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Subject[PATCH next v9 10/11] usb: common: add USB GPIO based connection detection driver
Date
Due to the requirement of usb-connector.txt binding, the old way
using extcon to support USB Dual-Role switch is now deprecated
when use Type-B connector.
This patch introduces a USB GPIO based connection detection driver,
used to support Type-B connector which typically uses an input GPIO
to detect USB ID pin, and try to replace the function provided
by the extcon-usb-gpio driver

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Tested-by: Nagarjuna Kristam <nkristam@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
v9 changes:
1. add reviewed-by Linus

v8 changes:
1. rename the driver name and usb new compatible suggested by Heikki
2. move the driver into usb/common from usb/roles suggested by Heikki

v7 changes:
1. remove macro DEV_PMS_OPS suggested by Andy
2. add tested-by Nagarjuna

v6 changes:
1. get usb-role-swtich by usb_role_switch_get()

v5 changes:
1. put usb_role_switch when error happens suggested by Biju
2. don't treat bype-B connector as a virtual device suggested by Rob

v4 changes:
1. remove linux/gpio.h suggested by Linus
2. put node when error happens

v3 changes:
1. treat bype-B connector as a virtual device;
2. change file name again

v2 changes:
1. file name is changed
2. use new compatible
---
drivers/usb/common/Kconfig | 13 ++
drivers/usb/common/Makefile | 1 +
drivers/usb/common/usb-conn-gpio.c | 284 +++++++++++++++++++++++++++++
3 files changed, 298 insertions(+)
create mode 100644 drivers/usb/common/usb-conn-gpio.c

diff --git a/drivers/usb/common/Kconfig b/drivers/usb/common/Kconfig
index 848545b099cf..d611477aae41 100644
--- a/drivers/usb/common/Kconfig
+++ b/drivers/usb/common/Kconfig
@@ -36,3 +36,16 @@ config USB_ULPI_BUS
To compile this driver as a module, choose M here: the module will
be called ulpi.

+config USB_CONN_GPIO
+ tristate "USB GPIO Based Connection Detection Driver"
+ depends on GPIOLIB
+ select USB_ROLE_SWITCH
+ help
+ The driver supports USB role switch between host and device via GPIO
+ based USB cable detection, used typically if an input GPIO is used
+ to detect USB ID pin, and another input GPIO may be also used to detect
+ Vbus pin at the same time, it also can be used to enable/disable
+ device if an input GPIO is only used to detect Vbus pin.
+
+ To compile the driver as a module, choose M here: the module will
+ be called usb-conn-gpio.ko
diff --git a/drivers/usb/common/Makefile b/drivers/usb/common/Makefile
index 0a7c45e85481..8227ffc2cf0b 100644
--- a/drivers/usb/common/Makefile
+++ b/drivers/usb/common/Makefile
@@ -7,5 +7,6 @@ obj-$(CONFIG_USB_COMMON) += usb-common.o
usb-common-y += common.o
usb-common-$(CONFIG_USB_LED_TRIG) += led.o

