debug-leds.c

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/*
 * linux/arch/arm/plat-omap/debug-leds.c
 *
 * Copyright 2011 by Bryan Wu <[email protected]>
 * Copyright 2003 by Texas Instruments Incorporated
 *
 * 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/init.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/io.h>
#include <linux/platform_data/gpio-omap.h>
#include <linux/slab.h>

#include <mach/hardware.h>
#include <asm/mach-types.h>

#include <plat/fpga.h>

/* Many OMAP development platforms reuse the same "debug board"; these
 * platforms include H2, H3, H4, and Perseus2.  There are 16 LEDs on the
 * debug board (all green), accessed through FPGA registers.
 */

static struct h2p2_dbg_fpga __iomem *fpga;

static u16 fpga_led_state;

struct dbg_led {
    struct led_classdev cdev;
    u16         mask;
};

static const struct {
    const char *name;
    const char *trigger;
} dbg_leds[] = {
    { "dbg:d4", "heartbeat", },
    { "dbg:d5", "cpu0", },
    { "dbg:d6", "default-on", },
    { "dbg:d7", },
    { "dbg:d8", },
    { "dbg:d9", },
    { "dbg:d10", },
    { "dbg:d11", },
    { "dbg:d12", },
    { "dbg:d13", },
    { "dbg:d14", },
    { "dbg:d15", },
    { "dbg:d16", },
    { "dbg:d17", },
    { "dbg:d18", },
    { "dbg:d19", },
};

/*
 * The triggers lines up below will only be used if the
 * LED triggers are compiled in.
 */
static void dbg_led_set(struct led_classdev *cdev,
                  enum led_brightness b)
{
    struct dbg_led *led = container_of(cdev, struct dbg_led, cdev);
    u16 reg;

    reg = __raw_readw(&fpga->leds);
    if (b != LED_OFF)
        reg |= led->mask;
    else
        reg &= ~led->mask;
    __raw_writew(reg, &fpga->leds);
}

static enum led_brightness dbg_led_get(struct led_classdev *cdev)
{
    struct dbg_led *led = container_of(cdev, struct dbg_led, cdev);
    u16 reg;

    reg = __raw_readw(&fpga->leds);
    return (reg & led->mask) ? LED_FULL : LED_OFF;
}

static int fpga_probe(struct platform_device *pdev)
{
    struct resource *iomem;
    int i;

    iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!iomem)
        return -ENODEV;

    fpga = ioremap(iomem->start, H2P2_DBG_FPGA_SIZE);
    __raw_writew(0xff, &fpga->leds);

    for (i = 0; i < ARRAY_SIZE(dbg_leds); i++) {
        struct dbg_led *led;

        led = kzalloc(sizeof(*led), GFP_KERNEL);
        if (!led)
            break;

        led->cdev.name = dbg_leds[i].name;
        led->cdev.brightness_set = dbg_led_set;
        led->cdev.brightness_get = dbg_led_get;
        led->cdev.default_trigger = dbg_leds[i].trigger;
        led->mask = BIT(i);

        if (led_classdev_register(NULL, &led->cdev) < 0) {
            kfree(led);
            break;
        }
    }

    return 0;
}

static int fpga_suspend_noirq(struct device *dev)
{
    fpga_led_state = __raw_readw(&fpga->leds);
    __raw_writew(0xff, &fpga->leds);

    return 0;
}

static int fpga_resume_noirq(struct device *dev)
{
    __raw_writew(~fpga_led_state, &fpga->leds);
    return 0;
}

static const struct dev_pm_ops fpga_dev_pm_ops = {
    .suspend_noirq = fpga_suspend_noirq,
    .resume_noirq = fpga_resume_noirq,
};

static struct platform_driver led_driver = {
    .driver.name    = "omap_dbg_led",
    .driver.pm  = &fpga_dev_pm_ops,
    .probe      = fpga_probe,
};

static int __init fpga_init(void)
{
    if (machine_is_omap_h4()
            || machine_is_omap_h3()
            || machine_is_omap_h2()
            || machine_is_omap_perseus2()
            )
        return platform_driver_register(&led_driver);
    return 0;
}
fs_initcall(fpga_init);