iicbus.c revision 294490
1/*- 2 * Copyright (c) 1998, 2001 Nicolas Souchu 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: stable/10/sys/dev/iicbus/iicbus.c 294490 2016-01-21 08:32:11Z dumbbell $"); 29 30/* 31 * Autoconfiguration and support routines for the Philips serial I2C bus 32 */ 33 34#include <sys/param.h> 35#include <sys/systm.h> 36#include <sys/kernel.h> 37#include <sys/lock.h> 38#include <sys/malloc.h> 39#include <sys/module.h> 40#include <sys/mutex.h> 41#include <sys/sysctl.h> 42#include <sys/bus.h> 43 44#include <dev/iicbus/iiconf.h> 45#include <dev/iicbus/iicbus.h> 46 47#include "iicbus_if.h" 48 49/* See comments below for why auto-scanning is a bad idea. */ 50#define SCAN_IICBUS 0 51 52static int 53iicbus_probe(device_t dev) 54{ 55 56 device_set_desc(dev, "Philips I2C bus"); 57 58 /* Allow other subclasses to override this driver. */ 59 return (BUS_PROBE_GENERIC); 60} 61 62#if SCAN_IICBUS 63static int 64iic_probe_device(device_t dev, u_char addr) 65{ 66 int count; 67 char byte; 68 69 if ((addr & 1) == 0) { 70 /* is device writable? */ 71 if (!iicbus_start(dev, (u_char)addr, 0)) { 72 iicbus_stop(dev); 73 return (1); 74 } 75 } else { 76 /* is device readable? */ 77 if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count)) 78 return (1); 79 } 80 81 return (0); 82} 83#endif 84 85/* 86 * We add all the devices which we know about. 87 * The generic attach routine will attach them if they are alive. 88 */ 89static int 90iicbus_attach(device_t dev) 91{ 92#if SCAN_IICBUS 93 unsigned char addr; 94#endif 95 struct iicbus_softc *sc = IICBUS_SOFTC(dev); 96 int strict; 97 98 sc->dev = dev; 99 mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF); 100 iicbus_init_frequency(dev, 0); 101 iicbus_reset(dev, IIC_FASTEST, 0, NULL); 102 if (resource_int_value(device_get_name(dev), 103 device_get_unit(dev), "strict", &strict) == 0) 104 sc->strict = strict; 105 else 106 sc->strict = 1; 107 108 /* device probing is meaningless since the bus is supposed to be 109 * hot-plug. Moreover, some I2C chips do not appreciate random 110 * accesses like stop after start to fast, reads for less than 111 * x bytes... 112 */ 113#if SCAN_IICBUS 114 printf("Probing for devices on iicbus%d:", device_get_unit(dev)); 115 116 /* probe any devices */ 117 for (addr = 16; addr < 240; addr++) { 118 if (iic_probe_device(dev, (u_char)addr)) { 119 printf(" <%x>", addr); 120 } 121 } 122 printf("\n"); 123#endif 124 bus_generic_probe(dev); 125 bus_enumerate_hinted_children(dev); 126 bus_generic_attach(dev); 127 return (0); 128} 129 130static int 131iicbus_detach(device_t dev) 132{ 133 struct iicbus_softc *sc = IICBUS_SOFTC(dev); 134 135 iicbus_reset(dev, IIC_FASTEST, 0, NULL); 136 bus_generic_detach(dev); 137 device_delete_children(dev); 138 mtx_destroy(&sc->lock); 139 return (0); 140} 141 142static int 143iicbus_print_child(device_t dev, device_t child) 144{ 145 struct iicbus_ivar *devi = IICBUS_IVAR(child); 146 int retval = 0; 147 148 retval += bus_print_child_header(dev, child); 149 if (devi->addr != 0) 150 retval += printf(" at addr %#x", devi->addr); 151 retval += bus_print_child_footer(dev, child); 152 153 return (retval); 154} 155 156static void 157iicbus_probe_nomatch(device_t bus, device_t child) 158{ 159 struct iicbus_ivar *devi = IICBUS_IVAR(child); 160 161 device_printf(bus, "<unknown card>"); 162 printf(" at addr %#x\n", devi->addr); 163 return; 164} 165 166static int 167iicbus_child_location_str(device_t bus, device_t child, char *buf, 168 size_t buflen) 169{ 170 struct iicbus_ivar *devi = IICBUS_IVAR(child); 171 172 snprintf(buf, buflen, "addr=%#x", devi->addr); 173 return (0); 174} 175 176static int 177iicbus_child_pnpinfo_str(device_t bus, device_t child, char *buf, 178 size_t buflen) 179{ 180 *buf = '\0'; 181 return (0); 182} 183 184static int 185iicbus_read_ivar(device_t bus, device_t child, int which, uintptr_t *result) 186{ 187 