[PATCH] USB: input/touchkitusb: handle multiple packets

Some versions of the controller seem to put multiple report packet into a
single urb. also it can happen that a packet is split across multiple urbs.
unpatched you get a jumpy cursor on some screens.
the patch does:
- handle multiple packets per urb
- handle packets split across multiple urb
- check packet type
- cleanups

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/input/touchkitusb.c b/drivers/usb/input/touchkitusb.c
index 75e7c12..3b3c7b4 100644 (file)
--- a/drivers/usb/input/touchkitusb.c
+++ b/drivers/usb/input/touchkitusb.c
@@ -1,7 +1,7 @@
 /******************************************************************************
  * touchkitusb.c  --  Driver for eGalax TouchKit USB Touchscreens
  *
- * Copyright (C) 2004 by Daniel Ritz
+ * Copyright (C) 2004-2005 by Daniel Ritz <daniel.ritz@gmx.ch>
  * Copyright (C) by Todd E. Johnson (mtouchusb.c)
  *
  * This program is free software; you can redistribute it and/or
@@ -41,15 +41,13 @@
 #define TOUCHKIT_MAX_YC                        0x07ff
 #define TOUCHKIT_YC_FUZZ               0x0
 #define TOUCHKIT_YC_FLAT               0x0
-#define TOUCHKIT_REPORT_DATA_SIZE      8
+#define TOUCHKIT_REPORT_DATA_SIZE      16
 
 #define TOUCHKIT_DOWN                  0x01
-#define TOUCHKIT_POINT_TOUCH           0x81
-#define TOUCHKIT_POINT_NOTOUCH         0x80
 
-#define TOUCHKIT_GET_TOUCHED(dat)      ((((dat)[0]) & TOUCHKIT_DOWN) ? 1 : 0)
-#define TOUCHKIT_GET_X(dat)            (((dat)[3] << 7) | (dat)[4])
-#define TOUCHKIT_GET_Y(dat)            (((dat)[1] << 7) | (dat)[2])
+#define TOUCHKIT_PKT_TYPE_MASK         0xFE
+#define TOUCHKIT_PKT_TYPE_REPT         0x80
+#define TOUCHKIT_PKT_TYPE_DIAG         0x0A
 
 #define DRIVER_VERSION                 "v0.1"
 #define DRIVER_AUTHOR                  "Daniel Ritz <daniel.ritz@gmx.ch>"
@@ -62,6 +60,8 @@ MODULE_PARM_DESC(swap_xy, "If set X and Y axes are swapped.");
 struct touchkit_usb {
        unsigned char *data;
        dma_addr_t data_dma;
+       char buffer[TOUCHKIT_REPORT_DATA_SIZE];
+       int buf_len;
        struct urb *irq;
        struct usb_device *udev;
        struct input_dev *input;
@@ -77,11 +77,128 @@ static struct usb_device_id touchkit_devices[] = {
        {}
 };
 
