/* *  i2c_adap_pxa.c * *  I2C adapter for the PXA I2C bus access. * *  Copyright (C) 2002 Intrinsyc Software Inc. *  *  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. * *  History: *    Apr 2002: Initial version [CS] *    Jun 2002: Properly seperated algo/adap [FB] */#include <linux/kernel.h>#include <linux/module.h>#include <linux/i2c.h>#include <linux/i2c-id.h>#include <linux/init.h>#include <linux/time.h>#include <linux/sched.h>#include <linux/delay.h>#include <asm/hardware.h>#include <asm/irq.h>#include <asm/arch/irqs.h>              /* for IRQ_I2C */#include "i2c-pxa.h"/* * Set this to zero to remove all the debug statements via dead code elimination. *///#define DEBUG       1#if DEBUGstatic unsigned int i2c_debug = DEBUG;#else#define i2c_debug	0#endifstatic int irq = 0;static int i2c_pending = 0;             /* interrupt pending when 1 */static volatile int bus_error = 0;static volatile int tx_finished = 0;static volatile int rx_finished = 0;static wait_queue_head_t i2c_wait;/* place a byte in the transmit register */static void i2c_pxa_write_byte(u8 value) {        IDBR = value;}/* read byte in the receive register */static u8 i2c_pxa_read_byte(void) {        return (u8) (0xff & IDBR);}static void i2c_pxa_start(void){	ICR |= ICR_START;	ICR &= ~(ICR_STOP | ICR_ALDIE | ICR_ACKNAK);	bus_error=0;            /* clear any bus_error from previous txfers */	tx_finished=0;          /* clear rx and tx interrupts from previous txfers */	rx_finished=0;}static void i2c_pxa_repeat_start(void){	ICR |= ICR_START;	ICR &= ~(ICR_STOP | ICR_ALDIE);	bus_error=0;            /* clear any bus_error from previous txfers */	tx_finished=0;          /* clear rx and tx interrupts from previous txfers */	rx_finished=0;}static void i2c_pxa_stop(void){	ICR |= ICR_STOP;	ICR &= ~(ICR_START);}static void i2c_pxa_midbyte(void){	ICR &= ~(ICR_START | ICR_STOP);}static void i2c_pxa_abort(void){	ICR |= ICR_MA;}static int i2c_pxa_wait_bus_not_busy( void){        int timeout = DEF_TIMEOUT;        while (timeout-- && (ISR & ISR_IBB)) {                udelay(100); /* wait for 100 us */        }        return (timeout<=0);}static void i2c_pxa_wait_for_ite(void){	unsigned long flags;	if (irq > 0) {		save_flags_cli(flags);		if (i2c_pending == 0) {			interruptible_sleep_on_timeout(&i2c_wait, I2C_SLEEP_TIMEOUT );		}		i2c_pending = 0;		restore_flags(flags);	} else {		udelay(100);	}}static int i2c_pxa_wait_for_int( int wait_type){        int timeout = DEF_TIMEOUT;#ifdef DEBUG	if (bus_error)		printk(KERN_INFO"i2c_pxa_wait_for_int: Bus error on enter\n");	if (rx_finished)		printk(KERN_INFO"i2c_pxa_wait_for_int: Receive interrupt on enter\n");	if (tx_finished)		printk(KERN_INFO"i2c_pxa_wait_for_int: Transmit interrupt on enter\n");#endif        if (wait_type == I2C_RECEIVE){         /* wait on receive */                while (timeout-- && !(rx_finished)){                        i2c_pxa_wait_for_ite();                }#ifdef DEBUG                if (timeout<0){                        if (tx_finished)                                printk("Error: i2c-algo-pxa.o: received a tx"                                        " interrupt while waiting on a rx in wait_for_int");                }#endif        } else {                  /* wait on transmit */                        while (timeout-- && !(tx_finished)){                        i2c_pxa_wait_for_ite();                }#ifdef DEBUG                if (timeout<0){                        if (rx_finished)                                printk("Error: i2c-algo-pxa.o: received a rx"                                        " interrupt while waiting on a tx in wait_for_int");                }#endif        }               udelay(ACK_DELAY);      /* this is needed for the bus error */        tx_finished=0;        rx_finished=0;        if (bus_error){                bus_error=0;                if( i2c_debug > 2)printk("wait_for_int: error - no ack.