/*-
* Copyright (C) 2008 MARVELL INTERNATIONAL LTD.
* All rights reserved.
*
* Developed by Semihalf.
*
* 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.
* 3. Neither the name of MARVELL nor the names of contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY 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 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.
*/
/*
* Driver for the TWSI (aka I2C, aka IIC) bus controller found on Marvell
* SoCs. Supports master operation only, and works in polling mode.
*
* Calls to DELAY() are needed per Application Note AN-179 "TWSI Software
* Guidelines for Discovery(TM), Horizon (TM) and Feroceon(TM) Devices".
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/resource.h>
#include <machine/_inttypes.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/rman.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <arm/mv/mvreg.h>
#include <arm/mv/mvvar.h>
#include "iicbus_if.h"
#define MV_TWSI_NAME "twsi"
#define IICBUS_DEVNAME "iicbus"
#define TWSI_SLAVE_ADDR 0x00
#define TWSI_EXT_SLAVE_ADDR 0x10
#define TWSI_DATA 0x04
#define TWSI_CONTROL 0x08
#define TWSI_CONTROL_ACK (1 << 2)
#define TWSI_CONTROL_IFLG (1 << 3)
#define TWSI_CONTROL_STOP (1 << 4)
#define TWSI_CONTROL_START (1 << 5)
#define TWSI_CONTROL_TWSIEN (1 << 6)
#define TWSI_CONTROL_INTEN (1 << 7)
#define TWSI_STATUS 0x0c
#define TWSI_STATUS_START 0x08
#define TWSI_STATUS_RPTD_START 0x10
#define TWSI_STATUS_ADDR_W_ACK 0x18
#define TWSI_STATUS_DATA_WR_ACK 0x28
#define TWSI_STATUS_ADDR_R_ACK 0x40
#define TWSI_STATUS_DATA_RD_ACK 0x50
#define TWSI_STATUS_DATA_RD_NOACK 0x58
#define TWSI_BAUD_RATE 0x0c
#define TWSI_BAUD_RATE_PARAM(M,N) ((((M) << 3) | ((N) & 0x7)) & 0x7f)
#define TWSI_BAUD_RATE_RAW(C,M,N) ((C)/((10*(M+1))<<(N+1)))
#define TWSI_BAUD_RATE_SLOW 50000 /* 50kHz */
#define TWSI_BAUD_RATE_FAST 100000 /* 100kHz */
#define TWSI_SOFT_RESET 0x1c
#define TWSI_DEBUG
#undef TWSI_DEBUG
#ifdef TWSI_DEBUG
#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0)
#else
#define debugf(fmt, args...)
#endif
struct mv_twsi_softc {
device_t dev;
struct resource *res[1]; /* SYS_RES_MEMORY */
struct mtx mutex;
device_t iicbus;
};
static struct mv_twsi_baud_rate {
uint32_t raw;
int param;
int m;
int n;
} baud_rate[IIC_FASTEST + 1];
static int mv_twsi_probe(device_t);
static int mv_twsi_attach(device_t);
static int mv_twsi_detach(device_t);
static int mv_twsi_reset(device_t dev, u_char speed, u_char addr,
u_char *oldaddr);
static int mv_twsi_repeated_start(device_t dev, u_char slave, int timeout);
static int mv_twsi_start(device_t dev, u_char slave, int timeout);
static int mv_twsi_stop(device_t dev);
static int mv_twsi_read(device_t dev, char *buf, int len, int *read, int last,
int delay);
static int mv_twsi_write(device_t dev, const char *buf, int len, int *sent,
int timeout);
static struct resource_spec res_spec[] = {
{ SYS_RES_MEMORY, 0, RF_ACTIVE },
{ -1, 0 }
};
static device_method_t mv_twsi_methods[] = {
/* device interface */
DEVMETHOD(device_probe, mv_twsi_probe),
DEVMETHOD(device_attach, mv_twsi_attach),
DEVMETHOD(device_detach, mv_twsi_detach),
/* iicbus interface */
DEVMETHOD(iicbus_callback, iicbus_null_callback),
