/*
* 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/workqueue.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;
struct work_struct work;
};
/*
* 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;
}
static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
{
int vbus;
vbus = gpio_get_value(pdata->gpio_vbus);
if (pdata->gpio_vbus_inverted)
vbus = !vbus;
return vbus;
}
static void gpio_vbus_work(struct work_struct *work)
{
struct gpio_vbus_data *gpio_vbus =
container_of(work, struct gpio_vbus_data, work);
struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
int gpio;
if (!gpio_vbus->otg.gadget)
return;
/* 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 (is_vbus_powered(pdata)) {
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;
}
}
/* 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);
dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
is_vbus_powered(pdata) ? "supplied" : "inactive",
gpio_vbus->otg.gadget ? gpio_vbus->otg.gadget->name : "none");
if (gpio_vbus->otg.gadget)
schedule_work(&gpio_vbus->work);
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;
}
INIT_WORK(&gpio_vbus->work, gpio_vbus_work);
/* 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");