\n");                return BUS_ERROR;        }        if (timeout <= 0)                return(-1);        else                return(0);}static void i2c_pxa_transfer( int lastbyte, int receive, int midbyte){	if( lastbyte)	{		if( receive==I2C_RECEIVE) ICR |= ICR_ACKNAK; 		i2c_pxa_stop();	}	else if( midbyte)	{		i2c_pxa_midbyte();	}	ICR |= ICR_TB;}static void i2c_pxa_reset( void){#ifdef DEBUG	printk("Resetting I2C Controller Unit\n");	printk("Status Register  %#x\n",ISR);	printk("Control Register %#x\n",ICR);	printk("Data Buffer      %#x\n",IDBR);	printk("Bus Monitor Reg  %#x\n",IBMR);#endif        /* disable unit */	ICR &= ~ICR_IUE;        /* reset the unit */	ICR |= ICR_UR;        udelay(100);        /* disable unit */	ICR &= ~ICR_IUE;                /* set the global I2C clock on */        CKEN |= CKEN14_I2C;        /* set our slave address */	ISAR = I2C_PXA_SLAVE_ADDR;        /* set control register values */	ICR = I2C_ICR_INIT;        /* set clear interrupt bits */	ISR = I2C_ISR_INIT;        /* enable unit */	ICR |= ICR_IUE;        udelay(100);}static void i2c_pxa_handler(int this_irq, void *dev_id, struct pt_regs *regs) {        int status;        status = (ISR);        if (status & ISR_BED){                (ISR) |= ISR_BED;                bus_error=ISR_BED;        }        if (status & ISR_ITE){                (ISR) |= ISR_ITE;                tx_finished=ISR_ITE;        }        if (status & ISR_IRF){                (ISR) |= ISR_IRF;                rx_finished=ISR_IRF;        }        i2c_pending = 1;        wake_up_interruptible(&i2c_wait);}static int i2c_pxa_resource_init( void){        init_waitqueue_head(&i2c_wait);        if (request_irq(IRQ_I2C, &i2c_pxa_handler, SA_INTERRUPT, "I2C_PXA", 0) < 0) {                irq = 0;                if( i2c_debug)			printk(KERN_INFO "I2C: Failed to register I2C irq %i\n", IRQ_I2C);                return -ENODEV;        }else{                irq = IRQ_I2C;                enable_irq(irq);        }        return 0;}static void i2c_pxa_resource_release( void){        if( irq > 0)        {                disable_irq(irq);                free_irq(irq,0);                irq=0;        }}static void i2c_pxa_inc_use(struct i2c_adapter *adap){#ifdef MODULE        MOD_INC_USE_COUNT;#endif}static void i2c_pxa_dec_use(struct i2c_adapter *adap){#ifdef MODULE        MOD_DEC_USE_COUNT;#endif}static int i2c_pxa_client_register(struct i2c_client *client){        return 0;}static int i2c_pxa_client_unregister(struct i2c_client *client){        return 0;}static struct i2c_algo_pxa_data i2c_pxa_data = {        write_byte:		i2c_pxa_write_byte,        read_byte:		i2c_pxa_read_byte,        start:			i2c_pxa_start,        repeat_start:		i2c_pxa_repeat_start,        stop:			i2c_pxa_stop,        abort:			i2c_pxa_abort,        wait_bus_not_busy:	i2c_pxa_wait_bus_not_busy,        wait_for_interrupt:	i2c_pxa_wait_for_int,        transfer:		i2c_pxa_transfer,        reset:			i2c_pxa_reset,	udelay:			10,	timeout:		DEF_TIMEOUT,};static struct i2c_adapter i2c_pxa_ops = {        name:                   "PXA-I2C-Adapter",        id:                     I2C_ALGO_PXA,        algo_data:              &i2c_pxa_data,        inc_use:                i2c_pxa_inc_use,        dec_use:                i2c_pxa_dec_use,        client_register:        i2c_pxa_client_register,        client_unregister:      i2c_pxa_client_unregister,        retries:                2,};extern int i2c_pxa_add_bus(struct i2c_adapter *);extern int i2c_pxa_del_bus(struct i2c_adapter *);static int __init i2c_adap_pxa_init(void){        if( i2c_pxa_resource_init() == 0) {                if (i2c_pxa_add_bus(&i2c_pxa_ops) < 0) {                        i2c_pxa_resource_release();                        printk(KERN_INFO "I2C: Failed to add bus\n");                        return -ENODEV;                }        } else {                return -ENODEV;        }        printk(KERN_INFO "I2C: Successfully added bus\n");        return 0;}static void i2c_adap_pxa_exit(void){        i2c_pxa_del_bus( &i2c_pxa_ops);        i2c_pxa_resource_release();        printk(KERN_INFO "I2C: Successfully removed bus\n");}module_init(i2c_adap_pxa_init);module_exit(i2c_adap_pxa_exit);