On Wed, Nov 27, 2013 at 04:19:05PM +0800, Tommy Will wrote:
> Hi Dmitry,
>
> Thanks for your reply.
>
> >
> > It would help greatly if you could document what parameters the new
> > initialization routine sets.
> >
> Ok, please let me explain what I did in initialization.
>
> >+static int alps_hw_init_v6(struct psmouse *psmouse)
> >+{
> >+ unsigned char param[2] = {0xC8, 0x14};
> >+
> >+ /* Enter passthrough mode to let trackpoint enter 6byte raw mode */
> >+ if (alps_passthrough_mode_v2(psmouse, true))
> >+ return -1;
>
> In order to initialize the trackpoint, we must first send command to
> enter passthrough mode so that the following
> command can directly be sent to trackpoint device.
>
> +
> >+ if (ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11) ||
> >+ ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11) ||
> >+ ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11) ||
> >+ ps2_command(&psmouse->ps2dev, ¶m[0], PSMOUSE_CMD_SETRATE) ||
> >+ ps2_command(&psmouse->ps2dev, ¶m[1], PSMOUSE_CMD_SETRATE))
> >+ return -1;
> >+
>
> Here are the commands to let trackpoint device enter 6byte raw mode.
> Because of the special MPU being
> used in this device, trackpoint's packet would always be encapsulated
> to the same packet size as Touchpad's.
> So, when touchpad is in 6byte mode, we should also let trackpoint in
> 6byte mode or trackpoint's output data would be messed.
> That's what spec requested.
>
> + if (alps_passthrough_mode_v2(psmouse, false))
> + return -1;
> +
>
> Stop talking with trackpoint.
>
> + if (alps_absolute_mode_v6(psmouse)) {
> + psmouse_err(psmouse, "Failed to enable absolute mode\n");
> + return -1;
> + }
> +
>
> Let touchpad enter 6byte raw mode.
>
> + return 0;
> +}
>
> And in alps_absolute_mode_v6() function. Please notice that there are
> two kinds of
> 6byte mode for this device. Let's temporary define them as RawModeA & RawModeB.
> Method to enter RawModeA: Send ALPS magic knock commad [F5 F5 F5
> F5]. (Same as protocol v2)
> Method to enter RawModeB: Write 0x181 to 0x000 register. (New)
>
> I checked spec and found RawModeB was suggested and now being used in
> Windows driver.
> Maybe the reason is it could provide a more accurate data output.
> In RawModeA, data output range is X:[0-1023], Y:[0-767], but
> in RawModeB, its range is X:[0-2047], Y:[0-1535].
>
> #Probably have any other reason that I did not know, so, I chose a
> safety way that was suggested
> by the spec although it needs adding much more source code.
>
>
> > +static int alps_absolute_mode_v6(struct psmouse *psmouse)
> > +{
> > + u16 reg_val = 0x181;
> > + int ret = -1;
> > +
>
> What we want to do is write 0x181 to 0x000 register. That would let
> device enter RawModeB.
>
> > + /* enter monitor mode, to write the register */
> > + if (alps_monitor_mode(psmouse, true))
> > + return -1;
> > +
> > + ret = alps_monitor_mode_write_reg(psmouse, 0x000, reg_val);
> > +
> > + if (alps_monitor_mode(psmouse, false))
> > + ret = -1;
> > +
> > + return ret;
> > +}
>
>
> >> 3. Add new packet process logic.
> >
> > I am curious why we need the new packet processing logic. Apparently the
> > touchpad can work in the original mode that we already know how to
> > parse; we just need to make sure the trackpoint is initialized properly.
> > Or yet another protocol flavor is a must?
> >
> Yes, you're right, as long as initialized trackpoint to 6byte raw mode
> and add decode logic into
> alps_process_packet_v1_v2(), both touchpad and trackpoint can work correctly.
>
> However, as I wrote in previous, spec suggested me to use another
> protocol to co-work with
> trackpoint's 6byte mode. So, I just did follow the spec.
>
> BTW, could you please let me know if you have any concern of adding a
> new protocol?
> In my opinion, assume that there would be no side-effect by using
> original touchpad
> protocol + new 6byte trackpoint protocol, although I could reuse the
> alps_process_packet_v1_v2(),
> I had to add a new flag to adjust the original logic to support
> trackpoint's 6byte decoding,
> which would also make source code harder to understand.
OK, fair enough. I will apply the patch, but I think the ALPS driver is
becoming a bit too unwieldy. It looks like we should split it into
alps-st (that woudl handle older single-touch models) and alps-mt (for
the newer multi-touch ones) and maybe a support library for the common
code.
Thanks.
--
Dmitry
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