linux-kernel - Re: [PATCH v8] psmouse - focaltech pass finger width to userspace

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Date:	Fri, 24 Apr 2015 12:23:09 +0200
From:	Mathias Gottschlag <mgottschlag@...il.com>
To:	Dmitry Tunin <hanipouspilot@...il.com>, linux-input@...r.kernel.org
CC:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8] psmouse - focaltech pass finger width to userspace


Hi,

Some comments below. If it is not a problem that width values are
outdated as soon as there are two or more fingers on the touchpad, I
think the change is good.

Regards,
Mathias

Am 24.04.2015 um 01:15 schrieb Dmitry Tunin:
> 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@...il.com>
> ---
>  drivers/input/mouse/focaltech.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/mouse/focaltech.c b/drivers/input/mouse/focaltech.c
> index 23d2594..ea53f8b 100644
> --- a/drivers/input/mouse/focaltech.c
> +++ b/drivers/input/mouse/focaltech.c
> @@ -90,6 +90,13 @@ struct focaltech_finger_state {
>  	 */
>  	unsigned int x;
>  	unsigned int y;
> +
> +	/*
> +	* Finger width 0-7 and 15 for 'latching'
You already describe below that 15 is latched - what you write above
should probably rather be something like "15 if a very large contact
area was detected" or something like that.
> +	* 15 value stays until the finger is released
> +	* Width is reported only in absolute packets
> +	*/
> +	unsigned int width;
>  };
>  
>  /*
> @@ -112,7 +119,7 @@ struct focaltech_data {
>  	struct focaltech_hw_state state;
>  };
>  
> -static void focaltech_report_state(struct psmouse *psmouse)
> +static void focaltech_report_state(struct psmouse *psmouse, bool abs)
>  {
>  	struct focaltech_data *priv = psmouse->private;
>  	struct focaltech_hw_state *state = &priv->state;
> @@ -137,6 +144,7 @@ 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 (abs) input_report_abs(dev, ABS_TOOL_WIDTH, state->width);
You are sending width here for *all* fingers, even though only one
finger has an up-to-date width value. Is that intentional? I fail to see
how that is different from always sending width no matter the packet
type, because in any case all but one fingers will have an outdated
width value.
>  		}
>  	}
>  	input_mt_report_pointer_emulation(dev, true);
> @@ -187,6 +195,7 @@ 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->fingers[finger].width = packet[5] >> 4;
>  	state->fingers[finger].valid = true;
>  }
>  
> @@ -228,14 +237,17 @@ static void focaltech_process_packet(struct psmouse *psmouse)
>  	switch (packet[0] & 0xf) {
>  	case FOC_TOUCH:
>  		focaltech_process_touch_packet(psmouse, packet);
> +		focaltech_report_state(psmouse, false);
>  		break;
>  
>  	case FOC_ABS:
>  		focaltech_process_abs_packet(psmouse, packet);
> +		focaltech_report_state(psmouse, true);
>  		break;
>  
>  	case FOC_REL:
>  		focaltech_process_rel_packet(psmouse, packet);
> +		focaltech_report_state(psmouse, false);
>  		break;
>  
>  	default:
> @@ -243,7 +255,6 @@ static void focaltech_process_packet(struct psmouse *psmouse)
>  		break;
>  	}
>  
Remove that blank line as well? :)
> -	focaltech_report_state(psmouse);
>  }
>  
>  static psmouse_ret_t focaltech_process_byte(struct psmouse *psmouse)
> @@ -331,6 +342,7 @@ 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);
>  }

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