Hi Chris
This patch has survived multiple runtime PM versions on sh-mobile without
changes, so, it should be good for the mainline. Please, queue for 3.1. We
might, however, eventually decide, that we don't want to be so aggressive
with our power savings;-) and want to add a flag to allow platforms to
sacrifice power and maximise performance. This would be an incremental
patch then.
Thanks
Guennadi
On Thu, 26 May 2011, Guennadi Liakhovetski wrote:
> This patch uses runtime PM to allow the system to power down the MMC
> controller, when the MMC closk is switched off.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> ---
>
> Patches have been submitted earlier for SDHCI to accomplish something
> similar, but they have complicated dependencies upon other different
> subsystems, especially on PCI. MMCIF is easier - it only exists in
> different SoCs, so, this change should also be easier to review, verify
> and test.
>
> drivers/mmc/host/sh_mmcif.c | 27 ++++++++++++++++++---------
> 1 files changed, 18 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
> index 14f8edb..557886b 100644
> --- a/drivers/mmc/host/sh_mmcif.c
> +++ b/drivers/mmc/host/sh_mmcif.c
> @@ -175,6 +175,7 @@ struct sh_mmcif_host {
> enum mmcif_state state;
> spinlock_t lock;
> bool power;
> + bool card_present;
>
> /* DMA support */
> struct dma_chan *chan_rx;
> @@ -877,23 +878,23 @@ static void sh_mmcif_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> spin_unlock_irqrestore(&host->lock, flags);
>
> if (ios->power_mode == MMC_POWER_UP) {
> - if (p->set_pwr)
> - p->set_pwr(host->pd, ios->power_mode);
> - if (!host->power) {
> + if (!host->card_present) {
> /* See if we also get DMA */
> sh_mmcif_request_dma(host, host->pd->dev.platform_data);
> - pm_runtime_get_sync(&host->pd->dev);
> - host->power = true;
> + host->card_present = true;
> }
> } else if (ios->power_mode == MMC_POWER_OFF || !ios->clock) {
> /* clock stop */
> sh_mmcif_clock_control(host, 0);
> if (ios->power_mode == MMC_POWER_OFF) {
> - if (host->power) {
> - pm_runtime_put(&host->pd->dev);
> + if (host->card_present) {
> sh_mmcif_release_dma(host);
> - host->power = false;
> + host->card_present = false;
> }
> + }
> + if (host->power) {
> + pm_runtime_put(&host->pd->dev);
> + host->power = false;
> if (p->down_pwr)
> p->down_pwr(host->pd);
> }
> @@ -901,8 +902,16 @@ static void sh_mmcif_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> return;
> }
>
> - if (ios->clock)
> + if (ios->clock) {
> + if (!host->power) {
> + if (p->set_pwr)
> + p->set_pwr(host->pd, ios->power_mode);
> + pm_runtime_get_sync(&host->pd->dev);
> + host->power = true;
> + sh_mmcif_sync_reset(host);
> + }
> sh_mmcif_clock_control(host, ios->clock);
> + }
>
> host->bus_width = ios->bus_width;
> host->state = STATE_IDLE;
> --
> 1.7.2.5
>
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>
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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