/* * <arch/arm/mach-davinci/leds-evm.c> * * LED support for TI DaVinci EVM * * 2006 (c) Texas Instruments, Inc. This file is licensed under * the terms of the GNU General Public License version 2. This program * is licensed "as is" without any warranty of any kind, whether express * or implied. */#include <linux/config.h>#include <linux/init.h>#include <linux/interrupt.h>#include <linux/types.h>#include <linux/i2c.h>#include <linux/errno.h>#include <asm/mach-types.h>#include <asm/hardware.h>#include <asm/leds.h>#include <asm/system.h>/* eight leds on a pcf8574a I2C gpio expander; 0 == ON, 1 == OFF *  - drivers can use leds_event(led_{green,amber,red,blue}_{on,off}) *  - userspace can do the same with /sys/devices/leds/leds0/event */#define	LED_DS8			(1 << 0)#define	LED_DS7			(1 << 1)#define	LED_DS6			(1 << 2)#define	LED_DS5			(1 << 3)#define	LED_DS4			(1 << 4)#define	LED_DS3			(1 << 5)#define	LED_DS2			(1 << 6)#define	LED_DS1			(1 << 7)#define LED_STATE_ENABLED	(1 << 8)#define LED_STATE_CLAIMED	(1 << 9)static u16	hw_led_state;static u8	leds_change;/* these leds use I2C not GPIO, so we can't change values * and remain "idle" ... so there's no "idle" LED. */#define	TIMER_LED		LED_DS8#define	GREEN_LED		LED_DS1#define	AMBER_LED		LED_DS2#define	RED_LED			LED_DS3#define	BLUE_LED		LED_DS4#define	APP_LEDS	(GREEN_LED | AMBER_LED | RED_LED | BLUE_LED)static DEFINE_RAW_SPINLOCK(lock);#define	EVM_I2C_ADDR	0x38#ifdef CONFIG_PREEMPT_RTstatic void pcf_work(unsigned long unused)#elsestatic void pcf_work(void *unused)#endif{	struct i2c_adapter	*adap;	int			err;	struct i2c_msg		msg;	adap = i2c_get_adapter(0);	if (!adap)		return;	for (;;) {		static u8	leds;		spin_lock_irq(&lock);		leds = (u8) hw_led_state;		err= leds_change;		leds_change = 0;		spin_unlock_irq(&lock);		if (!err)			break;		msg.addr = EVM_I2C_ADDR;		msg.flags = 0;		msg.len = 1;		msg.buf = &leds;		err = i2c_transfer(adap, &msg, 1);		if (err < 0)			pr_debug("LED: set to %02x, err %d\n", leds, err);	}}/* Under PREEMPT_RT, this code may be called from the timer interrupt * with is a real hard IRQ.  Therefore, workqueues cannot be used * because 'schedule_work()' can sleep.  OTOH, for non-RT, tasklets * cannot be used to call sleeping functions (such as i2c stack) */#ifdef CONFIG_PREEMPT_RTstatic DECLARE_TASKLET(work, pcf_work, 0);#define doit() tasklet_schedule(&work)#elsestatic DECLARE_WORK(work, pcf_work, NULL);#define doit() schedule_work(&work)#endifstatic void evm_leds_event(led_event_t evt){	unsigned long	flags;	u16		leds;	spin_lock_irqsave(&lock, flags);	if (!(hw_led_state & LED_STATE_ENABLED) && evt != led_start)		goto done;	leds = hw_led_state;	switch (evt) {	case led_start:		hw_led_state = LED_STATE_ENABLED | 0xff;		leds = 0;		break;	case led_halted:	case led_stop:		hw_led_state = 0xff;		// NOTE:  work may still be pending!!		break;	case led_claim:		hw_led_state |= LED_STATE_CLAIMED;		hw_led_state |= APP_LEDS;		break;	case led_release:		hw_led_state &= ~LED_STATE_CLAIMED;		hw_led_state |= APP_LEDS;		break;#ifdef	CONFIG_LEDS_TIMER	case led_timer:		hw_led_state ^= TIMER_LED;		break;#endif	/* actually all the LEDs are green */	case led_green_on:		if (leds & LED_STATE_CLAIMED)			hw_led_state &= ~GREEN_LED;		break;	case led_green_off:		if (leds & LED_STATE_CLAIMED)			hw_led_state |= GREEN_LED;		break;	case led_amber_on:		if (leds & LED_STATE_CLAIMED)			hw_led_state &= ~AMBER_LED;		break;	case led_amber_off:		if (leds & LED_STATE_CLAIMED)			hw_led_state |= AMBER_LED;		break;	case led_red_on:		if (leds & LED_STATE_CLAIMED)			hw_led_state &= ~RED_LED;		break;	case led_red_off:		if (leds & LED_STATE_CLAIMED)			hw_led_state |= RED_LED;		break;	case led_blue_on:		if (leds & LED_STATE_CLAIMED)			hw_led_state &= ~BLUE_LED;		break;	case led_blue_off:		if (leds & LED_STATE_CLAIMED)			hw_led_state |= BLUE_LED;		break;	default:		break;	}	leds ^= hw_led_state;	if (leds & 0xff) {		leds_change = (u8) leds;		doit();	}done:	spin_unlock_irqrestore(&lock, flags);}static int __init evm_leds_init(void){	if (!machine_is_davinci_evm())		return 0;	leds_event = evm_leds_event;	leds_event(led_start);	return 0;}/* i2c is subsys_initcall, davinci i2c is device_initcall; * this needs to follow both of them (sigh) */late_initcall(evm_leds_init);