linux-kernel - [ 021/173] drivers/leds/leds-lp5521.c: fix lp5521

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Message-Id: <20121228190334.425365762@decadent.org.uk>
Date:	Fri, 28 Dec 2012 20:03:51 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Dan Carpenter <dan.carpenter@...cle.com>,
	Milo <Milo.Kim@...com>, Richard Purdie <rpurdie@...ys.net>,
	Bryan Wu <bryan.wu@...onical.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [ 021/173] drivers/leds/leds-lp5521.c: fix lp5521_read() error handling

3.2-stable review patch.  If anyone has any objections, please let me know.

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

From: Dan Carpenter <dan.carpenter@...cle.com>

commit 5bc9ad774c063f6b41965e7314f2c26aa5e465a0 upstream.

Gcc 4.6.2 complains that:

  drivers/leds/leds-lp5521.c: In function `lp5521_load_program':
  drivers/leds/leds-lp5521.c:214:21: warning: `mode' may be used uninitialized in this function [-Wuninitialized]
  drivers/leds/leds-lp5521.c: In function `lp5521_probe':
  drivers/leds/leds-lp5521.c:788:5: warning: `buf' may be used uninitialized in this function [-Wuninitialized]
  drivers/leds/leds-lp5521.c:740:6: warning: `ret' may be used uninitialized in this function [-Wuninitialized]

These are real problems if lp5521_read() returns an error.  When that
happens we should handle it, instead of ignoring it or doing a bitwise
OR with all the other error codes and continuing.

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Cc: Milo <Milo.Kim@...com>
Cc: Richard Purdie <rpurdie@...ys.net>
Cc: Bryan Wu <bryan.wu@...onical.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/leds/leds-lp5521.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/leds/leds-lp5521.c b/drivers/leds/leds-lp5521.c
index 410a723..2381562 100644
--- a/drivers/leds/leds-lp5521.c
+++ b/drivers/leds/leds-lp5521.c
@@ -193,9 +193,14 @@ static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern)
 
 	/* move current engine to direct mode and remember the state */
 	ret = lp5521_set_engine_mode(eng, LP5521_CMD_DIRECT);
+	if (ret)
+		return ret;
+
 	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
 	usleep_range(1000, 2000);
-	ret |= lp5521_read(client, LP5521_REG_OP_MODE, &mode);
+	ret = lp5521_read(client, LP5521_REG_OP_MODE, &mode);
+	if (ret)
+		return ret;
 
 	/* For loading, all the engines to load mode */
 	lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
@@ -211,8 +216,7 @@ static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern)
 				LP5521_PROG_MEM_SIZE,
 				pattern);
 
-	ret |= lp5521_write(client, LP5521_REG_OP_MODE, mode);
-	return ret;
+	return lp5521_write(client, LP5521_REG_OP_MODE, mode);
 }
 
 static int lp5521_set_led_current(struct lp5521_chip *chip, int led, u8 curr)
@@ -785,7 +789,7 @@ static int __devinit lp5521_probe(struct i2c_client *client,
 	 * LP5521_REG_ENABLE register will not have any effect - strange!
 	 */
 	ret = lp5521_read(client, LP5521_REG_R_CURRENT, &buf);
-	if (buf != LP5521_REG_R_CURR_DEFAULT) {
+	if (ret || buf != LP5521_REG_R_CURR_DEFAULT) {
 		dev_err(&client->dev, "error in resetting chip\n");
 		goto fail2;
 	}


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