From 9f103b9cb5f8de4f196b5ef8f6ddb4749cd732ba Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Sat, 27 May 2017 11:37:17 -0600 Subject: dm: blk: Add a way to obtain a block device from its parent Many devices support a child block device (e.g. MMC, USB). Add a convenient way to get this device given the parent device. Signed-off-by: Simon Glass Reviewed-by: Tom Rini --- drivers/block/blk-uclass.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'drivers/block') diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c index 61456752718..23f131b7ad7 100644 --- a/drivers/block/blk-uclass.c +++ b/drivers/block/blk-uclass.c @@ -453,6 +453,32 @@ int blk_prepare_device(struct udevice *dev) return 0; } +int blk_get_from_parent(struct udevice *parent, struct udevice **devp) +{ + struct udevice *dev; + enum uclass_id id; + int ret; + + device_find_first_child(parent, &dev); + if (!dev) { + debug("%s: No block device found for parent '%s'\n", __func__, + parent->name); + return -ENODEV; + } + id = device_get_uclass_id(dev); + if (id != UCLASS_BLK) { + debug("%s: Incorrect uclass %s for block device '%s'\n", + __func__, uclass_get_name(id), dev->name); + return -ENOTBLK; + } + ret = device_probe(dev); + if (ret) + return ret; + *devp = dev; + + return 0; +} + int blk_find_max_devnum(enum if_type if_type) { struct udevice *dev; -- cgit v1.2.3