Hi Mark!
I have seen your email and I have checked 3.12-rc7:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/linux/spi/spi.h?id=refs/tags/v3.12-rc7
(Assuming this is the latest, but I would say that the version of Linus would
be authoritative)
What I have found is:
int (*prepare_transfer_hardware)(struct spi_master *master);
This one I have mentioned before, but this does prepare the hardware
(spi_master) prior to every time we start after an empty queue,
which does NOT do what I was asking for.
It is useful for starting up clocks and other power-management tasks...
It does not prepare a spi_message once allowing it to get processed faster
on calls to spi_async(...)!
So can you tell me which interface you are talking about that is supposed
to be in the mainline, which would solve my needs?
I would need an interface addition similar in intent to this:
The following would go into struct spi_master:
int (*prepare_message)(struct spi_device *dev,struct spi_message *mesg);
int (*unprepare_message)(struct spi_device *dev,struct spi_message *mesg);
static int spi_message_prepare(struct spi_device *spi, struct spi_message* msg)
{
return (dev->master->prepare_message)?
dev->master->prepare_message(spi,msg):0;
}
static int spi_message_unprepare(struct spi_device *spi, struct
spi_message*msg) {
return (dev->master->unprepare_message)?
dev->master->unprepare_message(spi,msg):0;
}
Plus some additional information in spi_message similar to this:
void *prepared;
struct spi_driver *prepared_for_device;
The second more to avoid "problems" when drivers prepare for one spi-device
and then use it on a different SPI device - mostly to croak about misuse of the
prepared message... If this field is in there, then the "unprepare" call could
even
do without the argument for SPI_device, as it would be already stored in
the message itself...
Thanks,
Martin
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