can: m_can: Map WoL to device_set_wakeup_enable

In some devices the pins of the m_can module can act as a wakeup source.
This patch helps do that by connecting the PHY_WAKE WoL option to
device_set_wakeup_enable. By marking this device as being wakeup
enabled, this setting can be used by platform code to decide which
sleep or poweroff mode to use.

Also this prepares the driver for the next patch in which the pinctrl
settings are changed depending on the desired wakeup source.

Reviewed-by: Vincent Mailhol <[e-mail]>
Reviewed-by: Kendall Willis <[e-mail]>
Signed-off-by: Markus Schneider-Pargmann (TI.com) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Marc Kleine-Budde <[e-mail]>

drivers/net/can/m_can/m_can.c

···
 	return 0;
 }
 
+static void m_can_get_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
+{
+	struct m_can_classdev *cdev = netdev_priv(dev);
+
+	wol->supported = device_can_wakeup(cdev->dev) ? WAKE_PHY : 0;
+	wol->wolopts = device_may_wakeup(cdev->dev) ? WAKE_PHY : 0;
+}
+
+static int m_can_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
+{
+	struct m_can_classdev *cdev = netdev_priv(dev);
+	bool wol_enable = !!(wol->wolopts & WAKE_PHY);
+	int ret;
+
+	if (wol->wolopts & ~WAKE_PHY)
+		return -EINVAL;
+
+	if (wol_enable == device_may_wakeup(cdev->dev))
+		return 0;
+
+	ret = device_set_wakeup_enable(cdev->dev, wol_enable);
+	if (ret) {
+		netdev_err(cdev->net, "Failed to set wakeup enable %pE\n",
+			   ERR_PTR(ret));
+		return ret;
+	}
+
+	return 0;
+}
+
 static const struct ethtool_ops m_can_ethtool_ops_coalescing = {
 	.supported_coalesce_params = ETHTOOL_COALESCE_RX_USECS_IRQ |
 		ETHTOOL_COALESCE_RX_MAX_FRAMES_IRQ |
···
 	.get_ts_info = ethtool_op_get_ts_info,
 	.get_coalesce = m_can_get_coalesce,
 	.set_coalesce = m_can_set_coalesce,
+	.get_wol = m_can_get_wol,
+	.set_wol = m_can_set_wol,
 };
 
 static const struct ethtool_ops m_can_ethtool_ops = {
 	.get_ts_info = ethtool_op_get_ts_info,
+	.get_wol = m_can_get_wol,
+	.set_wol = m_can_set_wol,
 };
 
 static int register_m_can_dev(struct m_can_classdev *cdev)
···
 		dev_err(dev, "Could not get Message RAM configuration.");
 		goto out;
 	}
+
+	if (dev->of_node && of_property_read_bool(dev->of_node, "wakeup-source"))
+		device_set_wakeup_capable(dev, true);
 
 	/* Get TX FIFO size
 	 * Defines the total amount of echo buffers for loopback