+/* 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;
+ }
+}
+
+