commit 3905e7ec084b0a43a5a28b232b7677d67f8c43e2
author Bo Zhang <bozhang@codeaurora.org> Mon Oct 15 13:05:50 2018 +0800
committer Bo Zhang <bozhang@codeaurora.org> Tue Oct 23 09:37:12 2018 +0800
tree 663849673613ee658c70602666bab13c4bf6fd0f
parent 3fd5243b9e492fd0a5f5a94d1095ea5f59c536e6

drivers/extcon:  Trigger gpio when device switch to usb host mode

Everytime device switch to usb host mode, trigger gpio to reset ethernet
bridge (LAN78xx), thus ethernet usb driver can be probed

Change-Id: I753c80cdcbf0a426738ce2bdcb44330bb2cabe71
Signed-off-by: Bo Zhang <bozhang@codeaurora.org>

drivers/extcon/extcon-usb-gpio.c

diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c
index 2b108fa..a7a29fb 100644
--- a/drivers/extcon/extcon-usb-gpio.c
+++ b/drivers/extcon/extcon-usb-gpio.c
@@ -27,6 +27,7 @@
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/acpi.h>
+#include <linux/delay.h>
 
 #define USB_GPIO_DEBOUNCE_MS	20	/* ms */
 
@@ -36,6 +37,7 @@
 
 	struct gpio_desc *id_gpiod;
 	struct gpio_desc *vbus_gpiod;
+	struct gpio_desc *trig_gpiod;
 	int id_irq;
 	int vbus_irq;
 
@@ -87,6 +89,12 @@
 
 	if (!id) {
 		extcon_set_state_sync(info->edev, EXTCON_USB_HOST, true);
+		if (info->trig_gpiod) {
+			gpiod_set_value(info->trig_gpiod, 1);
+			msleep(20);
+			gpiod_set_value(info->trig_gpiod, 0);
+			msleep(20);
+		}
 	} else {
 		if (vbus)
 			extcon_set_state_sync(info->edev, EXTCON_USB, true);
@@ -109,6 +117,7 @@
 	struct device_node *np = dev->of_node;
 	struct usb_extcon_info *info;
 	int ret;
+	const char *name = NULL;
 
 	if (!np && !ACPI_HANDLE(dev))
 		return -EINVAL;
@@ -121,6 +130,8 @@
 	info->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", GPIOD_IN);
 	info->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus",
 						   GPIOD_IN);
+	info->trig_gpiod = devm_gpiod_get_optional(&pdev->dev, "trig",
+						   GPIOD_OUT_LOW);
 
 	if (!info->id_gpiod && !info->vbus_gpiod) {
 		dev_err(dev, "failed to get gpios\n");
@@ -133,6 +144,9 @@
 	if (IS_ERR(info->vbus_gpiod))
 		return PTR_ERR(info->vbus_gpiod);
 
+	if (IS_ERR(info->trig_gpiod))
+		return PTR_ERR(info->trig_gpiod);
+
 	info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
 	if (IS_ERR(info->edev)) {
 		dev_err(dev, "failed to allocate extcon device\n");
@@ -145,6 +159,25 @@
 		return ret;
 	}
 
+	if (info->trig_gpiod) {
+		ret = of_property_read_string_index(np, "gpio-names", 0, &name);
+		if (ret) {
+			dev_err(dev, "Could not get gpio name\n");
+			return ret;
+		}
+
+		ret = gpiod_export(info->trig_gpiod, 0);
+		if (ret) {
+			dev_err(dev, "failed to export gpio\n");
+			return ret;
+		}
+
+		ret = gpiod_export_link(dev, name, info->trig_gpiod);
+		if (ret) {
+		dev_err(dev, "failed to export gpio link\n");
+		return ret;
+		}
+	}
 	if (info->id_gpiod)
 		ret = gpiod_set_debounce(info->id_gpiod,
 					 USB_GPIO_DEBOUNCE_MS * 1000);