[U-Boot] [PATCH 1/1] sunxi: mmc: Fix phase delays

[Maxime Ripard]

On Tue, Mar 27, 2018 at 04:57:23PM +0300, Stefan Mavrodiev wrote:
> U-boot driver for sunxi-mmc uses PLL6, unlike linux kernel where
> PLL5 is used, with clock rates respectively 600MHz and 768MHz.
> Thus there are different phase degree steps - 24 for the kernel and
> 30 for u-boot.
> 
> In the kernel driver the phase is set 90 deg for output and 120 for
> sample. Dividing by 30 will result values 3 and 4. Those are the
> values set in the u-boot driver.
> 
> However, the condition defining delays is wrong. MMC core driver
> requests clock of 52MHz, sunxi-driver sets clock of 50MHz, but
> phase is set 30 deg for output and 120 deg for sample.
> 
> Apparently this works for most cards.
> On A20-SOM204-EVB-eMMC there is eMMC card (KLMAG2GEND) which complains
> about it. Maybe there is other boards with similar problem?
> So the fix is to match delays for both u-boot and kernel.
> 
> Signed-off-by: Stefan Mavrodiev <stefan at olimex.com>

Acked-by: Maxime Ripard <maxime.ripard at bootlin.com>

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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