649b177fe3
Make it clearer what each one means in the comments that define them. IIC_BUSBSY was used in many places to mean two different things, either "someone else has reserved the bus so you have to wait until they're done" or "the signal level on the bus was not in the state I expected before/after issuing some command". Now IIC_BUSERR is used consistantly to refer to protocol/signaling errors, and IIC_BUSBSY refers to ownership/reservation of the bus.
428 lines
10 KiB
C
428 lines
10 KiB
C
/*-
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* Copyright (C) 2008-2009 Semihalf, Michal Hajduk
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/resource.h>
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#include <machine/bus.h>
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#include <machine/resource.h>
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#include <sys/rman.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include "iicbus_if.h"
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#define I2C_ADDR_REG 0x00 /* I2C slave address register */
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#define I2C_FDR_REG 0x04 /* I2C frequency divider register */
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#define I2C_CONTROL_REG 0x08 /* I2C control register */
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#define I2C_STATUS_REG 0x0C /* I2C status register */
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#define I2C_DATA_REG 0x10 /* I2C data register */
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#define I2C_DFSRR_REG 0x14 /* I2C Digital Filter Sampling rate */
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#define I2C_ENABLE 0x80 /* Module enable - interrupt disable */
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#define I2CSR_RXAK 0x01 /* Received acknowledge */
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#define I2CSR_MCF (1<<7) /* Data transfer */
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#define I2CSR_MASS (1<<6) /* Addressed as a slave */
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#define I2CSR_MBB (1<<5) /* Bus busy */
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#define I2CSR_MAL (1<<4) /* Arbitration lost */
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#define I2CSR_SRW (1<<2) /* Slave read/write */
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#define I2CSR_MIF (1<<1) /* Module interrupt */
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#define I2CCR_MEN (1<<7) /* Module enable */
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#define I2CCR_MSTA (1<<5) /* Master/slave mode */
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#define I2CCR_MTX (1<<4) /* Transmit/receive mode */
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#define I2CCR_TXAK (1<<3) /* Transfer acknowledge */
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#define I2CCR_RSTA (1<<2) /* Repeated START */
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#define I2C_BAUD_RATE_FAST 0x31
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#define I2C_BAUD_RATE_DEF 0x3F
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#define I2C_DFSSR_DIV 0x10
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#ifdef DEBUG
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#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0)
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#else
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#define debugf(fmt, args...)
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#endif
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struct i2c_softc {
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device_t dev;
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device_t iicbus;
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struct resource *res;
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struct mtx mutex;
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int rid;
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bus_space_handle_t bsh;
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bus_space_tag_t bst;
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};
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static int i2c_probe(device_t);
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static int i2c_attach(device_t);
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static int i2c_repeated_start(device_t dev, u_char slave, int timeout);
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static int i2c_start(device_t dev, u_char slave, int timeout);
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static int i2c_stop(device_t dev);
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static int i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr);
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static int i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay);
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static int i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout);
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static device_method_t i2c_methods[] = {
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DEVMETHOD(device_probe, i2c_probe),
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DEVMETHOD(device_attach, i2c_attach),
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DEVMETHOD(iicbus_callback, iicbus_null_callback),
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DEVMETHOD(iicbus_repeated_start, i2c_repeated_start),
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DEVMETHOD(iicbus_start, i2c_start),
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DEVMETHOD(iicbus_stop, i2c_stop),
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DEVMETHOD(iicbus_reset, i2c_reset),
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DEVMETHOD(iicbus_read, i2c_read),
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DEVMETHOD(iicbus_write, i2c_write),
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DEVMETHOD(iicbus_transfer, iicbus_transfer_gen),
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{ 0, 0 }
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};
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static driver_t i2c_driver = {
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"i2c",
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i2c_methods,
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sizeof(struct i2c_softc),
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};
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static devclass_t i2c_devclass;
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DRIVER_MODULE(i2c, simplebus, i2c_driver, i2c_devclass, 0, 0);
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DRIVER_MODULE(iicbus, i2c, iicbus_driver, iicbus_devclass, 0, 0);
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static __inline void
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i2c_write_reg(struct i2c_softc *sc, bus_size_t off, uint8_t val)
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{
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bus_space_write_1(sc->bst, sc->bsh, off, val);
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}
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static __inline uint8_t
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i2c_read_reg(struct i2c_softc *sc, bus_size_t off)
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{
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return (bus_space_read_1(sc->bst, sc->bsh, off));
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}
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static __inline void
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i2c_flag_set(struct i2c_softc *sc, bus_size_t off, uint8_t mask)
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{
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uint8_t status;
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status = i2c_read_reg(sc, off);
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status |= mask;
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i2c_write_reg(sc, off, status);
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}
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static int
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i2c_do_wait(device_t dev, struct i2c_softc *sc, int write, int start)
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{
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int err;
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uint8_t status;
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status = i2c_read_reg(sc, I2C_STATUS_REG);
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if (status & I2CSR_MIF) {
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if (write && start && (status & I2CSR_RXAK)) {
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debugf("no ack %s", start ?
