linux/drivers/usb/otg/gpio_vbus.c
Paul Gortmaker 6eb0de8270 usb: Add module.h to drivers/usb consumers who really use it.
The situation up to this point meant that module.h was pretty
much everywhere, regardless of whether you asked for it or not.
We are fixing that, so give the USB folks who want it an actual
include of it.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:31:25 -04:00

357 lines
9.2 KiB
C

/*
* 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/module.h>
#include <linux/slab.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);
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;
}
/* 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;
}
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");