mmc: tmio: runtime suspend the controller, where possible

The TMIO MMC controller cannot be powered off to save power, when no
card is plugged in, because then it will not be able to detect a new
card-insertion event. On some implementations, however, it is
possible to switch to using another source to detect card insertion.
This patch adds support for such implementations.

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

2 files changed, 61 insertions, 6 deletions

diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index c6bf726..8260bc2 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/drivers/mmc/host/tmio_mmc.h
@@ -131,4 +131,7 @@ int tmio_mmc_host_resume(struct device *dev);
 #define tmio_mmc_host_resume NULL
 #endif
 
+int tmio_mmc_host_runtime_suspend(struct device *dev);
+int tmio_mmc_host_runtime_resume(struct device *dev);
+
 #endif
diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
index af5d4f6..ad6347b 100644
--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -746,6 +746,7 @@ fail:
 static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
 	struct tmio_mmc_host *host = mmc_priv(mmc);
+	struct tmio_mmc_data *pdata = host->pdata;
 	unsigned long flags;
 
 	spin_lock_irqsave(&host->lock, flags);
@@ -775,13 +776,24 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 	/* Power sequence - OFF -> UP -> ON */
 	if (ios->power_mode == MMC_POWER_UP) {
+		if ((pdata->flags & TMIO_MMC_HAS_COLD_CD) && !pdata->power) {
+			pm_runtime_get_sync(&host->pdev->dev);
+			pdata->power = true;
+		}
 		/* power up SD bus */
 		if (host->set_pwr)
 			host->set_pwr(host->pdev, 1);
 	} else if (ios->power_mode == MMC_POWER_OFF || !ios->clock) {
 		/* power down SD bus */
-		if (ios->power_mode == MMC_POWER_OFF && host->set_pwr)
-			host->set_pwr(host->pdev, 0);
+		if (ios->power_mode == MMC_POWER_OFF) {
+			if (host->set_pwr)
+				host->set_pwr(host->pdev, 0);
+			if ((pdata->flags & TMIO_MMC_HAS_COLD_CD) &&
+			    pdata->power) {
+				pdata->power = false;
+				pm_runtime_put(&host->pdev->dev);
+			}
+		}
 		tmio_mmc_clk_stop(host);
 	} else {
 		/* start bus clock */
@@ -853,6 +865,7 @@ int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host,
 	if (!mmc)
 		return -ENOMEM;
 
+	pdata->dev = &pdev->dev;
 	_host = mmc_priv(mmc);
 	_host->pdata = pdata;
 	_host->mmc = mmc;
@@ -886,6 +899,7 @@ int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host,
 	else
 		mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
 
+	pdata->power = false;
 	pm_runtime_enable(&pdev->dev);
 	ret = pm_runtime_resume(&pdev->dev);
 	if (ret < 0)
@@ -907,7 +921,8 @@ int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host,
 	tmio_mmc_request_dma(_host, pdata);
 
 	/* We have to keep the device powered for its card detection to work */
-	pm_runtime_get_noresume(&pdev->dev);
+	if (!(pdata->flags & TMIO_MMC_HAS_COLD_CD))
+		pm_runtime_get_noresume(&pdev->dev);
 
 	mmc_add_host(mmc);
 
@@ -937,15 +952,25 @@ void tmio_mmc_host_remove(struct tmio_mmc_host *host)
 {
 	struct platform_device *pdev = host->pdev;
 
+	/*
+	 * We don't have to manipulate pdata->power here: if there is a card in
+	 * the slot, the runtime PM is active and our .runtime_resume() will not
+	 * be run. If there is no card in the slot and the platform can suspend
+	 * the controller, the runtime PM is suspended and pdata->power == false,
+	 * so, our .runtime_resume() will not try to detect a card in the slot.
+	 */
+	if (host->pdata->flags & TMIO_MMC_HAS_COLD_CD)
+		pm_runtime_get_sync(&pdev->dev);
+
 	mmc_remove_host(host->mmc);
 	cancel_delayed_work_sync(&host->delayed_reset_work);
 	tmio_mmc_release_dma(host);
-	iounmap(host->ctl);
-	mmc_free_host(host->mmc);
 
-	/* Compensate for pm_runtime_get_sync() in probe() above */
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+
+	iounmap(host->ctl);
+	mmc_free_host(host->mmc);
 }
 EXPORT_SYMBOL(tmio_mmc_host_remove);
 
@@ -970,6 +995,9 @@ int tmio_mmc_host_resume(struct device *dev)
 	struct mmc_host *mmc = dev_get_drvdata(dev);
 	struct tmio_mmc_host *host = mmc_priv(mmc);
 
+	/* The MMC core will perform the complete set up */
+	host->pdata->power = false;
+
 	if (!host->pm_error)
 		pm_runtime_get_sync(dev);
 
@@ -982,4 +1010,28 @@ EXPORT_SYMBOL(tmio_mmc_host_resume);
 
 #endif	/* CONFIG_PM */
 
+int tmio_mmc_host_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+EXPORT_SYMBOL(tmio_mmc_host_runtime_suspend);
+
+int tmio_mmc_host_runtime_resume(struct device *dev)
+{
+	struct mmc_host *mmc = dev_get_drvdata(dev);
+	struct tmio_mmc_host *host = mmc_priv(mmc);
+	struct tmio_mmc_data *pdata = host->pdata;
+
+	tmio_mmc_reset(host);
+
+	if (pdata->power) {
+		/* Only entered after a card-insert interrupt */
+		tmio_mmc_set_ios(mmc, &mmc->ios);
+		mmc_detect_change(mmc, msecs_to_jiffies(100));
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(tmio_mmc_host_runtime_resume);
+
 MODULE_LICENSE("GPL v2");