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* [PATCH] Input: usbtouchscreen - reduce number fo be16_to_cpu conversions
@ 2010-06-04  7:51 Dmitry Torokhov
  2010-06-04 10:35 ` Ondrej Zary
  0 siblings, 1 reply; 3+ messages in thread
From: Dmitry Torokhov @ 2010-06-04  7:51 UTC (permalink / raw)
  To: Ondrej Zary; +Cc: linux-input

Let's perform be16_to_cpu() conversions once for each received packet,
and then use cached values. Makes code a little bit easier to follow.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---

Ondrej,

Any chance you could test the following patch?

Thanks,
Dmitry


 drivers/input/touchscreen/usbtouchscreen.c |   34 +++++++++++++++-------------
 1 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index 567d572..5d6bf2a 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -849,29 +849,32 @@ static void nexio_exit(struct usbtouch_usb *usbtouch)
 
 static int nexio_read_data(struct usbtouch_usb *usbtouch, unsigned char *pkt)
 {
-	int x, y, begin_x, begin_y, end_x, end_y, w, h, ret;
 	struct nexio_touch_packet *packet = (void *) pkt;
 	struct nexio_priv *priv = usbtouch->priv;
+	unsigned int data_len = be16_to_cpu(packet->data_len);
+	unsigned int x_len = be16_to_cpu(packet->x_len);
+	unsigned int y_len = be16_to_cpu(packet->y_len);
+	int x, y, begin_x, begin_y, end_x, end_y, w, h, ret;
 
 	/* got touch data? */
 	if ((pkt[0] & 0xe0) != 0xe0)
 		return 0;
 
-	if (be16_to_cpu(packet->data_len) > 0xff)
-		packet->data_len = cpu_to_be16(be16_to_cpu(packet->data_len) - 0x100);
-	if (be16_to_cpu(packet->x_len) > 0xff)
-		packet->x_len = cpu_to_be16(be16_to_cpu(packet->x_len) - 0x80);
+	if (data_len > 0xff)
+		data_len -= 0x100;
+	if (x_len > 0xff)
+		x_len -= 0x80;
 
 	/* send ACK */
 	ret = usb_submit_urb(priv->ack, GFP_ATOMIC);
 
 	if (!usbtouch->type->max_xc) {
-		usbtouch->type->max_xc = 2 * be16_to_cpu(packet->x_len);
-		input_set_abs_params(usbtouch->input, ABS_X, 0,
-				     2 * be16_to_cpu(packet->x_len), 0, 0);
-		usbtouch->type->max_yc = 2 * be16_to_cpu(packet->y_len);
-		input_set_abs_params(usbtouch->input, ABS_Y, 0,
-				     2 * be16_to_cpu(packet->y_len), 0, 0);
+		usbtouch->type->max_xc = 2 * x_len;
+		input_set_abs_params(usbtouch->input, ABS_X,
+				     0, usbtouch->type->max_xc, 0, 0);
+		usbtouch->type->max_yc = 2 * y_len;
+		input_set_abs_params(usbtouch->input, ABS_Y,
+				     0, usbtouch->type->max_yc, 0, 0);
 	}
 	/*
 	 * The device reports state of IR sensors on X and Y axes.
@@ -881,22 +884,21 @@ static int nexio_read_data(struct usbtouch_usb *usbtouch, unsigned char *pkt)
 	 * it's disabled (and untested) here as there's no X driver for that.
 	 */
 	begin_x = end_x = begin_y = end_y = -1;
-	for (x = 0; x < be16_to_cpu(packet->x_len); x++) {
+	for (x = 0; x < x_len; x++) {
 		if (begin_x == -1 && packet->data[x] > NEXIO_THRESHOLD) {
 			begin_x = x;
 			continue;
 		}
 		if (end_x == -1 && begin_x != -1 && packet->data[x] < NEXIO_THRESHOLD) {
 			end_x = x - 1;
-			for (y = be16_to_cpu(packet->x_len);
-			     y < be16_to_cpu(packet->data_len); y++) {
+			for (y = x_len; y < data_len; y++) {
 				if (begin_y == -1 && packet->data[y] > NEXIO_THRESHOLD) {
-					begin_y = y - be16_to_cpu(packet->x_len);
+					begin_y = y - x_len;
 					continue;
 				}
 				if (end_y == -1 &&
 				    begin_y != -1 && packet->data[y] < NEXIO_THRESHOLD) {
-					end_y = y - 1 - be16_to_cpu(packet->x_len);
+					end_y = y - 1 - x_len;
 					w = end_x - begin_x;
 					h = end_y - begin_y;
 #if 0


^ permalink raw reply related	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2010-06-04 16:24 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2010-06-04  7:51 [PATCH] Input: usbtouchscreen - reduce number fo be16_to_cpu conversions Dmitry Torokhov
2010-06-04 10:35 ` Ondrej Zary
2010-06-04 16:24   ` Dmitry Torokhov

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