[PATCH] usb: chipidea: Use extcon framework for VBUS and ID detection

[Ivan T. Ivanov]

On recent Qualcomm platforms VBUS and ID lines are not routed to
USB PHY LINK controller. Use extcon framework to receive connect
and disconnect ID and VBUS notification.

Signed-off-by: Ivan T. Ivanov <ivan.ivanov@xxxxxxxxxx>
---

Suggestions for better solution are welcome!

 .../devicetree/bindings/usb/ci-hdrc-qcom.txt       |  9 +++
 drivers/usb/chipidea/Kconfig                       |  1 +
 drivers/usb/chipidea/ci.h                          | 18 +++++
 drivers/usb/chipidea/core.c                        | 77 ++++++++++++++++++++++
 drivers/usb/chipidea/otg.c                         | 19 +++++-
 5 files changed, 123 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt
index f2899b5..788da49 100644
--- a/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt
+++ b/Documentation/devicetree/bindings/usb/ci-hdrc-qcom.txt
@@ -7,6 +7,14 @@ Required properties:
 - usb-phy:      phandle for the PHY device
 - dr_mode:      Should be "peripheral"

+Optional properties:
+- extcon:       phandles to external connector devices. First phandle
+                should point to external connector, which provide "USB"
+                cable events, the second should point to external connector
+                device, which provide "USB-HOST" cable events. If one of
+                the external connector devices is not required empty <0>
+                phandle should be specified.
+
 Examples:
 	gadget@f9a55000 {
 		compatible = "qcom,ci-hdrc";
@@ -14,4 +22,5 @@ Examples:
 		dr_mode = "peripheral";
 		interrupts = <0 134 0>;
 		usb-phy = <&usbphy0>;
+		extcon = <&usb_vbus>, <&usb_id>;
 	};
diff --git a/drivers/usb/chipidea/Kconfig b/drivers/usb/chipidea/Kconfig
index 77b47d8..a67b67f 100644
--- a/drivers/usb/chipidea/Kconfig
+++ b/drivers/usb/chipidea/Kconfig
@@ -1,6 +1,7 @@
 config USB_CHIPIDEA
 	tristate "ChipIdea Highspeed Dual Role Controller"
 	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
+	depends on EXTCON
 	help
 	  Say Y here if your system has a dual role high speed USB
 	  controller based on ChipIdea silicon IP. Currently, only the
diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
index 65913d4..04e7aee 100644
--- a/drivers/usb/chipidea/ci.h
+++ b/drivers/usb/chipidea/ci.h
@@ -13,6 +13,7 @@
 #ifndef __DRIVERS_USB_CHIPIDEA_CI_H
 #define __DRIVERS_USB_CHIPIDEA_CI_H

+#include <linux/extcon.h>
 #include <linux/list.h>
 #include <linux/irqreturn.h>
 #include <linux/usb.h>
@@ -132,6 +133,18 @@ struct hw_bank {
 };

 /**
+ * struct ci_hdrc - structure for exteternal connector cable state tracking
+ * @state: current state of the line
+ * @nb: hold event notification callback
+ * @conn: used for notification registration
+ */
+struct ci_cable {
+	bool				state;
+	struct notifier_block		nb;
+	struct extcon_specific_cable_nb conn;
+};
+
+/**
  * struct ci_hdrc - chipidea device representation
  * @dev: pointer to parent device
  * @lock: access synchronization
@@ -169,6 +182,8 @@ struct hw_bank {
  * @b_sess_valid_event: indicates there is a vbus event, and handled
  * at ci_otg_work
  * @imx28_write_fix: Freescale imx28 needs swp instruction for writing
+ * @vbus: VBUS signal state trakining, using extcon framework
+ * @id: ID signal state trakining, using extcon framework
  */
 struct ci_hdrc {
 	struct device			*dev;
@@ -211,6 +226,9 @@ struct ci_hdrc {
 	bool				id_event;
 	bool				b_sess_valid_event;
 	bool				imx28_write_fix;
+
+	struct ci_cable			vbus;
+	struct ci_cable			id;
 };

 static inline struct ci_role_driver *ci_role(struct ci_hdrc *ci)
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index a57dc88..0f805bd 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -47,6 +47,7 @@
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
+#include <linux/extcon.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/module.h>
@@ -646,9 +647,36 @@ static void ci_get_otg_capable(struct ci_hdrc *ci)
 		dev_dbg(ci->dev, "It is OTG capable controller\n");
 }