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"after sending slave address" : "");
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err = IIC_ENOACK;
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goto error;
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}
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if (status & I2CSR_MAL) {
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debugf("arbitration lost");
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err = IIC_EBUSERR;
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goto error;
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}
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if (!write && !(status & I2CSR_MCF)) {
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debugf("transfer unfinished");
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err = IIC_EBUSERR;
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goto error;
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}
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}
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return (IIC_NOERR);
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error:
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i2c_write_reg(sc, I2C_STATUS_REG, 0x0);
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i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK);
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return (err);
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}
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static int
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i2c_probe(device_t dev)
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{
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struct i2c_softc *sc;
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if (!ofw_bus_is_compatible(dev, "fsl-i2c"))
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return (ENXIO);
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sc = device_get_softc(dev);
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sc->rid = 0;
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sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid,
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RF_ACTIVE);
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if (sc->res == NULL) {
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device_printf(dev, "could not allocate resources\n");
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return (ENXIO);
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}
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sc->bst = rman_get_bustag(sc->res);
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sc->bsh = rman_get_bushandle(sc->res);
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/* Enable I2C */
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i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE);
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bus_release_resource(dev, SYS_RES_MEMORY, sc->rid, sc->res);
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device_set_desc(dev, "I2C bus controller");
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return (BUS_PROBE_DEFAULT);
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}
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static int
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i2c_attach(device_t dev)
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{
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struct i2c_softc *sc;
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sc = device_get_softc(dev);
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sc->dev = dev;
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sc->rid = 0;
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mtx_init(&sc->mutex, device_get_nameunit(dev), "I2C", MTX_DEF);
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sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid,
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RF_ACTIVE);
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if (sc->res == NULL) {
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device_printf(dev, "could not allocate resources");
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mtx_destroy(&sc->mutex);
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return (ENXIO);
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}
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sc->bst = rman_get_bustag(sc->res);
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sc->bsh = rman_get_bushandle(sc->res);
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sc->iicbus = device_add_child(dev, "iicbus", -1);
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if (sc->iicbus == NULL) {
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device_printf(dev, "could not add iicbus child");
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mtx_destroy(&sc->mutex);
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return (ENXIO);
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}
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bus_generic_attach(dev);
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return (IIC_NOERR);
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}
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static int
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i2c_repeated_start(device_t dev, u_char slave, int timeout)
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{
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struct i2c_softc *sc;
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int error;
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sc = device_get_softc(dev);
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mtx_lock(&sc->mutex);
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/* Set repeated start condition */
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i2c_flag_set(sc, I2C_CONTROL_REG ,I2CCR_RSTA);
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/* Write target address - LSB is R/W bit */
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i2c_write_reg(sc, I2C_DATA_REG, slave);
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DELAY(1250);
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error = i2c_do_wait(dev, sc, 1, 1);
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mtx_unlock(&sc->mutex);
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if (error)
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return (error);
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return (IIC_NOERR);
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}
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static int
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i2c_start(device_t dev, u_char slave, int timeout)
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{
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struct i2c_softc *sc;
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uint8_t status;
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int error;
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sc = device_get_softc(dev);
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DELAY(1000);
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mtx_lock(&sc->mutex);
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status = i2c_read_reg(sc, I2C_STATUS_REG);
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/* Check if bus is idle or busy */
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if (status & I2CSR_MBB) {
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debugf("bus busy");
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mtx_unlock(&sc->mutex);
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i2c_stop(dev);
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return (IIC_EBUSERR);
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}
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/* Set start condition */
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i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA | I2CCR_MTX);
