Annotation of src/sys/dev/ic/pcf8584.c, Revision 1.1.4.2
1.1.4.2 ! ad 1: /* $NetBSD$ */
! 2:
! 3: /*-
! 4: * Copyright (c) 2007 The NetBSD Foundation, Inc.
! 5: * All rights reserved.
! 6: *
! 7: * This code is derived from software contributed to The NetBSD Foundation
! 8: * by Tobias Nygren.
! 9: *
! 10: * Redistribution and use in source and binary forms, with or without
! 11: * modification, are permitted provided that the following conditions
! 12: * are met:
! 13: * 1. Redistributions of source code must retain the above copyright
! 14: * notice, this list of conditions and the following disclaimer.
! 15: * 2. Redistributions in binary form must reproduce the above copyright
! 16: * notice, this list of conditions and the following disclaimer in the
! 17: * documentation and/or other materials provided with the distribution.
! 18: * 3. All advertising materials mentioning features or use of this software
! 19: * must display the following acknowledgement:
! 20: * This product includes software developed by the NetBSD
! 21: * Foundation, Inc. and its contributors.
! 22: * 4. Neither the name of The NetBSD Foundation nor the names of its
! 23: * contributors may be used to endorse or promote products derived
! 24: * from this software without specific prior written permission.
! 25: *
! 26: * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
! 27: * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
! 28: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
! 29: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
! 30: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
! 31: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
! 32: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
! 33: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
! 34: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
! 35: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
! 36: * POSSIBILITY OF SUCH DAMAGE.
! 37: */
! 38:
! 39: /*
! 40: * Philips PCF8584 I2C Bus Controller
! 41: *
! 42: * This driver does not yet support multi-master arbitration, concurrent access
! 43: * or interrupts, but it should be usable for single-master applications.
! 44: * It is currently used by the envctrl(4) driver on sparc64.
! 45: */
! 46:
! 47: #include <sys/cdefs.h>
! 48: __KERNEL_RCSID(0, "$NetBSD$");
! 49:
! 50: #include <sys/param.h>
! 51: #include <sys/device.h>
! 52: #include <sys/kernel.h>
! 53: #include <sys/systm.h>
! 54: #include <sys/condvar.h>
! 55: #include <sys/mutex.h>
! 56: #include <machine/bus.h>
! 57: #include <machine/param.h>
! 58: #include <dev/i2c/i2cvar.h>
! 59: #include <dev/ic/pcf8584reg.h>
! 60: #include <dev/ic/pcf8584var.h>
! 61:
! 62: static void pcf8584_bus_reset(struct pcf8584_handle *, int);
! 63: static int pcf8584_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
! 64: void *, size_t, int);
! 65: static int pcf8584_acquire_bus(void *, int);
! 66: static void pcf8584_release_bus(void *, int);
! 67: static void pcf8584_wait(struct pcf8584_handle *, int);
! 68:
! 69: /* Must delay for 500 ns between bus accesses according to manual. */
! 70: #define DATA_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 0, x))
! 71: #define DATA_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 0))
! 72: #define CSR_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 1, x))
! 73: #define STATUS_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 1))
! 74: #define BUSY() ((STATUS_R() & PCF8584_STATUS_BBN) == 0)
! 75: #define PENDING() ((STATUS_R() & PCF8584_STATUS_PIN) == 0)
! 76: #define NAK() ((STATUS_R() & PCF8584_STATUS_LRB) != 0)
! 77:
! 78: /*
! 79: * Wait for an interrupt.
! 80: */
! 81: static void
! 82: pcf8584_wait(struct pcf8584_handle *ha, int flags)
! 83: {
! 84: int timeo;
! 85:
! 86: if (flags & I2C_F_POLL) {
! 87: timeo = 20;
! 88: while (timeo && !PENDING()) {
! 89: DELAY(1000);
! 90: timeo--;
! 91: }
! 92: } else {
! 93: mutex_enter(&ha->ha_intrmtx);
! 94: cv_timedwait(&ha->ha_intrcond, &ha->ha_intrmtx, mstohz(20));
! 95: mutex_exit(&ha->ha_intrmtx);
! 96: }
! 97: }
! 98:
! 99: #ifdef notyet
! 100: static void
! 101: pcf8584_intr(struct pcf8584_handle *ha) {
! 102:
! 103: cv_wakeup(&ha->ha_intrcond);
! 104: }
! 105: #endif
! 106:
! 107: int
! 108: pcf8584_init(struct pcf8584_handle *ha)
! 109: {
! 110:
! 111: ha->ha_i2c.ic_cookie = ha;
! 112: ha->ha_i2c.ic_acquire_bus = pcf8584_acquire_bus;
! 113: ha->ha_i2c.ic_release_bus = pcf8584_release_bus;
! 114: ha->ha_i2c.ic_exec = pcf8584_exec;
! 115:
! 116: mutex_init(&ha->ha_intrmtx, MUTEX_DEFAULT, IPL_NONE);
! 117: cv_init(&ha->ha_intrcond, "pcf8584");
! 118:
! 119: pcf8584_bus_reset(ha, I2C_F_POLL);
! 120:
! 121: return 0;
! 122: }
! 123:
! 124: /*
! 125: * Reset i2c bus.
