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From: Joakim Zhang <qiangqing.zhang@nxp.com>
To: Marc Kleine-Budde <mkl@pengutronix.de>,
	"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>
Cc: "kernel@pengutronix.de" <kernel@pengutronix.de>
Subject: RE: [PATCH] can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery
Date: Thu, 19 Nov 2020 00:59:15 +0000	[thread overview]
Message-ID: <DB8PR04MB6795CE8D32EB70C084AC07C7E6E00@DB8PR04MB6795.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20201118150148.2664024-1-mkl@pengutronix.de>


> -----Original Message-----
> From: Marc Kleine-Budde <mkl@pengutronix.de>
> Sent: 2020年11月18日 23:02
> To: linux-can@vger.kernel.org
> Cc: Joakim Zhang <qiangqing.zhang@nxp.com>; kernel@pengutronix.de; Marc
> Kleine-Budde <mkl@pengutronix.de>
> Subject: [PATCH] can: flexcan: flexcan_chip_start(): fix erroneous
> flexcan_transceiver_enable() during bus-off recovery
> 
> If the CAN controller goes into bus off, the do_set_mode() callback with
> CAN_MODE_START can be used to recover the controller, which then calls
> flexcan_chip_start(). If configured, this is done automatically by the framework
> or manually by the user.
> 
> In flexcan_chip_start() there is an explicit call to flexcan_transceiver_enable(),
> which does a regulator_enable() on the transceiver regulator. This results in a
> net usage counter increase, as there is no corresponding
> flexcan_transceiver_disable() in the bus off code path.
> This further leads to the transceiver stuck enabled, even if the CAN interface is
> shut down.
> 
> To fix this problem the
> flexcan_transceiver_enable()/flexcan_transceiver_disable() are moved out of
> flexcan_chip_start()/flexcan_chip_stop() into flexcan_open()/flexcan_close().
> 
> Fixes: e955cead0311 ("CAN: Add Flexcan CAN controller driver")
> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Reviewed-by: Joakim Zhang <qiangqing.zhang@nxp.com>

Best Regards,
Joakim Zhang

      reply	other threads:[~2020-11-19  0:59 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-18 15:01 [PATCH] can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery Marc Kleine-Budde
2020-11-19  0:59 ` Joakim Zhang [this message]

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