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/*

 * 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");