[En-Nut-Discussion] SPI on Arm7 (EIR) Board

[Harald Kipp]

Hi Jörg,

On 9/7/2011 1:33 PM, Wiegelmann, Jörg wrote:
> With a lot of work I switched to the newest operationsystem direct from the NutOs trunk.

I recommend to use the 4.10 branch. The trunk is currently blocked,
waiting for Ulrich's CM3 update. To make live easier for Ulrich, I
applied all fixes to the 4.10 branch only.

> IMHO this is not sufficient for a proper operation. A mutex has to protect the whole hardware-SPI-Interface. 

Not sure, how I ever tested concurrent access, but I can't see a
problem. There is only one mutex per _bus_ interface. Thus, the mutex
will protect the whole bus, not just a single chip select.

In

 NutEventWait(&node1->node_bus->bus_mutex, tmo);
 NutEventWait(&node2->node_bus->bus_mutex, tmo);

both pointers ->node_bus refer to the same bus and thus, to the same mutex.

Did I overlook something?

Regards,

Harald