[RFC PATCH] sdhci: arasan: Add runtime PM support

[naranimanish at gmail.com]

From: Manish Narani <mnarani at xilinx.com>

This patch adds runtime PM support in Arasan SD driver.

Signed-off-by: Manish Narani <mnarani at xilinx.com>
---
 drivers/mmc/host/sdhci-of-arasan.c | 83 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 81 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
index c33a5f7..47196b5 100644
--- a/drivers/mmc/host/sdhci-of-arasan.c
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -23,6 +23,7 @@
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/phy/phy.h>
 #include <linux/regmap.h>
 #include <linux/of.h>
@@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
 			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
 };
 
+#ifdef CONFIG_PM
+/**
+ * sdhci_arasan_runtime_suspend - Suspend method for the driver
+ * @dev:	Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Put the device in a low power state.
+ */
+static int sdhci_arasan_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	ret = sdhci_runtime_suspend_host(host);
+	if (ret)
+		return ret;
+
+	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
+		mmc_retune_needed(host->mmc);
+
+	clk_disable(pltfm_host->clk);
+	clk_disable(sdhci_arasan->clk_ahb);
+
+	return 0;
+}
+
+/**
+ * sdhci_arasan_runtime_resume - Resume method for the driver
+ * @dev:	Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Resume operation after suspend
+ */
+static int sdhci_arasan_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	ret = clk_enable(sdhci_arasan->clk_ahb);
+	if (ret) {
+		dev_err(dev, "Cannot enable AHB clock.\n");
+		return ret;
+	}
+
+	ret = clk_enable(pltfm_host->clk);
+	if (ret) {
+		dev_err(dev, "Cannot enable SD clock.\n");
+		return ret;
+	}
+
+	ret = sdhci_runtime_resume_host(host);
+	if (ret)
+		goto out;
+
+	return 0;
+out:
+	clk_disable(pltfm_host->clk);
+	clk_disable(sdhci_arasan->clk_ahb);
+
+	return ret;
+}
+#endif /* ! CONFIG_PM */
+
 #ifdef CONFIG_PM_SLEEP
 /**
  * sdhci_arasan_suspend - Suspend method for the driver
@@ -443,8 +513,11 @@ static int sdhci_arasan_resume(struct device *dev)
 }
 #endif /* ! CONFIG_PM_SLEEP */
 
-static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend,
-			 sdhci_arasan_resume);
+static const struct dev_pm_ops sdhci_arasan_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sdhci_arasan_suspend, sdhci_arasan_resume)
+	SET_RUNTIME_PM_OPS(sdhci_arasan_runtime_suspend,
+			   sdhci_arasan_runtime_resume, NULL)
+};
 
 static const struct of_device_id sdhci_arasan_of_match[] = {
 	/* SoC-specific compatible strings w/ soc_ctl_map */
@@ -806,6 +879,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_add_host;
 
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_use_autosuspend(&pdev->dev);
+
 	return 0;
 
 err_add_host:
-- 
2.7.4