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charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-OriginatorOrg: lumal21.com.br X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: CP4P284MB2402.BRAP284.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-Network-Message-Id: 9aaff7d6-a9ce-4b00-b5e9-08dee1c7cc33 X-MS-Exchange-CrossTenant-originalarrivaltime: 14 Jul 2026 16:48:57.2662 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 99055dd4-6575-473d-944c-c3b1a5a6649e X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 1igqYHYVSzyr2hJAwdKJQ9/EJSeMSNXww3RVpmrDlS5ycURczeLPHRSZab42NqMLd7NjY59w8voSxO77B/jf64xnZhgMQBHYuCtxao1ARuU= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CP5P284MB1773 From: Lucas Martins Alves c_can_chip_config() was programming C_CAN_CTRL_REG without CONTROL_INIT, which may allow the controller to become active before c_can_set_bittiming() finishes. That creates a short timing window where the peripheral can interact with t= he bus using a different/default bitrate, potentially generating bus errors and corrupting traffic. Set CONTROL_INIT together with the control-mode writes in c_can_chip_config= () (normal, loopback and listen-only paths), so the controller stays halted un= til bit timing is fully programmed. This prevents transient bus disturbance during startup when the configured bitrate differs from the active bus bitrate. Signed-off-by: Lucas Martins Alves --- drivers/net/can/c_can/c_can_main.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_c= an_main.c index 3702cac7fbf0..32a3975b9d69 100644 --- a/drivers/net/can/c_can/c_can_main.c +++ b/drivers/net/can/c_can/c_can_main.c @@ -597,20 +597,20 @@ static int c_can_chip_config(struct net_device *dev) return err; =20 /* enable automatic retransmission */ - priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR); + priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR | CONTROL_INIT); =20 if ((priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) && (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)) { /* loopback + silent mode : useful for hot self-test */ - priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST); + priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST | CONTROL_INIT); priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK | TEST_SILENT); } else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) { /* loopback mode : useful for self-test function */ - priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST); + priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST | CONTROL_INIT); priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK); } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) { /* silent mode : bus-monitoring mode */ - priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST); + priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST | CONTROL_INIT ); priv->write_reg(priv, C_CAN_TEST_REG, TEST_SILENT); } =20 --=20 2.53.0