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