sys/dev/ic/pcf8584.c

   1 /*      $NetBSD: pcf8584.c,v 1.4 2008/04/08 12:07:27 cegger Exp $ */
   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  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Philips PCF8584 I2C Bus Controller
  34  *
  35  * This driver does not yet support multi-master arbitration, concurrent access
  36  * or interrupts, but it should be usable for single-master applications.
  37  * It is currently used by the envctrl(4) driver on sparc64.
  38  */
  39
  40 #include <sys/cdefs.h>
  41 __KERNEL_RCSID(0, "$NetBSD: pcf8584.c,v 1.4 2008/04/08 12:07:27 cegger Exp $");
  42
  43 #include <sys/param.h>
  44 #include <sys/device.h>
  45 #include <sys/kernel.h>
  46 #include <sys/systm.h>
  47 #include <sys/condvar.h>
  48 #include <sys/mutex.h>
  49 #include <sys/bus.h>
  50 #include <machine/param.h>
  51 #include <dev/i2c/i2cvar.h>
  52 #include <dev/ic/pcf8584reg.h>
  53 #include <dev/ic/pcf8584var.h>
  54
  55 static void pcf8584_bus_reset(struct pcf8584_handle *, int);
  56 static int pcf8584_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
  57                         void *, size_t, int);
  58 static int pcf8584_acquire_bus(void *, int);
  59 static void pcf8584_release_bus(void *, int);
  60 static void pcf8584_wait(struct pcf8584_handle *, int);
  61
  62 /*  Must delay for 500 ns between bus accesses according to manual. */
  63 #define DATA_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 0, x))
  64 #define DATA_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 0))
  65 #define CSR_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 1, x))
  66 #define STATUS_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 1))
  67 #define BUSY() ((STATUS_R() & PCF8584_STATUS_BBN) == 0)
  68 #define PENDING() ((STATUS_R() & PCF8584_STATUS_PIN) == 0)
  69 #define NAK() ((STATUS_R() & PCF8584_STATUS_LRB) != 0)
  70
  71 /*
  72  * Wait for an interrupt.
  73  */
  74 static void
  75 pcf8584_wait(struct pcf8584_handle *ha, int flags)
  76 {
  77         int timeo;
  78
  79         if (flags & I2C_F_POLL) {
  80                 timeo = 20;
  81                 while (timeo && !PENDING()) {
  82                         DELAY(1000);
  83                         timeo--;
  84                 }
  85         } else {
  86                 mutex_enter(&ha->ha_intrmtx);
  87                 cv_timedwait(&ha->ha_intrcond, &ha->ha_intrmtx, mstohz(20));
  88                 mutex_exit(&ha->ha_intrmtx);
  89         }
  90 }
  91
  92 #ifdef notyet
  93 static void
  94 pcf8584_intr(struct pcf8584_handle *ha) {
  95
  96         cv_wakeup(&ha->ha_intrcond);
  97 }
  98 #endif
  99
 100 int
 101 pcf8584_init(struct pcf8584_handle *ha)
 102 {
 103
 104         ha->ha_i2c.ic_cookie = ha;
 105         ha->ha_i2c.ic_acquire_bus = pcf8584_acquire_bus;
 106         ha->ha_i2c.ic_release_bus = pcf8584_release_bus;
 107         ha->ha_i2c.ic_exec = pcf8584_exec;
 108
 109         mutex_init(&ha->ha_intrmtx, MUTEX_DEFAULT, IPL_NONE);
 110         cv_init(&ha->ha_intrcond, "pcf8584");
 111
 112         pcf8584_bus_reset(ha, I2C_F_POLL);
 113
 114         return 0;
 115 }
 116
 117 /*
 118  * Reset i2c bus.
 119  */
 120 static void
 121 pcf8584_bus_reset(struct pcf8584_handle *ha, int flags)
 122 {
 123
 124         /* initialize PCF8584 */
 125         CSR_W(PCF8584_CTRL_PIN);
 126         DATA_W(0x55);
 127         CSR_W(PCF8584_CTRL_PIN | PCF8584_REG_S2);
 128         DATA_W(PCF8584_CLK_12 | PCF8584_SCL_90);
 129         CSR_W(PCF8584_CTRL_PIN | PCF8584_CTRL_ESO | PCF8584_CTRL_ACK);
 130
 131         /* XXX needs multi-master synchronization delay here */
 132
 133         /*
 134          * Blindly attempt a write at a nonexistent i2c address (0x7F).
