On Oct 04 2016 or thereabouts, Roderick Colenbrander wrote:
> From: Roderick Colenbrander <roderick.colenbrander@xxxxxxxx>
>
> Read the touch history field in the HID descriptor and use this value
> to determine how many touch events to read from the report. As part
> of this patch, we did a first attempt of making the offset calculation
> code less magical.
>
> Signed-off-by: Roderick Colenbrander <roderick.colenbrander@xxxxxxxx>
> ---
> drivers/hid/hid-sony.c | 76 +++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 50 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
> index 24f7d19..2387aaf 100644
> --- a/drivers/hid/hid-sony.c
> +++ b/drivers/hid/hid-sony.c
> @@ -1030,6 +1030,12 @@ struct motion_output_report_02 {
> #define SIXAXIS_REPORT_0xF5_SIZE 8
> #define MOTION_REPORT_0x02_SIZE 49
>
> +/* Offsets relative to USB input report (0x1). Bluetooth (0x11) requires an
> + * additional +2.
> + */
> +#define DS4_INPUT_REPORT_BATTERY_OFFSET 30
> +#define DS4_INPUT_REPORT_TOUCHPAD_OFFSET 33
> +
> static DEFINE_SPINLOCK(sony_dev_list_lock);
> static LIST_HEAD(sony_device_list);
> static DEFINE_IDA(sony_device_id_allocator);
> @@ -1226,19 +1232,17 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
> struct hid_input, list);
> struct input_dev *input_dev = hidinput->input;
> unsigned long flags;
> - int n, offset;
> + int n, m, offset, num_touch_data, max_touch_data;
> u8 cable_state, battery_capacity, battery_charging;
>
> - /*
> - * Battery and touchpad data starts at byte 30 in the USB report and
> - * 32 in Bluetooth report.
> - */
> - offset = (sc->quirks & DUALSHOCK4_CONTROLLER_USB) ? 30 : 32;
> + /* When using Bluetooth the header is 2 bytes longer, so skip these. */
> + int data_offset = (sc->quirks & DUALSHOCK4_CONTROLLER_USB) ? 0 : 2;
>
> /*
> - * The lower 4 bits of byte 30 contain the battery level
> + * The lower 4 bits of byte 30 (or 32 for BT) contain the battery level
> * and the 5th bit contains the USB cable state.
> */
> + offset = data_offset + DS4_INPUT_REPORT_BATTERY_OFFSET;
> cable_state = (rd[offset] >> 4) & 0x01;
> battery_capacity = rd[offset] & 0x0F;
>
> @@ -1265,30 +1269,50 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
> sc->battery_charging = battery_charging;
> spin_unlock_irqrestore(&sc->lock, flags);
>
> - offset += 5;
> -
> /*
> - * The Dualshock 4 multi-touch trackpad data starts at offset 35 on USB
> - * and 37 on Bluetooth.
> - * The first 7 bits of the first byte is a counter and bit 8 is a touch
> - * indicator that is 0 when pressed and 1 when not pressed.
> - * The next 3 bytes are two 12 bit touch coordinates, X and Y.
> - * The data for the second touch is in the same format and immediatly
> - * follows the data for the first.
> + * The Dualshock 4 multi-touch trackpad data starts at offset 33 on USB
> + * and 35 on Bluetooth.
> + * The first byte indicates the number of touch data in the report.
> + * Trackpad data starts 2 bytes later (e.g. 35 for USB).
> */
> - for (n = 0; n < 2; n++) {
> - u16 x, y;
> + offset = data_offset + DS4_INPUT_REPORT_TOUCHPAD_OFFSET;
> + max_touch_data = (sc->quirks & DUALSHOCK4_CONTROLLER_USB) ? 3 : 4;
> + if (rd[offset] > 0 && rd[offset] <= max_touch_data)
> + num_touch_data = rd[offset];
> + else
> + num_touch_data = 1;
> + offset += 1;
>
> - x = rd[offset+1] | ((rd[offset+2] & 0xF) << 8);
> - y = ((rd[offset+2] & 0xF0) >> 4) | (rd[offset+3] << 4);
> + for (m = 0; m < num_touch_data; m++) {
> + /* Skip past timestamp */
> + offset += 1;
>
> - input_mt_slot(input_dev, n);
> - input_mt_report_slot_state(input_dev, MT_TOOL_FINGER,
> - !(rd[offset] >> 7));
> - input_report_abs(input_dev, ABS_MT_POSITION_X, x);
> - input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
> + /*
> + * The first 7 bits of the first byte is a counter and bit 8 is
> + * a touch indicator that is 0 when pressed and 1 when not
> + * pressed.
> + * The next 3 bytes are two 12 bit touch coordinates, X and Y.
> + * The data for the second touch is in the same format and
> + * immediately follows the data for the first.
> + */
> + for (n = 0; n < 2; n++) {
> + u16 x, y;
> + bool active;
> +
> + x = rd[offset+1] | ((rd[offset+2] & 0xF) << 8);
> + y = ((rd[offset+2] & 0xF0) >> 4) | (rd[offset+3] << 4);
> +
> + active = !(rd[offset] >> 7);
> + input_mt_slot(input_dev, n);
Just to be sure, the device reports 2 touches only, and the
"num_touch_data" chunks are just the history of these 2 touches, the
last chunk being the last known touches?
If so, then why aren't you simply jumping to the last valid value?
If not, then you probably need to report (n+m*2) slot, and change the
input_mt_init_slot parameter as well.
Cheers,
Benjamin
> + input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, active);
>
> - offset += 4;
> + if (active) {
> + input_report_abs(input_dev, ABS_MT_POSITION_X, x);
> + input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
> + }
> +
> + offset += 4;
> + }
> }
> }
>
> --
> 2.7.4
>
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