i2cmux.c revision 1.9
1 /* $NetBSD: i2cmux.c,v 1.9 2025/09/15 15:31:45 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2020 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe. 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 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) 33 #include "acpica.h" 34 #endif 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: i2cmux.c,v 1.9 2025/09/15 15:31:45 thorpej Exp $"); 38 39 #include <sys/types.h> 40 #include <sys/device.h> 41 #include <sys/kernel.h> 42 #include <sys/kmem.h> 43 44 #include <dev/fdt/fdtvar.h> 45 #include <dev/i2c/i2cvar.h> 46 #include <dev/i2c/i2cmuxvar.h> 47 48 #if NACPICA > 0 49 #include <dev/acpi/acpivar.h> 50 #endif 51 52 /* 53 * i2c mux 54 * 55 * This works by interposing a set of virtual controllers behind the real 56 * i2c controller. We provide our own acquire and release functions that 57 * perform the following tasks: 58 * 59 * acquire -> acquire parent controller, program mux 60 * 61 * release -> idle mux, release parent controller 62 * 63 * All of the actual I/O operations are transparently passed through. 64 * 65 * N.B. the locking order; the generic I2C layer has already acquired 66 * our virtual controller's mutex before calling our acquire function, 67 * and we will then acquire the real controller's mutex when we acquire 68 * the bus, so the order is: 69 * 70 * mux virtual controller -> parent controller 71 * 72 * These are common routines used by various i2c mux controller 73 * implementations (gpio, pin mux, i2c device, etc.). 74 */ 75 76 /*****************************************************************************/ 77 78 static int 79 iicmux_acquire_bus(void * const v, int const flags) 80 { 81 struct iicmux_bus * const bus = v; 82 struct iicmux_softc * const sc = bus->mux; 83 int error; 84 85 error = iic_acquire_bus(sc->sc_i2c_parent, flags); 86 if (error) { 87 return error; 88 } 89 90 error = sc->sc_config->acquire_bus(bus, flags); 91 if (error) { 92 iic_release_bus(sc->sc_i2c_parent, flags); 93 } 94 95 return error; 96 } 97 98 static void 99 iicmux_release_bus(void * const v, int const flags) 100 { 101 struct iicmux_bus * const bus = v; 102 struct iicmux_softc * const sc = bus->mux; 103 104 sc->sc_config->release_bus(bus, flags); 105 iic_release_bus(sc->sc_i2c_parent, flags); 106 } 107 108 static int 109 iicmux_exec(void * const v, i2c_op_t const op, i2c_addr_t const addr, 110 const void * const cmdbuf, size_t const cmdlen, void * const databuf, 111 size_t const datalen, int const flags) 112 { 113 struct iicmux_bus * const bus = v; 114 struct iicmux_softc * const sc = bus->mux; 115 116 return iic_exec(sc->sc_i2c_parent, op, addr, cmdbuf, cmdlen, 117 databuf, datalen, flags); 118 } 119 120 /*****************************************************************************/ 121 122 static int 123 iicmux_count_children(struct iicmux_softc * const sc) 124 { 125 char name[32]; 126 int child, count; 127 128 restart: 129 for (child = OF_child(sc->sc_i2c_mux_phandle), count = 0; child; 130 child = OF_peer(child)) { 131 if (OF_getprop(child, "name", name, sizeof(name)) <= 0) { 132 continue; 133 } 134 if (strcmp(name, "i2c-mux") == 0) { 135 /* 136 * The node we encountered is the actual parent 137 * of the i2c bus children. Stash its phandle 138 * and restart the enumeration. 139 */ 140 sc->sc_i2c_mux_phandle = child; 141 goto restart; 142 } 143 count++; 144 } 145 146 return count; 147 } 148 149 /* XXX iicbus_print() should be able to do this. */ 150 static int 151 iicmux_print(void * const aux, const char * const pnp) 152 { 153 i2c_tag_t const tag = aux; 154 struct iicmux_bus * const bus = tag->ic_cookie; 155 int rv; 156 157 rv = iicbus_print(aux, pnp); 158 aprint_normal(" bus %d", bus->busidx); 159 160 return rv; 161 } 162 163 static void 164 iicmux_attach_bus(struct iicmux_softc * const sc, 165 uintptr_t const handle, enum i2c_cookie_type handletype, int const busidx) 166 { 167 struct iicmux_bus * const bus = &sc->sc_busses[busidx]; 168 169 bus->mux = sc; 170 bus->busidx = busidx; 171 bus->handle = handle; 172 bus->handletype = handletype; 173 174 bus->bus_data = sc->sc_config->get_bus_info(bus); 175 if (bus->bus_data == NULL) { 176 aprint_error_dev(sc->sc_dev, 177 "unable to get info for bus %d\n", busidx); 178 return; 179 } 180 181 iic_tag_init(&bus->controller); 182 bus->controller.ic_cookie = bus; 183 bus->controller.ic_acquire_bus = iicmux_acquire_bus; 184 bus->controller.ic_release_bus = iicmux_release_bus; 185 bus->controller.ic_exec = iicmux_exec; 186 187 switch (handletype) { 188 case I2C_COOKIE_OF: 189 fdtbus_register_i2c_controller(&bus->controller, 190 (int)bus->handle); 191 192 fdtbus_attach_i2cbus(sc->sc_dev, (int)bus->handle, 193 &bus->controller, iicmux_print); 194 break; 195 #if NACPICA > 0 196 case I2C_COOKIE_ACPI: { 197 iicbus_attach_with_devhandle(sc->sc_dev, &bus->controller, 198 devhandle_from_acpi(device_handle(sc->sc_dev), 199 (ACPI_HANDLE)handle)); 200 } break; 201 #endif 202 default: 203 aprint_error_dev(sc->sc_dev, "unknown handle type\n"); 204 break; 205 } 206 } 207 208 static void 209 iicmux_attach_fdt(struct iicmux_softc * const sc) 210 { 211 /* 212 * We start out assuming that the i2c bus nodes are children of 213 * our own node. We'll adjust later if we encounter an "i2c-mux" 214 * node when counting our children. If we encounter such a node, 215 * then it's that node that is the parent of the i2c bus children. 216 */ 217 sc->sc_i2c_mux_phandle = (int)sc->sc_handle; 218 219 sc->sc_nbusses = iicmux_count_children(sc); 220 if (sc->sc_nbusses == 0) { 221 return; 222 } 223 224 sc->sc_busses = kmem_zalloc(sizeof(*sc->sc_busses) * sc->sc_nbusses, 225 KM_SLEEP); 226 227 int child, idx; 228 for (child = OF_child(sc->sc_i2c_mux_phandle), idx = 0; child; 229 child = OF_peer(child), idx++) { 230 KASSERT(idx < sc->sc_nbusses); 231 iicmux_attach_bus(sc, child, I2C_COOKIE_OF, idx); 232 } 233 } 234 235 #if NACPICA > 0 236 static void 237 iicmux_attach_acpi(struct iicmux_softc * const sc) 238 { 239 ACPI_HANDLE hdl = (ACPI_HANDLE)sc->sc_handle; 240 struct acpi_devnode *devnode, *ad; 241 int idx; 242 243 devnode = acpi_match_node(hdl); 244 KASSERT(devnode != NULL); 245 246 /* Count child busses */ 247 sc->sc_nbusses = 0; 248 SIMPLEQ_FOREACH(ad, &devnode->ad_child_head, ad_child_list) { 249 if (ad->ad_devinfo->Type != ACPI_TYPE_DEVICE || 250 !acpi_device_present(ad->ad_handle)) { 251 continue; 252 } 253 sc->sc_nbusses++; 254 } 255 256 sc->sc_busses = kmem_zalloc(sizeof(*sc->sc_busses) * sc->sc_nbusses, 257 KM_SLEEP); 258 259 /* Attach child busses */ 260 idx = 0; 261 SIMPLEQ_FOREACH(ad, &devnode->ad_child_head, ad_child_list) { 262 if (ad->ad_devinfo->Type != ACPI_TYPE_DEVICE || 263 !acpi_device_present(ad->ad_handle)) { 264 continue; 265 } 266 iicmux_attach_bus(sc, (uintptr_t)ad->ad_handle, 267 I2C_COOKIE_ACPI, idx); 268 idx++; 269 } 270 } 271 #endif 272 273 void 274 iicmux_attach(struct iicmux_softc * const sc) 275 { 276 /* 277 * We expect sc->sc_handle, sc->sc_config, and sc->sc_i2c_parent 278 * to be initialized by the front-end. 279 */ 280 KASSERT(sc->sc_handle > 0); 281 KASSERT(sc->sc_config != NULL); 282 KASSERT(sc->sc_i2c_parent != NULL); 283 284 /* 285 * Gather up all of the various bits of information needed 286 * for this particular type of i2c mux. 287 */ 288 sc->sc_mux_data = sc->sc_config->get_mux_info(sc); 289 if (sc->sc_mux_data == NULL) { 290 aprint_error_dev(sc->sc_dev, "unable to get info for mux\n"); 291 return; 292 } 293 294 /* 295 * Do configuration method (OF, ACPI) specific setup. 296 */ 297 switch (sc->sc_handletype) { 298 case I2C_COOKIE_OF: 299 iicmux_attach_fdt(sc); 300 break; 301 #if NACPICA > 0 302 case I2C_COOKIE_ACPI: 303 iicmux_attach_acpi(sc); 304 break; 305 #endif 306 default: 307 aprint_error_dev(sc->sc_dev, "could not configure mux: " 308 "handle type %u not supported\n", sc->sc_handletype); 309 break; 310 } 311 } 312
Indexes created Thu Oct 02 01:09:59 GMT 2025