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-rw-r--r--doc/README.drivers.eth21
1 files changed, 13 insertions, 8 deletions
diff --git a/doc/README.drivers.eth b/doc/README.drivers.eth
index 7f2190998a..e06d3ad44b 100644
--- a/doc/README.drivers.eth
+++ b/doc/README.drivers.eth
@@ -25,9 +25,9 @@ system handling, but ultimately they will call the driver-specific register
function which in turn takes care of initializing that particular instance.
Keep in mind that you should code the driver to avoid storing state in global
-data as someone might want to hook up two of the same devices to one board. If
-the state is maintained as global data, it makes using both of those devices
-impossible.
+data as someone might want to hook up two of the same devices to one board.
+Any such information that is specific to an interface should be stored in a
+private, driver-defined data structure and pointed to by eth->priv (see below).
So the call graph at this stage would look something like:
board_init()
@@ -77,15 +77,20 @@ int ape_register(bd_t *bis, int iobase)
miiphy_register(dev->name, ape_mii_read, ape_mii_write);
#endif
- return 0;
+ return 1;
}
The exact arguments needed to initialize your device are up to you. If you
need to pass more/less arguments, that's fine. You should also add the
-prototype for your new register function to include/netdev.h. You might notice
-that many drivers seem to use xxx_initialize() rather than xxx_register().
-This is the old naming convention and should be avoided as it causes confusion
-with the driver-specific init function.
+prototype for your new register function to include/netdev.h.
+
+The return value for this function should be as follows:
+< 0 - failure (hardware failure, not probe failure)
+>=0 - number of interfaces detected
+
+You might notice that many drivers seem to use xxx_initialize() rather than
+xxx_register(). This is the old naming convention and should be avoided as it
+causes confusion with the driver-specific init function.
Other than locating the MAC address in dedicated hardware storage, you should
not touch the hardware in anyway. That step is handled in the driver-specific