Date:	Thu, 2 Jul 2015 09:05:47 +0100
From:	Phil Edworthy <phil.edworthy@...esas.com>
To:	Kishon Vijay Abraham I <kishon@...com>
Cc:	Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-usb@...r.kernel.org>, <linux-sh@...r.kernel.org>,
	Phil Edworthy <phil.edworthy@...esas.com>
Subject: [PATCH v2] phy: rcar-gen2 usb: Add Host/Function switching for USB0

Instead of statically selecting the PHY connection to either the
USBHS (Function) or PCI0 (Host) IP blocks, this change allows the
dts to specifiy gpio pins for the vbus and id signals. Additional
gpio pins are used to control power to an external OTG device and
an override to turn vbus on/off.

Note: the R-Car USB PHY only allows this Host/Function switching
on channel 0.

This has been tested on a r8a7791 based Koelsch board, which uses
a MAX3355 device to supply vbus power when needed.

Signed-off-by: Phil Edworthy <phil.edworthy@...esas.com>

---
Tested with patch "usb: renesas_usbhs: Allow an OTG PHY driver to provide VBUS"
and changes to koelsch dts.

v2:
  - Added -gpio to dts prop names of GPIO pins.
  - Document the new bindings.
---
 .../devicetree/bindings/phy/rcar-gen2-phy.txt      |  10 +
 drivers/phy/phy-rcar-gen2.c                        | 269 +++++++++++++++++++--
 2 files changed, 257 insertions(+), 22 deletions(-)

diff --git a/Documentation/devicetree/bindings/phy/rcar-gen2-phy.txt b/Documentation/devicetree/bindings/phy/rcar-gen2-phy.txt
index 00fc52a..3a501fe 100644
--- a/Documentation/devicetree/bindings/phy/rcar-gen2-phy.txt
+++ b/Documentation/devicetree/bindings/phy/rcar-gen2-phy.txt
@@ -30,6 +30,16 @@ the USB channel; see the selector meanings below:
 | 2         | PCI EHCI/OHCI | xHCI          |
 +-----------+---------------+---------------+
 
+Optional properties:
+  - renesas,pwr-gpio: 		A gpio specifier that will be active when the
+				PHY is powered on.
+  - renesas,id-gpio:		A gpio specifier that is read to get the USB
+				ID signal.
+  - renesas,vbus-gpio:		A gpio specifier that is read to get the USB
+				VBUS signal.
+  - renesas,vbus-pwr-gpio:	A gpio specifier that will be active when VBUS
+				is required to be powered.
+
 Example (Lager board):
 
 	usb-phy@...90100 {
diff --git a/drivers/phy/phy-rcar-gen2.c b/drivers/phy/phy-rcar-gen2.c
index 97d45f4..1e7a4d9 100644
--- a/drivers/phy/phy-rcar-gen2.c
+++ b/drivers/phy/phy-rcar-gen2.c
@@ -1,5 +1,5 @@
 /*
- * Renesas R-Car Gen2 PHY driver
+ * Renesas R-Car Gen2 USB PHY driver
  *
  * Copyright (C) 2014 Renesas Solutions Corp.
  * Copyright (C) 2014 Cogent Embedded, Inc.
@@ -12,11 +12,16 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/io.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/otg.h>
+#include <linux/workqueue.h>
 
 #include <asm/cmpxchg.h>
 
@@ -58,6 +63,18 @@ struct rcar_gen2_channel {
 	struct rcar_gen2_phy phys[PHYS_PER_CHANNEL];
 	int selected_phy;
 	u32 select_mask;
+
+	/* external power enable pin */
+	int			gpio_pwr;
+
+	/* Host/Function switching */
+	struct delayed_work	work;
+	int			use_otg;
+	int			gpio_vbus;
+	int			gpio_id;
+	int			gpio_vbus_pwr;
+	struct usb_phy		*usbphy;
+	struct usb_otg		*otg;
 };
 
 struct rcar_gen2_phy_driver {
@@ -68,31 +85,50 @@ struct rcar_gen2_phy_driver {
 	struct rcar_gen2_channel *channels;
 };
 
