usb: phy: msm: Use extcon framework for VBUS and ID detection

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@linaro.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Author: Ivan T. Ivanov

Documentation/devicetree/bindings/usb/msm-hsusb.txt

@@ -69,6 +69,13 @@ Optional properties:
                 (no, min, max) where each value represents either a voltage
                 in microvolts or a value corresponding to voltage corner.
 
+- 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.
+
 Example HSUSB OTG controller device node:
 
     usb@f9a55000 {

drivers/usb/phy/Kconfig

@@ -141,6 +141,7 @@ config USB_MSM_OTG
 	tristate "Qualcomm on-chip USB OTG controller support"
 	depends on (USB || USB_GADGET) && (ARCH_QCOM || COMPILE_TEST)
 	depends on RESET_CONTROLLER
+	depends on EXTCON
 	select USB_PHY
 	help
 	  Enable this to support the USB OTG transceiver on Qualcomm chips. It

drivers/usb/phy/phy-msm-usb.c

@@ -1436,9 +1436,42 @@ static const struct of_device_id msm_otg_dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, msm_otg_dt_match);
 
+static int msm_otg_vbus_notifier(struct notifier_block *nb, unsigned long event,
+				void *ptr)
+{
+	struct msm_usb_cable *vbus = container_of(nb, struct msm_usb_cable, nb);
+	struct msm_otg *motg = container_of(vbus, struct msm_otg, vbus);
+
+	if (event)
+		set_bit(B_SESS_VLD, &motg->inputs);
+	else
+		clear_bit(B_SESS_VLD, &motg->inputs);
+
+	schedule_work(&motg->sm_work);
+
+	return NOTIFY_DONE;
+}
+
+static int msm_otg_id_notifier(struct notifier_block *nb, unsigned long event,
+				void *ptr)
+{
+	struct msm_usb_cable *id = container_of(nb, struct msm_usb_cable, nb);
+	struct msm_otg *motg = container_of(id, struct msm_otg, id);
+
+	if (event)
+		clear_bit(ID, &motg->inputs);
+	else
+		set_bit(ID, &motg->inputs);
+
+	schedule_work(&motg->sm_work);
+
+	return NOTIFY_DONE;
+}
+
 static int msm_otg_read_dt(struct platform_device *pdev, struct msm_otg *motg)
 {
 	struct msm_otg_platform_data *pdata;
+	struct extcon_dev *ext_id, *ext_vbus;
 	const struct of_device_id *id;
 	struct device_node *node = pdev->dev.of_node;
 	struct property *prop;
@@ -1487,6 +1520,52 @@ static int msm_otg_read_dt(struct platform_device *pdev, struct msm_otg *motg)
 		motg->vdd_levels[VDD_LEVEL_MAX] = tmp[VDD_LEVEL_MAX];
 	}
 
+	ext_id = ERR_PTR(-ENODEV);
+	ext_vbus = ERR_PTR(-ENODEV);
+	if (of_property_read_bool(node, "extcon")) {
+
+		/* Each one of them is not mandatory */
+		ext_vbus = extcon_get_edev_by_phandle(&pdev->dev, 0);
+		if (IS_ERR(ext_vbus) && PTR_ERR(ext_vbus) != -ENODEV)
+			return PTR_ERR(ext_vbus);
+
+		ext_id = extcon_get_edev_by_phandle(&pdev->dev, 1);
+		if (IS_ERR(ext_id) && PTR_ERR(ext_id) != -ENODEV)
+			return PTR_ERR(ext_id);
+	}
+
+	if (!IS_ERR(ext_vbus)) {
+		motg->vbus.nb.notifier_call = msm_otg_vbus_notifier;
+		ret = extcon_register_interest(&motg->vbus.conn, ext_vbus->name,
+					       "USB", &motg->vbus.nb);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "register VBUS notifier failed\n");
+			return ret;
+		}
+
+		ret = extcon_get_cable_state(ext_vbus, "USB");
+		if (ret)
+			set_bit(B_SESS_VLD, &motg->inputs);
+		else
+			clear_bit(B_SESS_VLD, &motg->inputs);
+	}
+
+	if (!IS_ERR(ext_id)) {
+		motg->id.nb.notifier_call = msm_otg_id_notifier;
+		ret = extcon_register_interest(&motg->id.conn, ext_id->name,
+					       "USB-HOST", &motg->id.nb);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "register ID notifier failed\n");
+			return ret;
+		}
+
+		ret = extcon_get_cable_state(ext_id, "USB-HOST");
+		if (ret)
+			clear_bit(ID, &motg->inputs);
+		else
+			set_bit(ID, &motg->inputs);
+	}
+
 	prop = of_find_property(node, "qcom,phy-init-sequence", &len);
 	if (!prop || !len)
 		return 0;
@@ -1700,6 +1779,11 @@ static int msm_otg_remove(struct platform_device *pdev)
 	if (phy->otg->host || phy->otg->gadget)
 		return -EBUSY;
 
+	if (motg->id.conn.edev)
+		extcon_unregister_interest(&motg->id.conn);
+	if (motg->vbus.conn.edev)
+		extcon_unregister_interest(&motg->vbus.conn);
+
 	msm_otg_debugfs_cleanup();
 	cancel_delayed_work_sync(&motg->chg_work);
 	cancel_work_sync(&motg->sm_work);

include/linux/usb/msm_hsusb.h

@@ -18,6 +18,7 @@
 #ifndef __ASM_ARCH_MSM_HSUSB_H
 #define __ASM_ARCH_MSM_HSUSB_H
 
+#include <linux/extcon.h>
 #include <linux/types.h>
 #include <linux/usb/otg.h>
 #include <linux/clk.h>
@@ -119,6 +120,17 @@ struct msm_otg_platform_data {
 	void (*setup_gpio)(enum usb_otg_state state);
 };
 
+/**
+ * struct msm_usb_cable - structure for exteternal connector cable
+ *			  state tracking
+ * @nb: hold event notification callback
+ * @conn: used for notification registration
+ */
+struct msm_usb_cable {
+	struct notifier_block		nb;
+	struct extcon_specific_cable_nb conn;
+};
+
 /**
  * struct msm_otg: OTG driver data. Shared by HCD and DCD.
  * @otg: USB OTG Transceiver structure.
@@ -138,6 +150,8 @@ struct msm_otg_platform_data {
  * @chg_type: The type of charger attached.
  * @dcd_retires: The retry count used to track Data contact
  *               detection process.
+ * @vbus: VBUS signal state trakining, using extcon framework
+ * @id: ID signal state trakining, using extcon framework
  */
 struct msm_otg {
 	struct usb_phy phy;
@@ -166,6 +180,9 @@ struct msm_otg {
 	struct reset_control *phy_rst;
 	struct reset_control *link_rst;
 	int vdd_levels[3];
+
+	struct msm_usb_cable vbus;
+	struct msm_usb_cable id;
 };
 
 #endif