Re: How to correctly use spi_slave_tegra

[Federico Vaga <federico.vaga-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

> >> Hi,
> >> 
> >> I'm working on the SPI bus on a Nvidia Tegra 2 system (Toradex Colibri).
> >> I'm using kernel 2.6.32 with toradex and nvidia patches.
> > 
> > Laxman, are you able to help with these questions?
> 
> We have the driver from K2.6.39, K3.1 and K3.4.
> I suggest to use the driver from k2.6.39 rather than K2.3.36 version.

I checked again. I copied the wrong version, I'm on 2.6.36.2. I wrongly 
replaced the 6 with the last 2: sorry :/

> >> As I understand:
> >> - obviously I must configure SPI before master start communication
> >> - speed_hz must be the same of the master
> >> - I must use spi_async (spi_sync can freeze the driver)
> >> - Only messages with single transfer. If the master sends messages with
> >> multiple transfer, I must receive them with a single transfer
> >> - I have two callback. the message->complete from the SPI framework and
> >> the
> >> spi_tegra_register_callback from the spi_slave_tegra
> >> 
> >  From a very very very brief look at ouor android-tegra-nv-3.1 branch,
> > 
> > your understanding sounds at least reasonable even if not correct!
> 
> Yes, the above are correct. The way we wrote the driver is that to
> support the sync and async both.
> When driver configures spi controller and ready for receive data then
> the callback from client is called. This callback is registered through
> spi_tegra_register_callback(). The client code then can inform master in
> this callback to start transfer through some mechanism i.e. gpio

ok

-- 
Federico Vaga