-static int rcar_gen2_phy_init(struct phy *p)
+static void rcar_gen2_phy_switch(struct rcar_gen2_channel *channel,
+	u32 select_value)
 {
-	struct rcar_gen2_phy *phy = phy_get_drvdata(p);
-	struct rcar_gen2_channel *channel = phy->channel;
 	struct rcar_gen2_phy_driver *drv = channel->drv;
 	unsigned long flags;
 	u32 ugctrl2;
 
-	/*
-	 * Try to acquire exclusive access to PHY.  The first driver calling
-	 * phy_init()  on a given channel wins, and all attempts  to use another
-	 * PHY on this channel will fail until phy_exit() is called by the first
-	 * driver.   Achieving this with cmpxcgh() should be SMP-safe.
-	 */
-	if (cmpxchg(&channel->selected_phy, -1, phy->number) != -1)
-		return -EBUSY;
-
-	clk_prepare_enable(drv->clk);
-
 	spin_lock_irqsave(&drv->lock, flags);
 	ugctrl2 = readl(drv->base + USBHS_UGCTRL2);
 	ugctrl2 &= ~channel->select_mask;
-	ugctrl2 |= phy->select_value;
+	ugctrl2 |= select_value;
 	writel(ugctrl2, drv->base + USBHS_UGCTRL2);
 	spin_unlock_irqrestore(&drv->lock, flags);
+}
+
+static int rcar_gen2_phy_init(struct phy *p)
+{
+	struct rcar_gen2_phy *phy = phy_get_drvdata(p);
+	struct rcar_gen2_channel *channel = phy->channel;
+	struct rcar_gen2_phy_driver *drv = channel->drv;
+
+	if (!channel->use_otg) {
+		/*
+		 * Static Host/Function role.
+		 * Try to acquire exclusive access to PHY. The first driver
+		 * calling phy_init() on a given channel wins, and all attempts
+		 * to use another PHY on this channel will fail until
+		 * phy_exit() is called by the first driver. Achieving this
+		 * with cmpxcgh() should be SMP-safe.
+		 */
+		if (cmpxchg(&channel->selected_phy, -1, phy->number) != -1)
+			return -EBUSY;
+
+		clk_prepare_enable(drv->clk);
+		rcar_gen2_phy_switch(channel, phy->select_value);
+	} else {
+		/*
+		 * Using Host/Function switching, so schedule work to determine
+		 * which role to use.
+		 */
+		clk_prepare_enable(drv->clk);
+		schedule_delayed_work(&channel->work, 100);
+	}
+
 	return 0;
 }
 
@@ -117,9 +153,9 @@ static int rcar_gen2_phy_power_on(struct phy *p)
 	u32 value;
 	int err = 0, i;
 
-	/* Skip if it's not USBHS */
-	if (phy->select_value != USBHS_UGCTRL2_USB0SEL_HS_USB)
-		return 0;
+	/* Optional external power pin */
+	if (gpio_is_valid(phy->channel->gpio_pwr))
+		gpio_direction_output(phy->channel->gpio_pwr, 1);
 
 	spin_lock_irqsave(&drv->lock, flags);
 
@@ -160,9 +196,9 @@ static int rcar_gen2_phy_power_off(struct phy *p)
 	unsigned long flags;
 	u32 value;
 
-	/* Skip if it's not USBHS */
-	if (phy->select_value != USBHS_UGCTRL2_USB0SEL_HS_USB)
-		return 0;
+	/* External power pin */
+	if (gpio_is_valid(phy->channel->gpio_pwr))
+		gpio_direction_output(phy->channel->gpio_pwr, 0);
 
 	spin_lock_irqsave(&drv->lock, flags);
 
@@ -236,6 +272,132 @@ static const u32 select_value[][PHYS_PER_CHANNEL] = {
 	[2]	= { USBHS_UGCTRL2_USB2SEL_PCI, USBHS_UGCTRL2_USB2SEL_USB30 },
 };
 
