mmc: sh_mmcif: maximize power saving

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@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

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->card_present) {
+				sh_mmcif_release_dma(host);
+				host->card_present = false;
+			}
+		}
 		if (host->power) {
 			pm_runtime_put(&host->pd->dev);
-				sh_mmcif_release_dma(host);
 			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;