Re: [PATCH 10/12] Input: synaptics - decode AGM packet types

[Chase Douglas <chase.douglas@canonical.com>]

On 06/28/2011 10:07 PM, djkurtz@chromium.org wrote:
> From: Daniel Kurtz <djkurtz@chromium.org>
> 
> A Synaptics image sensor tracks 5 fingers, but can only report 2.
> This behavior is called "T5R2" = Track 5 Report 2
> 
> Algorithm for choosing which 2 fingers to report in which packet:
>   Touchpad maintains 5 slots, numbered 0 to 4.
>   Initially all slots are empty.
>   As new fingers are detected, they are assigned the lowest available
>   slot.
>   Touchpad always reports:
>     SGM: lowest numbered non-empty slot
>     AGM: highest numbered non-empty slot, if there is one.
> 
> In addition, T5R2 touchpads have a special AGM packet type which reports
> the number of fingers currently being tracked, and which finger is in
> each of the two slots.  Unfortunately, these "TYPE=2" packets are only used
> when more than 3 fingers are being tracked.  When less than 4 fingers
> are present, the 'w' value must be used to track how many fingers are
> present, and knowing which fingers are being reported is much more
> difficult, if not impossible.
> 
> Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
> ---
>  drivers/input/mouse/synaptics.c |   39 ++++++++++++++++++++++++++++++++++-----
>  drivers/input/mouse/synaptics.h |    7 ++++++-
>  include/linux/input.h           |    1 +
>  3 files changed, 41 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> index 2d7ac0a..19a9b7f 100644
> --- a/drivers/input/mouse/synaptics.c
> +++ b/drivers/input/mouse/synaptics.c
> @@ -401,6 +401,14 @@ static void synaptics_pt_create(struct psmouse *psmouse)
>  /*****************************************************************************
>   *	Functions to interpret the absolute mode packets
>   ****************************************************************************/
> +/* Set AGM-CONTACT finger state */
> +static void synaptics_agm_finger_update(struct synaptics_data *priv, int count,
> +					int sgm, int agm)
> +{
> +	priv->agm.finger_count = count;
> +	priv->agm.finger_sgm = sgm;
> +	priv->agm.finger_agm = agm;
> +}
>  
>  static int synaptics_parse_hw_state(const unsigned char buf[],
>  				    struct synaptics_data *priv,
> @@ -438,11 +446,31 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
>  		if ((SYN_CAP_ADV_GESTURE(priv->ext_cap_0c)
>  				|| SYN_CAP_IMAGE_SENSOR(priv->ext_cap_0c))
>  				&& hw->w == 2) {
> -			/* Gesture packet: (x, y, z) at half resolution */
> -			priv->agm.x = (((buf[4] & 0x0f) << 8) | buf[1]) << 1;
> -			priv->agm.y = INVERT_Y((((buf[4] & 0xf0) << 4)
> -					      | buf[2]) << 1);
> -			priv->agm.z = ((buf[3] & 0x30) | (buf[5] & 0x0f)) << 1;
> +			int type; /* Packet type */
> +
> +			type = (buf[5] & 0x30) >> 4;
> +
> +			switch (type) {
> +			case 1:
> +				/* Gesture packet: (x, y, z) half resolution */
> +				priv->agm.w = hw->w;
> +				priv->agm.x = (((buf[4] & 0x0f) << 8)
> +						| buf[1]) << 1;
> +				priv->agm.y = INVERT_Y((((buf[4] & 0xf0) << 4)
> +						       | buf[2]) << 1);
> +				priv->agm.z = ((buf[3] & 0x30)
> +						| (buf[5] & 0x0f)) << 1;
> +				break;
> +
> +			case 2:
> +				/* Finger slot update */
> +				synaptics_agm_finger_update(priv, buf[1],
> +							    buf[2], buf[4]);
> +				break;
> +
> +			default:
> +				break;
> +			}
>  			return 1;
>  		} else {
>  			hw->x = (((buf[3] & 0x10) << 8) |
> @@ -804,6 +832,7 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv)
>  	input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);
>  
>  	if (SYN_CAP_IMAGE_SENSOR(priv->ext_cap_0c)) {
> +		__set_bit(INPUT_PROP_SYNAPTICS_T5R2, dev->propbit);
>  		input_mt_init_slots(dev, SYN_TRACK_SLOT_COUNT);
>  		input_set_abs_params(dev, ABS_MT_POSITION_X, XMIN_NOMINAL,
>  				     priv->x_max ?: XMAX_NOMINAL, fuzz, 0);
> diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h
> index 1de2256..2214af6 100644
> --- a/drivers/input/mouse/synaptics.h
> +++ b/drivers/input/mouse/synaptics.h
> @@ -122,7 +122,7 @@
>  #define SYN_SLOT_AGM			2
>  
>  /* number of tracking slots for Image Sensor firmware */
> -#define SYN_TRACK_SLOT_COUNT		2
> +#define SYN_TRACK_SLOT_COUNT		5
>  
>  /*
>   * A structure to describe the state of the touchpad hardware (buttons and pad)
> @@ -140,6 +140,11 @@ struct synaptics_hw_state {
>  	unsigned int down:1;
>  	unsigned char ext_buttons;
>  	signed char scroll;
> +
> +	/* Reported in AGM-CONTACT packets */
> +	unsigned int finger_count;		/* num fingers being tracked */
> +	unsigned int finger_sgm;		/* finger described by sgm */
> +	unsigned int finger_agm;		/* finger described by agm */
>  };
>  
>  struct synaptics_data {
> diff --git a/include/linux/input.h b/include/linux/input.h
> index 771d6d8..732c14e 100644
> --- a/include/linux/input.h
> +++ b/include/linux/input.h
> @@ -137,6 +137,7 @@ struct input_keymap_entry {
>  #define INPUT_PROP_DIRECT		0x01	/* direct input devices */
>  #define INPUT_PROP_BUTTONPAD		0x02	/* has button(s) under pad */
>  #define INPUT_PROP_SEMI_MT		0x03	/* touch rectangle only */
> +#define INPUT_PROP_SYNAPTICS_T5R2	0x04	/* synaptics track 5 report 2 */
>  
>  #define INPUT_PROP_MAX			0x1f
>  #define INPUT_PROP_CNT			(INPUT_PROP_MAX + 1)

I'm trying to understand these later patches for T5R2. There are
"hidden" touch slots now. How does userspace tell whether a touch slot
is a hidden touch?

-- Chase