216 lines
6.1 KiB
C
216 lines
6.1 KiB
C
/*
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* IXP4XX GPIO driver LED driver
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*
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* Author: John Bowler <jbowler@acm.org>
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*
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* Copyright (c) 2006 John Bowler
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*
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* Permission is hereby granted, free of charge, to any
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* person obtaining a copy of this software and associated
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* documentation files (the "Software"), to deal in the
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* Software without restriction, including without
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* limitation the rights to use, copy, modify, merge,
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* publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the
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* following conditions:
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*
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* The above copyright notice and this permission notice
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* shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
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* ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
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* TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
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* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
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* SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
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* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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*/
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#include <linux/config.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include <linux/leds.h>
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#include <asm/arch/hardware.h>
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extern spinlock_t gpio_lock;
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/* Up to 16 gpio lines are possible. */
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#define GPIO_MAX 16
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static struct ixp4xxgpioled_device {
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struct led_classdev ancestor;
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int flags;
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} ixp4xxgpioled_devices[GPIO_MAX];
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void ixp4xxgpioled_brightness_set(struct led_classdev *pled,
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enum led_brightness value)
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{
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const struct ixp4xxgpioled_device *const ixp4xx_dev =
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container_of(pled, struct ixp4xxgpioled_device, ancestor);
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const u32 gpio_pin = ixp4xx_dev - ixp4xxgpioled_devices;
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if (gpio_pin < GPIO_MAX && ixp4xx_dev->ancestor.name != 0) {
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/* Set or clear the 'gpio_pin' bit according to the style
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* and the required setting (value > 0 == on)
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*/
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const int gpio_value =
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(value > 0) == (ixp4xx_dev->flags != IXP4XX_GPIO_LOW) ?
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IXP4XX_GPIO_HIGH : IXP4XX_GPIO_LOW;
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{
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unsigned long flags;
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spin_lock_irqsave(&gpio_lock, flags);
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gpio_line_set(gpio_pin, gpio_value);
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spin_unlock_irqrestore(&gpio_lock, flags);
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}
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}
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}
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/* LEDs are described in resources, the following iterates over the valid
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* LED resources.
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*/
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#define for_all_leds(i, pdev) \
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for (i=0; i<pdev->num_resources; ++i) \
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if (pdev->resource[i].start < GPIO_MAX && \
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pdev->resource[i].name != 0)
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/* The following applies 'operation' to each LED from the given platform,
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* the function always returns 0 to allow tail call elimination.
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*/
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static int apply_to_all_leds(struct platform_device *pdev,
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void (*operation)(struct led_classdev *pled))
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{
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int i;
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for_all_leds(i, pdev)
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operation(&ixp4xxgpioled_devices[pdev->resource[i].start].ancestor);
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return 0;
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}
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#ifdef CONFIG_PM
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static int ixp4xxgpioled_suspend(struct platform_device *pdev,
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pm_message_t state)
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{
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return apply_to_all_leds(pdev, led_classdev_suspend);
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}
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static int ixp4xxgpioled_resume(struct platform_device *pdev)
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{
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return apply_to_all_leds(pdev, led_classdev_resume);
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}
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#endif
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static void ixp4xxgpioled_remove_one_led(struct led_classdev *pled)
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{
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led_classdev_unregister(pled);
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pled->name = 0;
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}
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static int ixp4xxgpioled_remove(struct platform_device *pdev)
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{
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return apply_to_all_leds(pdev, ixp4xxgpioled_remove_one_led);
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}
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static int ixp4xxgpioled_probe(struct platform_device *pdev)
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{
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/* The board level has to tell the driver where the
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* LEDs are connected - there is no way to find out
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* electrically. It must also say whether the GPIO
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* lines are active high or active low.
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*
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* To do this read the num_resources (the number of
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* LEDs) and the struct resource (the data for each
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* LED). The name comes from the resource, and it
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* isn't copied.
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*/
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int i;
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for_all_leds(i, pdev) {
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const u8 gpio_pin = pdev->resource[i].start;
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int rc;
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if (ixp4xxgpioled_devices[gpio_pin].ancestor.name == 0) {
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unsigned long flags;
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spin_lock_irqsave(&gpio_lock, flags);
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gpio_line_config(gpio_pin, IXP4XX_GPIO_OUT);
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/* The config can, apparently, reset the state,
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* I suspect the gpio line may be an input and
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* the config may cause the line to be latched,
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* so the setting depends on how the LED is
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* connected to the line (which affects how it
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* floats if not driven).
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*/
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gpio_line_set(gpio_pin, IXP4XX_GPIO_HIGH);
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spin_unlock_irqrestore(&gpio_lock, flags);
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ixp4xxgpioled_devices[gpio_pin].flags =
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pdev->resource[i].flags & IORESOURCE_BITS;
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ixp4xxgpioled_devices[gpio_pin].ancestor.name =
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pdev->resource[i].name;
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/* This is how a board manufacturer makes the LED
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* come on on reset - the GPIO line will be high, so
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* make the LED light when the line is low...
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*/
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if (ixp4xxgpioled_devices[gpio_pin].flags != IXP4XX_GPIO_LOW)
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ixp4xxgpioled_devices[gpio_pin].ancestor.brightness = 100;
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else
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ixp4xxgpioled_devices[gpio_pin].ancestor.brightness = 0;
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ixp4xxgpioled_devices[gpio_pin].ancestor.flags = 0;
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ixp4xxgpioled_devices[gpio_pin].ancestor.brightness_set =
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ixp4xxgpioled_brightness_set;
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ixp4xxgpioled_devices[gpio_pin].ancestor.default_trigger = 0;
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}
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rc = led_classdev_register(&pdev->dev,
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&ixp4xxgpioled_devices[gpio_pin].ancestor);
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if (rc < 0) {
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ixp4xxgpioled_devices[gpio_pin].ancestor.name = 0;
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ixp4xxgpioled_remove(pdev);
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return rc;
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}
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}
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return 0;
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}
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static struct platform_driver ixp4xxgpioled_driver = {
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.probe = ixp4xxgpioled_probe,
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.remove = ixp4xxgpioled_remove,
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#ifdef CONFIG_PM
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.suspend = ixp4xxgpioled_suspend,
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.resume = ixp4xxgpioled_resume,
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#endif
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.driver = {
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.name = "IXP4XX-GPIO-LED",
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},
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};
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static int __init ixp4xxgpioled_init(void)
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{
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return platform_driver_register(&ixp4xxgpioled_driver);
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}
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static void __exit ixp4xxgpioled_exit(void)
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{
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platform_driver_unregister(&ixp4xxgpioled_driver);
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}
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module_init(ixp4xxgpioled_init);
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module_exit(ixp4xxgpioled_exit);
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MODULE_AUTHOR("John Bowler <jbowler@acm.org>");
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MODULE_DESCRIPTION("IXP4XX GPIO LED driver");
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MODULE_LICENSE("Dual MIT/GPL");
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