DEVMETHOD(iicbus_repeated_start, mv_twsi_repeated_start),
DEVMETHOD(iicbus_start, mv_twsi_start),
DEVMETHOD(iicbus_stop, mv_twsi_stop),
DEVMETHOD(iicbus_write, mv_twsi_write),
DEVMETHOD(iicbus_read, mv_twsi_read),
DEVMETHOD(iicbus_reset, mv_twsi_reset),
DEVMETHOD(iicbus_transfer, iicbus_transfer_gen),
{ 0, 0 }
};
static devclass_t mv_twsi_devclass;
static driver_t mv_twsi_driver = {
MV_TWSI_NAME,
mv_twsi_methods,
sizeof(struct mv_twsi_softc),
};
DRIVER_MODULE(twsi, simplebus, mv_twsi_driver, mv_twsi_devclass, 0, 0);
DRIVER_MODULE(iicbus, twsi, iicbus_driver, iicbus_devclass, 0, 0);
MODULE_DEPEND(twsi, iicbus, 1, 1, 1);
static __inline uint32_t
TWSI_READ(struct mv_twsi_softc *sc, bus_size_t off)
{
return (bus_read_4(sc->res[0], off));
}
static __inline void
TWSI_WRITE(struct mv_twsi_softc *sc, bus_size_t off, uint32_t val)
{
bus_write_4(sc->res[0], off, val);
}
static __inline void
twsi_control_clear(struct mv_twsi_softc *sc, uint32_t mask)
{
uint32_t val;
val = TWSI_READ(sc, TWSI_CONTROL);
val &= ~mask;
TWSI_WRITE(sc, TWSI_CONTROL, val);
}
static __inline void
twsi_control_set(struct mv_twsi_softc *sc, uint32_t mask)
{
uint32_t val;
val = TWSI_READ(sc, TWSI_CONTROL);
val |= mask;
TWSI_WRITE(sc, TWSI_CONTROL, val);
}
static __inline void
twsi_clear_iflg(struct mv_twsi_softc *sc)
{
DELAY(1000);
twsi_control_clear(sc, TWSI_CONTROL_IFLG);
DELAY(1000);
}
/*
* timeout given in us
* returns
* 0 on sucessfull mask change
* non-zero on timeout
*/
static int
twsi_poll_ctrl(struct mv_twsi_softc *sc, int timeout, uint32_t mask)
{
timeout /= 10;
while (!(TWSI_READ(sc, TWSI_CONTROL) & mask)) {
DELAY(10);
if (--timeout < 0)
return (timeout);
}
return (0);
}
/*
* 'timeout' is given in us. Note also that timeout handling is not exact --
* twsi_locked_start() total wait can be more than 2 x timeout
* (twsi_poll_ctrl() is called twice). 'mask' can be either TWSI_STATUS_START
* or TWSI_STATUS_RPTD_START
*/
static int
twsi_locked_start(device_t dev, struct mv_twsi_softc *sc, int32_t mask,
u_char slave, int timeout)
{
int read_access, iflg_set = 0;
uint32_t status;
mtx_assert(&sc->mutex, MA_OWNED);
if (mask == TWSI_STATUS_RPTD_START)
/* read IFLG to know if it should be cleared later; from NBSD */
iflg_set = TWSI_READ(sc, TWSI_CONTROL) & TWSI_CONTROL_IFLG;
twsi_control_set(sc, TWSI_CONTROL_START);
if (mask == TWSI_STATUS_RPTD_START && iflg_set) {
debugf("IFLG set, clearing\n");
twsi_clear_iflg(sc);
}
/*
* Without this delay we timeout checking IFLG if the timeout is 0.
* NBSD driver always waits here too.
*/
DELAY(1000);
if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
debugf("timeout sending %sSTART condition\n",
mask == TWSI_STATUS_START ? "" : "repeated ");
return (IIC_ETIMEOUT);
}
status = TWSI_READ(sc, TWSI_STATUS);
if (status != mask) {
debugf("wrong status (%02x) after sending %sSTART condition\n",
status, mask == TWSI_STATUS_START ? "" : "repeated ");
return (IIC_ESTATUS);
}
TWSI_WRITE(sc, TWSI_DATA, slave);
DELAY(1000);
twsi_clear_iflg(sc);
if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
debugf("timeout sending slave address\n");
return (IIC_ETIMEOUT);
}
read_access = (slave & 0x1) ? 1 : 0;
status = TWSI_READ(sc, TWSI_STATUS);
if (status != (read_access ?
