[U-Boot] [PATCH 2/2] sunxi: mmc: Properly setup mod-clk and clock sampling phases

[Ian Campbell]

On Sun, 2014-12-07 at 21:23 +0100, Hans de Goede wrote:
> The sunxi mmc controller has both an internal clock divider, as well as
> the divider in the mod0-clk for the mmc controller.
> 
> The internal divider cannot be used, as it conflicts with the setting of
> clock sampling phases which is done in the mod0-clk, so it must be set to
> 0 (divide by 1).
> 
> For some reason while the kernel has had this correct from day one, the
> u-boot sunxi mmc code has been using a fixed mod0-clk and setting its
> internal divider depending on the desired speed. This is something which
> we've inherited from the original Allwinner u-boot sources, but while this
> has been fixed in Allwinner's own u-boot code at least for the A23 and later
> upstream u-boot was still doing this wrong.
> 
> This commit fixes this, thereby also fixing mmc support not working reliable
> on the A23 (which seems more sensitive to this) and possible also fixes some
> other sunxi mmc issues.
> 
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>

Acked-by: Ian Campbell <ijc at hellion.org.uk>