iicbus.c

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/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 1998, 2001 Nicolas Souchu
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR 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.
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
/*
 * Autoconfiguration and support routines for the Philips serial I2C bus
 */
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/rman.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
 
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
 
#include "iicbus_if.h"
 
/* See comments below for why auto-scanning is a bad idea. */
#define SCAN_IICBUS 0
 
SYSCTL_NODE(_hw, OID_AUTO, i2c, CTLFLAG_RW, 0, "i2c controls");
 
static int
iicbus_probe(device_t dev)
{
 
        device_set_desc(dev, "Philips I2C bus");
 
        /* Allow other subclasses to override this driver. */
        return (BUS_PROBE_GENERIC);
}
 
#if SCAN_IICBUS
static int
iic_probe_device(device_t dev, u_char addr)
{
        int count;
        char byte;
 
        if ((addr & 1) == 0) {
                /* is device writable? */
                if (!iicbus_start(dev, (u_char)addr, 0)) {
                        iicbus_stop(dev);
                        return (1);
                }
        } else {
                /* is device readable? */
                if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
                        return (1);
        }
 
        return (0);
}
#endif
 
/*
 * We add all the devices which we know about.
 * The generic attach routine will attach them if they are alive.
 */
int
iicbus_attach_common(device_t dev, u_int bus_freq)
{
#if SCAN_IICBUS
        unsigned char addr;
#endif
        struct iicbus_softc *sc = IICBUS_SOFTC(dev);
        int strict;
 
        sc->dev = dev;
        mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
        iicbus_init_frequency(dev, bus_freq);
        iicbus_reset(dev, IIC_FASTEST, 0, NULL);
        if (resource_int_value(device_get_name(dev),
                device_get_unit(dev), "strict", &strict) == 0)
                sc->strict = strict;
        else
                sc->strict = 1;
 
        /* device probing is meaningless since the bus is supposed to be
         * hot-plug. Moreover, some I2C chips do not appreciate random
         * accesses like stop after start to fast, reads for less than
         * x bytes...
         */
#if SCAN_IICBUS
        printf("Probing for devices on iicbus%d:", device_get_unit(dev));
 
        /* probe any devices */
        for (addr = 16; addr < 240; addr++) {
                if (iic_probe_device(dev, (u_char)addr)) {
                        printf(" <%x>", addr);
                }
        }
        printf("\n");
#endif
        bus_generic_probe(dev);
        bus_enumerate_hinted_children(dev);
        bus_generic_attach(dev);
        return (0);
}
 
static int
iicbus_attach(device_t dev)
{
 
        return (iicbus_attach_common(dev, 0));
}
 
int
iicbus_detach(device_t dev)
{
        struct iicbus_softc *sc = IICBUS_SOFTC(dev);
        int err;
 
        if ((err = device_delete_children(dev)) != 0)
                return (err);
        iicbus_reset(dev, IIC_FASTEST, 0, NULL);
        mtx_destroy(&sc->lock);
        return (0);
}
 
static int
iicbus_print_child(device_t dev, device_t child)
{
        struct iicbus_ivar *devi = IICBUS_IVAR(child);
        int retval = 0;
 
        retval += bus_print_child_header(dev, child);
        if (devi->addr != 0)
                retval += printf(" at addr %#x", devi->addr);
        resource_list_print_type(&devi->rl, "irq", SYS_RES_IRQ, "%jd");
        retval += bus_print_child_footer(dev, child);
 
        return (retval);
}
 
void
iicbus_probe_nomatch(device_t bus, device_t child)
{
        struct iicbus_ivar *devi = IICBUS_IVAR(child);
 
        device_printf(bus, "<unknown card> at addr %#x\n", devi->addr);
}
 
int
iicbus_child_location(device_t bus, device_t child, struct sbuf *sb)
{
        struct iicbus_ivar *devi = IICBUS_IVAR(child);
 
        sbuf_printf(sb, "addr=%#x", devi->addr);
        return (0);
}
 
int
iicbus_child_pnpinfo(device_t bus, device_t child, struct sbuf *sb)
{
        return (0);
}
 
int
iicbus_read_ivar(device_t bus, device_t child, int which, uintptr_t *result)
{
        struct iicbus_ivar *devi = IICBUS_IVAR(child);
 
        switch (which) {
        default:
                return (EINVAL);
        case IICBUS_IVAR_ADDR:
                *result = devi->addr;
                break;
        }
        return (0);
}
 
int
iicbus_write_ivar(device_t bus, device_t child, int which, uintptr_t value)
{
        struct iicbus_ivar *devi = IICBUS_IVAR(child);
 
        switch (which) {
        default:
                return (EINVAL);
        case IICBUS_IVAR_ADDR:
                if (devi->addr != 0)
                        return (EINVAL);
                devi->addr = value;
        }
        return (0);
}
 
device_t
iicbus_add_child_common(device_t dev, u_int order, const char *name, int unit,
    size_t ivars_size)
{
        device_t child;
        struct iicbus_ivar *devi;
 
        child = device_add_child_ordered(dev, order, name, unit);
        if (child == NULL)
                return (child);
        devi = malloc(ivars_size, M_DEVBUF, M_NOWAIT | M_ZERO);
        if (devi == NULL) {
                device_delete_child(dev, child);
                return (0);
        }
        resource_list_init(&devi->rl);
        device_set_ivars(child, devi);
        return (child);
}
 
