Re: [PATCH v3 5/6] ARM: shmobile: lager: Set clock rates for SDHI

On Tue, 2015-06-30 at 02:29 +0100, Ben Hutchings wrote:

On Tue, 2015-06-30 at 01:02 +0100, Ben Hutchings wrote:

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On Mon, 2015-06-29 at 06:23 +0000, Kuninori Morimoto wrote:

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If so, why we can't use max-frequency ?
We can calculate/set SDHI IP clocks via 
max-frequency / clk_round_rate() / clk_set_rate()
since we know SDHI's divider capability.

SH-MMC is using this style. and I think it is flexible for every speed.
Please check sh_mmcif_clock_control(), sh_mmcif_clk_setup()
on ${LINUX}/drivers/mmc/host/sh_mmcif.c

That's certainly a nicer way of doing this.  The difficulty I see is
that tmio_mmc doesn't know anything about the input clock, and not all
of the drivers using it actually use the clock framework.

More importantly, that algrithm can result in overclocking the card.

...and some of the multiplications overflow!

Ben.