Re: [PATCH 6/6] Input: elantech - add v3 hardware support

JJ Ding
2011-08-22T06:03:22Z

Hi Éric,

Thanks for your comments, a few lines below:

On Fri, 19 Aug 2011 15:03:04 +0200, Éric Piel <E.A.B.Piel@tudelft.nl> wrote:
> Op 18-08-11 03:57, JJ Ding schreef:
> > v3 hardware's packet format is almost identical to v2 (one/three finger touch),
> > except when sensing two finger touch, the hardware sends 12 bytes of data.
> >
> > Signed-off-by: JJ Ding<jj_ding@emc.com.tw>
> Hi,
> A couple of comments, in line.
>
> :
> :
> > diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
> > index ddd40eb..e13a719 100644
> > --- a/drivers/input/mouse/elantech.c
> > +++ b/drivers/input/mouse/elantech.c
> :
> > +/*
> > + * Interpret complete data packets and report absolute mode input events for
> > + * hardware version 3. (12 byte packets for two fingers)
> > + */
> > +static void elantech_report_absolute_v3(struct psmouse *psmouse,
> > + int packet_type)
> > +{
> > + struct input_dev *dev = psmouse->dev;
> > + struct elantech_data *etd = psmouse->private;
> > + unsigned char *packet = psmouse->packet;
> > + unsigned int fingers = 0, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
> > + unsigned int width = 0, pres = 0;
> > +
> > + /* byte 0: n1 n0 . . . . R L */
> > + fingers = (packet[0]& 0xc0)>> 6;
> > +
> > + switch (fingers) {
> > + case 3:
> > + case 1:
> > + /*
> > + * byte 1: . . . . x11 x10 x9 x8
> > + * byte 2: x7 x6 x5 x4 x4 x2 x1 x0
> > + */
> > + x1 = ((packet[1]& 0x0f)<< 8) | packet[2];
> > + /*
> > + * byte 4: . . . . y11 y10 y9 y8
> > + * byte 5: y7 y6 y5 y4 y3 y2 y1 y0
> > + */
> > + y1 = etd->y_max - (((packet[4]& 0x0f)<< 8) | packet[5]);
> > +
> > + if (fingers == 3&& debounce(x1, y1))
> > + return;
> > +
> > + break;
> > +
> > + case 2:
> > + if (packet_type == PACKET_V3_HEAD) {
> > + /*
> > + * byte 1: . . . . ax11 ax10 ax9 ax8
> > + * byte 2: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
> > + */
> > + etd->prev_x = ((packet[1]& 0x0f)<< 8) | packet[2];
> > + /*
> > + * byte 4: . . . . ay11 ay10 ay9 ay8
> > + * byte 5: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0
> > + */
> > + etd->prev_y = etd->y_max -
> > + (((packet[4]& 0x0f)<< 8) | packet[5]);
> > + /*
> > + * wait for next packet
> > + */
> > + return;
> > + }
> > +
> > + /* packet_type == PACKET_V3_TAIL */
> > + x1 = etd->prev_x;
> > + y1 = etd->prev_y;
> > + x2 = ((packet[1]& 0x0f)<< 8) | packet[2];
> > + y2 = etd->y_max - (((packet[4]& 0x0f)<< 8) | packet[5]);
> > + break;
> > + }
> You actually have three times the same formula, so you could simplify it:
>
> if (fingers !=0 ) {
> /*
> * byte 1: . . . . x11 x10 x9 x8
> * byte 2: x7 x6 x5 x4 x4 x2 x1 x0
> */
> x1 = ((packet[1]& 0x0f)<< 8) | packet[2];
> /*
> * byte 4: . . . . y11 y10 y9 y8
> * byte 5: y7 y6 y5 y4 y3 y2 y1 y0
> */
> y1 = ((packet[4]& 0x0f)<< 8) | packet[5];
> }
>
> if ((fingers == 3) && debounce(x1, y1))
> return;
we need one more line here, for fingers != 2 :
y1 = etd->y_max - y1;
> if (fingers == 2) {
> if (packet_type == PACKET_V3_HEAD)) {
> /* wait for next packet */
> etd->prev_x = x1;
> etd->prev_y = etd->y_max - y1;
etd->prev_y = y1;
> return;
> } else {
> /* packet_type == PACKET_V3_TAIL */
> x2 = etd->prev_x;
> y2 = etd->prev_y;
> }
> }
I like this compact version, but it seems to me this is not as straight
forward as the original switch case. I am OK with either. Is there
anyone who has more to say about this?
>
> > +
> > + pres = (packet[1]& 0xf0) | ((packet[4]& 0xf0)>> 4);
> > + width = ((packet[0]& 0x30)>> 2) | ((packet[3]& 0x30)>> 4);
> What about the case of two fingers? Are pressure and width correct for
> both fingers? In that case, maybe it should also be saved from
> PACKET_V3_HEAD.
I am told (by our firmware guy) that pres and width are sent the same
value for two finger touch.
>
> > +
> > + input_report_key(dev, BTN_TOUCH, fingers != 0);
> > + input_report_abs(dev, ABS_X, x1);
> > + input_report_abs(dev, ABS_Y, y1);
> > + elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
> > + input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
> > + input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
> > + input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
> > + input_report_key(dev, BTN_LEFT, packet[0]& 0x01);
> > + input_report_key(dev, BTN_RIGHT, packet[0]& 0x02);
> > + input_report_abs(dev, ABS_PRESSURE, pres);
> > + input_report_abs(dev, ABS_TOOL_WIDTH, width);
> > +
> > + input_sync(dev);
> > +}
> > +
> :
> >
> > /*
> > * Set the appropriate event bits for the input subsystem
> > */
> > -static void elantech_set_input_params(struct psmouse *psmouse)
> > +static int elantech_set_input_params(struct psmouse *psmouse)
> > {
> > struct input_dev *dev = psmouse->dev;
> > struct elantech_data *etd = psmouse->private;
> > unsigned int x_min = 0, y_min = 0, x_max = 0, y_max = 0, y_2ft_max = 0;
> >
> > - set_range(psmouse,&x_min,&y_min,&x_max,&y_max,&y_2ft_max);
> > + if (set_range(psmouse,&x_min,&y_min,&x_max,&y_max,&y_2ft_max))
> > + return -1;
> >
> > __set_bit(EV_KEY, dev->evbit);
> > __set_bit(EV_ABS, dev->evbit);
> > @@ -582,10 +739,26 @@ static void elantech_set_input_params(struct psmouse *psmouse)
> > input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
> > input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
> > break;
> > +
> > + case 3:
> > + input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
> > + input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
> > + /* range of pressure and width is the same as v2 */
> > + input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
> > + ETP_PMAX_V2, 0, 0);
> > + input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
> > + ETP_WMAX_V2, 0, 0);
> > + __set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
> Does v3 have the same limitation in MT about only reporting the edges of
> the bounding box? Or are the two fingers always reported independently?
> If that is so, you can drop this line :-)
I suppose it's the same as v2, but I have to comfirm with our firmware team.
I will ckeck this.
>
> > + input_mt_init_slots(dev, 2);
> > + input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
> > + input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
> > + break;
> > }
> >
>
> Cheers,
> Éric
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