[PATCH] USB: add apple usb touchpad driver

This is a driver for the USB touchpad which can be found on post-February 2005
Apple PowerBooks.

This driver is derived from Johannes Berg's appletrackpad driver [1],
but it has been improved in some areas:
    * appletouch is a full kernel driver, no userspace program is necessary
    * appletouch can be interfaced with the synaptics X11 driver[2], in order
      to have touchpad acceleration, scrolling, two/three finger tap, etc.

This driver has been tested by the readers of the 'debian-powerpc' mailing
list for a few weeks now and I believe it is now ready for inclusion into the
mainline kernel.

Credits go to Johannes Berg for reverse-engineering the touchpad protocol,
Frank Arnold for further improvements, and Alex Harper for some additional
information about the inner workings of the touchpad sensors.

Signed-off-by: Stelian Pop <stelian@popies.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 490 insertions, 0 deletions

diff --git a/drivers/usb/input/Kconfig b/drivers/usb/input/Kconfig
index 482c4be521f5..1e53934907c0 100644
--- a/drivers/usb/input/Kconfig
+++ b/drivers/usb/input/Kconfig
@@ -286,3 +286,23 @@ config USB_KEYSPAN_REMOTE
 
           To compile this driver as a module, choose M here: the module will
           be called keyspan_remote.
+
+config USB_APPLETOUCH
+        tristate "Apple USB Touchpad support"
+        depends on USB && INPUT
+        ---help---
+          Say Y here if you want to use an Apple USB Touchpad.
+
+          These are the touchpads that can be found on post-February 2005
+          Apple Powerbooks (prior models have a Synaptics touchpad connected
+          to the ADB bus).
+
+          This driver provides a basic mouse driver but can be interfaced
+          with the synaptics X11 driver to provide acceleration and
+          scrolling in X11.
+
+          For further information, see
+          <file:Documentation/input/appletouch.txt>.
+
+          To compile this driver as a module, choose M here: the
+          module will be called appletouch.
diff --git a/drivers/usb/input/Makefile b/drivers/usb/input/Makefile
index 43b2f999edfe..5e03b93f29f6 100644
--- a/drivers/usb/input/Makefile
+++ b/drivers/usb/input/Makefile
@@ -41,3 +41,4 @@ obj-$(CONFIG_USB_WACOM)		+= wacom.o
 obj-$(CONFIG_USB_ACECAD)        += acecad.o
 obj-$(CONFIG_USB_YEALINK)       += yealink.o
 obj-$(CONFIG_USB_XPAD)          += xpad.o
+obj-$(CONFIG_USB_APPLETOUCH)    += appletouch.o
diff --git a/drivers/usb/input/appletouch.c b/drivers/usb/input/appletouch.c
new file mode 100644
index 000000000000..e03c1c567a14
--- /dev/null
+++ b/drivers/usb/input/appletouch.c
@@ -0,0 +1,469 @@
+/*
+ * Apple USB Touchpad (for post-February 2005 PowerBooks) driver
+ *
+ * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
+ * Copyright (C) 2005      Johannes Berg (johannes@sipsolutions.net)
+ * Copyright (C) 2005      Stelian Pop (stelian@popies.net)
+ * Copyright (C) 2005      Frank Arnold (frank@scirocco-5v-turbo.de)
+ * Copyright (C) 2005      Peter Osterlund (petero2@telia.com)
+ *
+ * Thanks to Alex Harper <basilisk@foobox.net> for his inputs.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/input.h>
+#include <linux/usb_input.h>
+
+/* Apple has powerbooks which have the keyboard with different Product IDs */
+#define APPLE_VENDOR_ID         0x05AC
+
+#define ATP_DEVICE(prod)                                        \
+        .match_flags = USB_DEVICE_ID_MATCH_DEVICE |             \
+                       USB_DEVICE_ID_MATCH_INT_CLASS |          \
+                       USB_DEVICE_ID_MATCH_INT_PROTOCOL,        \
+        .idVendor = APPLE_VENDOR_ID,                            \
+        .idProduct = (prod),                                    \
+        .bInterfaceClass = 0x03,                                \
+        .bInterfaceProtocol = 0x02
+
+/* table of devices that work with this driver */
+static struct usb_device_id atp_table [] = {
+        { ATP_DEVICE(0x020E) },
+        { ATP_DEVICE(0x020F) },
+        { ATP_DEVICE(0x030A) },
+        { ATP_DEVICE(0x030B) },
+        { }                                     /* Terminating entry */
+};
+MODULE_DEVICE_TABLE (usb, atp_table);
+
+/* size of a USB urb transfer */
+#define ATP_DATASIZE    81
+
+/*
+ * number of sensors. Note that only 16 instead of 26 X (horizontal)
+ * sensors exist on 12" and 15" PowerBooks. All models have 16 Y
+ * (vertical) sensors.
