Revert "ata: ahci-platform: add reset control support"

This reverts commit f0f56716.

According to Thierry's view,
https://www.spinics.net/lists/linux-ide/msg55357.html
some hardware-specific drivers already use their own resets,
and the common reset might make a path to occur double controls of resets.

For now, revert the commit that adds reset control support to ahci-platform,
and hold until the solution is confirmed not be affect all hardware-specific
drivers.

Fixes: f0f56716 ("ata: ahci-platform: add reset control support")
Reported-by: Thierry Reding <thierry.reding@gmail.com>
Suggested-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Documentation/devicetree/bindings/ata/ahci-platform.txt

@@ -30,7 +30,6 @@ compatible:
 Optional properties:
 - dma-coherent      : Present if dma operations are coherent
 - clocks            : a list of phandle + clock specifier pairs
-- resets            : a list of phandle + reset specifier pairs
 - target-supply     : regulator for SATA target power
 - phys              : reference to the SATA PHY node
 - phy-names         : must be "sata-phy"

drivers/ata/ahci.h

@@ -350,7 +350,6 @@ struct ahci_host_priv {
 	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 reset_control	*rsts;		/* Optional */
 	struct regulator	**target_pwrs;	/* Optional */
 	/*
 	 * If platform uses PHYs. There is a 1:1 relation between the port number and

drivers/ata/libahci_platform.c

@@ -25,7 +25,6 @@
 #include <linux/phy/phy.h>
 #include <linux/pm_runtime.h>
 #include <linux/of_platform.h>
-#include <linux/reset.h>
 #include "ahci.h"
 
 static void ahci_host_stop(struct ata_host *host);
@@ -196,8 +195,7 @@ EXPORT_SYMBOL_GPL(ahci_platform_disable_regulators);
  * following order:
  * 1) Regulator
  * 2) Clocks (through ahci_platform_enable_clks)
- * 3) Resets
- * 4) Phys
+ * 3) Phys
  *
  * If resource enabling fails at any point the previous enabled resources
  * are disabled in reverse order.
@@ -217,19 +215,12 @@ int ahci_platform_enable_resources(struct ahci_host_priv *hpriv)
 	if (rc)
 		goto disable_regulator;
 
-	rc = reset_control_deassert(hpriv->rsts);
-	if (rc)
-		goto disable_clks;
-
 	rc = ahci_platform_enable_phys(hpriv);
 	if (rc)
-		goto disable_resets;
+		goto disable_clks;
 
 	return 0;
 
-disable_resets:
-	reset_control_assert(hpriv->rsts);
-
 disable_clks:
 	ahci_platform_disable_clks(hpriv);
 
@@ -248,15 +239,12 @@ EXPORT_SYMBOL_GPL(ahci_platform_enable_resources);
  * following order:
  * 1) Phys
  * 2) Clocks (through ahci_platform_disable_clks)
- * 3) Resets
- * 4) Regulator
+ * 3) Regulator
  */
 void ahci_platform_disable_resources(struct ahci_host_priv *hpriv)
 {
 	ahci_platform_disable_phys(hpriv);
 
-	reset_control_assert(hpriv->rsts);
-
 	ahci_platform_disable_clks(hpriv);
 
 	ahci_platform_disable_regulators(hpriv);
@@ -405,12 +393,6 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev)
 		hpriv->clks[i] = clk;
 	}
 
-	hpriv->rsts = devm_reset_control_array_get_optional_shared(dev);
-	if (IS_ERR(hpriv->rsts)) {
-		rc = PTR_ERR(hpriv->rsts);
-		goto err_out;
-	}
-
 	hpriv->nports = child_nodes = of_get_child_count(dev->of_node);
 
 	/*