Re: [PATCH 07/11] spi: spi-sh-msiof: RSCR register may absent

[Simon Horman <horms@xxxxxxxxxxxx>]

On Wed, Feb 12, 2014 at 05:06:41PM +0100, Geert Uytterhoeven wrote:
> Hi Yoshii-san,
> 
> On Sun, Dec 1, 2013 at 7:19 PM,  <takasi-y@xxxxxxxxxxxxx> wrote:
> > On Ape6, Rcar-H2, and Rcar-M2,
> > MSIOF lacks RSCR(Receive Clock Select Register).
> > I guess this is a part of .rx_need_dummy_tx case, and use same flag.
> 
> Are you sure? I'm under the impression MSIOF on APE6 does have RSCR,
> just like on A1, and SH (e.g. 7724).

FWIW, the version of the APE6 documentation that I have access to
indicates that it does have RSCR.

> Given also that:
>   - dummy TX is needed during reception for  APE6, R-Car H2/M2, and
>      (perhaps --- this is not 100% clear to me) A1,
>   - RMDR1[15:0] must be zero on APE6, and R-Car H2/M2.
> 
> there are (at least) 4 different variants of MSIOF:
>   - SH
>   - A1
>   - APE6
>   - R-Car H2 and M2
> 
> And I don't know about SH7372 and SH73A0...
> 
> But we indeed may not need to distinguish between all variants.
> You just use the value of rx_need_dummy_tx as test condition.
> If this works for APE6 and A1, we can add a new platform device name
> "spi_sh_mobile_msiof" instead of adding the rx_need_dummy_tx flag
> to platform data (struct sh_msiof_spi_info).
> This would be in line with the currently defined (but so far unused) DT
> compatible values "renesas,sh-msiof" and "renesas,sh-mobile-msiof".
> 
> What do you think?
> 
> Thanks!
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
> 
> 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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