Re: [PATCH v2] net: ethernet: support "fixed-link" DT key/node on nb8800 driver

Sebastian Frias [off-list ref] writes:

On 02/05/2016 02:58 PM, Måns Rullgård wrote:

quoted

Sebastian Frias [off-list ref] writes:

quoted

Signed-off-by: Sebastian Frias <redacted>
---
  drivers/net/ethernet/aurora/nb8800.c | 15 ++++++++++++---
  1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/aurora/nb8800.c

b/drivers/net/ethernet/aurora/nb8800.c
index ecc4a33..dd7bedc 100644

--- a/drivers/net/ethernet/aurora/nb8800.c
+++ b/drivers/net/ethernet/aurora/nb8800.c

@@ -1462,9 +1462,18 @@ static int nb8800_probe(struct platform_device *pdev)

  	priv->phy_node = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
  	if (!priv->phy_node) {
-		dev_err(&pdev->dev, "no PHY specified\n");
-		ret = -ENODEV;
-		goto err_free_bus;
+		if (of_phy_is_fixed_link(pdev->dev.of_node)) {
+			ret = of_phy_register_fixed_link(pdev->dev.of_node);
+			if (ret < 0) {
+				dev_err(&pdev->dev, "bad fixed-link spec\n");
+				goto err_free_bus;
+			}
+			priv->phy_node = of_node_get(pdev->dev.of_node);
+		} else {
+			dev_err(&pdev->dev, "no PHY specified\n");
+			ret = -ENODEV;
+			goto err_free_bus;
+		}
  	}

Maybe it would be clearer to reduce the if() nesting a bit, like this
for instance:

	if (of_phy_is_fixed_link(pdev->dev.of_node)) {
		ret = of_phy_register_fixed_link(pdev->dev.of_node);
		if (ret < 0) {
			dev_err(&pdev->dev, "bad fixed-link spec\n");
			goto err_free_bus;
		}
		priv->phy_node = of_node_get(pdev->dev.of_node);
	}

	if (!priv->phy_node)
		priv->phy_node = of_parse_phandle(pdev->dev.of_node,
						  "phy-handle", 0);

	if (!priv->phy_node) {
		dev_err(&pdev->dev, "no PHY specified\n");
		ret = -ENODEV;
		goto err_free_bus;
	}

Thanks Måns for your comments.
With old code + my patch, we only hit 1 comparison in the general
case, and a 2nd one in "fixed-link" case.
With your suggestion above, it would mean that we hit 3 comparisons
all the time.
If you are ok with the 3 comparisons, I can post a v3.

This is code that runs once so IMO clarity is more important than a
minuscule speed difference.

-- 
Måns Rullgård

Signed-off-by: Sebastian Frias <redacted>
---
  drivers/net/ethernet/aurora/nb8800.c | 14 +++++++++++++-
  1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/aurora/nb8800.c 

b/drivers/net/ethernet/aurora/nb8800.c
index ecc4a33..e1fb071 100644

--- a/drivers/net/ethernet/aurora/nb8800.c
+++ b/drivers/net/ethernet/aurora/nb8800.c

@@ -1460,7 +1460,19 @@ static int nb8800_probe(struct platform_device *pdev)
  		goto err_disable_clk;
  	}

-	priv->phy_node = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
+	if (of_phy_is_fixed_link(pdev->dev.of_node)) {
+		ret = of_phy_register_fixed_link(pdev->dev.of_node);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "bad fixed-link spec\n");
+			goto err_free_bus;
+		}
+		priv->phy_node = of_node_get(pdev->dev.of_node);
+	}
+
+	if (!priv->phy_node)
+		priv->phy_node = of_parse_phandle(pdev->dev.of_node,
+						  "phy-handle", 0);
+
  	if (!priv->phy_node) {
  		dev_err(&pdev->dev, "no PHY specified\n");
  		ret = -ENODEV;

-- 
2.1.4