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/*-
* Copyright (C) 2008-2009 Semihalf, Michal Hajduk
* 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 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/powerpc/mpc85xx/i2c.c 209908 2010-07-11 21:08:29Z raj $");
#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/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 "iicbus_if.h"
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#define I2C_ADDR_REG 0x00 /* I2C slave address register */
#define I2C_FDR_REG 0x04 /* I2C frequency divider register */
#define I2C_CONTROL_REG 0x08 /* I2C control register */
#define I2C_STATUS_REG 0x0C /* I2C status register */
#define I2C_DATA_REG 0x10 /* I2C data register */
#define I2C_DFSRR_REG 0x14 /* I2C Digital Filter Sampling rate */
#define I2C_ENABLE 0x80 /* Module enable - interrupt disable */
#define I2CSR_RXAK 0x01 /* Received acknowledge */
#define I2CSR_MCF (1<<7) /* Data transfer */
#define I2CSR_MASS (1<<6) /* Addressed as a slave */
#define I2CSR_MBB (1<<5) /* Bus busy */
#define I2CSR_MAL (1<<4) /* Arbitration lost */
#define I2CSR_SRW (1<<2) /* Slave read/write */
#define I2CSR_MIF (1<<1) /* Module interrupt */
#define I2CCR_MEN (1<<7) /* Module enable */
#define I2CCR_MSTA (1<<5) /* Master/slave mode */
#define I2CCR_MTX (1<<4) /* Transmit/receive mode */
#define I2CCR_TXAK (1<<3) /* Transfer acknowledge */
#define I2CCR_RSTA (1<<2) /* Repeated START */
#define I2C_BAUD_RATE_FAST 0x31
#define I2C_BAUD_RATE_DEF 0x3F
#define I2C_DFSSR_DIV 0x10
#define DEBUG
#undef DEBUG
#ifdef DEBUG
#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0)
#else
#define debugf(fmt, args...)
#endif
struct i2c_softc {
device_t dev;
device_t iicbus;
struct resource *res;
struct mtx mutex;
int rid;
bus_space_handle_t bsh;
bus_space_tag_t bst;
};
static int i2c_probe(device_t);
static int i2c_attach(device_t);
static int i2c_repeated_start(device_t dev, u_char slave, int timeout);
static int i2c_start(device_t dev, u_char slave, int timeout);
static int i2c_stop(device_t dev);
static int i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr);
static int i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay);
static int i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout);
static device_method_t i2c_methods[] = {
DEVMETHOD(device_probe, i2c_probe),
DEVMETHOD(device_attach, i2c_attach),
DEVMETHOD(iicbus_callback, iicbus_null_callback),
DEVMETHOD(iicbus_repeated_start, i2c_repeated_start),
DEVMETHOD(iicbus_start, i2c_start),
DEVMETHOD(iicbus_stop, i2c_stop),
DEVMETHOD(iicbus_reset, i2c_reset),
DEVMETHOD(iicbus_read, i2c_read),
DEVMETHOD(iicbus_write, i2c_write),
DEVMETHOD(iicbus_transfer, iicbus_transfer_gen),
{ 0, 0 }
};
static driver_t i2c_driver = {
"i2c",
i2c_methods,
sizeof(struct i2c_softc),
};
static devclass_t i2c_devclass;
DRIVER_MODULE(i2c, simplebus, i2c_driver, i2c_devclass, 0, 0);
DRIVER_MODULE(iicbus, i2c, iicbus_driver, iicbus_devclass, 0, 0);
static __inline void
i2c_write_reg(struct i2c_softc *sc, bus_size_t off, uint8_t val)
{
bus_space_write_1(sc->bst, sc->bsh, off, val);
}
static __inline uint8_t
i2c_read_reg(struct i2c_softc *sc, bus_size_t off)
{
return (bus_space_read_1(sc->bst, sc->bsh, off));
}
static __inline void
i2c_flag_set(struct i2c_softc *sc, bus_size_t off, uint8_t mask)
{
uint8_t status;
status = i2c_read_reg(sc, off);
status |= mask;
i2c_write_reg(sc, off, status);
}
static int
i2c_do_wait(device_t dev, struct i2c_softc *sc, int write, int start)
{
int err;
uint8_t status;
status = i2c_read_reg(sc, I2C_STATUS_REG);
if (status & I2CSR_MIF) {
if (write && start && (status & I2CSR_RXAK)) {
debugf("no ack %s", start ?
