ahci-platform: Add support for devices with more then 1 clock

The allwinner-sun4i AHCI controller needs 2 clocks to be enabled and the
imx AHCI controller needs 3 clocks to be enabled.

tj: Minor comment formatting updates.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

4 files changed, 93 insertions, 28 deletions

diff --git a/Documentation/devicetree/bindings/ata/ahci-platform.txt b/Documentation/devicetree/bindings/ata/ahci-platform.txt
index 89de1564950c..3ced07dc8f56 100644
--- a/Documentation/devicetree/bindings/ata/ahci-platform.txt
+++ b/Documentation/devicetree/bindings/ata/ahci-platform.txt
@@ -10,6 +10,7 @@ Required properties:
 
 Optional properties:
 - dma-coherent      : Present if dma operations are coherent
+- clocks            : a list of phandle + clock specifier pairs
 
 Example:
         sata@ffe08000 {
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 64d1a99de5e4..c12862bd48ee 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -51,6 +51,7 @@
 
 enum {
         AHCI_MAX_PORTS          = 32,
+        AHCI_MAX_CLKS           = 3,
         AHCI_MAX_SG             = 168, /* hardware max is 64K */
         AHCI_DMA_BOUNDARY       = 0xffffffff,
         AHCI_MAX_CMDS           = 32,
@@ -321,7 +322,7 @@ 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 */
+        struct clk              *clks[AHCI_MAX_CLKS]; /* Optional */
         void                    *plat_data;     /* Other platform data */
         /*
          * Optional ahci_start_engine override, if not set this gets set to the
diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index 9302d8143393..8d5a9a7ce958 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -86,6 +86,60 @@ static struct scsi_host_template ahci_platform_sht = {
         AHCI_SHT("ahci_platform"),
 };
 
+/**
+ * ahci_platform_enable_clks - Enable platform clocks
+ * @hpriv: host private area to store config values
+ *
+ * This function enables all the clks found in hpriv->clks, starting at
+ * index 0. If any clk fails to enable it disables all the clks already
+ * enabled in reverse order, and then returns an error.
+ *
+ * RETURNS:
+ * 0 on success otherwise a negative error code
+ */
+int ahci_platform_enable_clks(struct ahci_host_priv *hpriv)
+{
+        int c, rc;
+
+        for (c = 0; c < AHCI_MAX_CLKS && hpriv->clks[c]; c++) {
+                rc = clk_prepare_enable(hpriv->clks[c]);
+                if (rc)
+                        goto disable_unprepare_clk;
+        }
+        return 0;
+
+disable_unprepare_clk:
+        while (--c >= 0)
+                clk_disable_unprepare(hpriv->clks[c]);
+        return rc;
+}
+EXPORT_SYMBOL_GPL(ahci_platform_enable_clks);
+
+/**
+ * ahci_platform_disable_clks - Disable platform clocks
+ * @hpriv: host private area to store config values
+ *
+ * This function disables all the clks found in hpriv->clks, in reverse
+ * order of ahci_platform_enable_clks (starting at the end of the array).
+ */
+void ahci_platform_disable_clks(struct ahci_host_priv *hpriv)
+{
+        int c;
+
+        for (c = AHCI_MAX_CLKS - 1; c >= 0; c--)
+                if (hpriv->clks[c])
+                        clk_disable_unprepare(hpriv->clks[c]);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_disable_clks);
+
+static void ahci_put_clks(struct ahci_host_priv *hpriv)
+{
+        int c;
+
+        for (c = 0; c < AHCI_MAX_CLKS && hpriv->clks[c]; c++)
+                clk_put(hpriv->clks[c]);
+}
+
 static int ahci_probe(struct platform_device *pdev)
 {
         struct device *dev = &pdev->dev;
@@ -96,6 +150,7 @@ static int ahci_probe(struct platform_device *pdev)
         struct ahci_host_priv *hpriv;
         struct ata_host *host;
         struct resource *mem;
+        struct clk *clk;
         int irq;
         int n_ports;
         int i;
@@ -130,17 +185,31 @@ static int 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;
+        for (i = 0; i < AHCI_MAX_CLKS; i++) {
+                /*
+                 * For now we must use clk_get(dev, NULL) for the first clock,
+                 * because some platforms (da850, spear13xx) are not yet
+                 * converted to use devicetree for clocks.  For new platforms
+                 * this is equivalent to of_clk_get(dev->of_node, 0).
+                 */
+                if (i == 0)
+                        clk = clk_get(dev, NULL);
+                else
+                        clk = of_clk_get(dev->of_node, i);
+
+                if (IS_ERR(clk)) {
+                        rc = PTR_ERR(clk);
+                        if (rc == -EPROBE_DEFER)
+                                goto free_clk;
+                        break;
                 }
+                hpriv->clks[i] = clk;
         }
 
+        rc = ahci_enable_clks(dev, hpriv);
+        if (rc)
+                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
@@ -221,11 +290,9 @@ pdata_exit:
         if (pdata && pdata->exit)
                 pdata->exit(dev);
 disable_unprepare_clk:
-        if (!IS_ERR(hpriv->clk))
-                clk_disable_unprepare(hpriv->clk);
+        ahci_disable_clks(hpriv);
 free_clk:
-        if (!IS_ERR(hpriv->clk))
-                clk_put(hpriv->clk);
+        ahci_put_clks(hpriv);
         return rc;
 }
 
@@ -238,10 +305,8 @@ static void ahci_host_stop(struct ata_host *host)
         if (pdata && pdata->exit)
                 pdata->exit(dev);
 
-        if (!IS_ERR(hpriv->clk)) {
-                clk_disable_unprepare(hpriv->clk);
-                clk_put(hpriv->clk);
-        }
+        ahci_disable_clks(hpriv);
+        ahci_put_clks(hpriv);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -276,8 +341,7 @@ 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);
+        ahci_disable_clks(hpriv);
 
         return 0;
 }
@@ -289,13 +353,9 @@ static int ahci_resume(struct device *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;
-                }
-        }
+        rc = ahci_enable_clks(dev, hpriv);
+        if (rc)
+                return rc;
 
         if (pdata && pdata->resume) {
                 rc = pdata->resume(dev);
@@ -316,8 +376,7 @@ static int ahci_resume(struct device *dev)
         return 0;
 
 disable_unprepare_clk:
-        if (!IS_ERR(hpriv->clk))
-                clk_disable_unprepare(hpriv->clk);
+        ahci_disable_clks(hpriv);
 
         return rc;
 }
diff --git a/include/linux/ahci_platform.h b/include/linux/ahci_platform.h
index 73a25005d88a..769d06525320 100644
--- a/include/linux/ahci_platform.h
+++ b/include/linux/ahci_platform.h
@@ -19,6 +19,7 @@
 
 struct device;
 struct ata_port_info;
+struct ahci_host_priv;
 
 struct ahci_platform_data {
         int (*init)(struct device *dev, void __iomem *addr);
@@ -30,4 +31,7 @@ struct ahci_platform_data {
         unsigned int mask_port_map;
 };
 
+int ahci_platform_enable_clks(struct ahci_host_priv *hpriv);
+void ahci_platform_disable_clks(struct ahci_host_priv *hpriv);
+
 #endif /* _AHCI_PLATFORM_H */