247 lines
6.8 KiB
C
247 lines
6.8 KiB
C
/* $NetBSD: pcf8584.c,v 1.1 2007/04/14 19:33:29 tnn Exp $ */
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/*-
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* Copyright (c) 2007 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Tobias Nygren.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Philips PCF8584 I2C Bus Controller
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*
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* This driver does not yet support multi-master arbitration, concurrent access
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* or interrupts, but it should be usable for single-master applications.
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* It is currently used by the envctrl(4) driver on sparc64.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: pcf8584.c,v 1.1 2007/04/14 19:33:29 tnn Exp $");
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#include <sys/param.h>
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#include <sys/device.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/condvar.h>
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#include <sys/mutex.h>
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#include <machine/bus.h>
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#include <machine/param.h>
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#include <dev/i2c/i2cvar.h>
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#include <dev/ic/pcf8584reg.h>
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#include <dev/ic/pcf8584var.h>
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static void pcf8584_bus_reset(struct pcf8584_handle *, int);
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static int pcf8584_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
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void *, size_t, int);
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static int pcf8584_acquire_bus(void *, int);
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static void pcf8584_release_bus(void *, int);
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static void pcf8584_wait(struct pcf8584_handle *, int);
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/* Must delay for 500 ns between bus accesses according to manual. */
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#define DATA_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 0, x))
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#define DATA_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 0))
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#define CSR_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 1, x))
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#define STATUS_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 1))
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#define BUSY() ((STATUS_R() & PCF8584_STATUS_BBN) == 0)
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#define PENDING() ((STATUS_R() & PCF8584_STATUS_PIN) == 0)
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#define NAK() ((STATUS_R() & PCF8584_STATUS_LRB) != 0)
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/*
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* Wait for an interrupt.
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*/
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static void
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pcf8584_wait(struct pcf8584_handle *ha, int flags)
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{
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int timeo;
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if (flags & I2C_F_POLL) {
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timeo = 20;
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while (timeo && !PENDING()) {
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DELAY(1000);
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timeo--;
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}
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} else {
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mutex_enter(&ha->ha_intrmtx);
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cv_timedwait(&ha->ha_intrcond, &ha->ha_intrmtx, mstohz(20));
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mutex_exit(&ha->ha_intrmtx);
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}
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}
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#ifdef notyet
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static void
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pcf8584_intr(struct pcf8584_handle *ha) {
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cv_wakeup(&ha->ha_intrcond);
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}
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#endif
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int
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pcf8584_init(struct pcf8584_handle *ha)
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{
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ha->ha_i2c.ic_cookie = ha;
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ha->ha_i2c.ic_acquire_bus = pcf8584_acquire_bus;
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ha->ha_i2c.ic_release_bus = pcf8584_release_bus;
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ha->ha_i2c.ic_exec = pcf8584_exec;
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mutex_init(&ha->ha_intrmtx, MUTEX_DEFAULT, IPL_NONE);
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cv_init(&ha->ha_intrcond, "pcf8584");
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pcf8584_bus_reset(ha, I2C_F_POLL);
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return 0;
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}
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/*
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* Reset i2c bus.
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*/
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static void
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pcf8584_bus_reset(struct pcf8584_handle *ha, int flags)
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{
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/* initialize PCF8584 */
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CSR_W(PCF8584_CTRL_PIN);
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DATA_W(0x55);
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CSR_W(PCF8584_CTRL_PIN | PCF8584_REG_S2);
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DATA_W(PCF8584_CLK_12 | PCF8584_SCL_90);
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CSR_W(PCF8584_CTRL_PIN | PCF8584_CTRL_ESO | PCF8584_CTRL_ACK);
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/* XXX needs multi-master synchronization delay here */
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/*
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* Blindly attempt a write at a nonexistent i2c address (0x7F).
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* This allows hung i2c devices to pick up the stop condition.
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*/
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DATA_W(0x7F << 1);
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CSR_W(PCF8584_CMD_START);
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pcf8584_wait(ha, flags);
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CSR_W(PCF8584_CMD_STOP);
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pcf8584_wait(ha, flags);
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}
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static int
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pcf8584_exec(void *cookie, i2c_op_t op, i2c_addr_t addr,
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const void *cmdbuf, size_t cmdlen, void *buf,
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size_t len, int flags)
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{
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int i;
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struct pcf8584_handle *ha = cookie;
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uint8_t *p = buf;
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KASSERT(cmdlen == 0);
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KASSERT(op == I2C_OP_READ_WITH_STOP || op == I2C_OP_WRITE_WITH_STOP);
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if (BUSY()) {
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/* We're the only master on the bus, something is wrong. */
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printf("*%s: i2c bus busy!\n", ha->ha_parent->dv_xname);
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pcf8584_bus_reset(ha, flags);
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}
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if (op == I2C_OP_READ_WITH_STOP)
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DATA_W((addr << 1) | 1);
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else
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DATA_W(addr << 1);
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CSR_W(PCF8584_CMD_START);
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pcf8584_wait(ha, flags);
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if (!PENDING()) {
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printf("%s: no intr after i2c sla\n", ha->ha_parent->dv_xname);
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}
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if (NAK())
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goto fail;
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if (op == I2C_OP_READ_WITH_STOP) {
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(void) DATA_R();/* dummy read */
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for (i = 0; i < len; i++) {
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/* wait for a byte to arrive */
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pcf8584_wait(ha, flags);
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if (!PENDING()) {
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printf("%s: lost intr during i2c read\n",
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ha->ha_parent->dv_xname);
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goto fail;
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}
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if (NAK())
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goto fail;
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if (i == len - 1) {
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/*
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* we're about to read the final byte, so we
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* set the controller to NAK the following
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* byte, if any.
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*/
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CSR_W(PCF8584_CMD_NAK);
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}
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*p++ = DATA_R();
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}
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pcf8584_wait(ha, flags);
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if (!PENDING()) {
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printf("%s: no intr on final i2c nak\n",
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ha->ha_parent->dv_xname);
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goto fail;
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}
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CSR_W(PCF8584_CMD_STOP);
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(void) DATA_R();/* dummy read */
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} else {
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for (i = 0; i < len; i++) {
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DATA_W(*p++);
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pcf8584_wait(ha, flags);
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if (!PENDING()) {
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printf("%s: no intr during i2c write\n",
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ha->ha_parent->dv_xname);
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goto fail;
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}
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if (NAK())
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goto fail;
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}
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CSR_W(PCF8584_CMD_STOP);
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}
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pcf8584_wait(ha, flags);
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return 0;
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fail:
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CSR_W(PCF8584_CMD_STOP);
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pcf8584_wait(ha, flags);
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return 1;
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}
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static int
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pcf8584_acquire_bus(void *cookie, int flags)
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{
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/* XXX concurrent access not yet implemented */
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return 0;
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}
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static void
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pcf8584_release_bus(void *cookie, int flags)
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{
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}
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