[3.13.y.z extended stable] Patch "can: at91_can: add missing prepare and unprepare of the clock" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Thu Oct 9 20:51:41 UTC 2014

This is a note to let you know that I have just added a patch titled

    can: at91_can: add missing prepare and unprepare of the clock

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:


This patch is scheduled to be released in version

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see



>From edd9a499c623569111e6ebdcfdc33dc28a48ef0c Mon Sep 17 00:00:00 2001
From: David Dueck <davidcdueck at googlemail.com>
Date: Wed, 17 Sep 2014 14:26:48 +0200
Subject: can: at91_can: add missing prepare and unprepare of the clock

commit e77980e50bc2850599d4d9c0192b67a9ffd6daac upstream.

In order to make the driver work with the common clock framework, this patch
converts the clk_enable()/clk_disable() to
clk_prepare_enable()/clk_disable_unprepare(). While there, add the missing
error handling.

Signed-off-by: David Dueck <davidcdueck at googlemail.com>
Signed-off-by: Anthony Harivel <anthony.harivel at emtrion.de>
Acked-by: Boris Brezillon <boris.brezillon at free-electrons.com>
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
 drivers/net/can/at91_can.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index cf0f63e..5e76a95 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -1120,7 +1120,9 @@ static int at91_open(struct net_device *dev)
 	struct at91_priv *priv = netdev_priv(dev);
 	int err;

-	clk_enable(priv->clk);
+	err = clk_prepare_enable(priv->clk);
+	if (err)
+		return err;

 	/* check or determine and set bittime */
 	err = open_candev(dev);
@@ -1146,7 +1148,7 @@ static int at91_open(struct net_device *dev)
-	clk_disable(priv->clk);
+	clk_disable_unprepare(priv->clk);

 	return err;
@@ -1163,7 +1165,7 @@ static int at91_close(struct net_device *dev)
 	at91_chip_stop(dev, CAN_STATE_STOPPED);

 	free_irq(dev->irq, dev);
-	clk_disable(priv->clk);
+	clk_disable_unprepare(priv->clk);



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