Re: [PATCH v5] psmouse - focaltech pass finger width to userspace

From: Dmitry Tunin
Date: Sun Apr 19 2015 - 11:13:28 EST


> Focaltech touchpads report finger width in packet[5] of absolute packet.
> Range for width in raw format is 0x10 - 0x70. Second half-byte is always 0.
> 0xff is reported, when a large contact area is detected.
> This can be handled in userspace.
>
> Signed-off-by: Dmitry Tunin <hanipouspilot@xxxxxxxxx>
> ---
> drivers/input/mouse/focaltech.c | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/input/mouse/focaltech.c b/drivers/input/mouse/focaltech.c
> index 23d2594..32f810c 100644
> --- a/drivers/input/mouse/focaltech.c
> +++ b/drivers/input/mouse/focaltech.c
> @@ -105,6 +105,16 @@ struct focaltech_hw_state {
>
> /* True if the clickpad has been pressed. */
> bool pressed;
> +
> + /*
> + * Finger width 0-7 and 15 for 'latching'
> + * 15 value stays until the finger is released
> + * Width is reported only when 1 finger is active
> + */
> + unsigned int width;
> +
> + /* Finger count */
> + unsigned int count;
> };
>
> struct focaltech_data {
> @@ -137,10 +147,12 @@ static void focaltech_report_state(struct psmouse *psmouse)
> input_report_abs(dev, ABS_MT_POSITION_X, clamped_x);
> input_report_abs(dev, ABS_MT_POSITION_Y,
> priv->y_max - clamped_y);
> + if (state->count == 1)
> + input_report_abs(dev, ABS_TOOL_WIDTH, state->width);
> }
> }
> - input_mt_report_pointer_emulation(dev, true);
> -
> + input_mt_report_finger_count(dev, state->count);
> + input_mt_report_pointer_emulation(dev, false);
> input_report_key(psmouse->dev, BTN_LEFT, state->pressed);
> input_sync(psmouse->dev);
> }
> @@ -152,13 +164,16 @@ static void focaltech_process_touch_packet(struct psmouse *psmouse,
> struct focaltech_hw_state *state = &priv->state;
> unsigned char fingers = packet[1];
> int i;
> + int count = 0;
>
> state->pressed = (packet[0] >> 4) & 1;
>
> /* the second byte contains a bitmap of all fingers touching the pad */
> for (i = 0; i < FOC_MAX_FINGERS; i++) {
> - state->fingers[i].active = fingers & 0x1;
> - if (!state->fingers[i].active) {
> + if (fingers & 0x1) {
> + state->fingers[i].active = true;
> + count++;
> + } else {
> /*
> * Even when the finger becomes active again, we still
> * will have to wait for the first valid position.
> @@ -167,6 +182,7 @@ static void focaltech_process_touch_packet(struct psmouse *psmouse,
> }
> fingers >>= 1;
> }
> + state->count = count;
> }
>
> static void focaltech_process_abs_packet(struct psmouse *psmouse,
> @@ -187,6 +203,7 @@ static void focaltech_process_abs_packet(struct psmouse *psmouse,
>
> state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
> state->fingers[finger].y = (packet[3] << 8) | packet[4];
> + state->width = packet[5] >> 4;
> state->fingers[finger].valid = true;
> }
>
> @@ -331,6 +348,7 @@ static void focaltech_set_input_params(struct psmouse *psmouse)
> __set_bit(EV_ABS, dev->evbit);
> input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
> input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
> + input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0);
> input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
> __set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
> }
>

This appear to work very will with xorg-synaptics.
Since touchpad does not report pressure and synaptics require both
pressure and width to detect palm, it is needed to set pressure to minimum value:
synclient PalmMinZ=1
Then it works great. Last Mathias's commit removed palm detection from the kernel driver.
With this patch users can toggle it as they like.
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