From: Ben Dooks <ben-linux@fluff.org>
Date: Tue, 1 Jul 2008 10:59:41 +0000 (+0100)
Subject: I2C: S3C2410: Check ACK on byte transmission
X-Git-Tag: v2.6.26-rc9~69^2~2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2709781be6141798162f1089df728fb218a590df;p=linux-2.6

I2C: S3C2410: Check ACK on byte transmission

We should check for the reception of an ACK after transmitting each
data byte. The address send has been correctly checking this, but the
data write byte state should have also been checking for these failures.

As part of the same fix, we remove the ACK checking from the receive
path where it should not have been checking for an ACK which our hardware
was sending.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
---

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 1305ef190f..7ad22c5356 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -323,7 +323,17 @@ static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 		 * end of the message, and if so, work out what to do
 		 */
 
+		if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
+			if (iicstat & S3C2410_IICSTAT_LASTBIT) {
+				dev_dbg(i2c->dev, "WRITE: No Ack\n");
+
+				s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
+				goto out_ack;
+			}
+		}
+
 	retry_write:
+
 		if (!is_msgend(i2c)) {
 			byte = i2c->msg->buf[i2c->msg_ptr++];
 			writeb(byte, i2c->regs + S3C2410_IICDS);
@@ -377,17 +387,6 @@ static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 		 * going to do any more read/write
 		 */
 
-		if (!(i2c->msg->flags & I2C_M_IGNORE_NAK) &&
-		    !(is_msglast(i2c) && is_lastmsg(i2c))) {
-
-			if (iicstat & S3C2410_IICSTAT_LASTBIT) {
-				dev_dbg(i2c->dev, "READ: No Ack\n");
-
-				s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
-				goto out_ack;
-			}
-		}
-
 		byte = readb(i2c->regs + S3C2410_IICDS);
 		i2c->msg->buf[i2c->msg_ptr++] = byte;