Re: [spi-devel-general] Re: [PATCH 2.6-git 0/4] SPI core refresh

[Rui S. <rui...@la...>]

On Tue, 2005-12-13 at 15:09 +0300, dmitry pervushin wrote:
> On Mon, 2005-12-12 at 19:01 +0100, Rui Sousa wrote:
> > How do you handle IRQ's generated by a SPI device (e.g ack the
> > interrupt, check if it was the SPI device that generated the
> > interrupt, ...) if you can't read/write on the SPI bus from interrupt
> > context?
> Hmm... what do you mean by "cannot read/write" ? Normally you can
> write/read registers in interrupt context

The registers I want to read are from a SPI device (a SPI slave attached
to a SPI bus). I need to use SPI bus transfers to access them.

> , and then set the
> flag/complete the completion/what else ?

If I read the API correctly reading/writing a byte from the SPI bus
(synchronously) always implies putting the task doing the read to sleep:

int spi_transfer(struct spi_msg *msg, void (*callback) (struct spi_msg
*, int))
{

...
	err = TO_SPI_BUS_DRIVER(bus->driver)->queue(msg);
	wait_for_completion(&msg->sync);
...
}

So, how can I, from an interrupt handler, read/write a couple of bytes
from my SPI device using this API?

> In other words, could you please share the code that causes problems ? 
> 

Rui