1 files changed, 168 insertions, 8 deletions

diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
index 3ec4c715e240..a983708b77a6 100644
--- a/drivers/extcon/extcon-axp288.c
+++ b/drivers/extcon/extcon-axp288.c
@@ -1,6 +1,7 @@
 /*
  * extcon-axp288.c - X-Power AXP288 PMIC extcon cable detection driver
  *
+ * Copyright (c) 2017-2018 Hans de Goede <hdegoede@redhat.com>
  * Copyright (C) 2015 Intel Corporation
  * Author: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
  *
@@ -14,6 +15,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/io.h>
@@ -25,6 +27,11 @@
 #include <linux/extcon-provider.h>
 #include <linux/regmap.h>
 #include <linux/mfd/axp20x.h>
+#include <linux/usb/role.h>
+#include <linux/workqueue.h>
+
+#include <asm/cpu_device_id.h>
+#include <asm/intel-family.h>
 
 /* Power source status register */
 #define PS_STAT_VBUS_TRIGGER		BIT(0)
@@ -97,9 +104,19 @@ struct axp288_extcon_info {
 	struct device *dev;
 	struct regmap *regmap;
 	struct regmap_irq_chip_data *regmap_irqc;
+	struct usb_role_switch *role_sw;
+	struct work_struct role_work;
 	int irq[EXTCON_IRQ_END];
 	struct extcon_dev *edev;
+	struct extcon_dev *id_extcon;
+	struct notifier_block id_nb;
 	unsigned int previous_cable;
+	bool vbus_attach;
+};
+
+static const struct x86_cpu_id cherry_trail_cpu_ids[] = {
+	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT, X86_FEATURE_ANY },
+	{}
 };
 
 /* Power up/down reason string array */
@@ -137,20 +154,74 @@ static void axp288_extcon_log_rsi(struct axp288_extcon_info *info)
 	regmap_write(info->regmap, AXP288_PS_BOOT_REASON_REG, clear_mask);
 }
 
-static int axp288_handle_chrg_det_event(struct axp288_extcon_info *info)
+/*
+ * The below code to control the USB role-switch on devices with an AXP288
+ * may seem out of place, but there are 2 reasons why this is the best place
+ * to control the USB role-switch on such devices:
+ * 1) On many devices the USB role is controlled by AML code, but the AML code
+ *    only switches between the host and none roles, because of Windows not
+ *    really using device mode. To make device mode work we need to toggle
+ *    between the none/device roles based on Vbus presence, and this driver
+ *    gets interrupts on Vbus insertion / removal.
+ * 2) In order for our BC1.2 charger detection to work properly the role
+ *    mux must be properly set to device mode before we do the detection.
+ */
+
+/* Returns the id-pin value, note pulled low / false == host-mode */
+static bool axp288_get_id_pin(struct axp288_extcon_info *info)
 {
-	int ret, stat, cfg, pwr_stat;
-	u8 chrg_type;
-	unsigned int cable = info->previous_cable;
-	bool vbus_attach = false;
+	enum usb_role role;
+
+	if (info->id_extcon)
+		return extcon_get_state(info->id_extcon, EXTCON_USB_HOST) <= 0;
+
+	/* We cannot access the id-pin, see what mode the AML code has set */
+	role = usb_role_switch_get_role(info->role_sw);
+	return role != USB_ROLE_HOST;
+}
+
+static void axp288_usb_role_work(struct work_struct *work)
+{
+	struct axp288_extcon_info *info =
+		container_of(work, struct axp288_extcon_info, role_work);
+	enum usb_role role;
+	bool id_pin;
+	int ret;
+
+	id_pin = axp288_get_id_pin(info);
+	if (!id_pin)
+		role = USB_ROLE_HOST;
+	else if (info->vbus_attach)
+		role = USB_ROLE_DEVICE;
+	else
+		role = USB_ROLE_NONE;
+
+	ret = usb_role_switch_set_role(info->role_sw, role);
+	if (ret)
+		dev_err(info->dev, "failed to set role: %d\n", ret);
+}
+
+static bool axp288_get_vbus_attach(struct axp288_extcon_info *info)
+{
+	int ret, pwr_stat;
 
 	ret = regmap_read(info->regmap, AXP288_PS_STAT_REG, &pwr_stat);
 	if (ret < 0) {
 		dev_err(info->dev, "failed to read vbus status\n");
-		return ret;
+		return false;
 	}
 
-	vbus_attach = (pwr_stat & PS_STAT_VBUS_VALID);
+	return !!(pwr_stat & PS_STAT_VBUS_VALID);
+}
+
+static int axp288_handle_chrg_det_event(struct axp288_extcon_info *info)
+{
+	int ret, stat, cfg;
+	u8 chrg_type;
+	unsigned int cable = info->previous_cable;
+	bool vbus_attach = false;
+
+	vbus_attach = axp288_get_vbus_attach(info);
 	if (!vbus_attach)
 		goto no_vbus;
 
