d1e99670ae
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.
471 lines
10 KiB
C
471 lines
10 KiB
C
/*-
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* Copyright (c) 2014 Ruslan Bukin <br@bsdpad.com>
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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 THE 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 THE 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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/*
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* Vybrid Family Inter-Integrated Circuit (I2C)
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* Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
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*/
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/*
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* This driver is based on the I2C driver for i.MX
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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/malloc.h>
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#include <sys/rman.h>
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#include <sys/timeet.h>
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#include <sys/timetc.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/fdt/fdt_common.h>
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#include <dev/ofw/openfirm.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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#include <machine/bus.h>
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#include <machine/cpu.h>
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#include <machine/intr.h>
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#include <arm/freescale/vybrid/vf_common.h>
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#define I2C_IBAD 0x0 /* I2C Bus Address Register */
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#define I2C_IBFD 0x1 /* I2C Bus Frequency Divider Register */
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#define I2C_IBCR 0x2 /* I2C Bus Control Register */
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#define IBCR_MDIS (1 << 7) /* Module disable. */
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#define IBCR_IBIE (1 << 6) /* I-Bus Interrupt Enable. */
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#define IBCR_MSSL (1 << 5) /* Master/Slave mode select. */
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#define IBCR_TXRX (1 << 4) /* Transmit/Receive mode select. */
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#define IBCR_NOACK (1 << 3) /* Data Acknowledge disable. */
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#define IBCR_RSTA (1 << 2) /* Repeat Start. */
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#define IBCR_DMAEN (1 << 1) /* DMA Enable. */
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#define I2C_IBSR 0x3 /* I2C Bus Status Register */
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#define IBSR_TCF (1 << 7) /* Transfer complete. */
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#define IBSR_IAAS (1 << 6) /* Addressed as a slave. */
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#define IBSR_IBB (1 << 5) /* Bus busy. */
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#define IBSR_IBAL (1 << 4) /* Arbitration Lost. */
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#define IBSR_SRW (1 << 2) /* Slave Read/Write. */
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#define IBSR_IBIF (1 << 1) /* I-Bus Interrupt Flag. */
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#define IBSR_RXAK (1 << 0) /* Received Acknowledge. */
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#define I2C_IBDR 0x4 /* I2C Bus Data I/O Register */
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#define I2C_IBIC 0x5 /* I2C Bus Interrupt Config Register */
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#define IBIC_BIIE (1 << 7) /* Bus Idle Interrupt Enable bit. */
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#define I2C_IBDBG 0x6 /* I2C Bus Debug Register */
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#ifdef DEBUG
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#define vf_i2c_dbg(_sc, fmt, args...) \
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device_printf((_sc)->dev, fmt, ##args)
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#else
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#define vf_i2c_dbg(_sc, fmt, args...)
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#endif
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static int i2c_repeated_start(device_t, u_char, int);
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static int i2c_start(device_t, u_char, int);
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static int i2c_stop(device_t);
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static int i2c_reset(device_t, u_char, u_char, u_char *);
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static int i2c_read(device_t, char *, int, int *, int, int);
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static int i2c_write(device_t, const char *, int, int *, int);
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struct i2c_softc {
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struct resource *res[2];
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bus_space_tag_t bst;
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bus_space_handle_t bsh;
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device_t dev;
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device_t iicbus;
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struct mtx mutex;
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};
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static struct resource_spec i2c_spec[] = {
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{ SYS_RES_MEMORY, 0, RF_ACTIVE },
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{ SYS_RES_IRQ, 0, RF_ACTIVE },
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{ -1, 0 }
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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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if (!ofw_bus_status_okay(dev))
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return (ENXIO);
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if (!ofw_bus_is_compatible(dev, "fsl,mvf600-i2c"))
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return (ENXIO);
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device_set_desc(dev, "Vybrid Family Inter-Integrated Circuit (I2C)");
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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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mtx_init(&sc->mutex, device_get_nameunit(dev), "I2C", MTX_DEF);
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if (bus_alloc_resources(dev, i2c_spec, sc->res)) {
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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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/* Memory interface */
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sc->bst = rman_get_bustag(sc->res[0]);
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sc->bsh = rman_get_bushandle(sc->res[0]);
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WRITE1(sc, I2C_IBIC, IBIC_BIIE);
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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 (0);
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}
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/* Wait for transfer interrupt flag */
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static int
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wait_for_iif(struct i2c_softc *sc)
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{
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int retry;
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retry = 1000;
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while (retry --) {
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if (READ1(sc, I2C_IBSR) & IBSR_IBIF) {
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WRITE1(sc, I2C_IBSR, IBSR_IBIF);
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return (IIC_NOERR);
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}
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DELAY(10);
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}
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return (IIC_ETIMEOUT);
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}
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/* Wait for free bus */
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static int
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wait_for_nibb(struct i2c_softc *sc)
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{
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int retry;
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retry = 1000;
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while (retry --) {
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if ((READ1(sc, I2C_IBSR) & IBSR_IBB) == 0)
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return (IIC_NOERR);
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DELAY(10);
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}
