3c3ed6cecd
Also, most device functions related to IRQ handling no longer take a device pointer. We make so many assumptions about the machine's layout in irq.c that this just seemed silly.
351 lines
7.7 KiB
C
351 lines
7.7 KiB
C
/* $NetBSD: iic.c,v 1.3 2001/01/23 23:58:32 bjh21 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>
|
|
|
|
__RCSID("$NetBSD: iic.c,v 1.3 2001/01/23 23:58:32 bjh21 Exp $");
|
|
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/conf.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/device.h>
|
|
|
|
#include <machine/bus.h>
|
|
#include <machine/cpu.h>
|
|
#include <arm26/iobus/iocreg.h>
|
|
#include <arm26/iobus/iocvar.h>
|
|
#include <arm26/ioc/iic.h>
|
|
|
|
#include "locators.h"
|
|
|
|
struct iic_softc {
|
|
struct device sc_dev;
|
|
};
|
|
|
|
/* Autoconfiguration glue */
|
|
static int iic_match (struct device *, struct cfdata *, void *);
|
|
static void iic_attach(struct device *, struct device *, void *);
|
|
static int iicsearch(struct device *, struct cfdata *, void *);
|
|
|
|
struct cfattach iic_ca = {
|
|
sizeof(struct iic_softc), iic_match, iic_attach
|
|
};
|
|
|
|
/* Local function prototypes */
|
|
|
|
static int iic_getack(struct device *);
|
|
static void iic_write_bit(struct device *, int);
|
|
static int iic_write_byte(struct device *, int);
|
|
static int iic_read_byte(struct device *);
|
|
static void iic_start_bit(struct device *);
|
|
static void iic_stop_bit(struct device *);
|
|
|
|
static int iicprint(void *, const char *);
|
|
|
|
/* Functions that do the bit twiddling */
|
|
static int iic_get_state(struct device *);
|
|
static void iic_set_state_and_ack(struct device *, int, int);
|
|
static void iic_set_state(struct device *, int, int);
|
|
|
|
/*
|
|
* iic device probe function
|
|
*/
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
iic_match(struct device *parent, struct cfdata *cf, void *aux)
|
|
{
|
|
|
|
return(1);
|
|
}
|
|
|
|
/*
|
|
* iic device attach function
|
|
*
|
|
* Initialise the softc structure and do a search for children
|
|
*/
|
|
|
|
static void
|
|
iic_attach(struct device *parent, struct device *self, void *aux)
|
|
{
|
|
|
|
printf("\n");
|
|
config_search(iicsearch, self, NULL);
|
|
}
|
|
|
|
/*
|
|
* Main entry to IIC driver.
|
|
*/
|
|
|
|
int
|
|
iic_control(struct device *self, int address, u_char *buffer, int count)
|
|
{
|
|
int loop;
|
|
|
|
/* Send the start bit */
|
|
|
|
iic_start_bit(self);
|
|
|
|
/* Send the address */
|
|
|
|
if (!iic_write_byte(self, address)) {
|
|
iic_stop_bit(self);
|
|
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(self, buffer[loop])) {
|
|
iic_stop_bit(self);
|
|
return -1;
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
/* Read bytes */
|
|
for (loop = 0; loop < count; ++loop) {
|
|
buffer[loop] = iic_read_byte(self);
|
|
|
|
/* Send final acknowledge */
|
|
|
|
if (loop == (count - 1))
|
|
iic_write_bit(self, 1);
|
|
else
|
|
iic_write_bit(self, 0);
|
|
}
|
|
}
|
|
|
|
/* Send stop bit */
|
|
|
|
iic_stop_bit(self);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int
|
|
iic_getack(struct device *self)
|
|
{
|
|
int ack;
|
|
|
|
iic_set_state(self, 1, 0);
|
|
delay(5);
|
|
iic_set_state_and_ack(self, 1, 1);
|
|
ack = iic_get_state(self);
|
|
delay(4);
|
|
iic_set_state(self, 1, 0);
|
|
delay(5); /* Clock low time (4.7 us) */
|
|
|
|
return (ack & 1) == 0;
|
|
}
|
|
|
|
/*
|
|
* Put the IIC bus lines in the given state (MD)
|
|
*/
|
|
static void
|
|
iic_set_state(struct device *self, int sda, int scl)
|
|
{
|
|
int bits;
|
|
|
|
bits = 0;
|
|
if (sda) bits |= IOC_CTL_SDA;
|
|
if (scl) bits |= IOC_CTL_SCL;
|
|
ioc_ctl_write(self->dv_parent, bits, IOC_CTL_SDA | IOC_CTL_SCL);
|
|
}
|
|
|
|
/*
|
|
* Put the IIC bus lines in a given state and wait for the SCL line
|
|
* to actually do what we asked (so the slave is ready).
