Re: [PATCH 2/2] input: Add LED support to Synaptics device

[Takashi Iwai <tiwai@suse.de>]

At Thu, 15 Apr 2010 21:12:18 +0200,
Pavel Machek wrote:
> 
> Hi!
> 
> > The new Synaptics devices have an LED on the top-left corner.
> > This is controlled via the command 0x0a with parameters 0x88 or 0x10.
> > 
> > The detection of the LED isn't clear yet.  It should have been the new
> > capability bits that indicate the presence, but on real machines, it
> > doesn't fit.  So, for the time being, the driver checks the product id
> > in the ext capability bits and assumes that LED exists on the known
> > devices.
> > 
> > The support of LED is controlled via a normal input event with EV_LED
> > bit mask.  It supports LED_MUTE bit.  X driver can detect the LED
> > support by checking these bits.
> 
> Could we use generic LED API for this?

Yeah, actually I started implementing with LED ADI at first.

But, then it turned out to be that it's much easier to use the
existing LED input bits since this LED is really tightly coupled with
the synaptics input device.  An individual LED device makes hard to
find out the corresponding input device.

If we assume there is only one synaptics and only one synaptics-LED
device, then yes, the situation can be a bit easier, though.

> It is not really 'mute' led after all...

If the problem is the misuse of LED_MUTE bit, how about adding a new
LED bit, e.g. LED_TOUCHPAD?


thanks,

Takashi