.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/tsc2007_core.c b/drivers/input/touchscreen/tsc2007_core.c
> index fdf81a2b989a..98dbefc3357d 100644
> --- a/drivers/input/touchscreen/tsc2007_core.c
> +++ b/drivers/input/touchscreen/tsc2007_core.c
> @@ -364,8 +364,7 @@ static int tsc2007_probe(struct i2c_client *client,
> 
> 	input_set_drvdata(input_dev, ts);
> 
> -	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
> -	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> +	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);

basically a good improvement, but removing the BIT_MASK(EV_ABS) makes problems
when replacing the next lines

> 
> 	input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
> 	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);

by touchscreen_parse_properties() as done by my patch set.

The problem is that touchscreen_parse_properties() does not call input_set_abs_params()
but touchscreen_set_params(). This does not call some input_set_capability(dev, EV_ABS, axis)
but rather checks that it has been set before! Hence we only see warnings in the log
and no input event properties (BTN_TOUCH works but without position information).

So we either must explicitly input_set_capability(dev, EV_ABS, axis) for all three
axises or remove the test in touchscreen_set_params and call
input_set_capability(dev, EV_ABS, axis); in the end.

This patch improves the existing driver but breaks my tsc2007 patch set in a location
that my patch set does not even touch (touchscreen_set_params).

Scratching my head how to come out of this...

BR and thanks,
Nikolaus