usb: mtu3: dual-role mode support

support dual-role mode; there are two ways to switch between
host and device modes, one is by idpin, another is by debugfs
which depends on user input.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/mtu3/Kconfig

@@ -2,7 +2,7 @@
 
 config USB_MTU3
 	tristate "MediaTek USB3 Dual Role controller"
-	depends on (USB || USB_GADGET) && HAS_DMA
+	depends on EXTCON && (USB || USB_GADGET) && HAS_DMA
 	depends on ARCH_MEDIATEK || COMPILE_TEST
 	select USB_XHCI_MTK if USB_SUPPORT && USB_XHCI_HCD
 	help
@@ -19,6 +19,7 @@ config USB_MTU3
 if USB_MTU3
 choice
 	bool "MTU3 Mode Selection"
+	default USB_MTU3_DUAL_ROLE if (USB && USB_GADGET)
 	default USB_MTU3_HOST if (USB && !USB_GADGET)
 	default USB_MTU3_GADGET if (!USB && USB_GADGET)
 
@@ -36,6 +37,18 @@ config USB_MTU3_GADGET
 	  Select this when you want to use MTU3 in gadget mode only,
 	  thereby the host feature will be regressed.
 
+config USB_MTU3_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on ((USB=y || USB=USB_MTU3) && (USB_GADGET=y || USB_GADGET=USB_MTU3))
+	help
+	  This is the default mode of working of MTU3 controller where
+	  both host and gadget features are enabled.
+
 endchoice
 
+config USB_MTU3_DEBUG
+	bool "Enable Debugging Messages"
+	help
+	  Say Y here to enable debugging messages in the MTU3 Driver.
+
 endif

drivers/usb/mtu3/Makefile

@@ -1,11 +1,18 @@
+
+ccflags-$(CONFIG_USB_MTU3_DEBUG)	+= -DDEBUG
+
 obj-$(CONFIG_USB_MTU3)	+= mtu3.o
 
 mtu3-y	:= mtu3_plat.o
 
-ifneq ($(filter y,$(CONFIG_USB_MTU3_HOST)),)
+ifneq ($(filter y,$(CONFIG_USB_MTU3_HOST) $(CONFIG_USB_MTU3_DUAL_ROLE)),)
 	mtu3-y	+= mtu3_host.o
 endif
 
-ifneq ($(filter y,$(CONFIG_USB_MTU3_GADGET)),)
+ifneq ($(filter y,$(CONFIG_USB_MTU3_GADGET) $(CONFIG_USB_MTU3_DUAL_ROLE)),)
 	mtu3-y	+= mtu3_core.o mtu3_gadget_ep0.o mtu3_gadget.o mtu3_qmu.o
 endif
+
+ifneq ($(CONFIG_USB_MTU3_DUAL_ROLE),)
+	mtu3-y	+= mtu3_dr.o
+endif

drivers/usb/mtu3/mtu3.h

@@ -21,6 +21,7 @@
 
 #include <linux/device.h>
 #include <linux/dmapool.h>
+#include <linux/extcon.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/phy/phy.h>
@@ -172,15 +173,44 @@ struct mtu3_gpd_ring {
 	struct qmu_gpd *enqueue;
 	struct qmu_gpd *dequeue;
 };
+
+/**
+* @vbus: vbus 5V used by host mode
+* @edev: external connector used to detect vbus and iddig changes
+* @vbus_nb: notifier for vbus detection
+* @vbus_nb: notifier for iddig(idpin) detection
+* @extcon_reg_dwork: delay work for extcon notifier register, waiting for
+*		xHCI driver initialization, it's necessary for system bootup
+*		as device.
+* @is_u3_drd: whether port0 supports usb3.0 dual-role device or not
+* @id_*: used to maually switch between host and device modes by idpin
+* @manual_drd_enabled: it's true when supports dual-role device by debugfs
+*		to switch host/device modes depending on user input.
+*/
+struct otg_switch_mtk {
+	struct regulator *vbus;
+	struct extcon_dev *edev;
+	struct notifier_block vbus_nb;
+	struct notifier_block id_nb;
+	struct delayed_work extcon_reg_dwork;
+	bool is_u3_drd;
+	/* dual-role switch by debugfs */
+	struct pinctrl *id_pinctrl;
+	struct pinctrl_state *id_float;
+	struct pinctrl_state *id_ground;
+	bool manual_drd_enabled;
+};
+
 /**
  * @mac_base: register base address of device MAC, exclude xHCI's
- * @ippc_base: register base address of ip port controller interface (IPPC)
+ * @ippc_base: register base address of IP Power and Clock interface (IPPC)
  * @vusb33: usb3.3V shared by device/host IP
  * @sys_clk: system clock of mtu3, shared by device/host IP
  * @dr_mode: works in which mode:
  *		host only, device only or dual-role mode
  * @u2_ports: number of usb2.0 host ports
  * @u3_ports: number of usb3.0 host ports
+ * @dbgfs_root: only used when supports manual dual-role switch via debugfs
  * @wakeup_en: it's true when supports remote wakeup in host mode
  * @wk_deb_p0: port0's wakeup debounce clock
  * @wk_deb_p1: it's optional, and depends on port1 is supported or not
@@ -196,10 +226,12 @@ struct ssusb_mtk {
 	struct regulator *vusb33;
 	struct clk *sys_clk;
 	/* otg */
+	struct otg_switch_mtk otg_switch;
 	enum usb_dr_mode dr_mode;
 	bool is_host;
 	int u2_ports;
 	int u3_ports;
+	struct dentry *dbgfs_root;
 	/* usb wakeup for host mode */
 	bool wakeup_en;
 	struct clk *wk_deb_p0;

