Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Vincent Mailhol <mailhol.vincent@wanadoo.fr>
To:     Marc Kleine-Budde <mkl@pengutronix.de>, linux-can@vger.kernel.org,
        Lukas Magel <lukas.magel@escrypt.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Subject: [PATCH v1] can: etas_es58x: es58x_init_netdev: populate net_device::dev_port
Date:   Wed, 27 Oct 2021 03:05:53 +0900
Message-Id: <20211026180553.1953189-1-mailhol.vincent@wanadoo.fr>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The field dev_port of struct net_device indicates the port number of a
network device [1]. This patch populates this field.

This field can be helpful to distinguish between the two network
interfaces of a dual channel device (i.e. ES581.4 or ES582.1). Indeed,
at the moment, all the network interfaces of a same device share the
same static udev attributes c.f. output of:

| udevadm info --attribute-walk /sys/class/net/canX

The dev_port attribute can then be used to write some udev rules to,
for example, assign a permanent name to each network interface based
on the serial/dev_port pair (which is convenient when you have a test
bench with several CAN devices connected simultaneously and wish to
keep consistent interface names upon reboot).

[1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-net

Suggested-by: Lukas Magel <lukas.magel@escrypt.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
 drivers/net/can/usb/etas_es58x/es58x_core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
index 96a13c770e4a..403de7e9d084 100644
--- a/drivers/net/can/usb/etas_es58x/es58x_core.c
+++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
@@ -2096,6 +2096,7 @@ static int es58x_init_netdev(struct es58x_device *es58x_dev, int channel_idx)
 
 	netdev->netdev_ops = &es58x_netdev_ops;
 	netdev->flags |= IFF_ECHO;	/* We support local echo */
+	netdev->dev_port = channel_idx;
 
 	ret = register_candev(netdev);
 	if (ret)
-- 
2.32.0