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authorSimon Glass <sjg@chromium.org>2014-10-13 23:41:51 -0600
committerSimon Glass <sjg@chromium.org>2014-10-22 10:36:46 -0600
commit547cea19b875ce83cc7c14ae750eca4973dab555 (patch)
treee4d9c7acf5ba6f26ba7a81ad024e4af00fd25756
parentaccd4b19b39bde7398aa8d1a8eeb66f3a14dde5b (diff)
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dm: core: Add a clarifying comment on struct udevice's seq member
The sequence number is unique within the uclass, so state this clearly. Signed-off-by: Simon Glass <sjg@chromium.org> Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
-rw-r--r--doc/driver-model/README.txt4
-rw-r--r--include/dm/device.h3
2 files changed, 5 insertions, 2 deletions
diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt
index c435cdc..8dfcf75 100644
--- a/doc/driver-model/README.txt
+++ b/doc/driver-model/README.txt
@@ -359,7 +359,9 @@ Device Sequence Numbers
U-Boot numbers devices from 0 in many situations, such as in the command
line for I2C and SPI buses, and the device names for serial ports (serial0,
serial1, ...). Driver model supports this numbering and permits devices
-to be locating by their 'sequence'.
+to be locating by their 'sequence'. This numbering unique identifies a
+device in its uclass, so no two devices within a particular uclass can have
+the same sequence number.
Sequence numbers start from 0 but gaps are permitted. For example, a board
may have I2C buses 0, 1, 4, 5 but no 2 or 3. The choice of how devices are
diff --git a/include/dm/device.h b/include/dm/device.h
index 56862d3..9ce95a8 100644
--- a/include/dm/device.h
+++ b/include/dm/device.h
@@ -57,7 +57,8 @@ struct driver_info;
* @sibling_node: Next device in list of all devices
* @flags: Flags for this device DM_FLAG_...
* @req_seq: Requested sequence number for this device (-1 = any)
- * @seq: Allocated sequence number for this device (-1 = none)
+ * @seq: Allocated sequence number for this device (-1 = none). This is set up
+ * when the device is probed and will be unique within the device's uclass.
*/
struct udevice {
struct driver *driver;