wl1251: add runtime PM support for SDIO

Add runtime PM support, similar to how it's done for wl1271.
This allows to power down the card when the driver is loaded but
network is not in use.

Cc: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Acked-by: Kalle Valo <kvalo@adurom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/wl1251/sdio.c

@@ -26,6 +26,7 @@
 #include <linux/platform_device.h>
 #include <linux/wl12xx.h>
 #include <linux/irq.h>
+#include <linux/pm_runtime.h>
 
 #include "wl1251.h"
 
@@ -173,10 +174,40 @@ static void wl1251_disable_line_irq(struct wl1251 *wl)
 
 static int wl1251_sdio_set_power(struct wl1251 *wl, bool enable)
 {
-	if (wl->set_power)
-		wl->set_power(enable);
+	struct sdio_func *func = wl_to_func(wl);
+	int ret;
 
-	return 0;
+	if (enable) {
+		/*
+		 * Power is controlled by runtime PM, but we still call board
+		 * callback in case it wants to do any additional setup,
+		 * for example enabling clock buffer for the module.
+		 */
+		if (wl->set_power)
+			wl->set_power(true);
+
+		ret = pm_runtime_get_sync(&func->dev);
+		if (ret < 0)
+			goto out;
+
+		sdio_claim_host(func);
+		sdio_enable_func(func);
+		sdio_release_host(func);
+	} else {
+		sdio_claim_host(func);
+		sdio_disable_func(func);
+		sdio_release_host(func);
+
+		ret = pm_runtime_put_sync(&func->dev);
+		if (ret < 0)
+			goto out;
+
+		if (wl->set_power)
+			wl->set_power(false);
+	}
+
+out:
+	return ret;
 }
 
 static struct wl1251_if_operations wl1251_sdio_ops = {
@@ -277,6 +308,10 @@ static int wl1251_sdio_probe(struct sdio_func *func,
 		goto out_free_irq;
 
 	sdio_set_drvdata(func, wl);
+
+	/* Tell PM core that we don't need the card to be powered now */
+	pm_runtime_put_noidle(&func->dev);
+
 	return ret;
 
 out_free_irq:
@@ -298,6 +333,9 @@ static void __devexit wl1251_sdio_remove(struct sdio_func *func)
 	struct wl1251 *wl = sdio_get_drvdata(func);
 	struct wl1251_sdio *wl_sdio = wl->if_priv;
 
+	/* Undo decrement done above in wl1251_probe */
+	pm_runtime_get_noresume(&func->dev);
+
 	if (wl->irq)
 		free_irq(wl->irq, wl);
 	kfree(wl_sdio);
@@ -309,11 +347,31 @@ static void __devexit wl1251_sdio_remove(struct sdio_func *func)
 	sdio_release_host(func);
 }
 
+static int wl1251_suspend(struct device *dev)
+{
+	/*
+	 * Tell MMC/SDIO core it's OK to power down the card
+	 * (if it isn't already), but not to remove it completely.
+	 */
+	return 0;
+}
+
+static int wl1251_resume(struct device *dev)
+{
+	return 0;
+}
+
+static const struct dev_pm_ops wl1251_sdio_pm_ops = {
+	.suspend        = wl1251_suspend,
+	.resume         = wl1251_resume,
+};
+
 static struct sdio_driver wl1251_sdio_driver = {
 	.name		= "wl1251_sdio",
 	.id_table	= wl1251_devices,
 	.probe		= wl1251_sdio_probe,
 	.remove		= __devexit_p(wl1251_sdio_remove),
+	.drv.pm		= &wl1251_sdio_pm_ops,
 };
 
 static int __init wl1251_sdio_init(void)