--- /dev/null
+/*
+ * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
+ *
+ * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/usb.h>
+
+#include <linux/regulator/consumer.h>
+
+#include <linux/usb/gadget.h>
+#include <linux/usb/gpio_vbus.h>
+#include <linux/usb/otg.h>
+
+
+/*
+ * A simple GPIO VBUS sensing driver for B peripheral only devices
+ * with internal transceivers. It can control a D+ pullup GPIO and
+ * a regulator to limit the current drawn from VBUS.
+ *
+ * Needs to be loaded before the UDC driver that will use it.
+ */
+struct gpio_vbus_data {
+ struct otg_transceiver otg;
+ struct device *dev;
+ struct regulator *vbus_draw;
+ int vbus_draw_enabled;
+ unsigned mA;
+};
+
+
+/*
+ * This driver relies on "both edges" triggering. VBUS has 100 msec to
+ * stabilize, so the peripheral controller driver may need to cope with
+ * some bouncing due to current surges (e.g. charging local capacitance)
+ * and contact chatter.
+ *
+ * REVISIT in desperate straits, toggling between rising and falling
+ * edges might be workable.
+ */
+#define VBUS_IRQ_FLAGS \
+ ( IRQF_SAMPLE_RANDOM | IRQF_SHARED \
+ | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING )
+
+
+/* interface to regulator framework */
+static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
+{
+ struct regulator *vbus_draw = gpio_vbus->vbus_draw;
+ int enabled;
+
+ if (!vbus_draw)
+ return;
+
+ enabled = gpio_vbus->vbus_draw_enabled;
+ if (mA) {
+ regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
+ if (!enabled) {
+ regulator_enable(vbus_draw);
+ gpio_vbus->vbus_draw_enabled = 1;
+ }
+ } else {
+ if (enabled) {
+ regulator_disable(vbus_draw);
+ gpio_vbus->vbus_draw_enabled = 0;
+ }
+ }
+ gpio_vbus->mA = mA;
+}
+
+/* VBUS change IRQ handler */
+static irqreturn_t gpio_vbus_irq(int irq, void *data)
+{
+ struct platform_device *pdev = data;
+ struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
+ struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
+ int gpio, vbus;
+
+ vbus = gpio_get_value(pdata->gpio_vbus);
+ if (pdata->gpio_vbus_inverted)
+ vbus = !vbus;
+
+ dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
+ vbus ? "supplied" : "inactive",
+ gpio_vbus->otg.gadget ? gpio_vbus->otg.gadget->name : "none");
+
+ if (!gpio_vbus->otg.gadget)
+ return IRQ_HANDLED;
+
+ /* Peripheral controllers which manage the pullup themselves won't have
+ * gpio_pullup configured here. If it's configured here, we'll do what
+ * isp1301_omap::b_peripheral() does and enable the pullup here... although
+ * that may complicate usb_gadget_{,dis}connect() support.
+ */
+ gpio = pdata->gpio_pullup;
+ if (vbus) {
+ gpio_vbus->otg.state = OTG_STATE_B_PERIPHERAL;
+ usb_gadget_vbus_connect(gpio_vbus->otg.gadget);
+
+ /* drawing a "unit load" is *always* OK, except for OTG */
+ set_vbus_draw(gpio_vbus, 100);
+
+ /* optionally enable D+ pullup */
+ if (gpio_is_valid(gpio))
+ gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
+ } else {
+ /* optionally disable D+ pullup */
+ if (gpio_is_valid(gpio))
+ gpio_set_value(gpio, pdata->gpio_pullup_inverted);
+
+ set_vbus_draw(gpio_vbus, 0);
+
+ usb_gadget_vbus_disconnect(gpio_vbus->otg.gadget);
+ gpio_vbus->otg.state = OTG_STATE_B_IDLE;
+ }
+
+ return IRQ_HANDLED;
+}
+
+/* OTG transceiver interface */
+
+/* bind/unbind the peripheral controller */
+static int gpio_vbus_set_peripheral(struct otg_transceiver *otg,
+ struct usb_gadget *gadget)
+{
+ struct gpio_vbus_data *gpio_vbus;
+ struct gpio_vbus_mach_info *pdata;
+ struct platform_device *pdev;
+ int gpio, irq;
+
+ gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);
+ pdev = to_platform_device(gpio_vbus->dev);
+ pdata = gpio_vbus->dev->platform_data;
+ irq = gpio_to_irq(pdata->gpio_vbus);
+ gpio = pdata->gpio_pullup;
+
+ if (!gadget) {
+ dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
+ otg->gadget->name);
+
+ /* optionally disable D+ pullup */
+ if (gpio_is_valid(gpio))
+ gpio_set_value(gpio, pdata->gpio_pullup_inverted);
+
+ set_vbus_draw(gpio_vbus, 0);
+
+ usb_gadget_vbus_disconnect(otg->gadget);
+ otg->state = OTG_STATE_UNDEFINED;
+
+ otg->gadget = NULL;
+ return 0;
+ }
+
+ otg->gadget = gadget;
+ dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
+
+ /* initialize connection state */
+ gpio_vbus_irq(irq, pdev);
+ return 0;
+}
+
+/* effective for B devices, ignored for A-peripheral */
+static int gpio_vbus_set_power(struct otg_transceiver *otg, unsigned mA)
+{
+ struct gpio_vbus_data *gpio_vbus;
+
+ gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);
+
+ if (otg->state == OTG_STATE_B_PERIPHERAL)
+ set_vbus_draw(gpio_vbus, mA);
+ return 0;
+}
+
+/* for non-OTG B devices: set/clear transceiver suspend mode */
+static int gpio_vbus_set_suspend(struct otg_transceiver *otg, int suspend)
+{
+ struct gpio_vbus_data *gpio_vbus;
+
+ gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);
+
+ /* draw max 0 mA from vbus in suspend mode; or the previously
+ * recorded amount of current if not suspended
+ *
+ * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
+ * if they're wake-enabled ... we don't handle that yet.
