Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 13 Aug 2019 08:53:14 +0200 | Subject | Re: [PATCH] i2c/busses: Add i2c-icy for I2C on m68k/Amiga |
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Hi Max,
On Tue, Aug 13, 2019 at 12:21 AM Max Staudt <max@enpas.org> wrote: > On 08/12/2019 11:37 AM, Geert Uytterhoeven wrote: > >> + iowrite8(val, address); > > > > As this is on a Zorro bus, z_writeb()? > > I forgot to ask about this. > > What is the reasoning behind having a separate z_writeb() for Zorro? > As far as I can see in arch/m68k/include/asm this maps 1:1 to a direct memory access, and it prohibits cross-arch code as in i2c-elektor.
write*() and friends are intended for PCI, and thus little endian, while the Zorro bus is big endian. For byte accesses this doesn't matter, obviously.
Note that this predates iowrite*(), which does have *be variants. If you want to add compile-testing to your driver, using iowrite*() is fine.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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