Add information about return values of xxx_eth_register() in documentation

As discussed on mailing list, <0 indicates failure, >=0 indicates number
of interfaces found.

Also added blurb about private data

Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

diff --git a/doc/README.drivers.eth b/doc/README.drivers.eth
index 7f2190998a629b23cfd075221a4aae6626e9042a..e06d3ad44ba1cfd2128a778de7daa800b325fbea 100644 (file)
--- 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
 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()
 
 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
 
        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
 }
 
 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
 
 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