Patch "can: sja1000: clear interrupts on start" has been added to the 4.2-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    can: sja1000: clear interrupts on start

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     can-sja1000-clear-interrupts-on-start.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7cecd9ab80f43972c056dc068338f7bcc407b71c Mon Sep 17 00:00:00 2001
From: Mirza Krak <mirza.krak@hostmobility.com>
Date: Tue, 10 Nov 2015 14:59:34 +0100
Subject: can: sja1000: clear interrupts on start

From: Mirza Krak <mirza.krak@hostmobility.com>

commit 7cecd9ab80f43972c056dc068338f7bcc407b71c upstream.

According to SJA1000 data sheet error-warning (EI) interrupt is not
cleared by setting the controller in to reset-mode.

Then if we have the following case:
- system is suspended (echo mem > /sys/power/state) and SJA1000 is left
  in operating state
- A bus error condition occurs which activates EI interrupt, system is
  still suspended which means EI interrupt will be not be handled nor
  cleared.

If the above two events occur, on resume there is no way to return the
SJA1000 to operating state, except to cycle power to it.

By simply reading the IR register on start we will clear any previous
conditions that could be present.

Signed-off-by: Mirza Krak <mirza.krak@hostmobility.com>
Reported-by: Christian Magnusson <Christian.Magnusson@semcon.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/can/sja1000/sja1000.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -218,6 +218,9 @@ static void sja1000_start(struct net_dev
 	priv->write_reg(priv, SJA1000_RXERR, 0x0);
 	priv->read_reg(priv, SJA1000_ECC);
 
+	/* clear interrupt flags */
+	priv->read_reg(priv, SJA1000_IR);
+
 	/* leave reset mode */
 	set_normal_mode(dev);
 }


Patches currently in stable-queue which might be from mirza.krak@hostmobility.com are

queue-4.2/can-sja1000-clear-interrupts-on-start.patch