can: m_can.c: fix setup of CCCR register: clear CCCR NISO bit before checking can...

BugLink: http://bugs.launchpad.net/bugs/1814813
commit 393753b217f05474e714aea36c37501546ed1202 upstream.

Inside m_can_chip_config(), when setting up the new value of the CCCR,
the CCCR_NISO bit is not cleared like the others, CCCR_TEST, CCCR_MON,
CCCR_BRSE and CCCR_FDOE, before checking the can.ctrlmode bits for
CAN_CTRLMODE_FD_NON_ISO.

This way once the controller was configured for CAN_CTRLMODE_FD_NON_ISO,
this mode could never be cleared again.

This fix is only relevant for controllers with version 3.1.x or 3.2.x.
Older versions do not support NISO.

Signed-off-by: Roman Fietze <roman.fietze@telemotive.de>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 5d4e61741476660b925e80a81ca1d41c17587f3b..ca3fa82316c2a9940865c4b7b056f76fd268db55 100644 (file)
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1073,7 +1073,8 @@ static void m_can_chip_config(struct net_device *dev)
 
        } else {
        /* Version 3.1.x or 3.2.x */
-               cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE);
+               cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE |
+                         CCCR_NISO);
 
                /* Only 3.2.x has NISO Bit implemented */
                if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)