TWSI_STATUS_ADDR_R_ACK : TWSI_STATUS_ADDR_W_ACK)) {
debugf("no ACK (status: %02x) after sending slave address\n",
status);
return (IIC_ENOACK);
}
return (IIC_NOERR);
}
static int
mv_twsi_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (!ofw_bus_is_compatible(dev, "mrvl,twsi"))
return (ENXIO);
device_set_desc(dev, "Marvell Integrated I2C Bus Controller");
return (BUS_PROBE_DEFAULT);
}
#define ABSSUB(a,b) (((a) > (b)) ? (a) - (b) : (b) - (a))
static void
mv_twsi_cal_baud_rate(const uint32_t target, struct mv_twsi_baud_rate *rate)
{
uint32_t clk, cur, diff, diff0;
int m, n, m0, n0;
/* Calculate baud rate. */
m0 = n0 = 4; /* Default values on reset */
diff0 = 0xffffffff;
clk = get_tclk();
for (n = 0; n < 8; n++) {
for (m = 0; m < 16; m++) {
cur = TWSI_BAUD_RATE_RAW(clk,m,n);
diff = ABSSUB(target, cur);
if (diff < diff0) {
m0 = m;
n0 = n;
diff0 = diff;
}
}
}
rate->raw = TWSI_BAUD_RATE_RAW(clk, m0, n0);
rate->param = TWSI_BAUD_RATE_PARAM(m0, n0);
rate->m = m0;
rate->n = n0;
}
static int
mv_twsi_attach(device_t dev)
{
struct mv_twsi_softc *sc;
phandle_t child, iicbusnode;
device_t childdev;
struct iicbus_ivar *devi;
char dname[32]; /* 32 is taken from struct u_device */
uint32_t paddr;
int len, error;
sc = device_get_softc(dev);
sc->dev = dev;
bzero(baud_rate, sizeof(baud_rate));
mtx_init(&sc->mutex, device_get_nameunit(dev), MV_TWSI_NAME, MTX_DEF);
/* Allocate IO resources */
if (bus_alloc_resources(dev, res_spec, sc->res)) {
device_printf(dev, "could not allocate resources\n");
mv_twsi_detach(dev);
return (ENXIO);
}
mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_SLOW, &baud_rate[IIC_SLOW]);
mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_FAST, &baud_rate[IIC_FAST]);
if (bootverbose)
device_printf(dev, "calculated baud rates are:\n"
" %" PRIu32 " kHz (M=%d, N=%d) for slow,\n"
" %" PRIu32 " kHz (M=%d, N=%d) for fast.\n",
baud_rate[IIC_SLOW].raw / 1000,
baud_rate[IIC_SLOW].m,
baud_rate[IIC_SLOW].n,
baud_rate[IIC_FAST].raw / 1000,
baud_rate[IIC_FAST].m,
baud_rate[IIC_FAST].n);
sc->iicbus = device_add_child(dev, IICBUS_DEVNAME, -1);
if (sc->iicbus == NULL) {
device_printf(dev, "could not add iicbus child\n");
mv_twsi_detach(dev);
return (ENXIO);
}
/* Attach iicbus. */
bus_generic_attach(dev);
iicbusnode = 0;
/* Find iicbus as the child devices in the device tree. */
for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
child = OF_peer(child)) {
len = OF_getproplen(child, "model");
if (len <= 0 || len > sizeof(dname) - 1)
continue;
error = OF_getprop(child, "model", &dname, len);
dname[len + 1] = '\0';
if (error == -1)
continue;
len = strlen(dname);
if (len == strlen(IICBUS_DEVNAME) &&
strncasecmp(dname, IICBUS_DEVNAME, len) == 0) {
iicbusnode = child;
break;
}
}
if (iicbusnode == 0)
goto attach_end;
/* Attach child devices onto iicbus. */
for (child = OF_child(iicbusnode); child != 0; child = OF_peer(child)) {
/* Get slave address. */
error = OF_getprop(child, "i2c-address", &paddr, sizeof(paddr));
if (error == -1)
error = OF_getprop(child, "reg", &paddr, sizeof(paddr));
if (error == -1)
continue;
/* Get device driver name. */
len = OF_getproplen(child, "model");
if (len <= 0 || len > sizeof(dname) - 1)
continue;
OF_getprop(child, "model", &dname, len);
dname[len + 1] = '\0';
if (bootverbose)
device_printf(dev, "adding a device %s at %d.\n",
dname, fdt32_to_cpu(paddr));
childdev = BUS_ADD_CHILD(sc->iicbus, 0, dname, -1);
devi = IICBUS_IVAR(childdev);
devi->addr = fdt32_to_cpu(paddr);
}
attach_end:
bus_generic_attach(sc->iicbus);
