397 lines
10 KiB
C
397 lines
10 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
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*
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* Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
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*/
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/gpio/consumer.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/usb.h>
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#include <linux/workqueue.h>
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#include <linux/regulator/consumer.h>
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#include <linux/usb/gadget.h>
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#include <linux/usb/otg.h>
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/*
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* A simple GPIO VBUS sensing driver for B peripheral only devices
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* with internal transceivers. It can control a D+ pullup GPIO and
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* a regulator to limit the current drawn from VBUS.
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*
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* Needs to be loaded before the UDC driver that will use it.
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*/
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struct gpio_vbus_data {
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struct gpio_desc *vbus_gpiod;
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struct gpio_desc *pullup_gpiod;
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struct usb_phy phy;
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struct device *dev;
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struct regulator *vbus_draw;
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int vbus_draw_enabled;
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unsigned mA;
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struct delayed_work work;
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int vbus;
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int irq;
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};
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/*
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* This driver relies on "both edges" triggering. VBUS has 100 msec to
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* stabilize, so the peripheral controller driver may need to cope with
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* some bouncing due to current surges (e.g. charging local capacitance)
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* and contact chatter.
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*
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* REVISIT in desperate straits, toggling between rising and falling
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* edges might be workable.
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*/
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#define VBUS_IRQ_FLAGS \
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(IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
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/* interface to regulator framework */
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static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
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{
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struct regulator *vbus_draw = gpio_vbus->vbus_draw;
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int enabled;
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int ret;
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if (!vbus_draw)
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return;
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enabled = gpio_vbus->vbus_draw_enabled;
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if (mA) {
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regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
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if (!enabled) {
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ret = regulator_enable(vbus_draw);
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if (ret < 0)
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return;
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gpio_vbus->vbus_draw_enabled = 1;
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}
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} else {
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if (enabled) {
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ret = regulator_disable(vbus_draw);
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if (ret < 0)
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return;
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gpio_vbus->vbus_draw_enabled = 0;
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}
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}
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gpio_vbus->mA = mA;
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}
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static int is_vbus_powered(struct gpio_vbus_data *gpio_vbus)
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{
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return gpiod_get_value(gpio_vbus->vbus_gpiod);
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}
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static void gpio_vbus_work(struct work_struct *work)
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{
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struct gpio_vbus_data *gpio_vbus =
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container_of(work, struct gpio_vbus_data, work.work);
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int status, vbus;
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if (!gpio_vbus->phy.otg->gadget)
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return;
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vbus = is_vbus_powered(gpio_vbus);
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if ((vbus ^ gpio_vbus->vbus) == 0)
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return;
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gpio_vbus->vbus = vbus;
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/* Peripheral controllers which manage the pullup themselves won't have
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* a pullup GPIO configured here. If it's configured here, we'll do
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* what isp1301_omap::b_peripheral() does and enable the pullup here...
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* although that may complicate usb_gadget_{,dis}connect() support.
