lib: devres: provide devm_ioremap_resource_wc()

Provide a variant of devm_ioremap_resource() for write-combined ioremap.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20191022084318.22256-4-brgl@bgdev.plSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -316,6 +316,7 @@ IOMAP
   devm_ioremap_nocache()
   devm_ioremap_wc()
   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_iounmap()
   pcim_iomap()

include/linux/device.h

@@ -962,6 +962,8 @@ extern void devm_free_pages(struct device *dev, unsigned long addr);
 
 void __iomem *devm_ioremap_resource(struct device *dev,
 				    const struct resource *res);
+void __iomem *devm_ioremap_resource_wc(struct device *dev,
+				       const struct resource *res);
 
 void __iomem *devm_of_iomap(struct device *dev,
 			    struct device_node *node, int index,

lib/devres.c

@@ -169,6 +169,21 @@ void __iomem *devm_ioremap_resource(struct device *dev,
 }
 EXPORT_SYMBOL(devm_ioremap_resource);
 
+/**
+ * devm_ioremap_resource_wc() - write-combined variant of
+ *				devm_ioremap_resource()
+ * @dev: generic device to handle the resource for
+ * @res: resource to be handled
+ *
+ * Returns a pointer to the remapped memory or an ERR_PTR() encoded error code
+ * on failure. Usage example:
+ */
+void __iomem *devm_ioremap_resource_wc(struct device *dev,
+				       const struct resource *res)
+{
+	return __devm_ioremap_resource(dev, res, DEVM_IOREMAP_WC);
+}
+
 /*
  * devm_of_iomap - Requests a resource and maps the memory mapped IO
  *		   for a given device_node managed by a given device