Re: [PATCH v2] spi: orion: support armada extended baud rates

Hi Greg,

On Fri, Sep 5, 2014 at 2:36 AM, Greg Ungerer [off-list ref] wrote:

quoted

Are the Orion rates and register bits a subset of the Armada ones?
I.e. does the Armada work with the Orion setup?

The bits used by the orion are a subset (bits 0-4 of the SPI
configuration register) of those used by the armada (bits 0-4 and
6-7).

In practice the defined prescalar values for the orion do give
the same divisor for the same bits set on armada. The extra bits
on the armada let you get to lower SPI baudrates (which is more of
a problem on the armada with its higher core clocks).

OK, so the answer is yes.

quoted

quoted

This change introduces a new device tree compatible device name
"armada-spi". This is used in place of "orion-spi" on the Armada SoC
parts.

quoted

-                               compatible = "marvell,orion-spi";
+                               compatible = "marvell,armada-spi";

If the answer to my above question is yes, you want to keep
"marvell,orion-spi" as a fallback.

Do you mean like this?

  compatible = "marvell,orion-spi", "marvell,armada-spi";

No, the other way around (from most-specific to least-specific):

    compatible = "marvell,armada-spi", "marvell,orion-spi"

So the Armada version is used if available, and the Orion version
is used as a fallback.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org

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when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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