driver core: Add fwnode_to_dev() to look up device from fwnode

It's often useful to look up a device that corresponds to a fwnode. So
add an API to do that irrespective of the bus on which the device has
been added to.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 2db62d9..510fabf 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2198,6 +2198,10 @@ int device_add(struct device *dev)
                                             BUS_NOTIFY_ADD_DEVICE, dev);
 
        kobject_uevent(&dev->kobj, KOBJ_ADD);
+
+       if (dev->fwnode && !dev->fwnode->dev)
+               dev->fwnode->dev = dev;
+
        bus_probe_device(dev);
        if (parent)
                klist_add_tail(&dev->p->knode_parent,
@@ -2342,6 +2346,9 @@ void device_del(struct device *dev)
        kill_device(dev);
        device_unlock(dev);
 
+       if (dev->fwnode && dev->fwnode->dev == dev)
+               dev->fwnode->dev = NULL;
+
        /* Notify clients of device removal.  This call must come
         * before dpm_sysfs_remove().
         */

diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index ababd6b..d8c6d23 100644 (file)
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -17,6 +17,7 @@ struct device;
 struct fwnode_handle {
        struct fwnode_handle *secondary;
        const struct fwnode_operations *ops;
+       struct device *dev;
 };
 
 /**
@@ -123,5 +124,6 @@ struct fwnode_operations {
                if (fwnode_has_op(fwnode, op))                          \
                        (fwnode)->ops->op(fwnode, ## __VA_ARGS__);      \
        } while (false)
+#define get_dev_from_fwnode(fwnode)    get_device((fwnode)->dev)
 
 #endif