Re: [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock

[Maxime Ripard]

On Sat, Feb 02, 2019 at 05:52:09PM +0200, Priit Laes wrote:
> Recent patch of improving MP clock rate calculations by taking
> into account whether adjusting parent rate is allowed, have
> unfortunately broken eMMC support on A20 Olinuxino-Lime2-eMMC
> boards which fail with following error:
> 
> [snip]
> EXT4-fs (mmcblk1p4): INFO: recovery required on readonly filesystem
> EXT4-fs (mmcblk1p4): write access will be enabled during recovery
> sunxi-mmc 1c11000.mmc: data error, sending stop command
> sunxi-mmc 1c11000.mmc: send stop command failed
> [/snip]
> 
> Previously, mmc2 clock was requesting 520MHz and settling at 512MHz
> clock rate with following parents:
> [snip]
> pll-ddr-base        2  2        0   768000000 0     0  50000
>    pll-ddr-other    1  1        0   768000000 0     0  50000
>       mmc2          0  0        0    51200000 0     0  50000
> [/snip]
> 
> Now, after the improvements, requested and settled rate are both
> 520MHz, but as mmc2 clock cannot adjust parent rate, the situation
> ends up like this:
> [snip]
> pll-periph-base     3  3        0  1200000000 0     0  50000
>    pll-periph       6  6        0   600000000 0     0  50000
>       mmc2          3  3        0    50000000 0     0  50000
> [/snip]
> 
> With this patch (allowing mmc2 to set parent rate), we end up with
> working tree with both mmc0 (sd-card) and mmc2 (eMMC) working:
> [snip]
> pll-periph-base     3  3        0   312000000 0     0  50000
>    mbus             1  1        0    78000000 0     0  50000
>    pll-periph-sata  1  1        0    26000000 0     0  50000
>       sata          1  1        0    26000000 0     0  50000
>    pll-periph       5  5        0   156000000 0     0  50000
>       mmc2          0  0        0    52000000 0     0  50000
>       mmc0          0  0        0    39000000 0     0  50000
> [/snip]
> 
> Fixes: 3f790433c3cb ("clk: sunxi-ng: Adjust MP clock parent rate when allowed")
> Signed-off-by: Priit Laes <plaes@xxxxxxxxx>

Applied, thanks!
Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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