usb: musb: sunxi: Add support for musb controller in A31 SoC

The A31 SoC uses the same musb controller as found in earlier SoCs, but it
is hooked up slightly different. Its SRAM is private and no longer controlled
through the SRAM controller, and its reset is controlled via a separate
reset controller. This commit adds support for this setup.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/devicetree/bindings/usb/allwinner,sun4i-a10-musb.txt

@@ -2,9 +2,10 @@ Allwinner sun4i A10 musb DRC/OTG controller
 -------------------------------------------
 
 Required properties:
- - compatible      : "allwinner,sun4i-a10-musb"
+ - compatible      : "allwinner,sun4i-a10-musb" or "allwinner,sun6i-a31-musb"
  - reg             : mmio address range of the musb controller
  - clocks          : clock specifier for the musb controller ahb gate clock
+ - reset           : reset specifier for the ahb reset (A31 and newer only)
  - interrupts      : interrupt to which the musb controller is connected
  - interrupt-names : must be "mc"
  - phys            : phy specifier for the otg phy

drivers/usb/musb/sunxi.c

@@ -26,6 +26,7 @@
 #include <linux/of.h>
 #include <linux/phy/phy-sun4i-usb.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/soc/sunxi/sunxi_sram.h>
 #include <linux/usb/musb.h>
 #include <linux/usb/of.h>
@@ -70,6 +71,8 @@
 #define SUNXI_MUSB_FL_HOSTMODE_PEND		2
 #define SUNXI_MUSB_FL_VBUS_ON			3
 #define SUNXI_MUSB_FL_PHY_ON			4
+#define SUNXI_MUSB_FL_HAS_SRAM			5
+#define SUNXI_MUSB_FL_HAS_RESET			6
 
 /* Our read/write methods need access and do not get passed in a musb ref :| */
 static struct musb *sunxi_musb;
@@ -78,6 +81,7 @@ struct sunxi_glue {
 	struct device		*dev;
 	struct platform_device	*musb;
 	struct clk		*clk;
+	struct reset_control	*rst;
 	struct phy		*phy;
 	struct platform_device	*usb_phy;
 	struct usb_phy		*xceiv;
@@ -229,14 +233,22 @@ static int sunxi_musb_init(struct musb *musb)
 	musb->phy = glue->phy;
 	musb->xceiv = glue->xceiv;
 
+	if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags)) {
 		ret = sunxi_sram_claim(musb->controller->parent);
 		if (ret)
 			return ret;
+	}
 
 	ret = clk_prepare_enable(glue->clk);
 	if (ret)
 		goto error_sram_release;
 
+	if (test_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags)) {
+		ret = reset_control_deassert(glue->rst);
+		if (ret)
+			goto error_clk_disable;
+	}
+
 	writeb(SUNXI_MUSB_VEND0_PIO_MODE, musb->mregs + SUNXI_MUSB_VEND0);
 
 	/* Register notifier before calling phy_init() */
@@ -244,7 +256,7 @@ static int sunxi_musb_init(struct musb *musb)
 		ret = extcon_register_notifier(glue->extcon, EXTCON_USB_HOST,
 					       &glue->host_nb);
 		if (ret)
-			goto error_clk_disable;
+			goto error_reset_assert;
 	}
 
 	ret = phy_init(glue->phy);
@@ -273,9 +285,13 @@ static int sunxi_musb_init(struct musb *musb)
 	if (musb->port_mode == MUSB_PORT_MODE_DUAL_ROLE)
 		extcon_unregister_notifier(glue->extcon, EXTCON_USB_HOST,
 					   &glue->host_nb);
+error_reset_assert:
+	if (test_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags))
+		reset_control_assert(glue->rst);
 error_clk_disable:
 	clk_disable_unprepare(glue->clk);
 error_sram_release:
+	if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
 		sunxi_sram_release(musb->controller->parent);
 	return ret;
 }
@@ -296,7 +312,11 @@ static int sunxi_musb_exit(struct musb *musb)
 		extcon_unregister_notifier(glue->extcon, EXTCON_USB_HOST,
 					   &glue->host_nb);
 
+	if (test_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags))
+		reset_control_assert(glue->rst);
+
 	clk_disable_unprepare(glue->clk);
+	if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
 		sunxi_sram_release(musb->controller->parent);
 
 	return 0;
@@ -617,6 +637,12 @@ static int sunxi_musb_probe(struct platform_device *pdev)
 	INIT_WORK(&glue->work, sunxi_musb_work);
 	glue->host_nb.notifier_call = sunxi_musb_host_notifier;
 
+	if (of_device_is_compatible(np, "allwinner,sun4i-a10-musb"))
+		set_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags);
+
+	if (of_device_is_compatible(np, "allwinner,sun6i-a31-musb"))
+		set_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags);
+
 	glue->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(glue->clk)) {
 		dev_err(&pdev->dev, "Error getting clock: %ld\n",
@@ -624,6 +650,17 @@ static int sunxi_musb_probe(struct platform_device *pdev)
 		return PTR_ERR(glue->clk);
 	}
 
+	if (test_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags)) {
+		glue->rst = devm_reset_control_get(&pdev->dev, NULL);
+		if (IS_ERR(glue->rst)) {
+			if (PTR_ERR(glue->rst) == -EPROBE_DEFER)
+				return -EPROBE_DEFER;
+			dev_err(&pdev->dev, "Error getting reset %ld\n",
+				PTR_ERR(glue->rst));
+			return PTR_ERR(glue->rst);
+		}
+	}
+
 	glue->phy = devm_phy_get(&pdev->dev, "usb");
 	if (IS_ERR(glue->phy)) {
 		if (PTR_ERR(glue->phy) == -EPROBE_DEFER)
@@ -685,6 +722,7 @@ static int sunxi_musb_remove(struct platform_device *pdev)
 
 static const struct of_device_id sunxi_musb_match[] = {
 	{ .compatible = "allwinner,sun4i-a10-musb", },
+	{ .compatible = "allwinner,sun6i-a31-musb", },
 	{}
 };