@@ -201,6 +272,12 @@ no_vbus:
 		info->previous_cable = cable;
 	}
 
+	if (info->role_sw && info->vbus_attach != vbus_attach) {
+		info->vbus_attach = vbus_attach;
+		/* Setting the role can take a while */
+		queue_work(system_long_wq, &info->role_work);
+	}
+
 	return 0;
 
 dev_det_ret:
@@ -210,6 +287,18 @@ dev_det_ret:
 	return ret;
 }
 
+static int axp288_extcon_id_evt(struct notifier_block *nb,
+				unsigned long event, void *param)
+{
+	struct axp288_extcon_info *info =
+		container_of(nb, struct axp288_extcon_info, id_nb);
+
+	/* We may not sleep and setting the role can take a while */
+	queue_work(system_long_wq, &info->role_work);
+
+	return NOTIFY_OK;
+}
+
 static irqreturn_t axp288_extcon_isr(int irq, void *data)
 {
 	struct axp288_extcon_info *info = data;
@@ -231,10 +320,20 @@ static void axp288_extcon_enable(struct axp288_extcon_info *info)
 					BC_GLOBAL_RUN, BC_GLOBAL_RUN);
 }
 
+static void axp288_put_role_sw(void *data)
+{
+	struct axp288_extcon_info *info = data;
+
+	cancel_work_sync(&info->role_work);
+	usb_role_switch_put(info->role_sw);
+}
+
 static int axp288_extcon_probe(struct platform_device *pdev)
 {
 	struct axp288_extcon_info *info;
 	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	const char *name;
 	int ret, i, pirq;
 
 	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
@@ -245,9 +344,33 @@ static int axp288_extcon_probe(struct platform_device *pdev)
 	info->regmap = axp20x->regmap;
 	info->regmap_irqc = axp20x->regmap_irqc;
 	info->previous_cable = EXTCON_NONE;
+	INIT_WORK(&info->role_work, axp288_usb_role_work);
+	info->id_nb.notifier_call = axp288_extcon_id_evt;
 
 	platform_set_drvdata(pdev, info);
 
+	info->role_sw = usb_role_switch_get(dev);
+	if (IS_ERR(info->role_sw))
+		return PTR_ERR(info->role_sw);
+	if (info->role_sw) {
+		ret = devm_add_action_or_reset(dev, axp288_put_role_sw, info);
+		if (ret)
+			return ret;
+
+		name = acpi_dev_get_first_match_name("INT3496", NULL, -1);
+		if (name) {
+			info->id_extcon = extcon_get_extcon_dev(name);
+			if (!info->id_extcon)
+				return -EPROBE_DEFER;
+
+			dev_info(dev, "controlling USB role\n");
+		} else {
+			dev_info(dev, "controlling USB role based on Vbus presence\n");
+		}
+	}
+
+	info->vbus_attach = axp288_get_vbus_attach(info);
+
 	axp288_extcon_log_rsi(info);
 
 	/* Initialize extcon device */
@@ -289,6 +412,19 @@ static int axp288_extcon_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (info->id_extcon) {
+		ret = devm_extcon_register_notifier_all(dev, info->id_extcon,
+							&info->id_nb);
+		if (ret)
+			return ret;
+	}
+
+	/* Make sure the role-sw is set correctly before doing BC detection */
+	if (info->role_sw) {
+		queue_work(system_long_wq, &info->role_work);
+		flush_work(&info->role_work);
+	}
+
 	/* Start charger cable type detection */
 	axp288_extcon_enable(info);
 
@@ -308,8 +444,32 @@ static struct platform_driver axp288_extcon_driver = {
 		.name = "axp288_extcon",
 	},
 };
-module_platform_driver(axp288_extcon_driver);
+
+static struct device_connection axp288_extcon_role_sw_conn = {
+	.endpoint[0] = "axp288_extcon",
+	.endpoint[1] = "intel_xhci_usb_sw-role-switch",
+	.id = "usb-role-switch",
+};
+
+static int __init axp288_extcon_init(void)
+{
+	if (x86_match_cpu(cherry_trail_cpu_ids))
+		device_connection_add(&axp288_extcon_role_sw_conn);
+
+	return platform_driver_register(&axp288_extcon_driver);
+}
+module_init(axp288_extcon_init);
+
+static void __exit axp288_extcon_exit(void)
+{
+	if (x86_match_cpu(cherry_trail_cpu_ids))
+		device_connection_remove(&axp288_extcon_role_sw_conn);
+
+	platform_driver_unregister(&axp288_extcon_driver);
+}
+module_exit(axp288_extcon_exit);
 
 MODULE_AUTHOR("Ramakrishna Pallala <ramakrishna.pallala@intel.com>");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 MODULE_DESCRIPTION("X-Powers AXP288 extcon driver");
 MODULE_LICENSE("GPL v2");