[PATCH v4] mmc: sdhci at91: add PM support

[Ludovic Desroches]

Add runtime PM support and use runtime_force_suspend|resume() for system
PM.

Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
---

Changes:
- from v3: add error handling of runtime PM
- from v2: cleanup thanks to Ulf feedback
- from v1: take a runtime PM centric approach

 drivers/mmc/host/sdhci-of-at91.c | 72 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
index 06d0b50..81ab9db 100644
--- a/drivers/mmc/host/sdhci-of-at91.c
+++ b/drivers/mmc/host/sdhci-of-at91.c
@@ -21,6 +21,8 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
 
 #include "sdhci-pltfm.h"
 
@@ -51,6 +53,60 @@ static const struct of_device_id sdhci_at91_dt_match[] = {
 	{}
 };
 
+#ifdef CONFIG_PM
+static int sdhci_at91_runtime_suspend(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_at91_priv *priv = pltfm_host->priv;
+	int ret;
+
+	ret = sdhci_runtime_suspend_host(host);
+
+	clk_disable_unprepare(priv->gck);
+	clk_disable_unprepare(priv->hclock);
+	clk_disable_unprepare(priv->mainck);
+
+	return ret;
+}
+
+static int sdhci_at91_runtime_resume(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_at91_priv *priv = pltfm_host->priv;
+	int ret;
+
+	ret = clk_prepare_enable(priv->mainck);
+	if (ret) {
+		dev_err(dev, "can't enable mainck\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(priv->hclock);
+	if (ret) {
+		dev_err(dev, "can't enable hclock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(priv->gck);
+	if (ret) {
+		dev_err(dev, "can't enable gck\n");
+		return ret;
+	}
+
+	return sdhci_runtime_resume_host(host);
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops sdhci_at91_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(sdhci_at91_runtime_suspend,
+			   sdhci_at91_runtime_resume,
+			   NULL)
+};
+
 static int sdhci_at91_probe(struct platform_device *pdev)
 {
 	const struct of_device_id	*match;
@@ -144,12 +200,20 @@ static int sdhci_at91_probe(struct platform_device *pdev)
 
 	sdhci_get_of_property(pdev);
 
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
+	pm_runtime_use_autosuspend(&pdev->dev);
+
 	ret = sdhci_add_host(host);
 	if (ret)
-		goto clocks_disable_unprepare;
+		goto pm_runtime_disable;
 
 	return 0;
 
+pm_runtime_disable:
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
 clocks_disable_unprepare:
 	clk_disable_unprepare(priv->gck);
 	clk_disable_unprepare(priv->mainck);
@@ -165,6 +229,10 @@ static int sdhci_at91_remove(struct platform_device *pdev)
 	struct sdhci_pltfm_host	*pltfm_host = sdhci_priv(host);
 	struct sdhci_at91_priv	*priv = pltfm_host->priv;
 
+	pm_runtime_get_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
 	sdhci_pltfm_unregister(pdev);
 
 	clk_disable_unprepare(priv->gck);
@@ -178,7 +246,7 @@ static struct platform_driver sdhci_at91_driver = {
 	.driver		= {
 		.name	= "sdhci-at91",
 		.of_match_table = sdhci_at91_dt_match,
-		.pm	= SDHCI_PLTFM_PMOPS,
+		.pm	= &sdhci_at91_dev_pm_ops,
 	},
 	.probe		= sdhci_at91_probe,
 	.remove		= sdhci_at91_remove,
-- 
2.5.0

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