+ */
+#define ATP_XSENSORS    26
+#define ATP_YSENSORS    16
+
+/* amount of fuzz this touchpad generates */
+#define ATP_FUZZ        16
+
+/* maximum pressure this driver will report */
+#define ATP_PRESSURE    300
+/*
+ * multiplication factor for the X and Y coordinates.
+ * We try to keep the touchpad aspect ratio while still doing only simple
+ * arithmetics.
+ * The factors below give coordinates like:
+ *      0 <= x <  960 on 12" and 15" Powerbooks
+ *      0 <= x < 1600 on 17" Powerbooks
+ *      0 <= y <  646
+ */
+#define ATP_XFACT       64
+#define ATP_YFACT       43
+
+/*
+ * Threshold for the touchpad sensors. Any change less than ATP_THRESHOLD is
+ * ignored.
+ */
+#define ATP_THRESHOLD    5
+
+/* Structure to hold all of our device specific stuff */
+struct atp {
+        struct usb_device *     udev;           /* usb device */
+        struct urb *            urb;            /* usb request block */
+        signed char *           data;           /* transferred data */
+        int                     open;           /* non-zero if opened */
+        struct input_dev        input;          /* input dev */
+        int                     valid;          /* are the sensors valid ? */
+        int                     x_old;          /* last reported x/y, */
+        int                     y_old;          /* used for smoothing */
+                                                /* current value of the sensors */
+        signed char             xy_cur[ATP_XSENSORS + ATP_YSENSORS];
+                                                /* last value of the sensors */
+        signed char             xy_old[ATP_XSENSORS + ATP_YSENSORS];
+                                                /* accumulated sensors */
+        int                     xy_acc[ATP_XSENSORS + ATP_YSENSORS];
+};
+
+#define dbg_dump(msg, tab) \
+        if (debug > 1) {                                                \
+                int i;                                                  \
+                printk("appletouch: %s %lld", msg, (long long)jiffies); \
+                for (i = 0; i < ATP_XSENSORS + ATP_YSENSORS; i++)       \
+                        printk(" %02x", tab[i]);                        \
+                printk("\n");                                           \
+        }
+
+#define dprintk(format, a...)                                           \
+        do {                                                            \
+                if (debug) printk(format, ##a);                         \
+        } while (0)
+
+MODULE_AUTHOR("Johannes Berg, Stelian Pop, Frank Arnold");
+MODULE_DESCRIPTION("Apple PowerBooks USB touchpad driver");
+MODULE_LICENSE("GPL");
+
+static int debug = 1;
+module_param(debug, int, 0644);
+MODULE_PARM_DESC(debug, "Activate debugging output");
+
+static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
+                             int *z, int *fingers)
+{
+        int i;
+        /* values to calculate mean */
+        int pcum = 0, psum = 0;
+
+        *fingers = 0;
+
+        for (i = 0; i < nb_sensors; i++) {
+                if (xy_sensors[i] < ATP_THRESHOLD)
+                        continue;
+                if ((i - 1 < 0) || (xy_sensors[i - 1] < ATP_THRESHOLD))
+                        (*fingers)++;
+                pcum += xy_sensors[i] * i;
+                psum += xy_sensors[i];
+        }
+
+        if (psum > 0) {
+                *z = psum;
+                return pcum * fact / psum;
+        }
+
+        return 0;
+}
+
+static inline void atp_report_fingers(struct input_dev *input, int fingers)
+{
+        input_report_key(input, BTN_TOOL_FINGER, fingers == 1);
+        input_report_key(input, BTN_TOOL_DOUBLETAP, fingers == 2);
+        input_report_key(input, BTN_TOOL_TRIPLETAP, fingers > 2);
+}
+
+static void atp_complete(struct urb* urb, struct pt_regs* regs)
+{
+        int x, y, x_z, y_z, x_f, y_f;