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*/
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if (vbus) {
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status = USB_EVENT_VBUS;
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gpio_vbus->phy.otg->state = OTG_STATE_B_PERIPHERAL;
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gpio_vbus->phy.last_event = status;
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usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
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/* drawing a "unit load" is *always* OK, except for OTG */
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set_vbus_draw(gpio_vbus, 100);
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/* optionally enable D+ pullup */
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if (gpio_vbus->pullup_gpiod)
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gpiod_set_value(gpio_vbus->pullup_gpiod, 1);
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atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
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status, gpio_vbus->phy.otg->gadget);
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usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_ENUMERATED);
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} else {
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/* optionally disable D+ pullup */
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if (gpio_vbus->pullup_gpiod)
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gpiod_set_value(gpio_vbus->pullup_gpiod, 0);
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set_vbus_draw(gpio_vbus, 0);
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usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
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status = USB_EVENT_NONE;
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gpio_vbus->phy.otg->state = OTG_STATE_B_IDLE;
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gpio_vbus->phy.last_event = status;
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atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
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status, gpio_vbus->phy.otg->gadget);
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usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_NONE);
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}
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}
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/* VBUS change IRQ handler */
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static irqreturn_t gpio_vbus_irq(int irq, void *data)
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{
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struct platform_device *pdev = data;
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struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
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struct usb_otg *otg = gpio_vbus->phy.otg;
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dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
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is_vbus_powered(gpio_vbus) ? "supplied" : "inactive",
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otg->gadget ? otg->gadget->name : "none");
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if (otg->gadget)
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schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
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return IRQ_HANDLED;
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}
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/* OTG transceiver interface */
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/* bind/unbind the peripheral controller */
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static int gpio_vbus_set_peripheral(struct usb_otg *otg,
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struct usb_gadget *gadget)
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{
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struct gpio_vbus_data *gpio_vbus;
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struct platform_device *pdev;
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gpio_vbus = container_of(otg->usb_phy, struct gpio_vbus_data, phy);
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pdev = to_platform_device(gpio_vbus->dev);
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if (!gadget) {
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dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
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otg->gadget->name);
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/* optionally disable D+ pullup */
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if (gpio_vbus->pullup_gpiod)
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gpiod_set_value(gpio_vbus->pullup_gpiod, 0);
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set_vbus_draw(gpio_vbus, 0);
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usb_gadget_vbus_disconnect(otg->gadget);
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otg->state = OTG_STATE_UNDEFINED;
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otg->gadget = NULL;
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return 0;
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}
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otg->gadget = gadget;
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dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
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/* initialize connection state */
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gpio_vbus->vbus = 0; /* start with disconnected */
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gpio_vbus_irq(gpio_vbus->irq, pdev);
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return 0;
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}
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/* effective for B devices, ignored for A-peripheral */
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static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
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{
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struct gpio_vbus_data *gpio_vbus;
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gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
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if (phy->otg->state == OTG_STATE_B_PERIPHERAL)
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set_vbus_draw(gpio_vbus, mA);
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return 0;
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}
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/* for non-OTG B devices: set/clear transceiver suspend mode */
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static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
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{
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struct gpio_vbus_data *gpio_vbus;
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gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
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/* draw max 0 mA from vbus in suspend mode; or the previously
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* recorded amount of current if not suspended
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*
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* NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
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* if they're wake-enabled ... we don't handle that yet.
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*/
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return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
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}
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/* platform driver interface */
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static int gpio_vbus_probe(struct platform_device *pdev)
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{
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struct gpio_vbus_data *gpio_vbus;
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struct resource *res;
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struct device *dev = &pdev->dev;
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int err, irq;
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unsigned long irqflags;
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gpio_vbus = devm_kzalloc(&pdev->dev, sizeof(struct gpio_vbus_data),
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GFP_KERNEL);
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if (!gpio_vbus)
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return -ENOMEM;
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gpio_vbus->phy.otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
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GFP_KERNEL);
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if (!gpio_vbus->phy.otg)
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return -ENOMEM;
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platform_set_drvdata(pdev, gpio_vbus);
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gpio_vbus->dev = &pdev->dev;
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gpio_vbus->phy.label = "gpio-vbus";
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gpio_vbus->phy.dev = gpio_vbus->dev;
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gpio_vbus->phy.set_power = gpio_vbus_set_power;
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gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
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gpio_vbus->phy.otg->state = OTG_STATE_UNDEFINED;
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gpio_vbus->phy.otg->usb_phy = &gpio_vbus->phy;
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gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
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/* Look up the VBUS sensing GPIO */
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gpio_vbus->vbus_gpiod = devm_gpiod_get(dev, "vbus", GPIOD_IN);
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if (IS_ERR(gpio_vbus->vbus_gpiod)) {
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err = PTR_ERR(gpio_vbus->vbus_gpiod);
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dev_err(&pdev->dev, "can't request vbus gpio, err: %d\n", err);
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return err;
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}
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gpiod_set_consumer_name(gpio_vbus->vbus_gpiod, "vbus_detect");
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res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
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if (res) {
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irq = res->start;
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irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
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} else {
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irq = gpiod_to_irq(gpio_vbus->vbus_gpiod);
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irqflags = VBUS_IRQ_FLAGS;
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}
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gpio_vbus->irq = irq;
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/*
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* The VBUS sensing GPIO should have a pulldown, which will normally be
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* part of a resistor ladder turning a 4.0V-5.25V level on VBUS into a
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* value the GPIO detects as active. Some systems will use comparators.
