Re: [PATCH v1] input: make use of the input_set_capability helper

[Olliver Schinagl]

HEy Dmitry,

On 07-01-15 09:26, Dmitry Torokhov wrote:
> On Wed, Jan 07, 2015 at 09:19:28AM +0100, Olliver Schinagl wrote:
> > Hey Dmitry,
> >
> > On 07-01-15 08:57, Dmitry Torokhov wrote:
> > > Hi Olliver,
> > >
> > > On Wed, Jan 07, 2015 at 08:31:06AM +0100, Olliver Schinagl wrote:
> > > > From: Olliver Schinagl <oliver@xxxxxxxxxxx>
> > > >
> > > > Almost all of the speaker drivers under input manipulate the ev bits
> > > > directly, which is not needed, as there is a helper available.
> > > >
> > > > This patch makes use of the helper for the speaker drivers.
> > > >
> > > > Signed-off-by: Olliver Schinagl <oliver@xxxxxxxxxxx>
> > > > ---
> > > >   drivers/input/misc/cm109.c         | 4 ++--
> > > >   drivers/input/misc/ixp4xx-beeper.c | 5 ++---
> > > >   drivers/input/misc/m68kspkr.c      | 5 ++---
> > > >   drivers/input/misc/pcspkr.c        | 5 ++---
> > > >   drivers/input/misc/pwm-beeper.c    | 5 +----
> > > >   drivers/input/misc/sparcspkr.c     | 6 ++----
> > > >   6 files changed, 11 insertions(+), 19 deletions(-)
> > > >
> > > > diff --git a/drivers/input/misc/cm109.c b/drivers/input/misc/cm109.c
> > > > index 9365535..8e41070 100644
> > > > --- a/drivers/input/misc/cm109.c
> > > > +++ b/drivers/input/misc/cm109.c
> > > > @@ -767,10 +767,10 @@ static int cm109_usb_probe(struct usb_interface *intf,
> > > >   	input_dev->keycodesize = sizeof(unsigned char);
> > > >   	input_dev->keycodemax = ARRAY_SIZE(dev->keymap);
> > > > -	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_SND);
> > > > -	input_dev->sndbit[0] = BIT_MASK(SND_BELL) | BIT_MASK(SND_TONE);
> > > > +	input_set_capability(input_dev, EV_SND, SND_BELL | SND_TONE);
> > > No, input_set_capability() takes single event code, not bitmask. The
> > > fact that it works for these 2 values of SND events is pure coincidence
> > > (the old code wasn't much better though).
> Ah, not, it does not work at all. Instead of setting bits 1 and 2 your
> code sets bit 3 in dev->sndbit.
>
> > What do you suggest we should do then? Fix input_set_capability to
> > take bit masks? or multiline events?
> > I'm not sure why __set_bits() wouldn't work for bitmasks, could you
> > educate me?
> Call it once per event:
>
> 	input_set_capability(input_dev, EV_SND, SND_BELL);
> 	input_set_capability(input_dev, EV_SND, SND_TONE);
roger, done
> > > >   	/* register available key events */
> > > > +	input_dev->evbit[0] = BIT_MASK(EV_KEY);
> > > Would prefer __set_bit(EV_KEY, input_dev->evbit); here instead.
> > I only moved the EV_KEY bit from above to its appropiate place here.
> The original code was setting combination of bits; here we set single
> one and __set_bit() is cleaner IMO.
The documentation contradicts this actually, it says to use set_bit() 
first, but favors the direct writing as above as it is 'shorter in some 
cases'.

Furthermore, I'm a little confused as what the purpose of 
input_set_capability() is, if we use set_bits (or __set_bits) here. It 
appears we use set_bits here because it is manipulating several entries 
in the array (well atleast index 0) and set_input_capability() doesn't 
handle arrays? But when I look at struct input_dev, all those entries 
are arrays, including sndbit. So we only use set_input_capabilities when 
manipulating index 0 when its the only one? Feels a little strange to 
me, but probably is my lack of knowledge herin, so appologies for that.

Olliver
> > I can change this one (and others) to use __set_bit() for now for
> > v2?
> Yes, please.
>
> Thanks.

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