NetBSD/sys/arch/arm32/dev/iic.c

/* $NetBSD: iic.c,v 1.6 1996/10/15 19:37:06 mark Exp $ */

/*
 * Copyright (c) 1994-1996 Mark Brinicombe.
 * Copyright (c) 1994 Brini.
 * All rights reserved.
 *
 * This code is derived from software written for Brini by Mark Brinicombe
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Mark Brinicombe.
 * 4. The name of the company nor the name of the author may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * RiscBSD kernel project
 *
 * iic.c
 *
 * Routines to communicate with IIC devices
 *
 * Created      : 13/10/94
 *
 * Based of kate/display/iiccontrol.c
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/device.h>

#include <machine/io.h>
#include <machine/iomd.h>
#include <machine/katelib.h>
#include <machine/cpu.h>
#include <machine/irqhandler.h>
#include <machine/iic.h>
#include <arm32/mainbus/mainbus.h>

/* Local function prototypes */

static int iic_getack		__P((void));
static void iic_write_bit	__P((int bit));
static int iic_write_byte	__P((u_char value));
static u_char iic_read_byte	__P((void));
static void iic_start_bit	__P((void));
static void iic_stop_bit	__P((void));

struct iic_softc {
	struct device	sc_dev;
	int		sc_flags;
#define IIC_BROKEN	1
#define IIC_OPEN	2
#define IIC_BUSY	4
};

void iicattach __P((struct device *parent, struct device *self, void *aux));
int iicmatch __P((struct device *parent, void *match, void *aux));

/*
 * Main entry to IIC driver.
 */

int
iic_control(address, buffer, count)
	u_char address;
	u_char *buffer;
	int count;
{
	int loop;

/* Send the start bit */

	iic_start_bit();

/* Send the address */

	if (!iic_write_byte(address)) {
		iic_stop_bit();
		return(-1);
	}

/* Read or write the data as required */

	if ((address & 1) == 0) {
/* Write bytes */
		for (loop = 0; loop < count; ++loop) {
			if (!iic_write_byte(buffer[loop])) {
				iic_stop_bit();
				return(-1);
			}
		}
	}
	else {
/* Read bytes */
		for (loop = 0; loop < count; ++loop) {
			buffer[loop] = iic_read_byte();

/* Send final acknowledge */

			if (loop == (count - 1))
				iic_write_bit(1);
			else
				iic_write_bit(0);
		}
	}

/* Send stop bit */

	iic_stop_bit();

	return(0);
}


static int
iic_getack()
{
	u_int oldirqstate;
	int ack;

	iic_set_state(1, 0);
	oldirqstate = disable_interrupts(I32_bit);
	iic_set_state_and_ack(1, 1);
	ack = ReadByte(IOMD_IOCR);
	iic_set_state(1, 0);
	restore_interrupts(oldirqstate);

	return((ack & 1) == 0);
}


static void
iic_write_bit(bit)
	int bit;
{
	u_int oldirqstate;

	iic_set_state(bit, 0);
	oldirqstate = disable_interrupts(I32_bit);
	iic_set_state_and_ack(bit, 1);
	iic_set_state(bit, 0);
	restore_interrupts(oldirqstate);
}


static int
iic_write_byte(value)
	u_char value;
{
	int loop;
	int bit;

	for (loop = 0x80; loop != 0; loop = loop >> 1) {
		bit = ((value & loop) != 0);
		iic_write_bit(bit);
	}

	return(iic_getack());
}


static u_char
iic_read_byte()
{
	int loop;
	u_char byte;
	u_int oldirqstate;

	iic_set_state(1,0);

	byte = 0;

	for (loop = 0; loop < 8; ++loop) {
		oldirqstate = disable_interrupts(I32_bit);
		iic_set_state_and_ack(1, 1);
		byte = (byte << 1) + (ReadByte(IOMD_IOCR) & 1);
		iic_set_state(1, 0);
		restore_interrupts(oldirqstate);
	}

