drivers: platform: provide devm_platform_ioremap_resource_wc()

Provide a write-combined variant of devm_platform_ioremap_resource().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20191022084318.22256-5-brgl@bgdev.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/driver-api/driver-model/devres.rst

@@ -318,6 +318,7 @@ IOMAP
   devm_ioremap_resource() : checks resource, requests memory region, ioremaps
   devm_ioremap_resource_wc()
   devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device
+  devm_platform_ioremap_resource_wc()
   devm_iounmap()
   pcim_iomap()
   pcim_iomap_regions()	: do request_region() and iomap() on multiple BARs

drivers/base/platform.c

@@ -60,6 +60,7 @@ struct resource *platform_get_resource(struct platform_device *dev,
 }
 EXPORT_SYMBOL_GPL(platform_get_resource);
 
+#ifdef CONFIG_HAS_IOMEM
 /**
  * devm_platform_ioremap_resource - call devm_ioremap_resource() for a platform
  *				    device
@@ -68,7 +69,6 @@ EXPORT_SYMBOL_GPL(platform_get_resource);
  *        resource management
  * @index: resource index
  */
-#ifdef CONFIG_HAS_IOMEM
 void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev,
 					     unsigned int index)
 {
@@ -78,6 +78,23 @@ void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev,
 	return devm_ioremap_resource(&pdev->dev, res);
 }
 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource);
+
+/**
+ * devm_platform_ioremap_resource_wc - write-combined variant of
+ *                                     devm_platform_ioremap_resource()
+ *
+ * @pdev: platform device to use both for memory resource lookup as well as
+ *        resource management
+ * @index: resource index
+ */
+void __iomem *devm_platform_ioremap_resource_wc(struct platform_device *pdev,
+						unsigned int index)
+{
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, index);
+	return devm_ioremap_resource_wc(&pdev->dev, res);
+}
 #endif /* CONFIG_HAS_IOMEM */
 
 /**

include/linux/platform_device.h

@@ -57,6 +57,9 @@ platform_find_device_by_driver(struct device *start,
 extern void __iomem *
 devm_platform_ioremap_resource(struct platform_device *pdev,
 			       unsigned int index);
+extern void __iomem *
+devm_platform_ioremap_resource_wc(struct platform_device *pdev,
+				  unsigned int index);
 extern int platform_get_irq(struct platform_device *, unsigned int);
 extern int platform_get_irq_optional(struct platform_device *, unsigned int);
 extern int platform_irq_count(struct platform_device *);