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

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Date:   Sun, 19 Feb 2017 17:10:45 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     "H. Nikolaus Schaller" <hns@...delico.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()

On Sat, Feb 18, 2017 at 03:58:39PM +0100, H. Nikolaus Schaller wrote:
> 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).

Yes, the driver is supposed to set defaults, then OF data may augment
them (or it may omit them and leave driver's defaults). You should not
have removed calls to

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

We may end up setting initial fuzz to 0, that's fine.

Thanks.

-- 
Dmitry