	return(byte);
}


static void
iic_start_bit()
{
	iic_set_state(1, 1);
	iic_set_state(0, 1);
	iic_delay(10);
	iic_set_state(0, 0);
}


static void
iic_stop_bit()
{
	iic_set_state(0, 1);
	iic_set_state(1, 1);
}


struct cfattach iic_ca = {
	sizeof(struct iic_softc), iicmatch, iicattach
};

struct cfdriver iic_cd = {
	NULL, "iic", DV_DULL, 0
};

int
iicmatch(parent, match, aux)
	struct device *parent;
	void *match;
	void *aux;
{
	int id;

/* Make sure we have an IOMD we understand */
    
	id = ReadByte(IOMD_ID0) | (ReadByte(IOMD_ID1) << 8);

/* So far I only know about this IOMD */

	switch (id) {
	case RPC600_IOMD_ID:
	case ARM7500_IOC_ID:
		return(1);
		break;
	default:
		printf("iic: Unknown IOMD id=%04x", id);
		break;
	}

	return(0);
}

int
iicprint(aux, name)
	void *aux;
	const char *name;
{
	struct iicbus_attach_args *ib = aux;

	if (!name) {
		if (ib->ib_addr)
			printf(" addr 0x%02x", ib->ib_addr);
	}

/* XXXX print flags */
	return (QUIET);
}


int
iicsubmatch(parent, match, aux)
	struct device *parent;
	void *match;
	void *aux;
{
	struct cfdata *cf = match;
	struct iicbus_attach_args *ib = aux;

	if (cf->cf_fstate == FSTATE_STAR)
		panic("eekkk, I'm stuffed");

	ib->ib_addr = cf->cf_loc[0];

	if (ib->ib_addr == -1)
		return(0);

	return((*cf->cf_attach->ca_match)(parent, match, aux));
}

void
iicattach(parent, self, aux)
	struct device *parent;
	struct device *self;
	void *aux;
{
	struct iicbus_attach_args iaa;

	printf("\n");

	while (config_found_sm(self, &iaa, iicprint, iicsubmatch));
}


int
iicopen(dev, flag, mode, p)
	dev_t dev;
	int flag;
	int mode;
	struct proc *p;
{
	struct iic_softc *sc;
	int unit = minor(dev);
    
	if (unit >= iic_cd.cd_ndevs)
		return(ENXIO);

	sc = iic_cd.cd_devs[unit];
    
	if (!sc) return(ENXIO);

	if (sc->sc_flags & IIC_OPEN) return(EBUSY);

	sc->sc_flags |= IIC_OPEN;

	return(0);
}


int
iicclose(dev, flag, mode, p)
	dev_t dev;
	int flag;
	int mode;
	struct proc *p;
{
	int unit = minor(dev);
	struct iic_softc *sc = iic_cd.cd_devs[unit];
    
	sc->sc_flags &= ~IIC_OPEN;

	return(0);
}


int
iicread(dev, uio, flag)
	dev_t dev;
	struct uio *uio;
	int flag;
{
/*	int unit = minor(dev);*/
/*	struct iic_softc *sc = iic_cd.cd_devs[unit];*/

	return(ENXIO);
}


int
iicwrite(dev, uio, flag)
	dev_t dev;
	struct uio *uio;
	int flag;
{
/*	int unit = minor(dev);*/
/*	struct iic_softc *sc = iic_cd.cd_devs[unit];*/

	return(ENXIO);
}


int
iicioctl(dev, cmd, data, flag, p)
	dev_t dev;
	int cmd;
	caddr_t data;
	int flag;
	struct proc *p;
{
/*	struct iic_softc *sc = iic_cd.cd_devs[minor(dev)];*/

/*
	switch (cmd) {
	case IICIOC_CONTROL:
		if (iiccontrol() != 0) {
			return(EIO);
		}
		return(0);
	}
*/

	return(EINVAL);
}

/* End of iic.c */