+obj-$(CONFIG_USB_CONN_GPIO) += usb-conn-gpio.o
obj-$(CONFIG_USB_OTG_FSM) += usb-otg-fsm.o
obj-$(CONFIG_USB_ULPI_BUS) += ulpi.o
diff --git a/drivers/usb/common/usb-conn-gpio.c b/drivers/usb/common/usb-conn-gpio.c
new file mode 100644
index 000000000000..e4935e99f295
--- /dev/null
+++ b/drivers/usb/common/usb-conn-gpio.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB GPIO Based Connection Detection Driver
+ *
+ * Copyright (C) 2019 MediaTek Inc.
+ *
+ * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
+ *
+ * Some code borrowed from drivers/extcon/extcon-usb-gpio.c
+ */
+
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/usb/role.h>
+
+#define USB_GPIO_DEB_MS 20 /* ms */
+#define USB_GPIO_DEB_US ((USB_GPIO_DEB_MS) * 1000) /* us */
+
+#define USB_CONN_IRQF \
+ (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT)
+
+struct usb_conn_info {
+ struct device *dev;
+ struct usb_role_switch *role_sw;
+ enum usb_role last_role;
+ struct regulator *vbus;
+ struct delayed_work dw_det;
+ unsigned long debounce_jiffies;
+
+ struct gpio_desc *id_gpiod;
+ struct gpio_desc *vbus_gpiod;
+ int id_irq;
+ int vbus_irq;
+};
+
+/**
+ * "DEVICE" = VBUS and "HOST" = !ID, so we have:
+ * Both "DEVICE" and "HOST" can't be set as active at the same time
+ * so if "HOST" is active (i.e. ID is 0) we keep "DEVICE" inactive
+ * even if VBUS is on.
+ *
+ * Role | ID | VBUS
+ * ------------------------------------
+ * [1] DEVICE | H | H
+ * [2] NONE | H | L
+ * [3] HOST | L | H
+ * [4] HOST | L | L
+ *
+ * In case we have only one of these signals:
+ * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1
+ * - ID only - we want to distinguish between [1] and [4], so VBUS = ID
+ */
+static void usb_conn_detect_cable(struct work_struct *work)
+{
+ struct usb_conn_info *info;
+ enum usb_role role;
+ int id, vbus, ret;
+
+ info = container_of(to_delayed_work(work),
+ struct usb_conn_info, dw_det);
+
+ /* check ID and VBUS */
+ id = info->id_gpiod ?
+ gpiod_get_value_cansleep(info->id_gpiod) : 1;
+ vbus = info->vbus_gpiod ?
+ gpiod_get_value_cansleep(info->vbus_gpiod) : id;
+
+ if (!id)
+ role = USB_ROLE_HOST;
+ else if (vbus)
+ role = USB_ROLE_DEVICE;
+ else
+ role = USB_ROLE_NONE;
+
+ dev_dbg(info->dev, "role %d/%d, gpios: id %d, vbus %d\n",
+ info->last_role, role, id, vbus);
+
+ if (info->last_role == role) {
+ dev_warn(info->dev, "repeated role: %d\n", role);
+ return;
+ }
+
+ if (info->last_role == USB_ROLE_HOST)
+ regulator_disable(info->vbus);
+
+ ret = usb_role_switch_set_role(info->role_sw, role);
+ if (ret)
+ dev_err(info->dev, "failed to set role: %d\n", ret);
+
+ if (role == USB_ROLE_HOST) {
+ ret = regulator_enable(info->vbus);
+ if (ret)
+ dev_err(info->dev, "enable vbus regulator failed\n");
+ }
+
+ info->last_role = role;
+
+ dev_dbg(info->dev, "vbus regulator is %s\n",
+ regulator_is_enabled(info->vbus) ? "enabled" : "disabled");
+}
+
+static void usb_conn_queue_dwork(struct usb_conn_info *info,
+ unsigned long delay)
+{
+ queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay);
+}
+
+static irqreturn_t usb_conn_isr(int irq, void *dev_id)
+{
+ struct usb_conn_info *info = dev_id;
+
+ usb_conn_queue_dwork(info, info->debounce_jiffies);
+
+ return IRQ_HANDLED;
+}
+
+static int usb_conn_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct usb_conn_info *info;
+ int ret = 0;
+
+ info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ info->dev = dev;
+ info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
+ if (IS_ERR(info->id_gpiod))
+ return PTR_ERR(info->id_gpiod);