|
|
*/
|
|
static void
|
|
iic_set_state_and_ack(struct device *self, int sda, int scl)
|
|
{
|
|
|
|
iic_set_state(self, sda, scl);
|
|
while ((ioc_ctl_read(self->dv_parent) & IOC_CTL_SCL) == 0)
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Read state of IIC data line
|
|
*/
|
|
static int
|
|
iic_get_state(struct device *self)
|
|
{
|
|
|
|
return (ioc_ctl_read(self->dv_parent) & IOC_CTL_SDA) != 0;
|
|
}
|
|
|
|
static void
|
|
iic_write_bit(struct device *self, int bit)
|
|
{
|
|
|
|
iic_set_state(self, bit, 0);
|
|
delay(1); /* Data setup time (250 ns) */
|
|
iic_set_state_and_ack(self, bit, 1);
|
|
delay(4); /* Clock high time (4.0 us) */
|
|
iic_set_state(self, bit, 0);
|
|
delay(5); /* Clock low time (4.7 us) */
|
|
}
|
|
|
|
|
|
static int
|
|
iic_write_byte(struct device *self, int value)
|
|
{
|
|
int loop;
|
|
int bit;
|
|
|
|
for (loop = 0x80; loop != 0; loop = loop >> 1) {
|
|
bit = ((value & loop) != 0);
|
|
iic_write_bit(self, bit);
|
|
}
|
|
|
|
return(iic_getack(self));
|
|
}
|
|
|
|
|
|
static int
|
|
iic_read_byte(struct device *self)
|
|
{
|
|
int loop;
|
|
u_char byte;
|
|
|
|
iic_set_state(self, 1, 0);
|
|
|
|
byte = 0;
|
|
|
|
for (loop = 0; loop < 8; ++loop) {
|
|
iic_set_state_and_ack(self, 1, 1);
|
|
delay(4); /* Clock high time (4.0 us) */
|
|
byte = (byte << 1) + (iic_get_state(self) & 1);
|
|
iic_set_state(self, 1, 0);
|
|
delay(5); /* Clock low time (4.7 us) */
|
|
}
|
|
|
|
return(byte);
|
|
}
|
|
|
|
|
|
static void
|
|
iic_start_bit(struct device *self)
|
|
{
|
|
|
|
iic_set_state(self, 1, 1);
|
|
delay(5); /* Bus free time (4.7 us) */
|
|
iic_set_state(self, 0, 1);
|
|
delay(4); /* Start hold time (4.0 us) */
|
|
iic_set_state(self, 0, 0);
|
|
delay(5); /* Clock low time (4.7 us) */
|
|
}
|
|
|
|
|
|
static void
|
|
iic_stop_bit(struct device *self)
|
|
{
|
|
|
|
iic_set_state(self, 0, 1);
|
|
delay(4); /* Stop setup time (4.0 us) */
|
|
iic_set_state(self, 1, 1);
|
|
}
|
|
|
|
/*
|
|
* int iicprint(void *aux, const char *name)
|
|
*
|
|
* print function for child device configuration
|
|
*/
|
|
|
|
static int
|
|
iicprint(void *aux, const char *name)
|
|
{
|
|
struct iicbus_attach_args *iba = aux;
|
|
|
|
if (!name) {
|
|
if (iba->ib_addr)
|
|
printf(" addr 0x%02x", iba->ib_addr);
|
|
}
|
|
|
|
/* XXXX print flags */
|
|
return (UNCONF);
|
|
}
|
|
|
|
/*
|
|
* iic search function
|
|
*
|
|
* search for devices that are children of the iic device
|
|
* fill out the attach arguments and call the probe and
|
|
* attach function (as required).
|
|
*
|
|
* Note: since the offsets of the devices need to be specified in the
|
|
* config file we ignore the FSTAT_STAR.
|
|
*/
|
|
|
|
static int
|
|
iicsearch(struct device *parent, struct cfdata *cf, void *aux)
|
|
{
|
|
struct iic_softc *sc = (struct iic_softc *)parent;
|
|
struct iicbus_attach_args iba;
|
|
int tryagain;
|
|
|
|
do {
|
|
iba.ib_iic_softc = sc;
|
|
iba.ib_addr = cf->cf_loc[IICCF_ADDR];
|
|
iba.ib_aux = NULL;
|
|
|
|
tryagain = 0;
|
|
if ((*cf->cf_attach->ca_match)(parent, cf, &iba) > 0) {
|
|
config_attach(parent, cf, &iba, iicprint);
|
|
/* tryagain = (cf->cf_fstate == FSTATE_STAR);*/
|
|
}
|
|
} while (tryagain);
|
|
|
|
return (0);
|
|
}
|