static device_t
iicbus_add_child(device_t dev, u_int order, const char *name, int unit)
{
 
        return (iicbus_add_child_common(
            dev, order, name, unit, sizeof(struct iicbus_ivar)));
}
 
static void
iicbus_hinted_child(device_t bus, const char *dname, int dunit)
{
        device_t child;
        int irq;
        struct iicbus_ivar *devi;
 
        child = BUS_ADD_CHILD(bus, 0, dname, dunit);
        devi = IICBUS_IVAR(child);
        resource_int_value(dname, dunit, "addr", &devi->addr);
        if (resource_int_value(dname, dunit, "irq", &irq) == 0) {
                if (bus_set_resource(child, SYS_RES_IRQ, 0, irq, 1) != 0)
                        device_printf(bus,
                            "warning: bus_set_resource() failed\n");
        }
}
 
static struct resource_list *
iicbus_get_resource_list(device_t bus __unused, device_t child)
{
        struct iicbus_ivar *devi;
 
        devi = IICBUS_IVAR(child);
        return (&devi->rl);
}
 
int
iicbus_generic_intr(device_t dev, int event, char *buf)
{
 
        return (0);
}
 
int
iicbus_null_callback(device_t dev, int index, caddr_t data)
{
 
        return (0);
}
 
int
iicbus_null_repeated_start(device_t dev, u_char addr)
{
 
        return (IIC_ENOTSUPP);
}
 
void
iicbus_init_frequency(device_t dev, u_int bus_freq)
{
        struct iicbus_softc *sc = IICBUS_SOFTC(dev);
 
        /*
         * If a bus frequency value was passed in, use it.  Otherwise initialize
         * it first to the standard i2c 100KHz frequency, then override that
         * from a hint if one exists.
         */
        if (bus_freq > 0)
                sc->bus_freq = bus_freq;
        else {
                sc->bus_freq = 100000;
                resource_int_value(device_get_name(dev), device_get_unit(dev),
                    "frequency", (int *)&sc->bus_freq);
        }
        /*
         * Set up the sysctl that allows the bus frequency to be changed.
         * It is flagged as a tunable so that the user can set the value in
         * loader(8), and that will override any other setting from any source.
         * The sysctl tunable/value is the one most directly controlled by the
         * user and thus the one that always takes precedence.
         */
        SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
            OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq,
            sc->bus_freq, "Bus frequency in Hz");
}
 
static u_int
iicbus_get_frequency(device_t dev, u_char speed)
{
        struct iicbus_softc *sc = IICBUS_SOFTC(dev);
 
        /*
         * If the frequency has not been configured for the bus, or the request
         * is specifically for SLOW speed, use the standard 100KHz rate, else
         * use the configured bus speed.
         */
        if (sc->bus_freq == 0 || speed == IIC_SLOW)
                return (100000);
        return (sc->bus_freq);
}
 
static device_method_t iicbus_methods[] = {
        /* device interface */
        DEVMETHOD(device_probe,         iicbus_probe),
        DEVMETHOD(device_attach,        iicbus_attach),
        DEVMETHOD(device_detach,        iicbus_detach),
        DEVMETHOD(device_suspend,       bus_generic_suspend),
        DEVMETHOD(device_resume,        bus_generic_resume),
 
        /* bus interface */
        DEVMETHOD(bus_setup_intr,       bus_generic_setup_intr),
        DEVMETHOD(bus_teardown_intr,    bus_generic_teardown_intr),
        DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
        DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
        DEVMETHOD(bus_adjust_resource,  bus_generic_adjust_resource),
        DEVMETHOD(bus_alloc_resource,   bus_generic_rl_alloc_resource),
        DEVMETHOD(bus_get_resource,     bus_generic_rl_get_resource),
        DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
        DEVMETHOD(bus_set_resource,     bus_generic_rl_set_resource),
        DEVMETHOD(bus_get_resource_list, iicbus_get_resource_list),
        DEVMETHOD(bus_add_child,        iicbus_add_child),
        DEVMETHOD(bus_print_child,      iicbus_print_child),
        DEVMETHOD(bus_probe_nomatch,    iicbus_probe_nomatch),
        DEVMETHOD(bus_read_ivar,        iicbus_read_ivar),
        DEVMETHOD(bus_write_ivar,       iicbus_write_ivar),
        DEVMETHOD(bus_child_pnpinfo,    iicbus_child_pnpinfo),
        DEVMETHOD(bus_child_location,   iicbus_child_location),
        DEVMETHOD(bus_hinted_child,     iicbus_hinted_child),
 
        /* iicbus interface */
        DEVMETHOD(iicbus_transfer,      iicbus_transfer),
        DEVMETHOD(iicbus_get_frequency, iicbus_get_frequency),
 
        DEVMETHOD_END
};
 
driver_t iicbus_driver = {
        "iicbus",
        iicbus_methods,
        sizeof(struct iicbus_softc),
};
 
devclass_t iicbus_devclass;
 
MODULE_VERSION(iicbus, IICBUS_MODVER);
DRIVER_MODULE(iicbus, iichb, iicbus_driver, iicbus_devclass, 0, 0);