[PATCH 13/13] platform: Add platform_find_device_by_driver() helper

[Suzuki K Poulose]

Provide a helper to lookup platform devices by matching device
driver in order to avoid drivers trying to use platform bus
internals.

Cc: Eric Anholt <eric@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Heiko StÃbner" <heiko@xxxxxxxxx>
Cc: Inki Dae <inki.dae@xxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Sandy Huang <hjc@xxxxxxxxxxxxxx>
Cc: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
 drivers/base/platform.c         | 14 ++++++++++++++
 include/linux/platform_device.h |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 4d17298..158ac24 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -1197,6 +1197,20 @@ struct bus_type platform_bus_type = {
 };
 EXPORT_SYMBOL_GPL(platform_bus_type);
 
+/**
+ * platform_find_device_by_driver - Find a platform device with a given
+ * driver.
+ * @start: The device to start the search from.
+ * @drv: The device driver to look for.
+ */
+struct device *platform_find_device_by_driver(struct device *start,
+					      const struct device_driver *drv)
+{
+	return bus_find_device(&platform_bus_type, start, drv,
+			       (void *)platform_match);
+}
+EXPORT_SYMBOL_GPL(platform_find_device_by_driver);
+
 int __init platform_bus_init(void)
 {
 	int error;
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index cc46485..36aa775 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -52,6 +52,9 @@ extern struct device platform_bus;
 extern void arch_setup_pdev_archdata(struct platform_device *);
 extern struct resource *platform_get_resource(struct platform_device *,
 					      unsigned int, unsigned int);
+extern struct device *
+platform_find_device_by_driver(struct device * dev,
+			       const struct device_driver *drv);
 extern void __iomem *
 devm_platform_ioremap_resource(struct platform_device *pdev,
 			       unsigned int index);
-- 
2.7.4