icee.c

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/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2006 M. Warner Losh <imp@FreeBSD.org>
 *
 * 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 ``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 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("$FreeBSD$");
/*
 * Generic IIC eeprom support, modeled after the AT24C family of products.
 */
 
#include "opt_platform.h"
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/resource.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <machine/bus.h>
 
#ifdef FDT
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif
 
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
 
#include "iicbus_if.h"
 
/*
 * AT24 parts have a "write page size" that differs per-device, and a "read page
 * size" that is always equal to the full device size.  We define maximum values
 * here to limit how long we occupy the bus with a single transfer, and because
 * there are temporary buffers of these sizes allocated on the stack.
 */
#define MAX_RD_SZ       256     /* Largest read size we support */
#define MAX_WR_SZ       256     /* Largest write size we support */
 
struct icee_softc {
        device_t        dev;            /* Myself */
        struct cdev     *cdev;          /* user interface */
        int             addr;           /* Slave address on the bus */
        int             size;           /* How big am I? */
        int             type;           /* What address type 8 or 16 bit? */
        int             wr_sz;          /* What's the write page size */
};
 
#ifdef FDT
struct eeprom_desc {
        int         type;
        int         size;
        int         wr_sz;
        const char *name;
};
 
static struct eeprom_desc type_desc[] = {
        { 8,        128,   8, "AT24C01"},
        { 8,        256,   8, "AT24C02"},
        { 8,        512,  16, "AT24C04"},
        { 8,       1024,  16, "AT24C08"},
        { 8,   2 * 1024,  16, "AT24C16"},
        {16,   4 * 1024,  32, "AT24C32"},
        {16,   8 * 1024,  32, "AT24C64"},
        {16,  16 * 1024,  64, "AT24C128"},
        {16,  32 * 1024,  64, "AT24C256"},
        {16,  64 * 1024, 128, "AT24C512"},
        {16, 128 * 1024, 256, "AT24CM01"},
};
 
static struct ofw_compat_data compat_data[] = {
        {"atmel,24c01",   (uintptr_t)(&type_desc[0])},
        {"atmel,24c02",   (uintptr_t)(&type_desc[1])},
        {"atmel,24c04",   (uintptr_t)(&type_desc[2])},
        {"atmel,24c08",   (uintptr_t)(&type_desc[3])},
        {"atmel,24c16",   (uintptr_t)(&type_desc[4])},
        {"atmel,24c32",   (uintptr_t)(&type_desc[5])},
        {"atmel,24c64",   (uintptr_t)(&type_desc[6])},
        {"atmel,24c128",  (uintptr_t)(&type_desc[7])},
        {"atmel,24c256",  (uintptr_t)(&type_desc[8])},
        {"atmel,24c512",  (uintptr_t)(&type_desc[9])},
        {"atmel,24c1024", (uintptr_t)(&type_desc[10])},
        {NULL,            (uintptr_t)NULL},
};
#endif
 
#define CDEV2SOFTC(dev)         ((dev)->si_drv1)
 
/* cdev routines */
static d_read_t icee_read;
static d_write_t icee_write;
 
static struct cdevsw icee_cdevsw =
{
        .d_version = D_VERSION,
        .d_read = icee_read,
        .d_write = icee_write
};
 
static int
icee_probe(device_t dev)
{
#ifdef FDT
        struct eeprom_desc *d;
 
        if (!ofw_bus_status_okay(dev))
                return (ENXIO);
 
        d = (struct eeprom_desc *)
            ofw_bus_search_compatible(dev, compat_data)->ocd_data;
        if (d != NULL) {
                device_set_desc(dev, d->name);
                return (BUS_PROBE_DEFAULT);
        }
#endif
        device_set_desc(dev, "I2C EEPROM");
        return (BUS_PROBE_NOWILDCARD);
}
 
static int
icee_init(struct icee_softc *sc)
{
        const char *dname;
        int dunit;
#ifdef FDT
        struct eeprom_desc *d;
 
        d = (struct eeprom_desc *)
            ofw_bus_search_compatible(sc->dev, compat_data)->ocd_data;
        if (d != NULL) {
                sc->size  = d->size;
                sc->type  = d->type;
                sc->wr_sz = d->wr_sz;
                return (0);
        }
#endif
        dname = device_get_name(sc->dev);
        dunit = device_get_unit(sc->dev);
        if (resource_int_value(dname, dunit, "type", &sc->type) != 0)
                return (ENOENT);
        if (resource_int_value(dname, dunit, "size", &sc->size) != 0)
                return (ENOENT);
        if (resource_int_value(dname, dunit, "wr_sz", &sc->wr_sz) != 0)
                return (ENOENT);
        return (0);
}
 
static int
icee_attach(device_t dev)
{
        struct icee_softc *sc = device_get_softc(dev);
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid_list *tree;
 
        sc->dev = dev;
        sc->addr = iicbus_get_addr(dev);
        if (icee_init(sc) != 0)
                return (EINVAL);
        if (bootverbose)
                device_printf(dev, "size: %d bytes, addressing: %d-bits\n",
                    sc->size, sc->type);
        sc->cdev = make_dev(&icee_cdevsw, device_get_unit(dev), UID_ROOT,
            GID_WHEEL, 0600, "icee%d", device_get_unit(dev));
        if (sc->cdev == NULL) {
                return (ENOMEM);
        }
        sc->cdev->si_drv1 = sc;
 