+        int retval, i;
+        struct atp *dev = urb->context;
+
+        switch (urb->status) {
+        case 0:
+                /* success */
+                break;
+        case -ECONNRESET:
+        case -ENOENT:
+        case -ESHUTDOWN:
+                /* This urb is terminated, clean up */
+                dbg("%s - urb shutting down with status: %d",
+                    __FUNCTION__, urb->status);
+                return;
+        default:
+                dbg("%s - nonzero urb status received: %d",
+                    __FUNCTION__, urb->status);
+                goto exit;
+        }
+
+        /* drop incomplete datasets */
+        if (dev->urb->actual_length != ATP_DATASIZE) {
+                dprintk("appletouch: incomplete data package.\n");
+                goto exit;
+        }
+
+        /* reorder the sensors values */
+        for (i = 0; i < 8; i++) {
+                /* X values */
+                dev->xy_cur[i     ] = dev->data[5 * i +  2];
+                dev->xy_cur[i +  8] = dev->data[5 * i +  4];
+                dev->xy_cur[i + 16] = dev->data[5 * i + 42];
+                if (i < 2)
+                        dev->xy_cur[i + 24] = dev->data[5 * i + 44];
+
+                /* Y values */
+                dev->xy_cur[i + 26] = dev->data[5 * i +  1];
+                dev->xy_cur[i + 34] = dev->data[5 * i +  3];
+        }
+
+        dbg_dump("sample", dev->xy_cur);
+
+        if (!dev->valid) {
+                /* first sample */
+                dev->valid = 1;
+                dev->x_old = dev->y_old = -1;
+                memcpy(dev->xy_old, dev->xy_cur, sizeof(dev->xy_old));
+
+                /* 17" Powerbooks have 10 extra X sensors */
+                for (i = 16; i < ATP_XSENSORS; i++)
+                        if (dev->xy_cur[i]) {
+                                printk("appletouch: 17\" model detected.\n");
+                                input_set_abs_params(&dev->input, ABS_X, 0,
+                                                     (ATP_XSENSORS - 1) *
+                                                     ATP_XFACT - 1,
+                                                     ATP_FUZZ, 0);
+                                break;
+                        }
+
+                goto exit;
+        }
+
+        for (i = 0; i < ATP_XSENSORS + ATP_YSENSORS; i++) {
+                /* accumulate the change */
+                signed char change = dev->xy_old[i] - dev->xy_cur[i];
+                dev->xy_acc[i] -= change;
+
+                /* prevent down drifting */
+                if (dev->xy_acc[i] < 0)
+                        dev->xy_acc[i] = 0;
+        }
+
+        memcpy(dev->xy_old, dev->xy_cur, sizeof(dev->xy_old));
+
+        dbg_dump("accumulator", dev->xy_acc);
+
+        x = atp_calculate_abs(dev->xy_acc, ATP_XSENSORS,
+                              ATP_XFACT, &x_z, &x_f);
+        y = atp_calculate_abs(dev->xy_acc + ATP_XSENSORS, ATP_YSENSORS,
+                              ATP_YFACT, &y_z, &y_f);
+
+        if (x && y) {
+                if (dev->x_old != -1) {
+                        x = (dev->x_old * 3 + x) >> 2;
+                        y = (dev->y_old * 3 + y) >> 2;
+                        dev->x_old = x;
+                        dev->y_old = y;
+
+                        if (debug > 1)
+                                printk("appletouch: X: %3d Y: %3d "
+                                       "Xz: %3d Yz: %3d\n",
+                                       x, y, x_z, y_z);
+
+                        input_report_key(&dev->input, BTN_TOUCH, 1);
+                        input_report_abs(&dev->input, ABS_X, x);
+                        input_report_abs(&dev->input, ABS_Y, y);
+                        input_report_abs(&dev->input, ABS_PRESSURE,
+                                         min(ATP_PRESSURE, x_z + y_z));
+                        atp_report_fingers(&dev->input, max(x_f, y_f));
