spi: pxa2xx: Return error codes from pxa2xx_spi_init_pdata()

For better understanding what's going on on error path,
return distinguished error codes instead of NULL pointer.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200224154556.11627-1-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-pxa2xx.c

@@ -1548,18 +1548,18 @@ pxa2xx_spi_init_pdata(struct platform_device *pdev)
 	else if (pcidev_id)
 		type = (enum pxa_ssp_type)pcidev_id->driver_data;
 	else
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	ssp = &pdata->ssp;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	ssp->mmio_base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(ssp->mmio_base))
-		return NULL;
+		return ERR_CAST(ssp->mmio_base);
 
 	ssp->phys_base = res->start;
 
@@ -1573,11 +1573,11 @@ pxa2xx_spi_init_pdata(struct platform_device *pdev)
 
 	ssp->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(ssp->clk))
-		return NULL;
+		return ERR_CAST(ssp->clk);
 
 	ssp->irq = platform_get_irq(pdev, 0);
 	if (ssp->irq < 0)
-		return NULL;
+		return ERR_PTR(ssp->irq);
 
 	ssp->type = type;
 	ssp->dev = &pdev->dev;
@@ -1634,9 +1634,9 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
 	platform_info = dev_get_platdata(dev);
 	if (!platform_info) {
 		platform_info = pxa2xx_spi_init_pdata(pdev);
-		if (!platform_info) {
+		if (IS_ERR(platform_info)) {
 			dev_err(&pdev->dev, "missing platform data\n");
-			return -ENODEV;
+			return PTR_ERR(platform_info);
 		}
 	}