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

["Éric Piel" <E.A.B.Piel@tudelft.nl>]

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;

if (fingers == 2) {
	if (packet_type == PACKET_V3_HEAD)) {
		/* wait for next packet */
		etd->prev_x = x1;
		etd->prev_y = etd->y_max - y1;
		return;
	} else {
		/* packet_type == PACKET_V3_TAIL */
		x2 = etd->prev_x;
		y2 = etd->prev_y;
	}
}


> +
> +	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.


> +
> +	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 :-)


> +		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