+                }
+                dev->x_old = x;
+                dev->y_old = y;
+        }
+        else if (!x && !y) {
+
+                dev->x_old = dev->y_old = -1;
+                input_report_key(&dev->input, BTN_TOUCH, 0);
+                input_report_abs(&dev->input, ABS_PRESSURE, 0);
+                atp_report_fingers(&dev->input, 0);
+
+                /* reset the accumulator on release */
+                memset(dev->xy_acc, 0, sizeof(dev->xy_acc));
+        }
+
+        input_report_key(&dev->input, BTN_LEFT, !!dev->data[80]);
+
+        input_sync(&dev->input);
+
+exit:
+        retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
+        if (retval) {
+                err("%s - usb_submit_urb failed with result %d",
+                    __FUNCTION__, retval);
+        }
+}
+
+static int atp_open(struct input_dev *input)
+{
+        struct atp *dev = input->private;
+
+        if (usb_submit_urb(dev->urb, GFP_ATOMIC))
+                return -EIO;
+
+        dev->open = 1;
+        return 0;
+}
+
+static void atp_close(struct input_dev *input)
+{
+        struct atp *dev = input->private;
+
+        usb_kill_urb(dev->urb);
+        dev->open = 0;
+}
+
+static int atp_probe(struct usb_interface *iface, const struct usb_device_id *id)
+{
+        struct atp *dev = NULL;
+        struct usb_host_interface *iface_desc;
+        struct usb_endpoint_descriptor *endpoint;
+        int int_in_endpointAddr = 0;
+        int i, retval = -ENOMEM;
+
+        /* allocate memory for our device state and initialize it */
+        dev = kmalloc(sizeof(struct atp), GFP_KERNEL);
+        if (dev == NULL) {
+                err("Out of memory");
+                goto err_kmalloc;
+        }
+        memset(dev, 0, sizeof(struct atp));
+
+        dev->udev = interface_to_usbdev(iface);
+
+        /* set up the endpoint information */
+        /* use only the first interrupt-in endpoint */
+        iface_desc = iface->cur_altsetting;
+        for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
+                endpoint = &iface_desc->endpoint[i].desc;
+                if (!int_in_endpointAddr &&
+                    (endpoint->bEndpointAddress & USB_DIR_IN) &&
+                    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
+                                        == USB_ENDPOINT_XFER_INT)) {
+                        /* we found an interrupt in endpoint */
+                        int_in_endpointAddr = endpoint->bEndpointAddress;
+                        break;
+                }
+        }
+        if (!int_in_endpointAddr) {
+                retval = -EIO;
+                err("Could not find int-in endpoint");
+                goto err_endpoint;
+        }
+
+        /* save our data pointer in this interface device */
+        usb_set_intfdata(iface, dev);
+
+        dev->urb = usb_alloc_urb(0, GFP_KERNEL);
+        if (!dev->urb) {
+                retval = -ENOMEM;
+                goto err_usballoc;
+        }
+        dev->data = usb_buffer_alloc(dev->udev, ATP_DATASIZE, GFP_KERNEL,
+                                     &dev->urb->transfer_dma);
+        if (!dev->data) {
+                retval = -ENOMEM;
+                goto err_usbbufalloc;
+        }
+        usb_fill_int_urb(dev->urb, dev->udev,
+                         usb_rcvintpipe(dev->udev, int_in_endpointAddr),
+                         dev->data, ATP_DATASIZE, atp_complete, dev, 1);
+
+        init_input_dev(&dev->input);
+        dev->input.name = "appletouch";
+        dev->input.dev = &iface->dev;
+        dev->input.private = dev;
+        dev->input.open = atp_open;
+        dev->input.close = atp_close;
+
+        usb_to_input_id(dev->udev, &dev->input.id);
+
+        set_bit(EV_ABS, dev->input.evbit);
+
+        /*
+         * 12" and 15" Powerbooks only have 16 x sensors,
+         * 17" models are detected later.
