Re: [PATCH] surface pro 3: Add support driver for Surface Pro 3 buttons

[Darren Hart <dvhart@infradead.org>]

On Thu, Aug 06, 2015 at 11:20:44AM +0000, Chen, Yu C wrote:
> Thanks Joe,
> On Wed, 2015-08-05 at 22:30 -0700, Joe Perches wrote:
> > On Thu, 2015-08-06 at 13:16 +0800, Chen Yu wrote:
> > > Since Surface Pro 3 does not follow the specs of "Windows ACPI Design
> > > Guide for SoC Platform", code in drivers/input/misc/soc_array.c can
> > > not detect these buttons on it.
> > 
> > style trivia:
> > 
> > > diff --git a/drivers/platform/x86/surfacepro3_button.c b/drivers/platform/x86/surfacepro3_button.c
> > []
> > > +static void surface_button_notify(struct acpi_device *device, u32 event)
> > > +{
> > []
> > > +	switch (event) {
> > > +	case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
> > > +		pressed = true;
> > > +		/*go through*/
> > 
> > /* fall through */ is more common
> > 
> OK.
> > > +	case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
> > > +		pressed = true;
> > > +	case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
> > > +		key_code = KEY_LEFTMETA;
> > > +		break;
> > 
> > It may be better to add a comment about the style or
> > maybe add a macro like
> > 
> > #define HANDLE_SURFACE_BUTTON_NOTIFY(type, code)	\
> > 	case SURFACE_BUTTON_NOTIFY_PRESS_##type:	\
> > 		pressed = true;	/* and fall-through */	\
> > 	case SURFACE_BUTTON_NOTIFY_RELEASE_##type:	\
> > 		key_code = code;			\
> > 		break;
> > 
> WRT macro HANDLE_SURFACE_BUTTON_NOTIFY, the checkpatch.pl
> complains that multi lines of codes should be wrapped in 'do
> while'state, but doing like this might lead to incorrect semantic.
> Is it ok to keep these codes and add comments like:
> /*
>  * When a button(power button/volume button/home button) is 
>  * pressed down or released, different ACPI notification codes 
>  * will be generated. We can distinguish different event code 
>  * and value of buttons by these notification codes, then pass
>  * (EV_KEY, event code(key_code), value(pressed)) to input layer.
>  */

The commentary is useful regardless. However, I suspect Joe was
referring to the approach pairing the PRESS and RELEASE cases?

-- 
Darren Hart
Intel Open Source Technology Center