[PATCH] serial: 8250_uniphier: Use dev_err_probe() in probe error paths

[Malathi A <malathi.a2000@gmail.com>]

devm_clk_get_enabled() returns -EPROBE_DEFER while the clock provider is
not registered yet, and uniphier_uart_probe() reports that with
dev_err(). Every retry of an intermittently deferred probe therefore
prints "failed to get and enable clock" at error level, which is only
dmesg noise.

Use dev_err_probe() instead: it demotes -EPROBE_DEFER to dev_dbg() and
records the reason for /sys/kernel/debug/devices_deferred. Convert the
other two error messages in probe as well, so the whole function follows
the "return dev_err_probe()" pattern already used by other 8250 drivers
such as 8250_em.c. Those two codes are never -EPROBE_DEFER, so there the
conversion is a readability change only.

Errors other than a deferral are still logged at error level, now with
the error code added by the helper. No functional change otherwise.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Malathi A <malathi.a2000@gmail.com>
---
This is the follow-up cleanup suggested during review of

  [PATCH v2] serial: 8250_uniphier: Use devm_clk_get_enabled()

and it applies on top of that patch: the clock hunk relies on its
context. That fix is not in tty-next as of today, so this one should be
applied after it.

 drivers/tty/serial/8250/8250_uniphier.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c
index 6fffac12277a..7d558b750f83 100644
--- a/drivers/tty/serial/8250/8250_uniphier.c
+++ b/drivers/tty/serial/8250/8250_uniphier.c
@@ -165,10 +165,8 @@ static int uniphier_uart_probe(struct platform_device *pdev)
 	int ret;
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!regs) {
-		dev_err(dev, "failed to get memory resource\n");
-		return -EINVAL;
-	}
+	if (!regs)
+		return dev_err_probe(dev, -EINVAL, "failed to get memory resource\n");
 
 	membase = devm_ioremap(dev, regs->start, resource_size(regs));
 	if (!membase)
@@ -181,10 +179,9 @@ static int uniphier_uart_probe(struct platform_device *pdev)
 	memset(&up, 0, sizeof(up));
 
 	priv->clk = devm_clk_get_enabled(dev, NULL);
-	if (IS_ERR(priv->clk)) {
-		dev_err(dev, "failed to get and enable clock\n");
-		return PTR_ERR(priv->clk);
-	}
+	if (IS_ERR(priv->clk))
+		return dev_err_probe(dev, PTR_ERR(priv->clk),
+				     "failed to get and enable clock\n");
 
 	up.port.uartclk = clk_get_rate(priv->clk);
 
@@ -216,10 +213,9 @@ static int uniphier_uart_probe(struct platform_device *pdev)
 	up.dl_write = uniphier_serial_dl_write;
 
 	ret = serial8250_register_8250_port(&up);
-	if (ret < 0) {
-		dev_err(dev, "failed to register 8250 port\n");
-		return ret;
-	}
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to register 8250 port\n");
+
 	priv->line = ret;
 
 	platform_set_drvdata(pdev, priv);
-- 
2.43.0