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Subject[v3 PATCH 4/6] usb: roles: add API to get usb_role_switch by node
Date
Add fwnode_usb_role_switch_get() to make easier to get
usb_role_switch by fwnode which register it.
It's useful when there is not device_connection registered
between two drivers and only knows the fwnode which register
usb_role_switch.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
v3 changes:
1. use fwnodes instead of node suggested by Andy
2. rebuild the API suggested by Heikki

v2 no changes
---
drivers/usb/roles/class.c | 31 +++++++++++++++++++++++++++++++
include/linux/usb/role.h | 2 ++
2 files changed, 33 insertions(+)

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index f45d8df5cfb8..5ecb57f8960b 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -12,6 +12,7 @@
#include <linux/device.h>
#include <linux/module.h>
#include <linux/mutex.h>
+#include <linux/of.h>
#include <linux/slab.h>

static struct class *role_class;
@@ -135,6 +136,36 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev)
}
EXPORT_SYMBOL_GPL(usb_role_switch_get);

+static int __switch_match_fwnode(struct device *dev, const void *fwnode)
+{
+ return dev_fwnode(dev->parent) == (const struct fwnode_handle *)fwnode;
+}
+
+/**
+ * fwnode_usb_role_switch_get - Find USB role switch by it's parent fwnode
+ * @fwnode: The fwnode that register USB role switch
+ *
+ * Finds and returns role switch registered by @fwnode. The reference count
+ * for the found switch is incremented.
+ */
+struct usb_role_switch *
+fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
+{
+ struct usb_role_switch *sw;
+ struct device *dev;
+
+ dev = class_find_device(role_class, NULL, fwnode,
+ __switch_match_fwnode);
+ if (!dev)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ sw = to_role_switch(dev);
+ WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
+
+ return sw;
+}
+EXPORT_SYMBOL_GPL(fwnode_usb_role_switch_get);
+
/**
* usb_role_switch_put - Release handle to a switch
* @sw: USB Role Switch
diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h
index c05ffa6abda9..d21cd55d9e45 100644
--- a/include/linux/usb/role.h
+++ b/include/linux/usb/role.h
@@ -46,6 +46,8 @@ int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role);
enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw);
struct usb_role_switch *usb_role_switch_get(struct device *dev);
void usb_role_switch_put(struct usb_role_switch *sw);
+struct usb_role_switch *
+fwnode_usb_role_switch_get(struct fwnode_handle *fwnode);

struct usb_role_switch *
usb_role_switch_register(struct device *parent,
--
2.20.1
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