debug-leds.c

linux 内核源代码

/*
 * linux/arch/arm/plat-omap/debug-leds.c
 *
 * 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/init.h>
#include <linux/platform_device.h>
#include <linux/leds.h>

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

#include <asm/arch/fpga.h>
#include <asm/arch/gpio.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.
 *
 * The "surfer" expansion board and H2 sample board also have two-color
 * green+red LEDs (in parallel), used here for timer and idle indicators
 * in preference to the ones on the debug board, for a "Disco LED" effect.
 *
 * This driver exports either the original ARM LED API, the new generic
 * one, or both.
 */

static spinlock_t			lock;
static struct h2p2_dbg_fpga __iomem	*fpga;
static u16				led_state, hw_led_state;


#ifdef	CONFIG_LEDS_OMAP_DEBUG
#define new_led_api()	1
#else
#define new_led_api()	0
#endif


/*-------------------------------------------------------------------------*/

/* original ARM debug LED API:
 *  - timer and idle leds (some boards use non-FPGA leds here);
 *  - up to 4 generic leds, easily accessed in-kernel (any context)
 */

#define GPIO_LED_RED		3
#define GPIO_LED_GREEN		OMAP_MPUIO(4)

#define LED_STATE_ENABLED	0x01
#define LED_STATE_CLAIMED	0x02
#define LED_TIMER_ON		0x04

#define GPIO_IDLE		GPIO_LED_GREEN
#define GPIO_TIMER		GPIO_LED_RED

static void h2p2_dbg_leds_event(led_event_t evt)
{
	unsigned long flags;

	spin_lock_irqsave(&lock, flags);

	if (!(led_state & LED_STATE_ENABLED) && evt != led_start)
		goto done;

	switch (evt) {
	case led_start:
		if (fpga)
			led_state |= LED_STATE_ENABLED;
		break;

	case led_stop:
	case led_halted:
		/* all leds off during suspend or shutdown */

		if (!(machine_is_omap_perseus2() || machine_is_omap_h4())) {
			omap_set_gpio_dataout(GPIO_TIMER, 0);
			omap_set_gpio_dataout(GPIO_IDLE, 0);
		}

		__raw_writew(~0, &fpga->leds);
		led_state &= ~LED_STATE_ENABLED;
		goto done;

	case led_claim:
		led_state |= LED_STATE_CLAIMED;
		hw_led_state = 0;
		break;

	case led_release:
		led_state &= ~LED_STATE_CLAIMED;
		break;

#ifdef CONFIG_LEDS_TIMER
	case led_timer:
		led_state ^= LED_TIMER_ON;

		if (machine_is_omap_perseus2() || machine_is_omap_h4())
			hw_led_state ^= H2P2_DBG_FPGA_P2_LED_TIMER;
		else {
			omap_set_gpio_dataout(GPIO_TIMER,
					led_state & LED_TIMER_ON);
			goto done;
		}

		break;
#endif

#ifdef CONFIG_LEDS_CPU
	/* LED lit iff busy */
	case led_idle_start:
		if (machine_is_omap_perseus2() || machine_is_omap_h4())
			hw_led_state &= ~H2P2_DBG_FPGA_P2_LED_IDLE;
		else {
			omap_set_gpio_dataout(GPIO_IDLE, 1);
			goto done;
		}

		break;

	case led_idle_end:
		if (machine_is_omap_perseus2() || machine_is_omap_h4())
			hw_led_state |= H2P2_DBG_FPGA_P2_LED_IDLE;
		else {
			omap_set_gpio_dataout(GPIO_IDLE, 0);
			goto done;
		}

		break;
#endif

	case led_green_on:
		hw_led_state |= H2P2_DBG_FPGA_LED_GREEN;
		break;
	case led_green_off:
		hw_led_state &= ~H2P2_DBG_FPGA_LED_GREEN;
		break;

	case led_amber_on:
		hw_led_state |= H2P2_DBG_FPGA_LED_AMBER;
		break;
	case led_amber_off:
		hw_led_state &= ~H2P2_DBG_FPGA_LED_AMBER;
		break;