return (0);
}
static int
mv_twsi_detach(device_t dev)
{
struct mv_twsi_softc *sc;
int rv;
sc = device_get_softc(dev);
if ((rv = bus_generic_detach(dev)) != 0)
return (rv);
if (sc->iicbus != NULL)
if ((rv = device_delete_child(dev, sc->iicbus)) != 0)
return (rv);
bus_release_resources(dev, res_spec, sc->res);
mtx_destroy(&sc->mutex);
return (0);
}
/*
* Only slave mode supported, disregard [old]addr
*/
static int
mv_twsi_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
{
struct mv_twsi_softc *sc;
uint32_t param;
sc = device_get_softc(dev);
switch (speed) {
case IIC_SLOW:
case IIC_FAST:
param = baud_rate[speed].param;
break;
case IIC_FASTEST:
case IIC_UNKNOWN:
default:
param = baud_rate[IIC_FAST].param;
break;
}
mtx_lock(&sc->mutex);
TWSI_WRITE(sc, TWSI_SOFT_RESET, 0x0);
DELAY(2000);
TWSI_WRITE(sc, TWSI_BAUD_RATE, param);
TWSI_WRITE(sc, TWSI_CONTROL, TWSI_CONTROL_TWSIEN | TWSI_CONTROL_ACK);
DELAY(1000);
mtx_unlock(&sc->mutex);
return (0);
}
/*
* timeout is given in us
*/
static int
mv_twsi_repeated_start(device_t dev, u_char slave, int timeout)
{
struct mv_twsi_softc *sc;
int rv;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
rv = twsi_locked_start(dev, sc, TWSI_STATUS_RPTD_START, slave,
timeout);
mtx_unlock(&sc->mutex);
if (rv) {
mv_twsi_stop(dev);
return (rv);
} else
return (IIC_NOERR);
}
/*
* timeout is given in us
*/
static int
mv_twsi_start(device_t dev, u_char slave, int timeout)
{
struct mv_twsi_softc *sc;
int rv;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
rv = twsi_locked_start(dev, sc, TWSI_STATUS_START, slave, timeout);
mtx_unlock(&sc->mutex);
if (rv) {
mv_twsi_stop(dev);
return (rv);
} else
return (IIC_NOERR);
}
static int
mv_twsi_stop(device_t dev)
{
struct mv_twsi_softc *sc;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
twsi_control_set(sc, TWSI_CONTROL_STOP);
DELAY(1000);
twsi_clear_iflg(sc);
mtx_unlock(&sc->mutex);
return (IIC_NOERR);
}
static int
mv_twsi_read(device_t dev, char *buf, int len, int *read, int last, int delay)
{
struct mv_twsi_softc *sc;
uint32_t status;
int last_byte, rv;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
*read = 0;
while (*read < len) {
/*
* Check if we are reading last byte of the last buffer,
* do not send ACK then, per I2C specs
*/
last_byte = ((*read == len - 1) && last) ? 1 : 0;
if (last_byte)
twsi_control_clear(sc, TWSI_CONTROL_ACK);
else
twsi_control_set(sc, TWSI_CONTROL_ACK);
DELAY (1000);
twsi_clear_iflg(sc);
if (twsi_poll_ctrl(sc, delay, TWSI_CONTROL_IFLG)) {
debugf("timeout reading data\n");
rv = IIC_ETIMEOUT;
goto out;
}
status = TWSI_READ(sc, TWSI_STATUS);
if (status != (last_byte ?
TWSI_STATUS_DATA_RD_NOACK : TWSI_STATUS_DATA_RD_ACK)) {
debugf("wrong status (%02x) while reading\n", status);
rv = IIC_ESTATUS;
goto out;
}
*buf++ = TWSI_READ(sc, TWSI_DATA);
(*read)++;
}
rv = IIC_NOERR;
out:
mtx_unlock(&sc->mutex);
return (rv);
}
static int
mv_twsi_write(device_t dev, const char *buf, int len, int *sent, int timeout)
{
struct mv_twsi_softc *sc;
uint32_t status;
int rv;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
*sent = 0;
while (*sent < len) {
TWSI_WRITE(sc, TWSI_DATA, *buf++);
twsi_clear_iflg(sc);
if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
debugf("timeout writing data\n");
rv = IIC_ETIMEOUT;
goto out;
}
status = TWSI_READ(sc, TWSI_STATUS);
if (status != TWSI_STATUS_DATA_WR_ACK) {
debugf("wrong status (%02x) while writing\n", status);
rv = IIC_ESTATUS;
goto out;
}
(*sent)++;
}
rv = IIC_NOERR;
out:
mtx_unlock(&sc->mutex);
return (rv);
}