+static int ci_vbus_notifier(struct notifier_block *nb, unsigned long event,
+			 void *ptr)
+{
+	struct ci_cable *vbus = container_of(nb, struct ci_cable, nb);
+
+	if (event)
+		vbus->state = true;
+	else
+		vbus->state = false;
+
+	return NOTIFY_DONE;
+}
+
+static int ci_host_notifier(struct notifier_block *nb, unsigned long event,
+		       void *ptr)
+{
+	struct ci_cable *id = container_of(nb, struct ci_cable, nb);
+
+	if (event)
+		id->state = false;
+	else
+		id->state = true;
+
+	return NOTIFY_DONE;
+}
+
 static int ci_hdrc_probe(struct platform_device *pdev)
 {
 	struct device	*dev = &pdev->dev;
+	struct extcon_dev *ext_vbus, *ext_id;
 	struct ci_hdrc	*ci;
 	struct resource	*res;
 	void __iomem	*base;
@@ -702,6 +730,51 @@ static int ci_hdrc_probe(struct platform_device *pdev)
 			ci->usb_phy = NULL;
 	}

+	ext_id = ERR_PTR(-ENODEV);
+	ext_vbus = ERR_PTR(-ENODEV);
+	if (of_property_read_bool(dev->parent->of_node, "extcon")) {
+		/* Each one of them is not mandatory */
+		ext_vbus = extcon_get_edev_by_phandle(dev->parent, 0);
+		if (IS_ERR(ext_vbus) && PTR_ERR(ext_vbus) != -ENODEV)
+			return PTR_ERR(ext_vbus);
+
+		ext_id = extcon_get_edev_by_phandle(dev->parent, 1);
+		if (IS_ERR(ext_id) && PTR_ERR(ext_id) != -ENODEV)
+			return PTR_ERR(ext_id);
+	}
+
+	if (!IS_ERR(ext_vbus)) {
+		ci->vbus.nb.notifier_call = ci_vbus_notifier;
+		ret = extcon_register_interest(&ci->vbus.conn, ext_vbus->name,
+					       "USB", &ci->vbus.nb);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "register VBUS failed\n");
+			return ret;
+		}
+
+		ret = extcon_get_cable_state(ext_vbus, "USB");
+		if (ret)
+			ci->vbus.state = true;
+		else
+			ci->vbus.state = false;
+	}
+
+	if (!IS_ERR(ext_id)) {
+		ci->id.nb.notifier_call = ci_host_notifier;
+		ret = extcon_register_interest(&ci->id.conn, ext_id->name,
+					       "USB-HOST", &ci->id.nb);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "register ID failed\n");
+			return ret;
+		}
+
+		ret = extcon_get_cable_state(ext_id, "USB-HOST");
+		if (ret)
+			ci->id.state = false;
+		else
+			ci->id.state = true;
+	}
+
 	ret = ci_usb_phy_init(ci);
 	if (ret) {
 		dev_err(dev, "unable to init phy: %d\n", ret);
@@ -807,6 +880,10 @@ static int ci_hdrc_remove(struct platform_device *pdev)
 {
 	struct ci_hdrc *ci = platform_get_drvdata(pdev);

+	if (ci->id.conn.edev)
+		extcon_unregister_interest(&ci->id.conn);
+	if (ci->vbus.conn.edev)
+		extcon_unregister_interest(&ci->vbus.conn);
 	dbg_remove_files(ci);
 	ci_role_destroy(ci);
 	ci_hdrc_enter_lpm(ci, true);
diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
index a048b08..2e97c0d 100644
--- a/drivers/usb/chipidea/otg.c
+++ b/drivers/usb/chipidea/otg.c
@@ -30,7 +30,24 @@
  */
 u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
 {
-	return hw_read(ci, OP_OTGSC, mask);
+	u32 val = hw_read(ci, OP_OTGSC, mask);
+
+	if ((mask & OTGSC_BSV) && ci->vbus.conn.edev) {
+		if (ci->vbus.state)
+			val |= OTGSC_BSV;
+		else
+			val &= ~OTGSC_BSV;
+	}
+
+	if ((mask & OTGSC_ID) && ci->id.conn.edev) {
+		if (ci->id.state)
+			val |= OTGSC_ID;
+		else
+			val &= ~OTGSC_ID;
+	}
+
+	val &= mask;
+	return val;
 }

 /**
--
1.9.1

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