freebsd-dev/sys/dev/iicbus/icee.c
Warner Losh 1a13e01f7f Don't use spinlocks here. The iicbus transactions can take a long
time, and this prevents interrupts (say for Hz/hardclock) from
happening.  Time stands still during the transfers...
2007-04-17 05:48:35 +00:00

292 lines
7.6 KiB
C

/*-
* Copyright (c) 2006 Warner Losh. 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 ``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 <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/mutex.h>
#include <sys/resource.h>
#include <sys/uio.h>
#include <machine/bus.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
#include "iicbus_if.h"
#define IIC_M_WR 0 /* write operation */
#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 sc_dev; /* Myself */
struct mtx sc_mtx; /* basically a perimeter lock */
struct cdev *cdev; /* user interface */
int addr;
int flags;
#define OPENED 1
int size; /* How big am I? */
int type; /* What type 8 or 16 bit? */
int rd_sz; /* What's the read page size */
int wr_sz; /* What's the write page size */
};
#define ICEE_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
#define ICEE_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
#define ICEE_LOCK_INIT(_sc) \
mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->sc_dev), "icee", MTX_DEF)
#define ICEE_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
#define ICEE_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED);
#define ICEE_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
#define CDEV2SOFTC(dev) ((dev)->si_drv1)
/* cdev routines */
static d_open_t icee_open;
static d_close_t icee_close;
static d_read_t icee_read;
static d_write_t icee_write;
static struct cdevsw icee_cdevsw =
{
.d_version = D_VERSION,
.d_open = icee_open,
.d_close = icee_close,
.d_read = icee_read,
.d_write = icee_write
};
static int
icee_probe(device_t dev)
{
/* XXX really probe? -- not until we know the size... */
device_set_desc(dev, "I2C EEPROM");
return (0);
}
static int
icee_attach(device_t dev)
{
struct icee_softc *sc = device_get_softc(dev);
const char *dname;
int dunit, err;
sc->sc_dev = dev;
iicbus_get_addr(dev, &sc->addr);
err = 0;
dname = device_get_name(dev);
dunit = device_get_unit(dev);
resource_int_value(dname, dunit, "size", &sc->size);
resource_int_value(dname, dunit, "type", &sc->type);
resource_int_value(dname, dunit, "rd_sz", &sc->rd_sz);
if (sc->rd_sz > MAX_RD_SZ)
sc->rd_sz = MAX_RD_SZ;
resource_int_value(dname, dunit, "wr_sz", &sc->wr_sz);
if (bootverbose)
device_printf(dev, "size: %d bytes bus_width: %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) {
err = ENOMEM;
goto out;
}
sc->cdev->si_drv1 = sc;
ICEE_LOCK_INIT(sc);
out:;
return (err);
}
static int
icee_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
struct icee_softc *sc;
sc = CDEV2SOFTC(dev);
ICEE_LOCK(sc);
if (!(sc->flags & OPENED)) {
sc->flags |= OPENED;
}
ICEE_UNLOCK(sc);
return (0);
}
static int
icee_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
struct icee_softc *sc;
sc = CDEV2SOFTC(dev);
ICEE_LOCK(sc);
sc->flags &= ~OPENED;
ICEE_UNLOCK(sc);
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);
ICEE_LOCK(sc);
slave = error = 0;
while (uio->uio_resid > 0) {
if (uio->uio_offset >= sc->size)
break;
len = MIN(sc->rd_sz - (uio->uio_offset & (sc->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(sc->sc_dev, msgs, 2);
if (error)
break;
error = uiomove(data, len, uio);
if (error)
break;
}
ICEE_UNLOCK(sc);
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);
ICEE_LOCK(sc);
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(sc->sc_dev, wr, 1);
if (error)
break;
// Now wait for the write to be done by trying to read
// the part.
waitlimit = 10000;
rd[0].slave = slave;
do
{
error = iicbus_transfer(sc->sc_dev, rd, 1);
} while (waitlimit-- > 0 && error != 0);
if (error) {
printf("waiting for write failed %d\n", error);
break;
}
}
ICEE_UNLOCK(sc);
return error;
}
static device_method_t icee_methods[] = {
DEVMETHOD(device_probe, icee_probe),
DEVMETHOD(device_attach, icee_attach),
{0, 0},
};
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);