[PATCH 4.9 31/50] can: rcar_can: fix suspend/resume

From: Greg Kroah-Hartman
Date: Mon Oct 25 2021 - 15:22:07 EST


From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>

commit f7c05c3987dcfde9a4e8c2d533db013fabebca0d upstream.

If the driver was not opened, rcar_can_suspend() should not call
clk_disable() because the clock was not enabled.

Fixes: fd1159318e55 ("can: add Renesas R-Car CAN driver")
Link: https://lore.kernel.org/all/20210924075556.223685-1-yoshihiro.shimoda.uh@xxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Tested-by: Ayumi Nakamichi <ayumi.nakamichi.kf@xxxxxxxxxxx>
Reviewed-by: Ulrich Hecht <uli+renesas@xxxxxxxx>
Tested-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/can/rcar/rcar_can.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)

--- a/drivers/net/can/rcar/rcar_can.c
+++ b/drivers/net/can/rcar/rcar_can.c
@@ -858,10 +858,12 @@ static int __maybe_unused rcar_can_suspe
struct rcar_can_priv *priv = netdev_priv(ndev);
u16 ctlr;

- if (netif_running(ndev)) {
- netif_stop_queue(ndev);
- netif_device_detach(ndev);
- }
+ if (!netif_running(ndev))
+ return 0;
+
+ netif_stop_queue(ndev);
+ netif_device_detach(ndev);
+
ctlr = readw(&priv->regs->ctlr);
ctlr |= RCAR_CAN_CTLR_CANM_HALT;
writew(ctlr, &priv->regs->ctlr);
@@ -880,6 +882,9 @@ static int __maybe_unused rcar_can_resum
u16 ctlr;
int err;

+ if (!netif_running(ndev))
+ return 0;
+
err = clk_enable(priv->clk);
if (err) {
netdev_err(ndev, "clk_enable() failed, error %d\n", err);
@@ -893,10 +898,9 @@ static int __maybe_unused rcar_can_resum
writew(ctlr, &priv->regs->ctlr);
priv->can.state = CAN_STATE_ERROR_ACTIVE;

- if (netif_running(ndev)) {
- netif_device_attach(ndev);
- netif_start_queue(ndev);
- }
+ netif_device_attach(ndev);
+ netif_start_queue(ndev);
+
return 0;
}