"after sending slave address" : "");
err = IIC_ENOACK;
goto error;
}
if (status & I2CSR_MAL) {
debugf("arbitration lost");
err = IIC_EBUSERR;
goto error;
}
if (!write && !(status & I2CSR_MCF)) {
debugf("transfer unfinished");
err = IIC_EBUSERR;
goto error;
}
}
return (IIC_NOERR);
error:
i2c_write_reg(sc, I2C_STATUS_REG, 0x0);
i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK);
return (err);
}
static int
i2c_probe(device_t dev)
{
struct i2c_softc *sc;
if (!ofw_bus_is_compatible(dev, "fsl-i2c"))
return (ENXIO);
sc = device_get_softc(dev);
sc->rid = 0;
sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid,
RF_ACTIVE);
if (sc->res == NULL) {
device_printf(dev, "could not allocate resources\n");
return (ENXIO);
}
sc->bst = rman_get_bustag(sc->res);
sc->bsh = rman_get_bushandle(sc->res);
/* Enable I2C */
i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE);
bus_release_resource(dev, SYS_RES_MEMORY, sc->rid, sc->res);
device_set_desc(dev, "I2C bus controller");
return (BUS_PROBE_DEFAULT);
}
static int
i2c_attach(device_t dev)
{
struct i2c_softc *sc;
sc = device_get_softc(dev);
sc->dev = dev;
sc->rid = 0;
mtx_init(&sc->mutex, device_get_nameunit(dev), "I2C", MTX_DEF);
sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid,
RF_ACTIVE);
if (sc->res == NULL) {
device_printf(dev, "could not allocate resources");
mtx_destroy(&sc->mutex);
return (ENXIO);
}
sc->bst = rman_get_bustag(sc->res);
sc->bsh = rman_get_bushandle(sc->res);
sc->iicbus = device_add_child(dev, "iicbus", -1);
if (sc->iicbus == NULL) {
device_printf(dev, "could not add iicbus child");
mtx_destroy(&sc->mutex);
return (ENXIO);
}
bus_generic_attach(dev);
return (IIC_NOERR);
}
static int
i2c_repeated_start(device_t dev, u_char slave, int timeout)
{
struct i2c_softc *sc;
int error;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
/* Set repeated start condition */
i2c_flag_set(sc, I2C_CONTROL_REG ,I2CCR_RSTA);
/* Write target address - LSB is R/W bit */
i2c_write_reg(sc, I2C_DATA_REG, slave);
DELAY(1250);
error = i2c_do_wait(dev, sc, 1, 1);
mtx_unlock(&sc->mutex);
if (error)
return (error);
return (IIC_NOERR);
}
static int
i2c_start(device_t dev, u_char slave, int timeout)
{
struct i2c_softc *sc;
uint8_t status;
int error;
sc = device_get_softc(dev);
DELAY(1000);
mtx_lock(&sc->mutex);
status = i2c_read_reg(sc, I2C_STATUS_REG);
/* Check if bus is idle or busy */
if (status & I2CSR_MBB) {
debugf("bus busy");
mtx_unlock(&sc->mutex);
i2c_stop(dev);
return (IIC_EBUSBSY);
}
/* Set start condition */
i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA | I2CCR_MTX);
/* Write target address - LSB is R/W bit */
i2c_write_reg(sc, I2C_DATA_REG, slave);
DELAY(1250);
error = i2c_do_wait(dev, sc, 1, 1);
mtx_unlock(&sc->mutex);
if (error)
return (error);
return (IIC_NOERR);
}
static int
i2c_stop(device_t dev)
{
struct i2c_softc *sc;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK);
DELAY(1000);
mtx_unlock(&sc->mutex);
return (IIC_NOERR);
}
static int
i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldadr)
{
struct i2c_softc *sc;
uint8_t baud_rate;
sc = device_get_softc(dev);
switch (speed) {
case IIC_FAST:
baud_rate = I2C_BAUD_RATE_FAST;
break;
case IIC_SLOW:
case IIC_UNKNOWN:
case IIC_FASTEST:
default:
baud_rate = I2C_BAUD_RATE_DEF;
break;
}
mtx_lock(&sc->mutex);
i2c_write_reg(sc, I2C_CONTROL_REG, 0x0);
i2c_write_reg(sc, I2C_STATUS_REG, 0x0);
DELAY(1000);
i2c_write_reg(sc, I2C_FDR_REG, baud_rate);
i2c_write_reg(sc, I2C_DFSRR_REG, I2C_DFSSR_DIV);
i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE);
DELAY(1000);
mtx_unlock(&sc->mutex);
return (IIC_NOERR);
}
static int
i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay)
{
struct i2c_softc *sc;
int error;
sc = device_get_softc(dev);
*read = 0;
mtx_lock(&sc->mutex);
if (len) {
if (len == 1)
i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
I2CCR_MSTA | I2CCR_TXAK);
else
i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
I2CCR_MSTA);
/* dummy read */
i2c_read_reg(sc, I2C_DATA_REG);
DELAY(1000);
}
while (*read < len) {
DELAY(1000);
error = i2c_do_wait(dev, sc, 0, 0);
if (error) {
mtx_unlock(&sc->mutex);
return (error);
}
if ((*read == len - 2) && last) {
i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
I2CCR_MSTA | I2CCR_TXAK);
}
if ((*read == len - 1) && last) {
i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
I2CCR_TXAK);
}
*buf++ = i2c_read_reg(sc, I2C_DATA_REG);
(*read)++;
DELAY(1250);
}
mtx_unlock(&sc->mutex);
return (IIC_NOERR);
}
static int
i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout)
{
struct i2c_softc *sc;
int error;
sc = device_get_softc(dev);
*sent = 0;
mtx_lock(&sc->mutex);
while (*sent < len) {
i2c_write_reg(sc, I2C_DATA_REG, *buf++);
DELAY(1250);
error = i2c_do_wait(dev, sc, 1, 0);
if (error) {
mtx_unlock(&sc->mutex);
return (error);
}
(*sent)++;
}
mtx_unlock(&sc->mutex);
return (IIC_NOERR);
}