PCI: tegra: Print -EPROBE_DEFER error message at debug level

Probe deferral is an expected error condition that will usually be
recovered from. Print such error messages at debug level to make them
available for diagnostic purposes when building with debugging enabled
and hide them otherwise to not spam the kernel log with them.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Vidya Sagar <vidyas@nvidia.com>
Tested-by: Vidya Sagar <vidyas@nvidia.com>

drivers/pci/controller/dwc/pcie-tegra194.c

@@ -1160,17 +1160,31 @@ static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
 	/* Endpoint mode specific DT entries */
 	pcie->pex_rst_gpiod = devm_gpiod_get(pcie->dev, "reset", GPIOD_IN);
 	if (IS_ERR(pcie->pex_rst_gpiod)) {
-		dev_err(pcie->dev, "Failed to get PERST GPIO: %ld\n",
-			PTR_ERR(pcie->pex_rst_gpiod));
-		return PTR_ERR(pcie->pex_rst_gpiod);
+		int err = PTR_ERR(pcie->pex_rst_gpiod);
+		const char *level = KERN_ERR;
+
+		if (err == -EPROBE_DEFER)
+			level = KERN_DEBUG;
+
+		dev_printk(level, pcie->dev,
+			   dev_fmt("Failed to get PERST GPIO: %d\n"),
+			   err);
+		return err;
 	}
 
 	pcie->pex_refclk_sel_gpiod = devm_gpiod_get(pcie->dev,
 						    "nvidia,refclk-select",
 						    GPIOD_OUT_HIGH);
 	if (IS_ERR(pcie->pex_refclk_sel_gpiod)) {
-		dev_info(pcie->dev, "Failed to get REFCLK select GPIOs: %ld\n",
-			 PTR_ERR(pcie->pex_refclk_sel_gpiod));
+		int err = PTR_ERR(pcie->pex_refclk_sel_gpiod);
+		const char *level = KERN_ERR;
+
+		if (err == -EPROBE_DEFER)
+			level = KERN_DEBUG;
+
+		dev_printk(level, pcie->dev,
+			   dev_fmt("Failed to get REFCLK select GPIOs: %d\n"),
+			   err);
 		pcie->pex_refclk_sel_gpiod = NULL;
 	}
 
@@ -2059,13 +2073,27 @@ static int tegra_pcie_dw_probe(struct platform_device *pdev)
 
 	ret = tegra_pcie_dw_parse_dt(pcie);
 	if (ret < 0) {
-		dev_err(dev, "Failed to parse device tree: %d\n", ret);
+		const char *level = KERN_ERR;
+
+		if (ret == -EPROBE_DEFER)
+			level = KERN_DEBUG;
+
+		dev_printk(level, dev,
+			   dev_fmt("Failed to parse device tree: %d\n"),
+			   ret);
 		return ret;
 	}
 
 	ret = tegra_pcie_get_slot_regulators(pcie);
 	if (ret < 0) {
-		dev_err(dev, "Failed to get slot regulators: %d\n", ret);
+		const char *level = KERN_ERR;
+
+		if (ret == -EPROBE_DEFER)
+			level = KERN_DEBUG;
+
+		dev_printk(level, dev,
+			   dev_fmt("Failed to get slot regulators: %d\n"),
+			   ret);
 		return ret;
 	}