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HID: magicmouse: Implement Multi-touch Protocol B (MT-B)
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The driver for Apple Magic Trackpad/Mouse currently uses
Multi-touch Protocol A (MT-A) to report touch events and uses
ABS_MT_TRACKING_ID to do finger tracking. The fact of the device
being able to track individual finger makes it possible to
report touch events using MT-B. This patch converts the driver
to use MT-B as it is preferred to MT-A.

V4: Removed BTN_TOUCH evnet.
V3: Removed the single touch related logic.
V2: Converting entirely to MT-B as Henrik Rydberg suggested.

Signed-off-by: Yufeng Shen <miletus@chromium.org>
Reviewed-and-tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Yufeng Shen authored and Jiri Kosina committed Jul 4, 2012
1 parent 6264307 commit a6d1bc1
Showing 1 changed file with 22 additions and 44 deletions.
66 changes: 22 additions & 44 deletions drivers/hid/hid-magicmouse.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/input/mt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
Expand Down Expand Up @@ -68,15 +69,6 @@ MODULE_PARM_DESC(report_undeciphered, "Report undeciphered multi-touch state fie

#define SCROLL_ACCEL_DEFAULT 7

/* Single touch emulation should only begin when no touches are currently down.
* This is true when single_touch_id is equal to NO_TOUCHES. If multiple touches
* are down and the touch providing for single touch emulation is lifted,
* single_touch_id is equal to SINGLE_TOUCH_UP. While single touch emulation is
* occurring, single_touch_id corresponds with the tracking id of the touch used.
*/
#define NO_TOUCHES -1
#define SINGLE_TOUCH_UP -2

/* Touch surface information. Dimension is in hundredths of a mm, min and max
* are in units. */
#define MOUSE_DIMENSION_X (float)9056
Expand Down Expand Up @@ -125,7 +117,6 @@ struct magicmouse_sc {
u8 size;
} touches[16];
int tracking_ids[16];
int single_touch_id;
};

static int magicmouse_firm_touch(struct magicmouse_sc *msc)
Expand Down Expand Up @@ -264,16 +255,14 @@ static void magicmouse_emit_touch(struct magicmouse_sc *msc, int raw_id, u8 *tda
}
}

if (down) {
if (down)
msc->ntouches++;
if (msc->single_touch_id == NO_TOUCHES)
msc->single_touch_id = id;
} else if (msc->single_touch_id == id)
msc->single_touch_id = SINGLE_TOUCH_UP;

input_mt_slot(input, id);
input_mt_report_slot_state(input, MT_TOOL_FINGER, down);

/* Generate the input events for this touch. */
if (down) {
input_report_abs(input, ABS_MT_TRACKING_ID, id);
input_report_abs(input, ABS_MT_TOUCH_MAJOR, touch_major << 2);
input_report_abs(input, ABS_MT_TOUCH_MINOR, touch_minor << 2);
input_report_abs(input, ABS_MT_ORIENTATION, -orientation);
Expand All @@ -286,8 +275,6 @@ static void magicmouse_emit_touch(struct magicmouse_sc *msc, int raw_id, u8 *tda
else /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
input_event(input, EV_MSC, MSC_RAW, tdata[8]);
}

input_mt_sync(input);
}
}

Expand All @@ -308,12 +295,6 @@ static int magicmouse_raw_event(struct hid_device *hdev,
for (ii = 0; ii < npoints; ii++)
magicmouse_emit_touch(msc, ii, data + ii * 9 + 4);

/* We don't need an MT sync here because trackpad emits a
* BTN_TOUCH event in a new frame when all touches are released.
*/
if (msc->ntouches == 0)
msc->single_touch_id = NO_TOUCHES;

clicks = data[1];

/* The following bits provide a device specific timestamp. They
Expand All @@ -331,9 +312,6 @@ static int magicmouse_raw_event(struct hid_device *hdev,
for (ii = 0; ii < npoints; ii++)
magicmouse_emit_touch(msc, ii, data + ii * 8 + 6);

if (msc->ntouches == 0)
input_mt_sync(input);

