On 28 August 2014 04:24, Kuninori Morimoto
<kuninori.morimoto.gx@xxxxxxxxx> wrote:
> From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
>
> This patch ensures that the clock has been stopped before
> it calls tmio_mmc_set_clock().
> The clock settings might be failed without this patch
>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
> ---
> v3 -> v4
>
> - based on latest git://git.linaro.org/people/ulf.hansson/mmc.git#next
>
> drivers/mmc/host/tmio_mmc_pio.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
> index ba45413..7289331 100644
> --- a/drivers/mmc/host/tmio_mmc_pio.c
> +++ b/drivers/mmc/host/tmio_mmc_pio.c
> @@ -924,12 +924,14 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> tmio_mmc_clk_stop(host);
> break;
> case MMC_POWER_UP:
> + tmio_mmc_clk_stop(host);
I don't think this is needed. Let me elaborate on why.
There two scenarios for when you may come down this path.
Either after ->probe() or after a MMC_POWER_OFF has been handled. In
both scenarios, tmio_mmc_clk_stop(host) has already been invoked.
Well, actually in the ->probe() we invoke tmio_mmc_clk_stop() and then
tmio_mmc_reset(), should those maybe be done in reverse order to make
sure the clock is stopped?
> tmio_mmc_set_clock(host, ios->clock);
> tmio_mmc_power_on(host, ios->vdd);
> tmio_mmc_clk_start(host);
> tmio_mmc_set_bus_width(host, ios->bus_width);
> break;
> case MMC_POWER_ON:
> + tmio_mmc_clk_stop(host);
> tmio_mmc_set_clock(host, ios->clock);
> tmio_mmc_clk_start(host);
> tmio_mmc_set_bus_width(host, ios->bus_width);
> @@ -1199,6 +1201,7 @@ int tmio_mmc_host_runtime_resume(struct device *dev)
> tmio_mmc_clk_update(host);
>
> if (host->clk_cache) {
> + tmio_mmc_clk_stop(host);
This should also not be needed.
To get runtime PM resumed, you must first be runtime PM suspended. In
the runtime PM suspend callback we have already invoked
tmio_mmc_set_clock().
Well, again it may depend on if tmio_mmc_reset() should be followed by
a tmio_mmc_clk_stop(), which isn't the case right now.
> tmio_mmc_set_clock(host, host->clk_cache);
> tmio_mmc_clk_start(host);
> }
> --
> 1.7.9.5
>
Finally, another question - somewhat related to clocks but not so much
to this patch.
Shouldn't tmio_mmc_set_clock() when requested rate is 0, actually
invoke tmio_mmc_clk_stop()? How will otherwise the clock be stopped?
Kind regards
Uffe
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