Re: [PATCH 1/4] dt-bindings: mmc: renesas_sdhi: Add r8a77470 support

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Wolfram,

On Mon, Sep 24, 2018 at 2:26 PM Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote:
> > It seems RZ/G1C has two slighty different types of SD card interfaces:
> >   1. SDHI0 and SDHI2 use SYS-DMAC,
> >   2. SDHI1 can also be used as an MMC interface, and has an internal DMAC.
> >
> > Do we need to distinguish between them using the compatible value, or
> > are there other ways?
>
> Yes, that seems to need an update to our current implementation which is
> per-SoC only. One idea from my side would be to whitelist SYS-DMAC for
> this compatible and then check if dma-properties are present, otherwise
> fall back to internal DMAC?

I'm afraid that won't work, as the "dmas" properties are optional. So you
cannot distinguish between optional properties missing and internal DMA
present.

A dirty hack would be checking the device name for xxxxxxxx.sdhi, like how
whitelisting is implemented in the IPMMU driver.

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



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux