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 <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
This commit is contained in:
Simon Glass 2017-05-27 11:37:17 -06:00 committed by Jaehoon Chung
parent fc69d47262
commit 9f103b9cb5
3 changed files with 51 additions and 0 deletions

View file

@ -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;

View file

@ -616,4 +616,11 @@ ulong blk_write_devnum(enum if_type if_type, int devnum, lbaint_t start,
*/
int blk_select_hwpart_devnum(enum if_type if_type, int devnum, int hwpart);
/**
* blk_get_from_parent() - obtain a block device by looking up its parent
*
* All devices with
*/
int blk_get_from_parent(struct udevice *parent, struct udevice **devp);
#endif

View file

@ -150,3 +150,21 @@ static int dm_test_blk_devnum(struct unit_test_state *uts)
return 0;
}
DM_TEST(dm_test_blk_devnum, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
/* Test that we can get a block from its parent */
static int dm_test_blk_get_from_parent(struct unit_test_state *uts)
{
struct udevice *dev, *blk;
ut_assertok(uclass_get_device(UCLASS_MMC, 0, &dev));
ut_assertok(blk_get_from_parent(dev, &blk));
ut_assertok(uclass_get_device(UCLASS_I2C, 0, &dev));
ut_asserteq(-ENOTBLK, blk_get_from_parent(dev, &blk));
ut_assertok(uclass_get_device(UCLASS_GPIO, 0, &dev));
ut_asserteq(-ENODEV, blk_get_from_parent(dev, &blk));
return 0;
}
DM_TEST(dm_test_blk_get_from_parent, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);