+
+ info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
+ if (IS_ERR(info->vbus_gpiod))
+ return PTR_ERR(info->vbus_gpiod);
+
+ if (!info->id_gpiod && !info->vbus_gpiod) {
+ dev_err(dev, "failed to get gpios\n");
+ return -ENODEV;
+ }
+
+ if (info->id_gpiod)
+ ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);
+ if (!ret && info->vbus_gpiod)
+ ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);
+ if (ret < 0)
+ info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);
+
+ INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
+
+ info->vbus = devm_regulator_get(dev, "vbus");
+ if (IS_ERR(info->vbus)) {
+ dev_err(dev, "failed to get vbus\n");
+ return PTR_ERR(info->vbus);
+ }
+
+ info->role_sw = usb_role_switch_get(dev);
+ if (IS_ERR(info->role_sw)) {
+ if (PTR_ERR(info->role_sw) != -EPROBE_DEFER)
+ dev_err(dev, "failed to get role switch\n");
+
+ return PTR_ERR(info->role_sw);
+ }
+
+ if (info->id_gpiod) {
+ info->id_irq = gpiod_to_irq(info->id_gpiod);
+ if (info->id_irq < 0) {
+ dev_err(dev, "failed to get ID IRQ\n");
+ ret = info->id_irq;
+ goto put_role_sw;
+ }
+
+ ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
+ usb_conn_isr, USB_CONN_IRQF,
+ pdev->name, info);
+ if (ret < 0) {
+ dev_err(dev, "failed to request ID IRQ\n");
+ goto put_role_sw;
+ }
+ }
+
+ if (info->vbus_gpiod) {
+ info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
+ if (info->vbus_irq < 0) {
+ dev_err(dev, "failed to get VBUS IRQ\n");
+ ret = info->vbus_irq;
+ goto put_role_sw;
+ }
+
+ ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
+ usb_conn_isr, USB_CONN_IRQF,
+ pdev->name, info);
+ if (ret < 0) {
+ dev_err(dev, "failed to request VBUS IRQ\n");
+ goto put_role_sw;
+ }
+ }
+
+ platform_set_drvdata(pdev, info);
+
+ /* Perform initial detection */
+ usb_conn_queue_dwork(info, 0);
+
+ return 0;
+
+put_role_sw:
+ usb_role_switch_put(info->role_sw);
+ return ret;
+}
+
+static int usb_conn_remove(struct platform_device *pdev)
+{
+ struct usb_conn_info *info = platform_get_drvdata(pdev);
+
+ cancel_delayed_work_sync(&info->dw_det);
+
+ if (info->last_role == USB_ROLE_HOST)
+ regulator_disable(info->vbus);
+
+ usb_role_switch_put(info->role_sw);
+
+ return 0;
+}
+
+static int __maybe_unused usb_conn_suspend(struct device *dev)
+{
+ struct usb_conn_info *info = dev_get_drvdata(dev);
+
+ if (info->id_gpiod)
+ disable_irq(info->id_irq);
+ if (info->vbus_gpiod)
+ disable_irq(info->vbus_irq);
+
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+static int __maybe_unused usb_conn_resume(struct device *dev)
+{
+ struct usb_conn_info *info = dev_get_drvdata(dev);
+
+ pinctrl_pm_select_default_state(dev);
+
+ if (info->id_gpiod)
+ enable_irq(info->id_irq);
+ if (info->vbus_gpiod)
+ enable_irq(info->vbus_irq);
+
+ usb_conn_queue_dwork(info, 0);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
+ usb_conn_suspend, usb_conn_resume);
+
+static const struct of_device_id usb_conn_dt_match[] = {
+ { .compatible = "linux,usb-conn-gpio", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
+
+static struct platform_driver usb_conn_driver = {
+ .probe = usb_conn_probe,
+ .remove = usb_conn_remove,
+ .driver = {
+ .name = "usb-conn-gpio",
+ .pm = &usb_conn_pm_ops,
+ .of_match_table = usb_conn_dt_match,
+ },
+};
+
+module_platform_driver(usb_conn_driver);
+
+MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");
+MODULE_DESCRIPTION("USB GPIO based connection detection driver");
+MODULE_LICENSE("GPL v2");
--
2.22.0
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