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/* Write target address - LSB is R/W bit */
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i2c_write_reg(sc, I2C_DATA_REG, slave);
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DELAY(1250);
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error = i2c_do_wait(dev, sc, 1, 1);
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mtx_unlock(&sc->mutex);
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if (error)
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return (error);
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return (IIC_NOERR);
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}
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static int
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i2c_stop(device_t dev)
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{
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struct i2c_softc *sc;
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sc = device_get_softc(dev);
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mtx_lock(&sc->mutex);
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i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK);
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DELAY(1000);
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mtx_unlock(&sc->mutex);
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return (IIC_NOERR);
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}
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static int
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i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldadr)
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{
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struct i2c_softc *sc;
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uint8_t baud_rate;
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sc = device_get_softc(dev);
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switch (speed) {
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case IIC_FAST:
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baud_rate = I2C_BAUD_RATE_FAST;
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break;
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case IIC_SLOW:
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case IIC_UNKNOWN:
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case IIC_FASTEST:
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default:
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baud_rate = I2C_BAUD_RATE_DEF;
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break;
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}
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mtx_lock(&sc->mutex);
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i2c_write_reg(sc, I2C_CONTROL_REG, 0x0);
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i2c_write_reg(sc, I2C_STATUS_REG, 0x0);
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DELAY(1000);
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i2c_write_reg(sc, I2C_FDR_REG, baud_rate);
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i2c_write_reg(sc, I2C_DFSRR_REG, I2C_DFSSR_DIV);
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i2c_write_reg(sc, I2C_CONTROL_REG, I2C_ENABLE);
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DELAY(1000);
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mtx_unlock(&sc->mutex);
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return (IIC_NOERR);
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}
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static int
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i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay)
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{
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struct i2c_softc *sc;
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int error;
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sc = device_get_softc(dev);
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*read = 0;
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mtx_lock(&sc->mutex);
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if (len) {
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if (len == 1)
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i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
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I2CCR_MSTA | I2CCR_TXAK);
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else
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i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
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I2CCR_MSTA);
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/* dummy read */
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i2c_read_reg(sc, I2C_DATA_REG);
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DELAY(1000);
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}
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while (*read < len) {
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DELAY(1000);
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error = i2c_do_wait(dev, sc, 0, 0);
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if (error) {
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mtx_unlock(&sc->mutex);
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return (error);
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}
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if ((*read == len - 2) && last) {
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i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
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I2CCR_MSTA | I2CCR_TXAK);
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}
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if ((*read == len - 1) && last) {
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i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN |
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I2CCR_TXAK);
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}
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*buf++ = i2c_read_reg(sc, I2C_DATA_REG);
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(*read)++;
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DELAY(1250);
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}
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mtx_unlock(&sc->mutex);
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return (IIC_NOERR);
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}
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static int
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i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout)
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{
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struct i2c_softc *sc;
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int error;
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sc = device_get_softc(dev);
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*sent = 0;
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mtx_lock(&sc->mutex);
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while (*sent < len) {
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i2c_write_reg(sc, I2C_DATA_REG, *buf++);
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DELAY(1250);
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error = i2c_do_wait(dev, sc, 1, 0);
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if (error) {
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mtx_unlock(&sc->mutex);
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return (error);
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}
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(*sent)++;
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}
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mtx_unlock(&sc->mutex);
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return (IIC_NOERR);
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}
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