	case led_red_on:
		hw_led_state |= H2P2_DBG_FPGA_LED_RED;
		break;
	case led_red_off:
		hw_led_state &= ~H2P2_DBG_FPGA_LED_RED;
		break;

	case led_blue_on:
		hw_led_state |= H2P2_DBG_FPGA_LED_BLUE;
		break;
	case led_blue_off:
		hw_led_state &= ~H2P2_DBG_FPGA_LED_BLUE;
		break;

	default:
		break;
	}


	/*
	 *  Actually burn the LEDs
	 */
	if (led_state & LED_STATE_ENABLED)
		__raw_writew(~hw_led_state, &fpga->leds);

done:
	spin_unlock_irqrestore(&lock, flags);
}

/*-------------------------------------------------------------------------*/

/* "new" LED API
 *  - with syfs access and generic triggering
 *  - not readily accessible to in-kernel drivers
 */

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

static struct dbg_led dbg_leds[] = {
	/* REVISIT at least H2 uses different timer & cpu leds... */
#ifndef CONFIG_LEDS_TIMER
	{ .mask = 1 << 0,  .cdev.name =  "d4:green",
		.cdev.default_trigger = "heartbeat", },
#endif
#ifndef CONFIG_LEDS_CPU
	{ .mask = 1 << 1,  .cdev.name =  "d5:green", },		/* !idle */
#endif
	{ .mask = 1 << 2,  .cdev.name =  "d6:green", },
	{ .mask = 1 << 3,  .cdev.name =  "d7:green", },

	{ .mask = 1 << 4,  .cdev.name =  "d8:green", },
	{ .mask = 1 << 5,  .cdev.name =  "d9:green", },
	{ .mask = 1 << 6,  .cdev.name = "d10:green", },
	{ .mask = 1 << 7,  .cdev.name = "d11:green", },

	{ .mask = 1 << 8,  .cdev.name = "d12:green", },
	{ .mask = 1 << 9,  .cdev.name = "d13:green", },
	{ .mask = 1 << 10, .cdev.name = "d14:green", },
	{ .mask = 1 << 11, .cdev.name = "d15:green", },

#ifndef	CONFIG_LEDS
	{ .mask = 1 << 12, .cdev.name = "d16:green", },
	{ .mask = 1 << 13, .cdev.name = "d17:green", },
	{ .mask = 1 << 14, .cdev.name = "d18:green", },
	{ .mask = 1 << 15, .cdev.name = "d19:green", },
#endif
};

static void
fpga_led_set(struct led_classdev *cdev, enum led_brightness value)
{
	struct dbg_led	*led = container_of(cdev, struct dbg_led, cdev);
	unsigned long	flags;

	spin_lock_irqsave(&lock, flags);
	if (value == LED_OFF)
		hw_led_state &= ~led->mask;
	else
		hw_led_state |= led->mask;
	__raw_writew(~hw_led_state, &fpga->leds);
	spin_unlock_irqrestore(&lock, flags);
}

static void __init newled_init(struct device *dev)
{
	unsigned	i;
	struct dbg_led	*led;
	int		status;

	for (i = 0, led = dbg_leds; i < ARRAY_SIZE(dbg_leds); i++, led++) {
		led->cdev.brightness_set = fpga_led_set;
		status = led_classdev_register(dev, &led->cdev);
		if (status < 0)
			break;
	}
	return;
}


/*-------------------------------------------------------------------------*/

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

	spin_lock_init(&lock);

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

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

#ifdef	CONFIG_LEDS
	leds_event = h2p2_dbg_leds_event;
	leds_event(led_start);
#endif

	if (new_led_api()) {
		newled_init(&pdev->dev);
	}

	return 0;
}

static int fpga_suspend_late(struct platform_device *pdev, pm_message_t mesg)
{
	__raw_writew(~0, &fpga->leds);
	return 0;
}

static int fpga_resume_early(struct platform_device *pdev)
{
	__raw_writew(~hw_led_state, &fpga->leds);
	return 0;
}


static struct platform_driver led_driver = {
	.driver.name	= "omap_dbg_led",
	.probe		= fpga_probe,
	.suspend_late	= fpga_suspend_late,
	.resume_early	= fpga_resume_early,
};

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);