/* When emulating three-button mode, it is important
* to have the current touch information before
* generating a click event.
Expand Down Expand Up @@ -366,25 +344,17 @@ static int magicmouse_raw_event(struct hid_device *hdev,
input_report_rel(input, REL_Y, y);
} else { /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
input_report_key(input, BTN_MOUSE, clicks & 1);
input_report_key(input, BTN_TOUCH, msc->ntouches > 0);
input_report_key(input, BTN_TOOL_FINGER, msc->ntouches == 1);
input_report_key(input, BTN_TOOL_DOUBLETAP, msc->ntouches == 2);
input_report_key(input, BTN_TOOL_TRIPLETAP, msc->ntouches == 3);
input_report_key(input, BTN_TOOL_QUADTAP, msc->ntouches == 4);
if (msc->single_touch_id >= 0) {
input_report_abs(input, ABS_X,
msc->touches[msc->single_touch_id].x);
input_report_abs(input, ABS_Y,
msc->touches[msc->single_touch_id].y);
}
input_mt_report_pointer_emulation(input, true);
}

input_sync(input);
return 1;
}

static void magicmouse_setup_input(struct input_dev *input, struct hid_device *hdev)
static int magicmouse_setup_input(struct input_dev *input, struct hid_device *hdev)
{
int error;

__set_bit(EV_KEY, input->evbit);

if (input->id.product == USB_DEVICE_ID_APPLE_MAGICMOUSE) {
Expand Down Expand Up @@ -413,6 +383,7 @@ static void magicmouse_setup_input(struct input_dev *input, struct hid_device *h
__set_bit(BTN_TOOL_DOUBLETAP, input->keybit);
__set_bit(BTN_TOOL_TRIPLETAP, input->keybit);
__set_bit(BTN_TOOL_QUADTAP, input->keybit);
__set_bit(BTN_TOOL_QUINTTAP, input->keybit);
__set_bit(BTN_TOUCH, input->keybit);
__set_bit(INPUT_PROP_POINTER, input->propbit);
__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
Expand All @@ -421,7 +392,9 @@ static void magicmouse_setup_input(struct input_dev *input, struct hid_device *h

__set_bit(EV_ABS, input->evbit);

input_set_abs_params(input, ABS_MT_TRACKING_ID, 0, 15, 0, 0);
error = input_mt_init_slots(input, 16);
if (error)
return error;
input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255 << 2,
4, 0);
input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, 255 << 2,
Expand Down Expand Up @@ -468,6 +441,8 @@ static void magicmouse_setup_input(struct input_dev *input, struct hid_device *h
__set_bit(EV_MSC, input->evbit);
__set_bit(MSC_RAW, input->mscbit);
}

return 0;
}

static int magicmouse_input_mapping(struct hid_device *hdev,
Expand Down Expand Up @@ -506,8 +481,6 @@ static int magicmouse_probe(struct hid_device *hdev,
msc->quirks = id->driver_data;
hid_set_drvdata(hdev, msc);

msc->single_touch_id = NO_TOUCHES;

ret = hid_parse(hdev);
if (ret) {
hid_err(hdev, "magicmouse hid parse failed\n");
Expand All @@ -523,8 +496,13 @@ static int magicmouse_probe(struct hid_device *hdev,
/* We do this after hid-input is done parsing reports so that
* hid-input uses the most natural button and axis IDs.
*/
if (msc->input)
magicmouse_setup_input(msc->input, hdev);
if (msc->input) {
ret = magicmouse_setup_input(msc->input, hdev);
if (ret) {
hid_err(hdev, "magicmouse setup input failed (%d)\n", ret);
goto err_stop_hw;
}
}

if (id->product == USB_DEVICE_ID_APPLE_MAGICMOUSE)
report = hid_register_report(hdev, HID_INPUT_REPORT,
Expand Down

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