+
+#define VBUS_IRQ_FLAGS \
+	(IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
+
+static void gpio_vbus_work(struct work_struct *work)
+{
+	struct rcar_gen2_channel *channel = container_of(work,
+					struct rcar_gen2_channel, work.work);
+	struct usb_phy *usbphy = channel->usbphy;
+	int status, vbus, id;
+
+	vbus = !!gpio_get_value(channel->gpio_vbus);
+	id = !!gpio_get_value(channel->gpio_id);
+
+	/* Switch the PHY over */
+	if (id)
+		rcar_gen2_phy_switch(channel, USBHS_UGCTRL2_USB0SEL_HS_USB);
+	else
+		rcar_gen2_phy_switch(channel, USBHS_UGCTRL2_USB0SEL_PCI);
+
+	/* If VBUS is powered and we are not the initial Host, turn off VBUS */
+	if (gpio_is_valid(channel->gpio_vbus_pwr))
+		gpio_direction_output(channel->gpio_vbus_pwr, !(id && vbus));
+
+	if (!channel->otg->gadget)
+		return;
+
+	/* Function handling: vbus=1 when initially plugged into a Host */
+	if (vbus) {
+		status = USB_EVENT_VBUS;
+		usbphy->otg->state = OTG_STATE_B_PERIPHERAL;
+		usbphy->last_event = status;
+		usb_gadget_vbus_connect(usbphy->otg->gadget);
+
+		atomic_notifier_call_chain(&usbphy->notifier,
+					   status, usbphy->otg->gadget);
+	} else {
+		usb_gadget_vbus_disconnect(usbphy->otg->gadget);
+		status = USB_EVENT_NONE;
+		usbphy->otg->state = OTG_STATE_B_IDLE;
+		usbphy->last_event = status;
+
+		atomic_notifier_call_chain(&usbphy->notifier,
+					   status, usbphy->otg->gadget);
+	}
+}
+
+/* VBUS change IRQ handler */
+static irqreturn_t gpio_vbus_irq(int irq, void *data)
+{
+	struct rcar_gen2_channel *channel = data;
+
+	/* Wait 20ms before doing anything as VBUS needs to settle */
+	schedule_delayed_work(&channel->work, msecs_to_jiffies(20));
+
+	return IRQ_HANDLED;
+}
+
+static int probe_otg(struct platform_device *pdev,
+	struct rcar_gen2_phy_driver *drv)
+{
+	struct device *dev = &pdev->dev;
+	struct rcar_gen2_channel *ch = drv->channels;
+	int irq;
+	int ret;
+
+	/* GPIOs for Host/Fn switching */
+	ch->gpio_id = of_get_named_gpio_flags(dev->of_node,
+				"renesas,id-gpio", 0, NULL);
+	ch->gpio_vbus = of_get_named_gpio_flags(dev->of_node,
+				"renesas,vbus-gpio", 0, NULL);
+
+	/* Need valid ID and VBUS gpios for Host/Fn switching */
+	if (gpio_is_valid(ch->gpio_id) && gpio_is_valid(ch->gpio_vbus)) {
+		ch->use_otg = 1;
+
+		/* GPIO for ID input */
+		ret = devm_gpio_request_one(dev, ch->gpio_id, GPIOF_IN, "id");
+		if (ret)
+			return ret;
+
+		/* GPIO for VBUS input */
+		ret = devm_gpio_request_one(dev, ch->gpio_vbus, GPIOF_IN, "vbus");
+		if (ret)
+			return ret;
+
+		irq = gpio_to_irq(ch->gpio_vbus);
+		ret = devm_request_irq(dev, irq, gpio_vbus_irq, VBUS_IRQ_FLAGS,
+				"vbus_detect", ch);
+		if (ret)
+			return ret;
+
+		/* Optional GPIO for VBUS power */
+		ch->gpio_vbus_pwr = of_get_named_gpio_flags(dev->of_node,
+						"renesas,vbus-pwr-gpio", 0, NULL);
+		if (gpio_is_valid(ch->gpio_id)) {
+			ret = devm_gpio_request_one(dev, ch->gpio_vbus_pwr,
+					GPIOF_OUT_INIT_LOW, "vbus-pwr");
+			if (ret)
+				return ret;
+		}
+
+	} else if (gpio_is_valid(ch->gpio_id)) {
+		dev_err(dev, "Failed to get VBUS gpio\n");
+		return ch->gpio_vbus;
+	} else if (gpio_is_valid(ch->gpio_vbus)) {
+		dev_err(dev, "Failed to get ID gpio\n");
+		return ch->gpio_id;
+	}
+
+	return 0;
+}
+
+/* bind/unbind the peripheral controller */
+static int rcar_gen2_usb_set_peripheral(struct usb_otg *otg,
+					struct usb_gadget *gadget)
+{
+	otg->gadget = gadget;
+	if (!gadget) {
+		usb_gadget_vbus_disconnect(otg->gadget);
+		otg->state = OTG_STATE_UNDEFINED;
+	}
+
+	return 0;
+}
+
 static int rcar_gen2_phy_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -245,7 +407,9 @@ static int rcar_gen2_phy_probe(struct platform_device *pdev)
 	struct resource *res;
 	void __iomem *base;
 	struct clk *clk;
+	struct usb_otg *otg;
 	int i = 0;
+	int err;
 
