ata/ahci_platform: Add clock framework support

On many architectures, drivers are supposed to prepare/unprepare &
enable/disable functional clock of device. This patch adds clock support for
ahci_platform.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/ahci.h

@@ -35,6 +35,7 @@
 #ifndef _AHCI_H
 #define _AHCI_H
 
+#include <linux/clk.h>
 #include <linux/libata.h>
 
 /* Enclosure Management Control */
@@ -316,6 +317,7 @@ 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 */
+	struct clk		*clk;		/* Only for platforms supporting clk */
 };
 
 extern int ahci_ignore_sss;

drivers/ata/ahci_platform.c

@@ -12,6 +12,7 @@
  * any later version.
  */
 
+#include <linux/clk.h>
 #include <linux/kernel.h>
 #include <linux/gfp.h>
 #include <linux/module.h>
@@ -118,6 +119,17 @@ static int __init ahci_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
+	hpriv->clk = clk_get(dev, NULL);
+	if (IS_ERR(hpriv->clk)) {
+		dev_err(dev, "can't get clock\n");
+	} else {
+		rc = clk_prepare_enable(hpriv->clk);
+		if (rc) {
+			dev_err(dev, "clock prepare enable failed");
+			goto free_clk;
+		}
+	}
+
 	/*
 	 * Some platforms might need to prepare for mmio region access,
 	 * which could be done in the following init call. So, the mmio
@@ -127,7 +139,7 @@ static int __init ahci_probe(struct platform_device *pdev)
 	if (pdata && pdata->init) {
 		rc = pdata->init(dev, hpriv->mmio);
 		if (rc)
-			return rc;
+			goto disable_unprepare_clk;
 	}
 
 	ahci_save_initial_config(dev, hpriv,
@@ -153,7 +165,7 @@ static int __init ahci_probe(struct platform_device *pdev)
 	host = ata_host_alloc_pinfo(dev, ppi, n_ports);
 	if (!host) {
 		rc = -ENOMEM;
-		goto err0;
+		goto pdata_exit;
 	}
 
 	host->private_data = hpriv;
@@ -183,20 +195,26 @@ static int __init ahci_probe(struct platform_device *pdev)
 
 	rc = ahci_reset_controller(host);
 	if (rc)
-		goto err0;
+		goto pdata_exit;
 
 	ahci_init_controller(host);
 	ahci_print_info(host, "platform");
 
 	rc = ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
 			       &ahci_platform_sht);
 	if (rc)
-		goto err0;
+		goto pdata_exit;
 
 	return 0;
-err0:
+pdata_exit:
 	if (pdata && pdata->exit)
 		pdata->exit(dev);
+disable_unprepare_clk:
+	if (!IS_ERR(hpriv->clk))
+		clk_disable_unprepare(hpriv->clk);
+free_clk:
+	if (!IS_ERR(hpriv->clk))
+		clk_put(hpriv->clk);
 	return rc;
 }
 
@@ -205,12 +223,18 @@ static int __devexit ahci_remove(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct ahci_platform_data *pdata = dev_get_platdata(dev);
 	struct ata_host *host = dev_get_drvdata(dev);
+	struct ahci_host_priv *hpriv = host->private_data;
 
 	ata_host_detach(host);
 
 	if (pdata && pdata->exit)
 		pdata->exit(dev);
 
+	if (!IS_ERR(hpriv->clk)) {
+		clk_disable_unprepare(hpriv->clk);
+		clk_put(hpriv->clk);
+	}
+
 	return 0;
 }
 
@@ -245,32 +269,51 @@ static int ahci_suspend(struct device *dev)
 
 	if (pdata && pdata->suspend)
 		return pdata->suspend(dev);
+
+	if (!IS_ERR(hpriv->clk))
+		clk_disable_unprepare(hpriv->clk);
+
 	return 0;
 }
 
 static int ahci_resume(struct device *dev)
 {
 	struct ahci_platform_data *pdata = dev_get_platdata(dev);
 	struct ata_host *host = dev_get_drvdata(dev);
+	struct ahci_host_priv *hpriv = host->private_data;
 	int rc;
 
+	if (!IS_ERR(hpriv->clk)) {
+		rc = clk_prepare_enable(hpriv->clk);
+		if (rc) {
+			dev_err(dev, "clock prepare enable failed");
+			return rc;
+		}
+	}
+
 	if (pdata && pdata->resume) {
 		rc = pdata->resume(dev);
 		if (rc)
-			return rc;
+			goto disable_unprepare_clk;
 	}
 
 	if (dev->power.power_state.event == PM_EVENT_SUSPEND) {
 		rc = ahci_reset_controller(host);
 		if (rc)
-			return rc;
+			goto disable_unprepare_clk;
 
 		ahci_init_controller(host);
 	}
 
 	ata_host_resume(host);
 
 	return 0;
+
+disable_unprepare_clk:
+	if (!IS_ERR(hpriv->clk))
+		clk_disable_unprepare(hpriv->clk);
+
+	return rc;
 }
 #endif