! 126: */
! 127: static void
! 128: pcf8584_bus_reset(struct pcf8584_handle *ha, int flags)
! 129: {
! 130:
! 131: /* initialize PCF8584 */
! 132: CSR_W(PCF8584_CTRL_PIN);
! 133: DATA_W(0x55);
! 134: CSR_W(PCF8584_CTRL_PIN | PCF8584_REG_S2);
! 135: DATA_W(PCF8584_CLK_12 | PCF8584_SCL_90);
! 136: CSR_W(PCF8584_CTRL_PIN | PCF8584_CTRL_ESO | PCF8584_CTRL_ACK);
! 137:
! 138: /* XXX needs multi-master synchronization delay here */
! 139:
! 140: /*
! 141: * Blindly attempt a write at a nonexistent i2c address (0x7F).
! 142: * This allows hung i2c devices to pick up the stop condition.
! 143: */
! 144: DATA_W(0x7F << 1);
! 145: CSR_W(PCF8584_CMD_START);
! 146: pcf8584_wait(ha, flags);
! 147: CSR_W(PCF8584_CMD_STOP);
! 148: pcf8584_wait(ha, flags);
! 149: }
! 150:
! 151: static int
! 152: pcf8584_exec(void *cookie, i2c_op_t op, i2c_addr_t addr,
! 153: const void *cmdbuf, size_t cmdlen, void *buf,
! 154: size_t len, int flags)
! 155: {
! 156: int i;
! 157: struct pcf8584_handle *ha = cookie;
! 158: uint8_t *p = buf;
! 159:
! 160: KASSERT(cmdlen == 0);
! 161: KASSERT(op == I2C_OP_READ_WITH_STOP || op == I2C_OP_WRITE_WITH_STOP);
! 162:
! 163: if (BUSY()) {
! 164: /* We're the only master on the bus, something is wrong. */
! 165: printf("*%s: i2c bus busy!\n", ha->ha_parent->dv_xname);
! 166: pcf8584_bus_reset(ha, flags);
! 167: }
! 168: if (op == I2C_OP_READ_WITH_STOP)
! 169: DATA_W((addr << 1) | 1);
! 170: else
! 171: DATA_W(addr << 1);
! 172:
! 173: CSR_W(PCF8584_CMD_START);
! 174: pcf8584_wait(ha, flags);
! 175: if (!PENDING()) {
! 176: printf("%s: no intr after i2c sla\n", ha->ha_parent->dv_xname);
! 177: }
! 178: if (NAK())
! 179: goto fail;
! 180:
! 181: if (op == I2C_OP_READ_WITH_STOP) {
! 182: (void) DATA_R();/* dummy read */
! 183: for (i = 0; i < len; i++) {
! 184: /* wait for a byte to arrive */
! 185: pcf8584_wait(ha, flags);
! 186: if (!PENDING()) {
! 187: printf("%s: lost intr during i2c read\n",
! 188: ha->ha_parent->dv_xname);
! 189: goto fail;
! 190: }
! 191: if (NAK())
! 192: goto fail;
! 193: if (i == len - 1) {
! 194: /*
! 195: * we're about to read the final byte, so we
! 196: * set the controller to NAK the following
! 197: * byte, if any.
! 198: */
! 199: CSR_W(PCF8584_CMD_NAK);
! 200: }
! 201: *p++ = DATA_R();
! 202: }
! 203: pcf8584_wait(ha, flags);
! 204: if (!PENDING()) {
! 205: printf("%s: no intr on final i2c nak\n",
! 206: ha->ha_parent->dv_xname);
! 207: goto fail;
! 208: }
! 209: CSR_W(PCF8584_CMD_STOP);
! 210: (void) DATA_R();/* dummy read */
! 211: } else {
! 212: for (i = 0; i < len; i++) {
! 213: DATA_W(*p++);
! 214: pcf8584_wait(ha, flags);
! 215: if (!PENDING()) {
! 216: printf("%s: no intr during i2c write\n",
! 217: ha->ha_parent->dv_xname);
! 218: goto fail;
! 219: }
! 220: if (NAK())
! 221: goto fail;
! 222: }
! 223: CSR_W(PCF8584_CMD_STOP);
! 224: }
! 225: pcf8584_wait(ha, flags);
! 226: return 0;
! 227: fail:
! 228: CSR_W(PCF8584_CMD_STOP);
! 229: pcf8584_wait(ha, flags);
! 230:
! 231: return 1;
! 232: }
! 233:
! 234: static int
! 235: pcf8584_acquire_bus(void *cookie, int flags)
! 236: {
! 237:
! 238: /* XXX concurrent access not yet implemented */
! 239: return 0;
! 240: }
! 241:
! 242: static void
! 243: pcf8584_release_bus(void *cookie, int flags)
! 244: {
! 245:
! 246: }
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