[RFC PATCH] hid-magicmouse: Map inputs rather than munging input devices

[Michael Poole <mdpoole@troilus.org>]

Let the HID core handle input device setup and HID-compliant reports.
This driver then only has to worry about the non-standard reports.

Signed-off-by: Michael Poole <mdpoole@troilus.org>
---
Jiri (Slaby), is this the kind of change you had in mind for getting rid
of the input device setup for hid-magicmouse?

(This applies on top of commit a462230e16 from the magicmouse branch at
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid.git.)

 drivers/hid/hid-magicmouse.c |   87
+++++++++++------------------------------
 1 files changed, 24 insertions(+), 63 deletions(-)

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index 8791a08..3778f9b 100644
--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -278,14 +278,12 @@ static int magicmouse_raw_event(struct hid_device
*hdev,
 	struct input_dev *input = msc->input;
 	int x = 0, y = 0, ii, clicks = 0, npoints;
 
+	/* Slightly paranoid, but "input" only gets set when our
+	 * input_mapping sees the right field. */
+	if (!input)
+		return 0;
+
 	switch (data[0]) {
-	case 0x10:
-		if (size != 6)
-			return 0;
-		x = (__s16)(data[2] | data[3] << 8);
-		y = (__s16)(data[4] | data[5] << 8);
-		clicks = data[1];
-		break;
 	case TRACKPAD_REPORT_ID:
 		/* Expect four bytes of prefix, and N*9 bytes of touch data. */
 		if (size < 4 || ((size - 4) % 9) != 0)
@@ -343,13 +341,6 @@ static int magicmouse_raw_event(struct hid_device
*hdev,
 		magicmouse_raw_event(hdev, report, data + 2 + data[1],
 			size - 2 - data[1]);
 		break;
-	case 0x20: /* Theoretically battery status (0-100), but I have
-		    * never seen it -- maybe it is only upon request.
-		    */
-	case 0x60: /* Unknown, maybe laser on/off. */
-	case 0x61: /* Laser reflection status change.
-		    * data[1]: 0 = spotted, 1 = lost
-		    */
 	default:
 		return 0;
 	}
@@ -377,36 +368,8 @@ static int magicmouse_raw_event(struct hid_device
*hdev,
 	return 1;
 }
 
-static int magicmouse_input_open(struct input_dev *dev)
-{
-	struct hid_device *hid = input_get_drvdata(dev);
-
-	return hid->ll_driver->open(hid);
-}
-
-static void magicmouse_input_close(struct input_dev *dev)
-{
-	struct hid_device *hid = input_get_drvdata(dev);
-
-	hid->ll_driver->close(hid);
-}
-
 static void magicmouse_setup_input(struct input_dev *input, struct
hid_device *hdev)
 {
-	input_set_drvdata(input, hdev);
-	input->event = hdev->ll_driver->hidinput_input_event;
-	input->open = magicmouse_input_open;
-	input->close = magicmouse_input_close;
-
-	input->name = hdev->name;
-	input->phys = hdev->phys;
-	input->uniq = hdev->uniq;
-	input->id.bustype = hdev->bus;
-	input->id.vendor = hdev->vendor;
-	input->id.product = hdev->product;
-	input->id.version = hdev->version;
-	input->dev.parent = hdev->dev.parent;
-
 	__set_bit(EV_KEY, input->evbit);
 
 	if (input->id.product == USB_DEVICE_ID_APPLE_MAGICMOUSE) {
@@ -466,11 +429,22 @@ static void magicmouse_setup_input(struct
input_dev *input, struct hid_device *h
 	}
 }
 
+static int magicmouse_input_mapping(struct hid_device *hdev,
+		struct hid_input *hi, struct hid_field *field,
+		struct hid_usage *usage, unsigned long **bit, int *max)
+{
+	struct magicmouse_sc *msc = hid_get_drvdata(hdev);
+
+	if (!msc->input)
+		msc->input = hi->input;
+
+	return 0;
+}
+
 static int magicmouse_probe(struct hid_device *hdev,
 	const struct hid_device_id *id)
 {
 	__u8 feature[] = { 0xd7, 0x01 };
-	struct input_dev *input;
 	struct magicmouse_sc *msc;
 	struct hid_report *report;
 	int ret;
@@ -500,8 +474,12 @@ static int magicmouse_probe(struct hid_device
*hdev,
 		goto err_free;
 	}
 
-	/* we are handling the input ourselves */
-	hidinput_disconnect(hdev);
+	/* We do this after HID maps its inputs so that the
+	 * Magic Mouse's HID-compliant report gets the right
+	 * button and axis IDs.
+	 */
+	if (msc->input)
+		magicmouse_setup_input(msc->input, hdev);
 
 	if (id->product == USB_DEVICE_ID_APPLE_MAGICMOUSE)
 		report = hid_register_report(hdev, HID_INPUT_REPORT,
@@ -528,24 +506,7 @@ static int magicmouse_probe(struct hid_device
*hdev,
 		goto err_stop_hw;
 	}
 
-	input = input_allocate_device();
-	if (!input) {
-		dev_err(&hdev->dev, "can't alloc input device\n");
-		ret = -ENOMEM;
-		goto err_stop_hw;
-	}
-	magicmouse_setup_input(input, hdev);
-
-	ret = input_register_device(input);
-	if (ret) {
-		dev_err(&hdev->dev, "input device registration failed\n");
-		goto err_input;
-	}
-	msc->input = input;
-
 	return 0;
-err_input:
-	input_free_device(input);
 err_stop_hw:
 	hid_hw_stop(hdev);
 err_free:
@@ -558,7 +519,6 @@ static void magicmouse_remove(struct hid_device
*hdev)
 	struct magicmouse_sc *msc = hid_get_drvdata(hdev);
 
 	hid_hw_stop(hdev);
-	input_unregister_device(msc->input);
 	kfree(msc);
 }
 
@@ -577,6 +537,7 @@ static struct hid_driver magicmouse_driver = {
 	.probe = magicmouse_probe,
 	.remove = magicmouse_remove,
 	.raw_event = magicmouse_raw_event,
+	.input_mapping = magicmouse_input_mapping,
 };
 
 static int __init magicmouse_init(void)
-- 
1.7.2.2