+         */
+        input_set_abs_params(&dev->input, ABS_X, 0,
+                             (16 - 1) * ATP_XFACT - 1, ATP_FUZZ, 0);
+        input_set_abs_params(&dev->input, ABS_Y, 0,
+                             (ATP_YSENSORS - 1) * ATP_YFACT - 1, ATP_FUZZ, 0);
+        input_set_abs_params(&dev->input, ABS_PRESSURE, 0, ATP_PRESSURE, 0, 0);
+
+        set_bit(EV_KEY, dev->input.evbit);
+        set_bit(BTN_TOUCH, dev->input.keybit);
+        set_bit(BTN_TOOL_FINGER, dev->input.keybit);
+        set_bit(BTN_TOOL_DOUBLETAP, dev->input.keybit);
+        set_bit(BTN_TOOL_TRIPLETAP, dev->input.keybit);
+        set_bit(BTN_LEFT, dev->input.keybit);
+
+        input_register_device(&dev->input);
+
+        printk(KERN_INFO "input: appletouch connected\n");
+
+        return 0;
+
+err_usbbufalloc:
+        usb_free_urb(dev->urb);
+err_usballoc:
+        usb_set_intfdata(iface, NULL);
+err_endpoint:
+        kfree(dev);
+err_kmalloc:
+        return retval;
+}
+
+static void atp_disconnect(struct usb_interface *iface)
+{
+        struct atp *dev = usb_get_intfdata(iface);
+
+        usb_set_intfdata(iface, NULL);
+        if (dev) {
+                usb_kill_urb(dev->urb);
+                input_unregister_device(&dev->input);
+                usb_free_urb(dev->urb);
+                usb_buffer_free(dev->udev, ATP_DATASIZE,
+                                dev->data, dev->urb->transfer_dma);
+                kfree(dev);
+        }
+        printk(KERN_INFO "input: appletouch disconnected\n");
+}
+
+static int atp_suspend(struct usb_interface *iface, pm_message_t message)
+{
+        struct atp *dev = usb_get_intfdata(iface);
+        usb_kill_urb(dev->urb);
+        dev->valid = 0;
+        return 0;
+}
+
+static int atp_resume(struct usb_interface *iface)
+{
+        struct atp *dev = usb_get_intfdata(iface);
+        if (dev->open && usb_submit_urb(dev->urb, GFP_ATOMIC))
+                return -EIO;
+
+        return 0;
+}
+
+static struct usb_driver atp_driver = {
+        .owner          = THIS_MODULE,
+        .name           = "appletouch",
+        .probe          = atp_probe,
+        .disconnect     = atp_disconnect,
+        .suspend        = atp_suspend,
+        .resume         = atp_resume,
+        .id_table       = atp_table,
+};
+
+static int __init atp_init(void)
+{
+        return usb_register(&atp_driver);
+}
+
+static void __exit atp_exit(void)
+{
+        usb_deregister(&atp_driver);
+}
+
+module_init(atp_init);
+module_exit(atp_exit);