linux-kernel - [050/103] i2c-pca: Fix waitforcompletion() return value

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Message-Id: <20101022185231.835057682@clark.site>
Date:	Fri, 22 Oct 2010 11:51:24 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Yegor Yefremov <yegorslists@...glemail.com>,
	Jean Delvare <khali@...ux-fr.org>
Subject: [050/103] i2c-pca: Fix waitforcompletion() return value

2.6.35-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Yegor Yefremov <yegor_sub1@...ionsystems.de>

commit 6abb930af064fb1cf4177d32e2c7bfb89eee0fe5 upstream.

ret is still -1, if during the polling read_byte() returns at once
with I2C_PCA_CON_SI set. So ret > 0 would lead *_waitforcompletion()
to return 0, in spite of the proper behavior.

The routine was rewritten, so that ret has always a proper value,
before returning.

Signed-off-by: Yegor Yefremov <yegorslists@...glemail.com>
Reviewed-by: Wolfram Sang <w.sang@...gutronix.de>
Signed-off-by: Jean Delvare <khali@...ux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/i2c/busses/i2c-pca-isa.c      |   12 ++++++++----
 drivers/i2c/busses/i2c-pca-platform.c |   11 +++++++----
 2 files changed, 15 insertions(+), 8 deletions(-)

--- a/drivers/i2c/busses/i2c-pca-isa.c
+++ b/drivers/i2c/busses/i2c-pca-isa.c
@@ -71,8 +71,8 @@ static int pca_isa_readbyte(void *pd, in
 
 static int pca_isa_waitforcompletion(void *pd)
 {
-	long ret = ~0;
 	unsigned long timeout;
+	long ret;
 
 	if (irq > -1) {
 		ret = wait_event_timeout(pca_wait,
@@ -81,11 +81,15 @@ static int pca_isa_waitforcompletion(voi
 	} else {
 		/* Do polling */
 		timeout = jiffies + pca_isa_ops.timeout;
-		while (((pca_isa_readbyte(pd, I2C_PCA_CON)
-				& I2C_PCA_CON_SI) == 0)
-				&& (ret = time_before(jiffies, timeout)))
+		do {
+			ret = time_before(jiffies, timeout);
+			if (pca_isa_readbyte(pd, I2C_PCA_CON)
+					& I2C_PCA_CON_SI)
+				break;
 			udelay(100);
+		} while (ret);
 	}
+
 	return ret > 0;
 }
 
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@@ -80,8 +80,8 @@ static void i2c_pca_pf_writebyte32(void
 static int i2c_pca_pf_waitforcompletion(void *pd)
 {
 	struct i2c_pca_pf_data *i2c = pd;
-	long ret = ~0;
 	unsigned long timeout;
+	long ret;
 
 	if (i2c->irq) {
 		ret = wait_event_timeout(i2c->wait,
@@ -90,10 +90,13 @@ static int i2c_pca_pf_waitforcompletion(
 	} else {
 		/* Do polling */
 		timeout = jiffies + i2c->adap.timeout;
-		while (((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
-				& I2C_PCA_CON_SI) == 0)
-				&& (ret = time_before(jiffies, timeout)))
+		do {
+			ret = time_before(jiffies, timeout);
+			if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
+					& I2C_PCA_CON_SI)
+				break;
 			udelay(100);
+		} while (ret);
 	}
 
 	return ret > 0;


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