can: dev: add transceiver capabilities to xilinx_can

Currently the xilinx_can driver does not support adding a phy like the
"ti,tcan1043" to its devicetree.

This code makes it possible to add such phy, so that the kernel makes
sure that the PHY is in operational state, when the link is set to an
"up" state.

Signed-off-by: Marcel Hellwig <git@cookiesoft.de>
Link: https://lore.kernel.org/r/20230417085204.179268-1-git@cookiesoft.de
[mkl: call phy_power_off() after pm_runtime_put()]
[mkl: remove error message for phy_power_on() failure]
[mkl: update kernel-doc for struct xcan_priv]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
State: upstream (d7588f0)

drivers/net/can/xilinx_can.c

@@ -28,6 +28,7 @@
 #include <linux/types.h>
 #include <linux/can/dev.h>
 #include <linux/can/error.h>
+#include <linux/phy/phy.h>
 #include <linux/pm_runtime.h>
 #include <linux/reset.h>
 
@@ -199,6 +200,7 @@ struct xcan_devtype_data {
  * @bus_clk:			Pointer to struct clk
  * @can_clk:			Pointer to struct clk
  * @devtype:			Device type specific constants
+ * @transceiver:		Optional pointer to associated CAN transceiver
  */
 struct xcan_priv {
 	struct can_priv can;
@@ -216,6 +218,7 @@ struct xcan_priv {
 	struct clk *bus_clk;
 	struct clk *can_clk;
 	struct xcan_devtype_data devtype;
+	struct phy *transceiver;
 	struct reset_control *rstc;
 };
 
@@ -1421,6 +1424,10 @@ static int xcan_open(struct net_device *ndev)
 	struct xcan_priv *priv = netdev_priv(ndev);
 	int ret;
 
+	ret = phy_power_on(priv->transceiver);
+	if (ret)
+		return ret;
+
 	ret = pm_runtime_get_sync(priv->dev);
 	if (ret < 0) {
 		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
@@ -1464,6 +1471,7 @@ static int xcan_open(struct net_device *ndev)
 	free_irq(ndev->irq, ndev);
 err:
 	pm_runtime_put(priv->dev);
+	phy_power_off(priv->transceiver);
 
 	return ret;
 }
@@ -1485,6 +1493,7 @@ static int xcan_close(struct net_device *ndev)
 	close_candev(ndev);
 
 	pm_runtime_put(priv->dev);
+	phy_power_off(priv->transceiver);
 
 	return 0;
 }
@@ -1715,6 +1724,7 @@ static int xcan_probe(struct platform_device *pdev)
 {
 	struct net_device *ndev;
 	struct xcan_priv *priv;
+	struct phy *transceiver;
 	const struct of_device_id *of_id;
 	const struct xcan_devtype_data *devtype = &xcan_axi_data;
 	void __iomem *addr;
@@ -1856,6 +1866,14 @@ static int xcan_probe(struct platform_device *pdev)
 		goto err_reset;
 	}
 
+	transceiver = devm_phy_optional_get(&pdev->dev, NULL);
+	if (IS_ERR(transceiver)) {
+		ret = PTR_ERR(transceiver);
+		dev_err_probe(&pdev->dev, ret, "failed to get phy\n");
+		goto err_reset;
+	}
+	priv->transceiver = transceiver;
+
 	priv->write_reg = xcan_write_reg_le;
 	priv->read_reg = xcan_read_reg_le;
 
@@ -1882,6 +1900,7 @@ static int xcan_probe(struct platform_device *pdev)
 		goto err_disableclks;
 	}
 
+	of_can_transceiver(ndev);
 	pm_runtime_put(&pdev->dev);
 
 	if (priv->devtype.flags & XCAN_FLAG_CANFD_2) {