[U-Boot] [PATCH v4 03/29] dm: core: Allow parents to pass data to children during probe

[Simon Glass]

Buses sometimes want to pass data to their children when they are probed.
For example, a SPI bus may want to tell the slave device about the chip
select it is connected to.

Add a new function to permit the parent data to be supplied to the child.

Signed-off-by: Simon Glass <sjg at chromium.org>
Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki at gmail.com>
---

Changes in v4: None
Changes in v3:
- Add new patch to allow parents to pass data to children during probe

Changes in v2: None

 drivers/core/device.c        |  9 ++++++++-
 include/dm/device-internal.h | 13 +++++++++++++
 include/dm/device.h          |  4 ++++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/core/device.c b/drivers/core/device.c
index 9538874..49faa29 100644
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -232,7 +232,7 @@ static void device_free(struct udevice *dev)
 	}
 }
 
-int device_probe(struct udevice *dev)
+int device_probe_child(struct udevice *dev, void *parent_priv)
 {
 	struct driver *drv;
 	int size = 0;
@@ -282,6 +282,8 @@ int device_probe(struct udevice *dev)
 				ret = -ENOMEM;
 				goto fail;
 			}
+			if (parent_priv)
+				memcpy(dev->parent_priv, parent_priv, size);
 		}
 
 		ret = device_probe(dev->parent);
@@ -335,6 +337,11 @@ fail:
 	return ret;
 }
 
+int device_probe(struct udevice *dev)
+{
+	return device_probe_child(dev, NULL);
+}
+
 int device_remove(struct udevice *dev)
 {
 	struct driver *drv;
diff --git a/include/dm/device-internal.h b/include/dm/device-internal.h
index 7005d03..44cb7ef 100644
--- a/include/dm/device-internal.h
+++ b/include/dm/device-internal.h
@@ -66,6 +66,19 @@ int device_bind_by_name(struct udevice *parent, bool pre_reloc_only,
 int device_probe(struct udevice *dev);
 
 /**
+ * device_probe() - Probe a child device, activating it
+ *
+ * Activate a device so that it is ready for use. All its parents are probed
+ * first. The child is provided with parent data if parent_priv is not NULL.
+ *
+ * @dev: Pointer to device to probe
+ * @parent_priv: Pointer to parent data. If non-NULL then this is provided to
+ * the child.
+ * @return 0 if OK, -ve on error
+ */
+int device_probe_child(struct udevice *dev, void *parent_priv);
+
+/**
  * device_remove() - Remove a device, de-activating it
  *
  * De-activate a device so that it is no longer ready for use. All its
diff --git a/include/dm/device.h b/include/dm/device.h
index 4d277db..c24707e 100644
--- a/include/dm/device.h
+++ b/include/dm/device.h
@@ -133,6 +133,10 @@ struct udevice_id {
  * @per_child_auto_alloc_size: Each device can hold private data owned by
  * its parent. If required this will be automatically allocated if this
  * value is non-zero.
+ * TODO(sjg at chromium.org): I'm considering dropping this, and just having
+ * device_probe_child() pass it in. So far the use case for allocating it
+ * is SPI, but I found that unsatisfactory. Since it is here I will leave it
+ * until things are clearer.
  * @ops: Driver-specific operations. This is typically a list of function
  * pointers defined by the driver, to implement driver functions required by
  * the uclass.
-- 
2.1.0.rc2.206.gedb03e5