 	if (!dev->of_node) {
 		dev_err(dev,
@@ -280,6 +444,57 @@ static int rcar_gen2_phy_probe(struct platform_device *pdev)
 	if (!drv->channels)
 		return -ENOMEM;
 
+	/* USB0 optional GPIO power pin for external devices */
+	drv->channels->gpio_pwr = of_get_named_gpio_flags(dev->of_node,
+						"renesas,pwr-gpio", 0, NULL);
+	if (drv->channels->gpio_pwr == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+
+	if (gpio_is_valid(drv->channels->gpio_pwr)) {
+		err = devm_gpio_request(dev, drv->channels->gpio_pwr, "pwr");
+		if (err)
+			return err;
+	}
+
+	/* USB0 Host/Function switching info */
+	err = probe_otg(pdev, drv);
+	if (err)
+		return err;
+
+	/*
+	 * The PHY connected to channel 0 can be used to steer signals to the
+	 * USB Host IP that stils behind a PCI bridge (pci0), or the USB Func
+	 * IP (hsusb). We can dynamically switch this based on VBUS and ID
+	 * signals connected to gpios, to get something approaching OTG.
+	 */
+	if (drv->channels->use_otg) {
+		struct usb_phy *usbphy;
+
+		usbphy = devm_kzalloc(dev, sizeof(*usbphy), GFP_KERNEL);
+		if (!usbphy)
+			return -ENOMEM;
+
+		otg = devm_kzalloc(dev, sizeof(*otg), GFP_KERNEL);
+		if (!otg)
+			return -ENOMEM;
+
+		usbphy->dev		= dev;
+		usbphy->otg		= otg;
+
+		otg->usb_phy		= usbphy;
+		otg->state		= OTG_STATE_UNDEFINED;
+		otg->set_peripheral	= rcar_gen2_usb_set_peripheral;
+
+		drv->channels->otg	= otg;
+		drv->channels->usbphy	= usbphy;
+
+		ATOMIC_INIT_NOTIFIER_HEAD(&usbphy->notifier);
+
+		INIT_DELAYED_WORK(&drv->channels->work, gpio_vbus_work);
+
+		usb_add_phy_dev(usbphy);
+	}
+
 	for_each_child_of_node(dev->of_node, np) {
 		struct rcar_gen2_channel *channel = drv->channels + i;
 		u32 channel_num;
@@ -288,6 +503,8 @@ static int rcar_gen2_phy_probe(struct platform_device *pdev)
 		channel->of_node = np;
 		channel->drv = drv;
 		channel->selected_phy = -1;
+		if (i != 0)
+			channel->gpio_pwr = -ENOENT;
 
 		error = of_property_read_u32(np, "reg", &channel_num);
 		if (error || channel_num > 2) {
@@ -323,6 +540,14 @@ static int rcar_gen2_phy_probe(struct platform_device *pdev)
 
 	dev_set_drvdata(dev, drv);
 
+	/*
+	 * If we already have something plugged into USB0, we won't get an edge
+	 * on VBUS, so we have to manually schedule work to look at the VBUS
+	 * and ID signals.
+	 */
+	if (drv->channels->use_otg)
+		schedule_delayed_work(&drv->channels->work, msecs_to_jiffies(100));
+
 	return 0;
 }
 
-- 
1.9.1

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