+/* helpers to read the data */
+static inline int touchkit_get_touched(char *data)
+{
+       return (data[0] & TOUCHKIT_DOWN) ? 1 : 0;
+}
+
+static inline int touchkit_get_x(char *data)
+{
+       return ((data[3] & 0x0F) << 7) | (data[4] & 0x7F);
+}
+
+static inline int touchkit_get_y(char *data)
+{
+       return ((data[1] & 0x0F) << 7) | (data[2] & 0x7F);
+}
+
+
+/* processes one input packet. */
+static void touchkit_process_pkt(struct touchkit_usb *touchkit,
+                                 struct pt_regs *regs, char *pkt)
+{
+       int x, y;
+
+       /* only process report packets */
+       if ((pkt[0] & TOUCHKIT_PKT_TYPE_MASK) != TOUCHKIT_PKT_TYPE_REPT)
+               return;
+
+       if (swap_xy) {
+               y = touchkit_get_x(pkt);
+               x = touchkit_get_y(pkt);
+       } else {
+               x = touchkit_get_x(pkt);
+               y = touchkit_get_y(pkt);
+       }
+
+       input_regs(touchkit->input, regs);
+       input_report_key(touchkit->input, BTN_TOUCH, touchkit_get_touched(pkt));
+       input_report_abs(touchkit->input, ABS_X, x);
+       input_report_abs(touchkit->input, ABS_Y, y);
+       input_sync(touchkit->input);
+}
+
+
+static int touchkit_get_pkt_len(char *buf)
+{
+       switch (buf[0] & TOUCHKIT_PKT_TYPE_MASK) {
+       case TOUCHKIT_PKT_TYPE_REPT:
+               return 5;
+
+       case TOUCHKIT_PKT_TYPE_DIAG:
+               return buf[1] + 2;
+       }
+
+       return 0;
+}
+
+static void touchkit_process(struct touchkit_usb *touchkit, int len,
+                             struct pt_regs *regs)
+{
+       char *buffer;
+       int pkt_len, buf_len, pos;
+
+       /* if the buffer contains data, append */
+       if (unlikely(touchkit->buf_len)) {
+               int tmp;
+
+               /* if only 1 byte in buffer, add another one to get length */
+               if (touchkit->buf_len == 1)
+                       touchkit->buffer[1] = touchkit->data[0];
+
+               pkt_len = touchkit_get_pkt_len(touchkit->buffer);
+
+               /* unknown packet: drop everything */
+               if (!pkt_len)
+                       return;
+
+               /* append, process */
+               tmp = pkt_len - touchkit->buf_len;
+               memcpy(touchkit->buffer + touchkit->buf_len, touchkit->data, tmp);
+               touchkit_process_pkt(touchkit, regs, touchkit->buffer);
+
+               buffer = touchkit->data + tmp;
+               buf_len = len - tmp;
+       } else {
+               buffer = touchkit->data;
+               buf_len = len;
+       }
+
+       /* only one byte left in buffer */
+       if (unlikely(buf_len == 1)) {
+               touchkit->buffer[0] = buffer[0];
+               touchkit->buf_len = 1;
+               return;
+       }
+
+       /* loop over the buffer */
+       pos = 0;
+       while (pos < buf_len) {
+               /* get packet len */
+               pkt_len = touchkit_get_pkt_len(buffer + pos);
+
+               /* unknown packet: drop everything */
+               if (unlikely(!pkt_len))
+                       return;
+
+               /* full packet: process */
+               if (likely(pkt_len <= buf_len)) {
+                       touchkit_process_pkt(touchkit, regs, buffer + pos);
+               } else {
+                       /* incomplete packet: save in buffer */
+                       memcpy(touchkit->buffer, buffer + pos, buf_len - pos);
+                       touchkit->buf_len = buf_len - pos;
+               }
+               pos += pkt_len;
+       }
+}
+
+
 static void touchkit_irq(struct urb *urb, struct pt_regs *regs)
 {
        struct touchkit_usb *touchkit = urb->context;
        int retval;
-       int x, y;
 
        switch (urb->status) {
        case 0:
@@ -105,20 +222,7 @@ static void touchkit_irq(struct urb *urb, struct pt_regs *regs)
                goto exit;
        }
 
-       if (swap_xy) {
-               y = TOUCHKIT_GET_X(touchkit->data);
-               x = TOUCHKIT_GET_Y(touchkit->data);
-       } else {
-               x = TOUCHKIT_GET_X(touchkit->data);
-               y = TOUCHKIT_GET_Y(touchkit->data);
-       }
-
-       input_regs(touchkit->input, regs);
-       input_report_key(touchkit->input, BTN_TOUCH,
-                        TOUCHKIT_GET_TOUCHED(touchkit->data));
-       input_report_abs(touchkit->input, ABS_X, x);
-       input_report_abs(touchkit->input, ABS_Y, y);
-       input_sync(touchkit->input);
+       touchkit_process(touchkit, urb->actual_length, regs);
 
 exit:
        retval = usb_submit_urb(urb, GFP_ATOMIC);