+ */
+ return gpio_vbus_set_power(otg, suspend ? 0 : gpio_vbus->mA);
+}
+
+/* platform driver interface */
+
+static int __init gpio_vbus_probe(struct platform_device *pdev)
+{
+ struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
+ struct gpio_vbus_data *gpio_vbus;
+ struct resource *res;
+ int err, gpio, irq;
+
+ if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
+ return -EINVAL;
+ gpio = pdata->gpio_vbus;
+
+ gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
+ if (!gpio_vbus)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, gpio_vbus);
+ gpio_vbus->dev = &pdev->dev;
+ gpio_vbus->otg.label = "gpio-vbus";
+ gpio_vbus->otg.state = OTG_STATE_UNDEFINED;
+ gpio_vbus->otg.set_peripheral = gpio_vbus_set_peripheral;
+ gpio_vbus->otg.set_power = gpio_vbus_set_power;
+ gpio_vbus->otg.set_suspend = gpio_vbus_set_suspend;
+
+ err = gpio_request(gpio, "vbus_detect");
+ if (err) {
+ dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
+ gpio, err);
+ goto err_gpio;
+ }
+ gpio_direction_input(gpio);
+
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (res) {
+ irq = res->start;
+ res->flags &= IRQF_TRIGGER_MASK;
+ res->flags |= IRQF_SAMPLE_RANDOM | IRQF_SHARED;
+ } else
+ irq = gpio_to_irq(gpio);
+
+ /* if data line pullup is in use, initialize it to "not pulling up" */
+ gpio = pdata->gpio_pullup;
+ if (gpio_is_valid(gpio)) {
+ err = gpio_request(gpio, "udc_pullup");
+ if (err) {
+ dev_err(&pdev->dev,
+ "can't request pullup gpio %d, err: %d\n",
+ gpio, err);
+ gpio_free(pdata->gpio_vbus);
+ goto err_gpio;
+ }
+ gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
+ }
+
+ err = request_irq(irq, gpio_vbus_irq, VBUS_IRQ_FLAGS,
+ "vbus_detect", pdev);
+ if (err) {
+ dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
+ irq, err);
+ goto err_irq;
+ }
+
+ /* only active when a gadget is registered */
+ err = otg_set_transceiver(&gpio_vbus->otg);
+ if (err) {
+ dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
+ err);
+ goto err_otg;
+ }
+
+ gpio_vbus->vbus_draw = regulator_get(&pdev->dev, "vbus_draw");
+ if (IS_ERR(gpio_vbus->vbus_draw)) {
+ dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
+ PTR_ERR(gpio_vbus->vbus_draw));
+ gpio_vbus->vbus_draw = NULL;
+ }
+
+ return 0;
+err_otg:
+ free_irq(irq, &pdev->dev);
+err_irq:
+ if (gpio_is_valid(pdata->gpio_pullup))
+ gpio_free(pdata->gpio_pullup);
+ gpio_free(pdata->gpio_vbus);
+err_gpio:
+ platform_set_drvdata(pdev, NULL);
+ kfree(gpio_vbus);
+ return err;
+}
+
+static int __exit gpio_vbus_remove(struct platform_device *pdev)
+{
+ struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
+ struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
+ int gpio = pdata->gpio_vbus;
+
+ regulator_put(gpio_vbus->vbus_draw);
+
+ otg_set_transceiver(NULL);
+
+ free_irq(gpio_to_irq(gpio), &pdev->dev);
+ if (gpio_is_valid(pdata->gpio_pullup))
+ gpio_free(pdata->gpio_pullup);
+ gpio_free(gpio);
+ platform_set_drvdata(pdev, NULL);
+ kfree(gpio_vbus);
+
+ return 0;
+}
+
+/* NOTE: the gpio-vbus device may *NOT* be hotplugged */
+
+MODULE_ALIAS("platform:gpio-vbus");
+
+static struct platform_driver gpio_vbus_driver = {
+ .driver = {
+ .name = "gpio-vbus",
+ .owner = THIS_MODULE,
+ },
+ .remove = __exit_p(gpio_vbus_remove),
+};
+
+static int __init gpio_vbus_init(void)
+{
+ return platform_driver_probe(&gpio_vbus_driver, gpio_vbus_probe);
+}
+module_init(gpio_vbus_init);
+
+static void __exit gpio_vbus_exit(void)
+{
+ platform_driver_unregister(&gpio_vbus_driver);
+}
+module_exit(gpio_vbus_exit);
+
+MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
+MODULE_AUTHOR("Philipp Zabel");
+MODULE_LICENSE("GPL");
projects / h-e-n / blobdiff