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

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Date:   Mon, 20 Feb 2017 17:51:09 +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 20.02.2017 um 02:10 schrieb Dmitry Torokhov <dmitry.torokhov@...il.com>:
> 
> 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).

Ok.

> You should not
> have removed calls to
> 
> 	input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);

Wouldn't it suffice to call

	input_set_capability(input_dev, EV_ABS, ABS_X);
	input_set_capability(input_dev, EV_ABS, ABS_Y);

since fuzz default is already 0?

BR,
Nikolaus