[PATCH v2] mmc: sunxi: Handle the 'New Timings'

[Mark Rutland]

On Mon, Aug 01, 2016 at 03:10:29PM +0200, Jean-Francois Moine wrote:
> Some MMC devices as mmc2 in the A83T or mmc1 and mmc2 in the H3 have
> a 'New Timings' mode.
> Set this capacity in the DT and use it when possible.

What exactly is this "New Timings" mode?

Why do we wnat to set it? Improved performance, power?

Is it *necessary* to use it?

> Signed-off-by: Jean-Francois Moine <moinejf at free.fr>
> ---
> I don't know if this mode works or is needed at 25MHz.
> ---
>  Documentation/devicetree/bindings/mmc/sunxi-mmc.txt |  1 +
>  drivers/mmc/host/sunxi-mmc.c                        | 21 +++++++++++++++++++--
>  2 files changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt b/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt
> index 4bf41d8..a541bf4 100644
> --- a/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt
> @@ -19,6 +19,7 @@ Optional properties:
>   - reset-names : must contain "ahb"
>   - for cd, bus-width and additional generic mmc parameters
>     please refer to mmc.txt within this directory
> + - allwinner,new-timings: the controller may accept the "New Timings" mode

It's not at all clear to me what this means. This needs a better
description.

Which devices have this? Can we determine this based on compatible
string?

Mark.