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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@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 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("$FreeBSD$");
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#include "iicbus_if.h"
#include "iicmux_if.h"
static struct chip_info {
const char *partname;
const char *description;
int numchannels;
} chip_infos[] = {
{"ltc4305", "LTC4305 I2C Mux", 2},
{"ltc4306", "LTC4306 I2C Mux", 4},
};
#define CHIP_NONE (-1)
#define CHIP_LTC4305 0
#define CHIP_LTC4306 1
#ifdef FDT
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>
static struct ofw_compat_data compat_data[] = {
{"lltc,ltc4305", CHIP_LTC4305},
{"lltc,ltc4306", CHIP_LTC4306},
{NULL, CHIP_NONE}
};
IICBUS_FDT_PNP_INFO(compat_data);
#endif
#include <dev/iicbus/mux/iicmux.h>
struct ltc430x_softc {
struct iicmux_softc mux;
bool idle_disconnect;
};
/*
* The datasheet doesn't name the registers, it calls them control register 0-3.
*/
#define LTC430X_CTLREG_0 0
#define LTC430X_CTLREG_1 1
#define LTC430X_CTLREG_2 2
#define LTC430X_CR2_ENABLE_MW (1u << 3) /* Enable mass write address. */
#define LTC430X_CTLREG_3 3
static int
ltc430x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
{
struct ltc430x_softc *sc = device_get_softc(dev);
uint8_t busbits;
/*
* The iicmux caller ensures busidx is between 0 and the number of buses
* we passed to iicmux_init_softc(), no need for validation here. If
* the fdt data has the idle_disconnect property we idle the bus by
* selecting no downstream buses, otherwise we just leave the current
* bus active. The upper bits of control register 3 activate the
* downstream buses; bit 7 is the first bus, bit 6 the second, etc.
*/
if (busidx == IICMUX_SELECT_IDLE) {
if (sc->idle_disconnect)
busbits = 0;
else
return (0);
} else {
busbits = 1u << (7 - busidx);
}
/*
* We have to add the IIC_RECURSIVE flag because the iicmux core has
* already reserved the bus for us, and iicdev_writeto() is going to try
* to reserve it again, which is allowed with the recursive flag.
*/
return (iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits),
rd->flags | IIC_RECURSIVE));
}
static int
ltc430x_find_chiptype(device_t dev)
{
#ifdef FDT
return (ofw_bus_search_compatible(dev, compat_data)->ocd_data);
#else
const char *type;
int i;
if (resource_string_value(device_get_name(dev), device_get_unit(dev),
"chip_type", &type) == 0) {
for (i = 0; i < nitems(chip_infos); ++i) {
if (strcasecmp(type, chip_infos[i].partname) == 0) {
return (i);
}
}
}
return (CHIP_NONE);
#endif
}
static int
ltc430x_probe(device_t dev)
{
int type;
#ifdef FDT
if (!ofw_bus_status_okay(dev))
return (ENXIO);
#endif
type = ltc430x_find_chiptype(dev);
if (type == CHIP_NONE)
return (ENXIO);
device_set_desc(dev, chip_infos[type].description);
return (BUS_PROBE_DEFAULT);
}
static int
ltc430x_attach(device_t dev)
{
struct ltc430x_softc *sc __unused;
int chip, err, numchan, val;
uint8_t busbits, ctlreg2;
sc = device_get_softc(dev);
busbits = 0;
ctlreg2 = LTC430X_CR2_ENABLE_MW;
/*
* Check for the idle-disconnect and ctlreg2 options, first in FDT data,
* then allow them to be overriden by hints data.
*/
#ifdef FDT
phandle_t node;
node = ofw_bus_get_node(dev);
sc->idle_disconnect = OF_hasprop(node, "i2c-mux-idle-disconnect");
if (OF_getprop(node, "freebsd,ctlreg2", &val, sizeof(val)) > 0) {
ctlreg2 = val;
}
#endif
if (resource_int_value(device_get_name(dev), device_get_unit(dev),
"idle_disconnect", &val) == 0) {
sc->idle_disconnect = val;
}
if (resource_int_value(device_get_name(dev), device_get_unit(dev),
"ctlreg2", &val) == 0) {
ctlreg2 = val;
}
/* We found the chip type when probing, so now it "can't fail". */
if ((chip = ltc430x_find_chiptype(dev)) == CHIP_NONE) {
device_printf(dev, "impossible: can't identify chip type\n");
return (ENXIO);
}
numchan = chip_infos[chip].numchannels;
/* Set control reg 2 with configured (or default) values. */
iicdev_writeto(dev, LTC430X_CTLREG_2, &ctlreg2, sizeof(ctlreg2),
IIC_WAIT);
/* If configured for idle-disconnect, ensure we start disconnected. */
if (sc->idle_disconnect) {
iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits),
IIC_WAIT);
}
/*
* Invoke the iicmux framework's attach code, and if it succeeds, invoke
* the probe and attach code of any child iicbus instances it added.
*/
if ((err = iicmux_attach(dev, device_get_parent(dev), numchan)) == 0)
bus_generic_attach(dev);
return (err);
}
static int
ltc430x_detach(device_t dev)
{
int err;
if ((err = iicmux_detach(dev)) != 0)
return (err);
return (0);
}
static device_method_t ltc430x_methods[] = {
/* device methods */
DEVMETHOD(device_probe, ltc430x_probe),
DEVMETHOD(device_attach, ltc430x_attach),
DEVMETHOD(device_detach, ltc430x_detach),
/* iicmux methods */
DEVMETHOD(iicmux_bus_select, ltc430x_bus_select),
DEVMETHOD_END
};
static devclass_t ltc430x_devclass;
DEFINE_CLASS_1(ltc430x, ltc430x_driver, ltc430x_methods,
sizeof(struct ltc430x_softc), iicmux_driver);
DRIVER_MODULE(ltc430x, iicbus, ltc430x_driver, ltc430x_devclass, 0, 0);
#ifdef FDT
DRIVER_MODULE(ofw_iicbus, ltc430x, ofw_iicbus_driver, ofw_iicbus_devclass, 0, 0);
#else
DRIVER_MODULE(iicbus, ltc430x, iicbus_driver, iicbus_devclass, 0, 0);
#endif
MODULE_DEPEND(ltc430x, iicmux, 1, 1, 1);
MODULE_DEPEND(ltc430x, iicbus, 1, 1, 1);
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