 135          * This allows hung i2c devices to pick up the stop condition.
 136          */
 137         DATA_W(0x7F << 1);
 138         CSR_W(PCF8584_CMD_START);
 139         pcf8584_wait(ha, flags);
 140         CSR_W(PCF8584_CMD_STOP);
 141         pcf8584_wait(ha, flags);
 142 }
 143
 144 static int
 145 pcf8584_exec(void *cookie, i2c_op_t op, i2c_addr_t addr,
 146     const void *cmdbuf, size_t cmdlen, void *buf,
 147     size_t len, int flags)
 148 {
 149         int i;
 150         struct pcf8584_handle *ha = cookie;
 151         uint8_t *p = buf;
 152
 153         KASSERT(cmdlen == 0);
 154         KASSERT(op == I2C_OP_READ_WITH_STOP || op == I2C_OP_WRITE_WITH_STOP);
 155
 156         if (BUSY()) {
 157                 /* We're the only master on the bus, something is wrong. */
 158                 printf("*%s: i2c bus busy!\n", device_xname(ha->ha_parent));
 159                 pcf8584_bus_reset(ha, flags);
 160         }
 161         if (op == I2C_OP_READ_WITH_STOP)
 162                 DATA_W((addr << 1) | 1);
 163         else
 164                 DATA_W(addr << 1);
 165
 166         CSR_W(PCF8584_CMD_START);
 167         pcf8584_wait(ha, flags);
 168         if (!PENDING()) {
 169                 printf("%s: no intr after i2c sla\n", device_xname(ha->ha_parent));
 170         }
 171         if (NAK())
 172                 goto fail;
 173
 174         if (op == I2C_OP_READ_WITH_STOP) {
 175                 (void) DATA_R();/* dummy read */
 176                 for (i = 0; i < len; i++) {
 177                         /* wait for a byte to arrive */
 178                         pcf8584_wait(ha, flags);
 179                         if (!PENDING()) {
 180                                 printf("%s: lost intr during i2c read\n",
 181                                     device_xname(ha->ha_parent));
 182                                 goto fail;
 183                         }
 184                         if (NAK())
 185                                 goto fail;
 186                         if (i == len - 1) {
 187                                 /*
 188                                  * we're about to read the final byte, so we
 189                                  * set the controller to NAK the following
 190                                  * byte, if any.
 191                                  */
 192                                 CSR_W(PCF8584_CMD_NAK);
 193                         }
 194                         *p++ = DATA_R();
 195                 }
 196                 pcf8584_wait(ha, flags);
 197                 if (!PENDING()) {
 198                         printf("%s: no intr on final i2c nak\n",
 199                             device_xname(ha->ha_parent));
 200                         goto fail;
 201                 }
 202                 CSR_W(PCF8584_CMD_STOP);
 203                 (void) DATA_R();/* dummy read */
 204         } else {
 205                 for (i = 0; i < len; i++) {
 206                         DATA_W(*p++);
 207                         pcf8584_wait(ha, flags);
 208                         if (!PENDING()) {
 209                                 printf("%s: no intr during i2c write\n",
 210                                     device_xname(ha->ha_parent));
 211                                 goto fail;
 212                         }
 213                         if (NAK())
 214                                 goto fail;
 215                 }
 216                 CSR_W(PCF8584_CMD_STOP);
 217         }
 218         pcf8584_wait(ha, flags);
 219         return 0;
 220 fail:
 221         CSR_W(PCF8584_CMD_STOP);
 222         pcf8584_wait(ha, flags);
 223
 224         return 1;
 225 }
 226
 227 static int
 228 pcf8584_acquire_bus(void *cookie, int flags)
 229 {
 230
 231         /* XXX concurrent access not yet implemented */
 232         return 0;
 233 }
 234
 235 static void
 236 pcf8584_release_bus(void *cookie, int flags)
 237 {
 238
 239 }