[PATCH v2] tty: xilinx_uartps: Correct return value in probe

[Rajan Vaja]

Existing driver checks for alternate clock if devm_clk_get() fails
and returns error code for last clock failure. If xilinx_uartps is
called before clock driver, devm_clk_get() returns -EPROBE_DEFER.
In this case, probe should not check for alternate clock as main
clock is already present in DTS and return -EPROBE_DEFER only.

This patch fixes it by not checking for alternate clock when main
clock get returns -EPROBE_DEFER.

Signed-off-by: Rajan Vaja <rajan.vaja@xxxxxxxxxx>
---
Changes in v2:
  * Handle dynamic port allocation error cases
---
 drivers/tty/serial/xilinx_uartps.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 094f295..f7ae73e 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1547,27 +1547,33 @@ static int cdns_uart_probe(struct platform_device *pdev)
 	}
 
 	cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "pclk");
+	if (PTR_ERR(cdns_uart_data->pclk) == -EPROBE_DEFER) {
+		rc = PTR_ERR(cdns_uart_data->pclk);
+		goto err_out_unregister_driver;
+	}
+
 	if (IS_ERR(cdns_uart_data->pclk)) {
 		cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "aper_clk");
-		if (!IS_ERR(cdns_uart_data->pclk))
-			dev_err(&pdev->dev, "clock name 'aper_clk' is deprecated.\n");
+		if (IS_ERR(cdns_uart_data->pclk)) {
+			rc = PTR_ERR(cdns_uart_data->pclk);
+			goto err_out_unregister_driver;
+		}
+		dev_err(&pdev->dev, "clock name 'aper_clk' is deprecated.\n");
 	}
-	if (IS_ERR(cdns_uart_data->pclk)) {
-		dev_err(&pdev->dev, "pclk clock not found.\n");
-		rc = PTR_ERR(cdns_uart_data->pclk);
+
+	cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "uart_clk");
+	if (PTR_ERR(cdns_uart_data->uartclk) == -EPROBE_DEFER) {
+		rc = PTR_ERR(cdns_uart_data->uartclk);
 		goto err_out_unregister_driver;
 	}
 
-	cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "uart_clk");
 	if (IS_ERR(cdns_uart_data->uartclk)) {
 		cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "ref_clk");
-		if (!IS_ERR(cdns_uart_data->uartclk))
-			dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n");
-	}
-	if (IS_ERR(cdns_uart_data->uartclk)) {
-		dev_err(&pdev->dev, "uart_clk clock not found.\n");
-		rc = PTR_ERR(cdns_uart_data->uartclk);
-		goto err_out_unregister_driver;
+		if (IS_ERR(cdns_uart_data->uartclk)) {
+			rc = PTR_ERR(cdns_uart_data->uartclk);
+			goto err_out_unregister_driver;
+		}
+		dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n");
 	}
 
 	rc = clk_prepare_enable(cdns_uart_data->pclk);
-- 
2.7.4