USB: otg: gpio_vbus transceiver stub
gpio_vbus provides simple GPIO VBUS sensing for peripheral controllers with an internal transceiver. Optionally, a second GPIO can be used to control D+ pullup. It also interfaces with the regulator framework to limit charging currents when powered via USB. gpio_vbus requests the regulator supplying "vbus_draw" and can enable/disable it or limit its current depending on USB state. [dbrownell@users.sourceforge.net: use drivers/otg, cleanups ] Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Philipp Zabel
Greg Kroah-Hartman
parent
b8da8677d4
commit
6084f1bf0c
4 changed files with 383 additions and 0 deletions
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@ -14,6 +14,19 @@ config USB_OTG_UTILS
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Select this to make sure the build includes objects from
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the OTG infrastructure directory.
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#
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# USB Transceiver Drivers
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#
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config USB_GPIO_VBUS
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tristate "GPIO based peripheral-only VBUS sensing 'transceiver'"
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depends on GENERIC_GPIO
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select USB_OTG_UTILS
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help
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Provides simple GPIO VBUS sensing for controllers with an
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internal transceiver via the otg_transceiver interface, and
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optionally control of a D+ pullup GPIO as well as a VBUS
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current limit regulator.
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config ISP1301_OMAP
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tristate "Philips ISP1301 with OMAP OTG"
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depends on I2C && ARCH_OMAP_OTG
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@ -1,3 +1,8 @@
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#
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# OTG infrastructure and transceiver drivers
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#
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obj-$(CONFIG_USB_GPIO_VBUS) += gpio_vbus.o
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obj-$(CONFIG_ISP1301_OMAP) += isp1301_omap.o
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ifeq ($(CONFIG_USB_DEBUG),y)
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335
drivers/usb/otg/gpio_vbus.c
Normal file
335
drivers/usb/otg/gpio_vbus.c
Normal file
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@ -0,0 +1,335 @@
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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.h>
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#include <linux/interrupt.h>
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#include <linux/usb.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/gpio_vbus.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 otg_transceiver otg;
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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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};
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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_SAMPLE_RANDOM | IRQF_SHARED \
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| 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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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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regulator_enable(vbus_draw);
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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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regulator_disable(vbus_draw);
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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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/* 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_mach_info *pdata = pdev->dev.platform_data;
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struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
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int gpio, vbus;
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vbus = gpio_get_value(pdata->gpio_vbus);
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if (pdata->gpio_vbus_inverted)
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vbus = !vbus;
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dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
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vbus ? "supplied" : "inactive",
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gpio_vbus->otg.gadget ? gpio_vbus->otg.gadget->name : "none");
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if (!gpio_vbus->otg.gadget)
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return IRQ_HANDLED;
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/* Peripheral controllers which manage the pullup themselves won't have
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* gpio_pullup configured here. If it's configured here, we'll do what
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* isp1301_omap::b_peripheral() does and enable the pullup here... although
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* that may complicate usb_gadget_{,dis}connect() support.
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*/
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gpio = pdata->gpio_pullup;
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if (vbus) {
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gpio_vbus->otg.state = OTG_STATE_B_PERIPHERAL;
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usb_gadget_vbus_connect(gpio_vbus->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_is_valid(gpio))
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gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
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} else {
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/* optionally disable D+ pullup */
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if (gpio_is_valid(gpio))
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gpio_set_value(gpio, pdata->gpio_pullup_inverted);
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set_vbus_draw(gpio_vbus, 0);
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usb_gadget_vbus_disconnect(gpio_vbus->otg.gadget);
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gpio_vbus->otg.state = OTG_STATE_B_IDLE;
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}
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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 otg_transceiver *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 gpio_vbus_mach_info *pdata;
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struct platform_device *pdev;
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int gpio, irq;
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gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);
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pdev = to_platform_device(gpio_vbus->dev);
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pdata = gpio_vbus->dev->platform_data;
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irq = gpio_to_irq(pdata->gpio_vbus);
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gpio = pdata->gpio_pullup;
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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_is_valid(gpio))
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gpio_set_value(gpio, pdata->gpio_pullup_inverted);
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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_irq(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 otg_transceiver *otg, unsigned mA)
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{
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struct gpio_vbus_data *gpio_vbus;
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gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);
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if (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 otg_transceiver *otg, int suspend)
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{
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struct gpio_vbus_data *gpio_vbus;
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gpio_vbus = container_of(otg, struct gpio_vbus_data, otg);
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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(otg, suspend ? 0 : gpio_vbus->mA);
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}
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/* platform driver interface */
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static int __init gpio_vbus_probe(struct platform_device *pdev)
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{
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struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
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struct gpio_vbus_data *gpio_vbus;