struct iicbus_ivar *devi = IICBUS_IVAR(child); 188 189 switch (which) { 190 default: 191 return (EINVAL); 192 case IICBUS_IVAR_ADDR: 193 *result = devi->addr; 194 break; 195 } 196 return (0); 197} 198 199static device_t 200iicbus_add_child(device_t dev, u_int order, const char *name, int unit) 201{ 202 device_t child; 203 struct iicbus_ivar *devi; 204 205 child = device_add_child_ordered(dev, order, name, unit); 206 if (child == NULL) 207 return (child); 208 devi = malloc(sizeof(struct iicbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO); 209 if (devi == NULL) { 210 device_delete_child(dev, child); 211 return (0); 212 } 213 device_set_ivars(child, devi); 214 return (child); 215} 216 217static void 218iicbus_hinted_child(device_t bus, const char *dname, int dunit) 219{ 220 device_t child; 221 struct iicbus_ivar *devi; 222 223 child = BUS_ADD_CHILD(bus, 0, dname, dunit); 224 devi = IICBUS_IVAR(child); 225 resource_int_value(dname, dunit, "addr", &devi->addr); 226} 227 228int 229iicbus_generic_intr(device_t dev, int event, char *buf) 230{ 231 232 return (0); 233} 234 235int 236iicbus_null_callback(device_t dev, int index, caddr_t data) 237{ 238 239 return (0); 240} 241 242int 243iicbus_null_repeated_start(device_t dev, u_char addr) 244{ 245 246 return (IIC_ENOTSUPP); 247} 248 249void 250iicbus_init_frequency(device_t dev, u_int bus_freq) 251{ 252 struct iicbus_softc *sc = IICBUS_SOFTC(dev); 253 254 /* 255 * If a bus frequency value was passed in, use it. Otherwise initialize 256 * it first to the standard i2c 100KHz frequency, then override that 257 * from a hint if one exists. 258 */ 259 if (bus_freq > 0) 260 sc->bus_freq = bus_freq; 261 else { 262 sc->bus_freq = 100000; 263 resource_int_value(device_get_name(dev), device_get_unit(dev), 264 "frequency", (int *)&sc->bus_freq); 265 } 266 /* 267 * Set up the sysctl that allows the bus frequency to be changed. 268 * It is flagged as a tunable so that the user can set the value in 269 * loader(8), and that will override any other setting from any source. 270 * The sysctl tunable/value is the one most directly controlled by the 271 * user and thus the one that always takes precedence. 272 */ 273 SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev), 274 SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), 275 OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq, 276 sc->bus_freq, "Bus frequency in Hz"); 277} 278 279static u_int 280iicbus_get_frequency(device_t dev, u_char speed) 281{ 282 struct iicbus_softc *sc = IICBUS_SOFTC(dev); 283 284 /* 285 * If the frequency has not been configured for the bus, or the request 286 * is specifically for SLOW speed, use the standard 100KHz rate, else 287 * use the configured bus speed. 288 */ 289 if (sc->bus_freq == 0 || speed == IIC_SLOW) 290 return (100000); 291 return (sc->bus_freq); 292} 293 294static device_method_t iicbus_methods[] = { 295 /* device interface */ 296 DEVMETHOD(device_probe, iicbus_probe), 297 DEVMETHOD(device_attach, iicbus_attach), 298 DEVMETHOD(device_detach, iicbus_detach), 299 300 /* bus interface */ 301 DEVMETHOD(bus_add_child, iicbus_add_child), 302 DEVMETHOD(bus_print_child, iicbus_print_child), 303 DEVMETHOD(bus_probe_nomatch, iicbus_probe_nomatch), 304 DEVMETHOD(bus_read_ivar, iicbus_read_ivar), 305 DEVMETHOD(bus_child_pnpinfo_str, iicbus_child_pnpinfo_str), 306 DEVMETHOD(bus_child_location_str, iicbus_child_location_str), 307 DEVMETHOD(bus_hinted_child, iicbus_hinted_child), 308 309 /* iicbus interface */ 310 DEVMETHOD(iicbus_transfer, iicbus_transfer), 311 DEVMETHOD(iicbus_get_frequency, iicbus_get_frequency), 312 313 DEVMETHOD_END 314}; 315 316driver_t iicbus_driver = { 317 "iicbus", 318 iicbus_methods, 319 sizeof(struct iicbus_softc), 320}; 321 322devclass_t iicbus_devclass; 323 324MODULE_VERSION(iicbus, IICBUS_MODVER); 325DRIVER_MODULE(iicbus, iichb, iicbus_driver, iicbus_devclass, 0, 0); 326 327