drivers/usb/mtu3/mtu3_core.c

@@ -150,7 +150,6 @@ static void mtu3_intr_disable(struct mtu3 *mtu)
 
 	/* Disable level 1 interrupts */
 	mtu3_writel(mbase, U3D_LV1IECR, ~0x0);
-
 	/* Disable endpoint interrupts */
 	mtu3_writel(mbase, U3D_EPIECR, ~0x0);
 }
@@ -161,13 +160,10 @@ static void mtu3_intr_status_clear(struct mtu3 *mtu)
 
 	/* Clear EP0 and Tx/Rx EPn interrupts status */
 	mtu3_writel(mbase, U3D_EPISR, ~0x0);
-
 	/* Clear U2 USB common interrupts status */
 	mtu3_writel(mbase, U3D_COMMON_USB_INTR, ~0x0);
-
 	/* Clear U3 LTSSM interrupts status */
 	mtu3_writel(mbase, U3D_LTSSM_INTR, ~0x0);
-
 	/* Clear speed change interrupt status */
 	mtu3_writel(mbase, U3D_DEV_LINK_INTR, ~0x0);
 }
@@ -268,7 +264,6 @@ void mtu3_start(struct mtu3 *mtu)
 
 	/* Initialize the default interrupts */
 	mtu3_intr_enable(mtu);
-
 	mtu->is_active = 1;
 
 	if (mtu->softconnect)
@@ -516,7 +511,6 @@ static int mtu3_mem_alloc(struct mtu3 *mtu)
 	mtu->out_eps = &ep_array[mtu->num_eps];
 	/* ep0 uses in_eps[0], out_eps[0] is reserved */
 	mtu->ep0 = mtu->in_eps;
-
 	mtu->ep0->mtu = mtu;
 	mtu->ep0->epnum = 0;
 
@@ -560,6 +554,7 @@ static void mtu3_set_speed(struct mtu3 *mtu)
 		/* HS/FS detected by HW */
 		mtu3_setbits(mbase, U3D_POWER_MANAGEMENT, HS_ENABLE);
 	}
+
 	dev_info(mtu->dev, "max_speed: %s\n",
 		usb_speed_string(mtu->max_speed));
 }
@@ -586,13 +581,10 @@ static void mtu3_regs_init(struct mtu3 *mtu)
 
 	/* delay about 0.1us from detecting reset to send chirp-K */
 	mtu3_clrbits(mbase, U3D_LINK_RESET_INFO, WTCHRP_MSK);
-
 	/* U2/U3 detected by HW */
 	mtu3_writel(mbase, U3D_DEVICE_CONF, 0);
-
 	/* enable QMU 16B checksum */
 	mtu3_setbits(mbase, U3D_QCR0, QMU_CS16B_EN);
-
 	/* vbus detected by HW */
 	mtu3_clrbits(mbase, U3D_MISC_CTRL, VBUS_FRC_EN | VBUS_ON);
 }
@@ -838,6 +830,10 @@ int ssusb_gadget_init(struct ssusb_mtk *ssusb)
 		goto gadget_err;
 	}
 
+	/* init as host mode, power down device IP for power saving */
+	if (mtu->ssusb->dr_mode == USB_DR_MODE_OTG)
+		mtu3_stop(mtu);
+
 	dev_dbg(dev, " %s() done...\n", __func__);
 
 	return 0;