ata: ahci_platform: runtime resume the device before use

On OMAP platforms the device needs to be runtime resumed before it can
be accessed. The OMAP HWMOD framework takes care of enabling the
module and its resources based on the device's runtime PM state.

In this patch we runtime resume during .probe() and runtime suspend
after .remove().

We also update the runtime PM state during .resume().

CC: Balaji T K <balajitk@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/ahci.h

@@ -324,6 +324,7 @@ struct ahci_host_priv {
 	u32 			em_loc; /* enclosure management location */
 	u32			em_buf_sz;	/* EM buffer size in byte */
 	u32			em_msg_type;	/* EM message type */
+	bool			got_runtime_pm; /* Did we do pm_runtime_get? */
 	struct clk		*clks[AHCI_MAX_CLKS]; /* Optional */
 	struct regulator	*target_pwr;	/* Optional */
 	struct phy		*phy;		/* If platform uses phy */

drivers/ata/ahci_platform.c

@@ -23,6 +23,7 @@
 #include <linux/libata.h>
 #include <linux/ahci_platform.h>
 #include <linux/phy/phy.h>
+#include <linux/pm_runtime.h>
 #include "ahci.h"
 
 static void ahci_host_stop(struct ata_host *host);
@@ -216,6 +217,11 @@ static void ahci_platform_put_resources(struct device *dev, void *res)
 	struct ahci_host_priv *hpriv = res;
 	int c;
 
+	if (hpriv->got_runtime_pm) {
+		pm_runtime_put_sync(dev);
+		pm_runtime_disable(dev);
+	}
+
 	for (c = 0; c < AHCI_MAX_CLKS && hpriv->clks[c]; c++)
 		clk_put(hpriv->clks[c]);
 }
@@ -309,6 +315,10 @@ struct ahci_host_priv *ahci_platform_get_resources(
 		}
 	}
 
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+	hpriv->got_runtime_pm = true;
+
 	devres_remove_group(dev, NULL);
 	return hpriv;
 
@@ -603,6 +613,11 @@ int ahci_platform_resume(struct device *dev)
 	if (rc)
 		goto disable_resources;
 
+	/* We resumed so update PM runtime state */
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
 	return 0;
 
 disable_resources: