When the interface goes down, the CPK should no longer take an active
part in the CAN-bus communication, like sending acks and error frames.
So enable configuration mode in ti_hecc_stop, so the CPK is no longer
active.
When a transceiver switch is present the acks and errors don't make it
to the bus, but disabling the CPK then does prevent oddities, like
ti_hecc_reset failing, since the CPK can become bus-off and starts
counting the 11 bit recessive bits, which seems to block the reset. It
can also cause invalid interrupts and disrupt the CAN-bus, since
transmission can be stopped in the middle of a message, by disabling
the tranceiver while the CPK is sending.
Since the CPK is disabled after normal power on, it is typically only
seen when the interface is restarted.
Signed-off-by: Jeroen Hofstee <jhofstee@xxxxxxxxxxxxxxxxx>
---
drivers/net/can/ti_hecc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index 461c28ab6d66..b82c011ddbec 100644
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -400,6 +400,9 @@ static void ti_hecc_stop(struct net_device *ndev)
{
struct ti_hecc_priv *priv = netdev_priv(ndev);
+ /* Disable the CPK; stop sending, erroring and acking */
+ hecc_set_bit(priv, HECC_CANMC, HECC_CANMC_CCR);
+
/* Disable interrupts and disable mailboxes */
hecc_write(priv, HECC_CANGIM, 0);
hecc_write(priv, HECC_CANMIM, 0);
--
2.17.1
