[RFC] Attempt to add fixed link functionality to macb

[RFC] Attempt to add fixed link functionality to macb

[Moritz Fischer]

Hi all,

I'm trying to make the dt 'fixed-link' work with the Zynq's GEM on my board.
The endgoal will be to hook it up to an ethernet switch in the PL (FPGA) logic.

Does the attached patch look halfway reasonable? Note the code is pretty hacky,
and it's not 100% working, so I'm more looking for pointers on obvious mistakes than
for a thorough code review.

Thanks in advance,

    Moritz

Moritz Fischer (1):
  net: macb: Attempt to make fixed link working on macb

 drivers/net/ethernet/cadence/macb.c | 63 ++++++++++++++++++++++++-------------
 drivers/net/ethernet/cadence/macb.h |  1 +
 2 files changed, 43 insertions(+), 21 deletions(-)

-- 
2.7.2

[RFC] net: macb: Attempt to make fixed link working on macb

[Moritz Fischer]

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
---
 drivers/net/ethernet/cadence/macb.c | 63 ++++++++++++++++++++++++-------------
 drivers/net/ethernet/cadence/macb.h |  1 +
 2 files changed, 43 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 50c9410..4a3d45d 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -375,27 +375,37 @@ static int macb_mii_probe(struct net_device *dev)
 	int phy_irq;
 	int ret;
 
-	phydev = phy_find_first(bp->mii_bus);
-	if (!phydev) {
-		netdev_err(dev, "no PHY found\n");
-		return -ENXIO;
-	}
+	if (bp->phy_node) {
+		phydev = of_phy_connect(dev, bp->phy_node,
+					&macb_handle_link_change, 0,
+					bp->phy_interface);
+		if (!phydev)
+			return -ENODEV;
+	} else {
+		phydev = phy_find_first(bp->mii_bus);
+		if (!phydev) {
+			netdev_err(dev, "no PHY found\n");
+			return -ENXIO;
+		}
 
-	pdata = dev_get_platdata(&bp->pdev->dev);
-	if (pdata && gpio_is_valid(pdata->phy_irq_pin)) {
-		ret = devm_gpio_request(&bp->pdev->dev, pdata->phy_irq_pin, "phy int");
-		if (!ret) {
-			phy_irq = gpio_to_irq(pdata->phy_irq_pin);
-			phydev->irq = (phy_irq < 0) ? PHY_POLL : phy_irq;
+		pdata = dev_get_platdata(&bp->pdev->dev);
+		if (pdata && gpio_is_valid(pdata->phy_irq_pin)) {
+			ret = devm_gpio_request(&bp->pdev->dev,
+						pdata->phy_irq_pin, "phy int");
+			if (!ret) {
+				phy_irq = gpio_to_irq(pdata->phy_irq_pin);
+				phydev->irq = (phy_irq < 0)
+					? PHY_POLL : phy_irq;
+			}
 		}
-	}
 
-	/* attach the mac to the phy */
-	ret = phy_connect_direct(dev, phydev, &macb_handle_link_change,
-				 bp->phy_interface);
-	if (ret) {
-		netdev_err(dev, "Could not attach to PHY\n");
-		return ret;
+		/* attach the mac to the phy */
+		ret = phy_connect_direct(dev, phydev, &macb_handle_link_change,
+					 bp->phy_interface);
+		if (ret) {
+			netdev_err(dev, "Could not attach to PHY\n");
+			return ret;
+		}
 	}
 
 	/* mask with MAC supported features */
@@ -2910,14 +2920,21 @@ static int macb_probe(struct platform_device *pdev)
 		macb_get_hwaddr(bp);
 
 	/* Power up the PHY if there is a GPIO reset */
-	phy_node =  of_get_next_available_child(np, NULL);
-	if (phy_node) {
+	phy_node = of_parse_phandle(np, "phy-handle", 0);
+	if (!phy_node && of_phy_is_fixed_link(np)) {
+		err = of_phy_register_fixed_link(np);
+		if (err < 0) {
+			dev_err(&pdev->dev, "broken fixed-link specification");
+			goto failed_phy;
+		}
+		phy_node = of_node_get(np);
+		bp->phy_node = phy_node;
+	} else {
 		int gpio = of_get_named_gpio(phy_node, "reset-gpios", 0);
 		if (gpio_is_valid(gpio))
 			bp->reset_gpio = gpio_to_desc(gpio);
 		gpiod_set_value(bp->reset_gpio, GPIOD_OUT_HIGH);
 	}
-	of_node_put(phy_node);
 
 	err = of_get_phy_mode(np);
 	if (err < 0) {
@@ -2959,6 +2976,9 @@ static int macb_probe(struct platform_device *pdev)
 err_out_unregister_netdev:
 	unregister_netdev(dev);
 
+failed_phy:
+	of_node_put(phy_node);
+
 err_out_free_netdev:
 	free_netdev(dev);
 
@@ -2991,6 +3011,7 @@ static int macb_remove(struct platform_device *pdev)
 		clk_disable_unprepare(bp->tx_clk);
 		clk_disable_unprepare(bp->hclk);
 		clk_disable_unprepare(bp->pclk);
+		of_node_put(bp->phy_node);
 		free_netdev(dev);
 	}
 
diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 0d4ecfc..0373aa47 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -822,6 +822,7 @@ struct macb {
 
 	struct mii_bus		*mii_bus;
 	struct phy_device	*phy_dev;
+	struct device_node	*phy_node;
 	int 			link;
 	int 			speed;
 	int 			duplex;
-- 
2.7.2