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* Get the optional D+ or D- pullup GPIO. If the data line pullup is
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* in use, initialize it to "not pulling up"
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*/
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gpio_vbus->pullup_gpiod = devm_gpiod_get_optional(dev, "pullup",
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GPIOD_OUT_LOW);
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if (IS_ERR(gpio_vbus->pullup_gpiod)) {
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err = PTR_ERR(gpio_vbus->pullup_gpiod);
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dev_err(&pdev->dev, "can't request pullup gpio, err: %d\n",
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err);
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return err;
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}
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if (gpio_vbus->pullup_gpiod)
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gpiod_set_consumer_name(gpio_vbus->pullup_gpiod, "udc_pullup");
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err = devm_request_irq(&pdev->dev, irq, gpio_vbus_irq, irqflags,
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"vbus_detect", pdev);
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if (err) {
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dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
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irq, err);
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return err;
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}
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INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
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gpio_vbus->vbus_draw = devm_regulator_get(&pdev->dev, "vbus_draw");
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if (IS_ERR(gpio_vbus->vbus_draw)) {
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dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
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PTR_ERR(gpio_vbus->vbus_draw));
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gpio_vbus->vbus_draw = NULL;
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}
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/* only active when a gadget is registered */
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err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
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if (err) {
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dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
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err);
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return err;
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}
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/* TODO: wakeup could be enabled here with device_init_wakeup(dev, 1) */
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return 0;
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}
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static int gpio_vbus_remove(struct platform_device *pdev)
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{
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struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
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device_init_wakeup(&pdev->dev, 0);
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cancel_delayed_work_sync(&gpio_vbus->work);
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usb_remove_phy(&gpio_vbus->phy);
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return 0;
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}
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#ifdef CONFIG_PM
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static int gpio_vbus_pm_suspend(struct device *dev)
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{
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struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
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if (device_may_wakeup(dev))
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enable_irq_wake(gpio_vbus->irq);
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return 0;
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}
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static int gpio_vbus_pm_resume(struct device *dev)
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{
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struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
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|
if (device_may_wakeup(dev))
|
||
|
|
disable_irq_wake(gpio_vbus->irq);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
|
||
|
|
.suspend = gpio_vbus_pm_suspend,
|
||
|
|
.resume = gpio_vbus_pm_resume,
|
||
|
|
};
|
||
|
|
#endif
|
||
|
|
|
||
|
|
MODULE_ALIAS("platform:gpio-vbus");
|
||
|
|
|
||
|
|
/*
|
||
|
|
* NOTE: this driver matches against "gpio-usb-b-connector" for
|
||
|
|
* devices that do NOT support role switch.
|
||
|
|
*/
|
||
|
|
static const struct of_device_id gpio_vbus_of_match[] = {
|
||
|
|
{
|
||
|
|
.compatible = "gpio-usb-b-connector",
|
||
|
|
},
|
||
|
|
{},
|
||
|
|
};
|
||
|
|
|
||
|
|
static struct platform_driver gpio_vbus_driver = {
|
||
|
|
.driver = {
|
||
|
|
.name = "gpio-vbus",
|
||
|
|
#ifdef CONFIG_PM
|
||
|
|
.pm = &gpio_vbus_dev_pm_ops,
|
||
|
|
#endif
|
||
|
|
.of_match_table = gpio_vbus_of_match,
|
||
|
|
},
|
||
|
|
.probe = gpio_vbus_probe,
|
||
|
|
.remove = gpio_vbus_remove,
|
||
|
|
};
|
||
|
|
|
||
|
|
module_platform_driver(gpio_vbus_driver);
|
||
|
|
|
||
|
|
MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
|
||
|
|
MODULE_AUTHOR("Philipp Zabel");
|
||
|
|
MODULE_LICENSE("GPL");
|