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struct resource *res;
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int err, gpio, irq;
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if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
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return -EINVAL;
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gpio = pdata->gpio_vbus;
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gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
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if (!gpio_vbus)
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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->otg.label = "gpio-vbus";
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gpio_vbus->otg.state = OTG_STATE_UNDEFINED;
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gpio_vbus->otg.set_peripheral = gpio_vbus_set_peripheral;
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gpio_vbus->otg.set_power = gpio_vbus_set_power;
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gpio_vbus->otg.set_suspend = gpio_vbus_set_suspend;
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err = gpio_request(gpio, "vbus_detect");
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if (err) {
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dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
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gpio, err);
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goto err_gpio;
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}
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gpio_direction_input(gpio);
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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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res->flags &= IRQF_TRIGGER_MASK;
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res->flags |= IRQF_SAMPLE_RANDOM | IRQF_SHARED;
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} else
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irq = gpio_to_irq(gpio);
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/* if data line pullup is in use, initialize it to "not pulling up" */
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gpio = pdata->gpio_pullup;
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if (gpio_is_valid(gpio)) {
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err = gpio_request(gpio, "udc_pullup");
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if (err) {
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dev_err(&pdev->dev,
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"can't request pullup gpio %d, err: %d\n",
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gpio, err);
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gpio_free(pdata->gpio_vbus);
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goto err_gpio;
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}
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gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
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}
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err = request_irq(irq, gpio_vbus_irq, VBUS_IRQ_FLAGS,
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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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goto err_irq;
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}
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/* only active when a gadget is registered */
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err = otg_set_transceiver(&gpio_vbus->otg);
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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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goto err_otg;
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}
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gpio_vbus->vbus_draw = 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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return 0;
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err_otg:
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free_irq(irq, &pdev->dev);
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err_irq:
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if (gpio_is_valid(pdata->gpio_pullup))
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gpio_free(pdata->gpio_pullup);
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gpio_free(pdata->gpio_vbus);
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err_gpio:
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platform_set_drvdata(pdev, NULL);
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kfree(gpio_vbus);
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return err;
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}
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static int __exit 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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struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
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int gpio = pdata->gpio_vbus;
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regulator_put(gpio_vbus->vbus_draw);
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otg_set_transceiver(NULL);
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free_irq(gpio_to_irq(gpio), &pdev->dev);
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if (gpio_is_valid(pdata->gpio_pullup))
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gpio_free(pdata->gpio_pullup);
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gpio_free(gpio);
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platform_set_drvdata(pdev, NULL);
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kfree(gpio_vbus);
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return 0;
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}
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/* NOTE: the gpio-vbus device may *NOT* be hotplugged */
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MODULE_ALIAS("platform:gpio-vbus");
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static struct platform_driver gpio_vbus_driver = {
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.driver = {
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.name = "gpio-vbus",
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.owner = THIS_MODULE,
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},
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.remove = __exit_p(gpio_vbus_remove),
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};
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static int __init gpio_vbus_init(void)
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{
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return platform_driver_probe(&gpio_vbus_driver, gpio_vbus_probe);
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}
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module_init(gpio_vbus_init);
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static void __exit gpio_vbus_exit(void)
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{
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platform_driver_unregister(&gpio_vbus_driver);
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}
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module_exit(gpio_vbus_exit);
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MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
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MODULE_AUTHOR("Philipp Zabel");
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MODULE_LICENSE("GPL");
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30
include/linux/usb/gpio_vbus.h
Normal file
30
include/linux/usb/gpio_vbus.h
Normal file
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@ -0,0 +1,30 @@
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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.
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* Optionally D+ pullup can be controlled by a second GPIO.
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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/**
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* struct gpio_vbus_mach_info - configuration for gpio_vbus
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* @gpio_vbus: VBUS sensing GPIO
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* @gpio_pullup: optional D+ or D- pullup GPIO (else negative/invalid)
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* @gpio_vbus_inverted: true if gpio_vbus is active low
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* @gpio_pullup_inverted: true if gpio_pullup is active low
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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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*/
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struct gpio_vbus_mach_info {
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int gpio_vbus;
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int gpio_pullup;
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bool gpio_vbus_inverted;
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bool gpio_pullup_inverted;
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};
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