        ctx = device_get_sysctl_ctx(dev);
        tree = SYSCTL_CHILDREN(device_get_sysctl_tree(dev));
        SYSCTL_ADD_INT(ctx, tree, OID_AUTO, "address_size", CTLFLAG_RD,
            &sc->type, 0, "Memory array address size in bits");
        SYSCTL_ADD_INT(ctx, tree, OID_AUTO, "device_size", CTLFLAG_RD,
            &sc->size, 0, "Memory array capacity in bytes");
        SYSCTL_ADD_INT(ctx, tree, OID_AUTO, "write_size", CTLFLAG_RD,
            &sc->wr_sz, 0, "Memory array page write size in bytes");
 
        return (0);
}
 
static int
icee_detach(device_t dev)
{
        struct icee_softc *sc = device_get_softc(dev);
 
        destroy_dev(sc->cdev);
        return (0);
}
 
static int
icee_read(struct cdev *dev, struct uio *uio, int ioflag)
{
        struct icee_softc *sc;
        uint8_t addr[2];
        uint8_t data[MAX_RD_SZ];
        int error, i, len, slave;
        struct iic_msg msgs[2] = {
             { 0, IIC_M_WR, 1, addr },
             { 0, IIC_M_RD, 0, data },
        };
 
        sc = CDEV2SOFTC(dev);
        if (uio->uio_offset == sc->size)
                return (0);
        if (uio->uio_offset > sc->size)
                return (EIO);
        if (sc->type != 8 && sc->type != 16)
                return (EINVAL);
        slave = error = 0;
        while (uio->uio_resid > 0) {
                if (uio->uio_offset >= sc->size)
                        break;
                len = MIN(MAX_RD_SZ - (uio->uio_offset & (MAX_RD_SZ - 1)),
                    uio->uio_resid);
                switch (sc->type) {
                case 8:
                        slave = (uio->uio_offset >> 7) | sc->addr;
                        msgs[0].len = 1;
                        msgs[1].len = len;
                        addr[0] = uio->uio_offset & 0xff;
                        break;
                case 16:
                        slave = sc->addr | (uio->uio_offset >> 15);
                        msgs[0].len = 2;
                        msgs[1].len = len;
                        addr[0] = (uio->uio_offset >> 8) & 0xff;
                        addr[1] = uio->uio_offset & 0xff;
                        break;
                }
                for (i = 0; i < 2; i++)
                        msgs[i].slave = slave;
                error = iicbus_transfer_excl(sc->dev, msgs, 2, IIC_INTRWAIT);
                if (error) {
                        error = iic2errno(error);
                        break;
                }
                error = uiomove(data, len, uio);
                if (error)
                        break;
        }
        return (error);
}
 
/*
 * Write to the part.  We use three transfers here since we're actually
 * doing a write followed by a read to make sure that the write finished.
 * It is easier to encode the dummy read here than to break things up
 * into smaller chunks...
 */
static int
icee_write(struct cdev *dev, struct uio *uio, int ioflag)
{
        struct icee_softc *sc;
        int error, len, slave, waitlimit;
        uint8_t data[MAX_WR_SZ + 2];
        struct iic_msg wr[1] = {
             { 0, IIC_M_WR, 0, data },
        };
        struct iic_msg rd[1] = {
             { 0, IIC_M_RD, 1, data },
        };
 
        sc = CDEV2SOFTC(dev);
        if (uio->uio_offset >= sc->size)
                return (EIO);
        if (sc->type != 8 && sc->type != 16)
                return (EINVAL);
 
        slave = error = 0;
        while (uio->uio_resid > 0) {
                if (uio->uio_offset >= sc->size)
                        break;
                len = MIN(sc->wr_sz - (uio->uio_offset & (sc->wr_sz - 1)),
                    uio->uio_resid);
                switch (sc->type) {
                case 8:
                        slave = (uio->uio_offset >> 7) | sc->addr;
                        wr[0].len = 1 + len;
                        data[0] = uio->uio_offset & 0xff;
                        break;
                case 16:
                        slave = sc->addr | (uio->uio_offset >> 15);
                        wr[0].len = 2 + len;
                        data[0] = (uio->uio_offset >> 8) & 0xff;
                        data[1] = uio->uio_offset & 0xff;
                        break;
                }
                wr[0].slave = slave;
                error = uiomove(data + sc->type / 8, len, uio);
                if (error)
                        break;
                error = iicbus_transfer_excl(sc->dev, wr, 1, IIC_INTRWAIT);
                if (error) {
                        error = iic2errno(error);
                        break;
                }
                /* Read after write to wait for write-done. */
                waitlimit = 10000;
                rd[0].slave = slave;
                do {
                        error = iicbus_transfer_excl(sc->dev, rd, 1,
                            IIC_INTRWAIT);
                } while (waitlimit-- > 0 && error != 0);
                if (error) {
                        error = iic2errno(error);
                        break;
                }
        }
        return error;
}
 
static device_method_t icee_methods[] = {
        DEVMETHOD(device_probe,         icee_probe),
        DEVMETHOD(device_attach,        icee_attach),
        DEVMETHOD(device_detach,        icee_detach),
 
        DEVMETHOD_END
};
 
static driver_t icee_driver = {
        "icee",
        icee_methods,
        sizeof(struct icee_softc),
};
static devclass_t icee_devclass;
 
DRIVER_MODULE(icee, iicbus, icee_driver, icee_devclass, 0, 0);
MODULE_VERSION(icee, 1);
MODULE_DEPEND(icee, iicbus, 1, 1, 1);
IICBUS_FDT_PNP_INFO(compat_data);