ahci_probe consists of 3 steps:
1) Get resources (get mmio, clks, regulator)
2) Enable resources, handled by ahci_platform_enable_resouces
3) The more or less standard ahci-host controller init sequence

This commit refactors step 1 and 3 into separate functions, so the platform
drivers for AHCI implementations which need a specific order in step 2,
and / or need to do some custom register poking at some time, can re-use
ahci-platform.c code without needing to copy and paste it.

Note that ahci_platform_init_host's prototype takes the 3 non function
members of ahci_platform_data as arguments, the idea is that drivers using
the new exported utility functions will not use ahci_platform_data at all,
and hopefully in the future ahci_platform_data can go away entirely.

Signed-off-by: Hans de Goede <redacted>
---
 drivers/ata/ahci_platform.c   | 195 ++++++++++++++++++++++++++++--------------
 include/linux/ahci_platform.h |  14 +++
 2 files changed, 144 insertions(+), 65 deletions(-)

diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index 6ebbc17..7f3f2ac 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c

@@ -201,64 +201,64 @@ void ahci_platform_disable_resources(struct ahci_host_priv *hpriv)
 }
 EXPORT_SYMBOL_GPL(ahci_platform_disable_resources);
 
-static void ahci_put_clks(struct ahci_host_priv *hpriv)
+static void ahci_platform_put_resources(struct device *dev, void *res)
 {
+	struct ahci_host_priv *hpriv = res;
 	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)
+/**
+ *	ahci_platform_get_resources - Get platform resources
+ *	@pdev: platform device to get resources for
+ *
+ *	This function allocates an ahci_host_priv struct, and gets the
+ *	following resources, storing a reference to them inside the returned
+ *	struct:
+ *
+ *	1) mmio registers (IORESOURCE_MEM 0, mandatory)
+ *	2) regulator for controlling the targets power (optional)
+ *	3) 0 - AHCI_MAX_CLKS clocks, as specified in the devs devicetree node,
+ *	   or for non devicetree enabled platforms a single clock
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	The allocated ahci_host_priv on success, otherwise an ERR_PTR value
+ */
+struct ahci_host_priv *ahci_platform_get_resources(
+	struct platform_device *pdev)

 	}
 
 	hpriv->target_pwr = devm_regulator_get_optional(dev, "target");
 	if (IS_ERR(hpriv->target_pwr)) {
 		rc = PTR_ERR(hpriv->target_pwr);
 		if (rc == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
+			goto err_out;
 		hpriv->target_pwr = NULL;
 	}
 

@@ -277,33 +277,62 @@ static int ahci_probe(struct platform_device *pdev)
 		if (IS_ERR(clk)) {
 			rc = PTR_ERR(clk);
 			if (rc == -EPROBE_DEFER)
-				goto free_clk;
+				goto err_out;
 			break;
 		}
 		hpriv->clks[i] = clk;
 	}
 
-	rc = ahci_platform_enable_resources(hpriv);
-	if (rc)
-		goto free_clk;
+	devres_remove_group(dev, NULL);
+	return hpriv;
 
-	/*
-	 * Some platforms might need to prepare for mmio region access,
-	 * which could be done in the following init call. So, the mmio
-	 * region shouldn't be accessed before init (if provided) has
-	 * returned successfully.
-	 */
-	if (pdata && pdata->init) {
-		rc = pdata->init(dev, hpriv->mmio);
-		if (rc)
-			goto disable_resources;
-	}
+err_out:
+	devres_release_group(dev, NULL);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_get_resources);