Re: [spi-devel-general] [PATCH] TXx9 SPI controller driver

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

On Sat, 23 Jun 2007 09:09:51 -0700, David Brownell <david-b@pacbell.net> wrote:
> > And for mmiowb() issue, I put it just only I was not sure whether
> > gpio_set_value() guarantee I/O barrier.  Now I see i2c-gpio.c, etc. do
> > not have such barriers.  I will remove these barriers and fix platform
> > gpio codes.
> 
> I don't think this is a case where there'd be a benefit to
> allowing non-barriered implementations, and thus requiring
> all portable code to include platform-neutral I/O barriers.
> I don't know that such neutral primitives actually exist...
> 
> I'll update the GPIO docs to make that clear, unless you
> have some strong argument to the contrary.

No contrary argument.  Some guide to writers of GPIO implementations
about the I/O barriers should be appreciated.

---
Atsushi Nemoto