/*-
* Copyright (c) 2014 Ruslan Bukin
* 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 EXPREC OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNEC 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 BUSINEC 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.
*/
/*
* Samsung Chromebook Embedded Controller
*/
#include
__FBSDID("$FreeBSD: releng/11.0/sys/arm/samsung/exynos/chrome_ec.c 297793 2016-04-10 23:07:00Z pfg $");
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "iicbus_if.h"
#include "gpio_if.h"
#include
struct ec_softc {
device_t dev;
int have_arbitrator;
pcell_t our_gpio;
pcell_t ec_gpio;
};
struct ec_softc *ec_sc;
/*
* bus_claim, bus_release
* both functions used for bus arbitration
* in multi-master mode
*/
static int
bus_claim(struct ec_softc *sc)
{
device_t gpio_dev;
int status;
if (sc->our_gpio == 0 || sc->ec_gpio == 0) {
device_printf(sc->dev, "i2c arbitrator is not configured\n");
return (1);
}
gpio_dev = devclass_get_device(devclass_find("gpio"), 0);
if (gpio_dev == NULL) {
device_printf(sc->dev, "cant find gpio_dev\n");
return (1);
}
/* Say we want the bus */
GPIO_PIN_SET(gpio_dev, sc->our_gpio, GPIO_PIN_LOW);
/* TODO: insert a delay to allow EC to react. */
/* Check EC decision */
GPIO_PIN_GET(gpio_dev, sc->ec_gpio, &status);
if (status == 1) {
/* Okay. We have bus */
return (0);
}
/* EC is master */
return (-1);
}
static int
bus_release(struct ec_softc *sc)
{
device_t gpio_dev;
if (sc->our_gpio == 0 || sc->ec_gpio == 0) {
device_printf(sc->dev, "i2c arbitrator is not configured\n");
return (1);
}
gpio_dev = devclass_get_device(devclass_find("gpio"), 0);
if (gpio_dev == NULL) {
device_printf(sc->dev, "cant find gpio_dev\n");
return (1);
}
GPIO_PIN_SET(gpio_dev, sc->our_gpio, GPIO_PIN_HIGH);
return (0);
}
static int
ec_probe(device_t dev)
{
device_set_desc(dev, "Chromebook Embedded Controller");
return (BUS_PROBE_DEFAULT);
}
static int
fill_checksum(uint8_t *data_out, int len)
{
int res;
int i;
res = 0;
for (i = 0; i < len; i++) {
res += data_out[i];
}
data_out[len] = (res & 0xff);
return (0);
}
int
ec_command(uint8_t cmd, uint8_t *dout, uint8_t dout_len,
uint8_t *dinp, uint8_t dinp_len)
{
struct ec_softc *sc;
uint8_t *msg_dout;
uint8_t *msg_dinp;
int ret;
int i;
msg_dout = malloc(dout_len + 4, M_DEVBUF, M_NOWAIT);
msg_dinp = malloc(dinp_len + 3, M_DEVBUF, M_NOWAIT);
if (ec_sc == NULL)
return (-1);
sc = ec_sc;
msg_dout[0] = EC_CMD_VERSION0;
msg_dout[1] = cmd;
msg_dout[2] = dout_len;
for (i = 0; i < dout_len; i++) {
msg_dout[i + 3] = dout[i];
}
fill_checksum(msg_dout, dout_len + 3);
struct iic_msg msgs[] = {
{ 0x1e, IIC_M_WR, dout_len + 4, msg_dout, },
{ 0x1e, IIC_M_RD, dinp_len + 3, msg_dinp, },
};
ret = iicbus_transfer(sc->dev, msgs, 2);
if (ret != 0) {
device_printf(sc->dev, "i2c transfer returned %d\n", ret);
free(msg_dout, M_DEVBUF);
free(msg_dinp, M_DEVBUF);
return (-1);
}
for (i = 0; i < dinp_len; i++) {
dinp[i] = msg_dinp[i + 2];
}
free(msg_dout, M_DEVBUF);
free(msg_dinp, M_DEVBUF);
return (0);
}
int ec_hello(void)
{
uint8_t data_in[4];
uint8_t data_out[4];
data_in[0] = 0x40;
data_in[1] = 0x30;
data_in[2] = 0x20;
data_in[3] = 0x10;
ec_command(EC_CMD_HELLO, data_in, 4,
data_out, 4);
return (0);
}
static void
configure_i2c_arbitrator(struct ec_softc *sc)
{
phandle_t arbitrator;
/* TODO: look for compatible entry instead of hard-coded path */
arbitrator = OF_finddevice("/i2c-arbitrator");
if (arbitrator > 0 &&
OF_hasprop(arbitrator, "freebsd,our-gpio") &&
OF_hasprop(arbitrator, "freebsd,ec-gpio")) {
sc->have_arbitrator = 1;
OF_getencprop(arbitrator, "freebsd,our-gpio",
&sc->our_gpio, sizeof(sc->our_gpio));
OF_getencprop(arbitrator, "freebsd,ec-gpio",
&sc->ec_gpio, sizeof(sc->ec_gpio));
} else {
sc->have_arbitrator = 0;
sc->our_gpio = 0;
sc->ec_gpio = 0;
}
}
static int
ec_attach(device_t dev)
{
struct ec_softc *sc;
sc = device_get_softc(dev);
sc->dev = dev;
ec_sc = sc;
configure_i2c_arbitrator(sc);
/*
* Claim the bus.
*
* We don't know cases when EC is master,
* so hold the bus forever for us.
*
*/
if (sc->have_arbitrator && bus_claim(sc) != 0) {
return (ENXIO);
}
return (0);
}
static int
ec_detach(device_t dev)
{
struct ec_softc *sc;
sc = device_get_softc(dev);
if (sc->have_arbitrator) {
bus_release(sc);
}
return (0);
}
static device_method_t ec_methods[] = {
DEVMETHOD(device_probe, ec_probe),
DEVMETHOD(device_attach, ec_attach),
DEVMETHOD(device_detach, ec_detach),
{ 0, 0 }
};
static driver_t ec_driver = {
"chrome_ec",
ec_methods,
sizeof(struct ec_softc),
};
static devclass_t ec_devclass;
DRIVER_MODULE(chrome_ec, iicbus, ec_driver, ec_devclass, 0, 0);
MODULE_VERSION(chrome_ec, 1);
MODULE_DEPEND(chrome_ec, iicbus, 1, 1, 1);