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return (IIC_ETIMEOUT);
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}
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/* Wait for transfer complete+interrupt flag */
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static int
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wait_for_icf(struct i2c_softc *sc)
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{
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int retry;
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retry = 1000;
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while (retry --) {
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if (READ1(sc, I2C_IBSR) & IBSR_TCF) {
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if (READ1(sc, I2C_IBSR) & IBSR_IBIF) {
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WRITE1(sc, I2C_IBSR, IBSR_IBIF);
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return (IIC_NOERR);
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}
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}
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DELAY(10);
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}
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return (IIC_ETIMEOUT);
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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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int reg;
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sc = device_get_softc(dev);
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vf_i2c_dbg(sc, "i2c repeated start\n");
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mtx_lock(&sc->mutex);
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WRITE1(sc, I2C_IBAD, slave);
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if ((READ1(sc, I2C_IBSR) & IBSR_IBB) == 0) {
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mtx_unlock(&sc->mutex);
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return (IIC_EBUSERR);
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}
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/* Set repeated start condition */
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DELAY(10);
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reg = READ1(sc, I2C_IBCR);
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reg |= (IBCR_RSTA | IBCR_IBIE);
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WRITE1(sc, I2C_IBCR, reg);
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DELAY(10);
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/* Write target address - LSB is R/W bit */
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WRITE1(sc, I2C_IBDR, slave);
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error = wait_for_iif(sc);
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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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int error;
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int reg;
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sc = device_get_softc(dev);
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vf_i2c_dbg(sc, "i2c start\n");
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mtx_lock(&sc->mutex);
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WRITE1(sc, I2C_IBAD, slave);
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if (READ1(sc, I2C_IBSR) & IBSR_IBB) {
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mtx_unlock(&sc->mutex);
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vf_i2c_dbg(sc, "cant i2c start: IIC_EBUSBSY\n");
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return (IIC_EBUSERR);
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}
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/* Set start condition */
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reg = (IBCR_MSSL | IBCR_NOACK | IBCR_IBIE);
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WRITE1(sc, I2C_IBCR, reg);
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DELAY(100);
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reg |= (IBCR_TXRX);
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WRITE1(sc, I2C_IBCR, reg);
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/* Write target address - LSB is R/W bit */
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WRITE1(sc, I2C_IBDR, slave);
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error = wait_for_iif(sc);
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mtx_unlock(&sc->mutex);
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if (error) {
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vf_i2c_dbg(sc, "cant i2c start: iif error\n");
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return (error);
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}
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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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vf_i2c_dbg(sc, "i2c stop\n");
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mtx_lock(&sc->mutex);
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WRITE1(sc, I2C_IBCR, IBCR_NOACK | IBCR_IBIE);
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DELAY(100);
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/* Reset controller if bus still busy after STOP */
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if (wait_for_nibb(sc) == IIC_ETIMEOUT) {
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WRITE1(sc, I2C_IBCR, IBCR_MDIS);
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DELAY(1000);
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WRITE1(sc, I2C_IBCR, IBCR_NOACK);
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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_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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sc = device_get_softc(dev);
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vf_i2c_dbg(sc, "i2c reset\n");
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switch (speed) {
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case IIC_FAST:
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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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break;
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}
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mtx_lock(&sc->mutex);
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WRITE1(sc, I2C_IBCR, IBCR_MDIS);
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DELAY(1000);
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WRITE1(sc, I2C_IBFD, 20);
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WRITE1(sc, I2C_IBCR, 0x0); /* Enable i2c */
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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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vf_i2c_dbg(sc, "i2c read\n");
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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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WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | \
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IBCR_NOACK);
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else
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WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL);
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/* dummy read */
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READ1(sc, I2C_IBDR);
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DELAY(1000);
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}
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while (*read < len) {
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error = wait_for_icf(sc);
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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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/* NO ACK on last byte */
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WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | \
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IBCR_NOACK);
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}
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if ((*read == len - 1) && last) {
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/* Transfer done, remove master bit */
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WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_NOACK);
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}
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*buf++ = READ1(sc, I2C_IBDR);
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(*read)++;
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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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vf_i2c_dbg(sc, "i2c write\n");
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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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WRITE1(sc, I2C_IBDR, *buf++);
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error = wait_for_iif(sc);
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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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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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