[PATCH net] net: axienet: Handle deferred probe on clock properly

[PATCH net] net: axienet: Handle deferred probe on clock properly

[Robert Hancock]

This driver is set up to use a clock mapping in the device tree if it is
present, but still work without one for backward compatibility. However,
if getting the clock returns -EPROBE_DEFER, then we need to abort and
return that error from our driver initialization so that the probe can
be retried later after the clock is set up.

Move clock initialization to earlier in the process so we do not waste as
much effort if the clock is not yet available. Switch to use
devm_clk_get_optional and abort initialization on any error reported.
Also enable the clock regardless of whether the controller is using an MDIO
bus, as the clock is required in any case.

Fixes: 09a0354cadec267be7f ("net: axienet: Use clock framework to get device clock rate")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
---
 .../net/ethernet/xilinx/xilinx_axienet_main.c | 26 +++++++++----------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 6fea980acf64..b4a0bfce5b76 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -1817,6 +1817,18 @@ static int axienet_probe(struct platform_device *pdev)
 	lp->options = XAE_OPTION_DEFAULTS;
 	lp->rx_bd_num = RX_BD_NUM_DEFAULT;
 	lp->tx_bd_num = TX_BD_NUM_DEFAULT;
+
+	lp->clk = devm_clk_get_optional(&pdev->dev, NULL);
+	if (IS_ERR(lp->clk)) {
+		ret = PTR_ERR(lp->clk);
+		goto free_netdev;
+	}
+	ret = clk_prepare_enable(lp->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to enable clock: %d\n", ret);
+		goto free_netdev;
+	}
+
 	/* Map device registers */
 	ethres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	lp->regs = devm_ioremap_resource(&pdev->dev, ethres);
@@ -1992,20 +2004,6 @@ static int axienet_probe(struct platform_device *pdev)
 
 	lp->phy_node = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
 	if (lp->phy_node) {
-		lp->clk = devm_clk_get(&pdev->dev, NULL);
-		if (IS_ERR(lp->clk)) {
-			dev_warn(&pdev->dev, "Failed to get clock: %ld\n",
-				 PTR_ERR(lp->clk));
-			lp->clk = NULL;
-		} else {
-			ret = clk_prepare_enable(lp->clk);
-			if (ret) {
-				dev_err(&pdev->dev, "Unable to enable clock: %d\n",
-					ret);
-				goto free_netdev;
-			}
-		}
-
 		ret = axienet_mdio_setup(lp);
 		if (ret)
 			dev_warn(&pdev->dev,
-- 
2.27.0

Re: [PATCH net] net: axienet: Handle deferred probe on clock properly

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Fri, 12 Feb 2021 18:17:48 -0600 you wrote:
> This driver is set up to use a clock mapping in the device tree if it is
> present, but still work without one for backward compatibility. However,
> if getting the clock returns -EPROBE_DEFER, then we need to abort and
> return that error from our driver initialization so that the probe can
> be retried later after the clock is set up.
> 
> Move clock initialization to earlier in the process so we do not waste as
> much effort if the clock is not yet available. Switch to use
> devm_clk_get_optional and abort initialization on any error reported.
> Also enable the clock regardless of whether the controller is using an MDIO
> bus, as the clock is required in any case.
> 
> [...]

Here is the summary with links:
  - [net] net: axienet: Handle deferred probe on clock properly
    https://git.kernel.org/netdev/net/c/57baf8cc70ea

You are awesome, thank you!
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