[RFC PATCH 09/13] can: slcan: send the close command to the adapter

From: Dario Binacchi <dario.binacchi@amarulasolutions.com>
To: linux-kernel@vger.kernel.org
Cc: Amarula patchwork <linux-amarula@amarulasolutions.com>,
	michael@amarulasolutions.com,
	Dario Binacchi <dario.binacchi@amarulasolutions.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	Paolo Abeni <pabeni@redhat.com>,
	Wolfgang Grandegger <wg@grandegger.com>,
	linux-can@vger.kernel.org, netdev@vger.kernel.org
Subject: [RFC PATCH 09/13] can: slcan: send the close command to the adapter
Date: Tue,  7 Jun 2022 11:47:48 +0200	[thread overview]
Message-ID: <20220607094752.1029295-10-dario.binacchi@amarulasolutions.com> (raw)
In-Reply-To: <20220607094752.1029295-1-dario.binacchi@amarulasolutions.com>

In case the bitrate has been set via ip tool, it sends the close command
("C\r") to the adapter.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

 drivers/net/can/slcan.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
index f18097c62222..d63d270d21da 100644
--- a/drivers/net/can/slcan.c
+++ b/drivers/net/can/slcan.c
@@ -438,9 +438,20 @@ static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd)
 static int slc_close(struct net_device *dev)
 {
 	struct slcan *sl = netdev_priv(dev);
+	int err;
 
 	spin_lock_bh(&sl->lock);
 	if (sl->tty) {
+		if (sl->can.bittiming.bitrate &&
+		    sl->can.bittiming.bitrate != -1) {
+			spin_unlock_bh(&sl->lock);
+			err = slcan_transmit_cmd(sl, "C\r");
+			spin_lock_bh(&sl->lock);
+			if (err)
+				netdev_warn(dev,
+					    "failed to send close command 'C\\r'\n");
+		}
+
 		/* TTY discipline is running. */
 		clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 	}
-- 
2.32.0

