platform: Add platform_find_device_by_driver() helper

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 <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Heiko Stübner" <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Sandy Huang <[email protected]>
Cc: Seung-Woo Kim <[email protected]>
Tested-by: Heiko Stuebner <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 506a0175a5a7..a174ce5ea17c 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;