1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org> 5 * Copyright (c) 2010 Luiz Otavio O Souza 6 * Copyright (c) 2019 Ian Lepore <ian@freebsd.org> 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 #include "opt_platform.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/bus.h> 36 #include <sys/gpio.h> 37 #include <sys/kernel.h> 38 #include <sys/module.h> 39 40 #include <dev/gpio/gpiobusvar.h> 41 #include <dev/iicbus/iiconf.h> 42 43 #include "gpiobus_if.h" 44 #include "iicbb_if.h" 45 46 #define GPIOIIC_SCL_DFLT 0 47 #define GPIOIIC_SDA_DFLT 1 48 #define GPIOIIC_MIN_PINS 2 49 50 struct gpioiic_softc 51 { 52 device_t dev; 53 gpio_pin_t sclpin; 54 gpio_pin_t sdapin; 55 }; 56 57 #ifdef FDT 58 59 #include <dev/ofw/ofw_bus.h> 60 61 static struct ofw_compat_data compat_data[] = { 62 {"i2c-gpio", true}, /* Standard devicetree compat string */ 63 {"gpioiic", true}, /* Deprecated old freebsd compat string */ 64 {NULL, false} 65 }; 66 OFWBUS_PNP_INFO(compat_data); 67 SIMPLEBUS_PNP_INFO(compat_data); 68 69 static phandle_t 70 gpioiic_get_node(device_t bus, device_t dev) 71 { 72 73 /* Share our fdt node with iicbus so it can find its child nodes. */ 74 return (ofw_bus_get_node(bus)); 75 } 76 77 static int 78 gpioiic_setup_fdt_pins(struct gpioiic_softc *sc) 79 { 80 phandle_t node; 81 int err; 82 83 node = ofw_bus_get_node(sc->dev); 84 85 /* 86 * Historically, we used the first two array elements of the gpios 87 * property. The modern bindings specify separate scl-gpios and 88 * sda-gpios properties. We cope with whichever is present. 89 */ 90 if (OF_hasprop(node, "gpios")) { 91 if ((err = gpio_pin_get_by_ofw_idx(sc->dev, node, 92 GPIOIIC_SCL_DFLT, &sc->sclpin)) != 0) { 93 device_printf(sc->dev, "invalid gpios property\n"); 94 return (err); 95 } 96 if ((err = gpio_pin_get_by_ofw_idx(sc->dev, node, 97 GPIOIIC_SDA_DFLT, &sc->sdapin)) != 0) { 98 device_printf(sc->dev, "ivalid gpios property\n"); 99 return (err); 100 } 101 } else { 102 if ((err = gpio_pin_get_by_ofw_property(sc->dev, node, 103 "scl-gpios", &sc->sclpin)) != 0) { 104 device_printf(sc->dev, "missing scl-gpios property\n"); 105 return (err); 106 } 107 if ((err = gpio_pin_get_by_ofw_property(sc->dev, node, 108 "sda-gpios", &sc->sdapin)) != 0) { 109 device_printf(sc->dev, "missing sda-gpios property\n"); 110 return (err); 111 } 112 } 113 return (0); 114 } 115 #endif /* FDT */ 116 117 static int 118 gpioiic_setup_hinted_pins(struct gpioiic_softc *sc) 119 { 120 device_t busdev; 121 const char *busname, *devname; 122 int err, numpins, sclnum, sdanum, unit; 123 124 devname = device_get_name(sc->dev); 125 unit = device_get_unit(sc->dev); 126 busdev = device_get_parent(sc->dev); 127 128 /* 129 * If there is not an "at" hint naming our actual parent, then we 130 * weren't instantiated as a child of gpiobus via hints, and we thus 131 * can't access ivars that only exist for such children. 132 */ 133 if (resource_string_value(devname, unit, "at", &busname) != 0 || 134 (strcmp(busname, device_get_nameunit(busdev)) != 0 && 135 strcmp(busname, device_get_name(busdev)) != 0)) { 136 return (ENOENT); 137 } 138 139 /* Make sure there were hints for at least two pins. */ 140 numpins = gpiobus_get_npins(sc->dev); 141 if (numpins < GPIOIIC_MIN_PINS) { 142 #ifdef FDT 143 /* 144 * Be silent when there are no hints on FDT systems; the FDT 145 * data will provide the pin config (we'll whine if it doesn't). 146 */ 147 if (numpins == 0) { 148 return (ENOENT); 149 } 150 #endif 151 device_printf(sc->dev, 152 "invalid pins hint; it must contain at least %d pins\n", 153 GPIOIIC_MIN_PINS); 154 return (EINVAL); 155 } 156 157 /* 158 * Our parent bus has already parsed the pins hint and it will use that 159 * info when we call gpio_pin_get_by_child_index(). But we have to 160 * handle the scl/sda index hints that tell us which of the two pins is 161 * the clock and which is the data. They're optional, but if present 162 * they must be a valid index (0 <= index < numpins). 163 */ 164 if ((err = resource_int_value(devname, unit, "scl", &sclnum)) != 0) 165 sclnum = GPIOIIC_SCL_DFLT; 166 else if (sclnum < 0 || sclnum >= numpins) { 167 device_printf(sc->dev, "invalid scl hint %d\n", sclnum); 168 return (EINVAL); 169 } 170 if ((err = resource_int_value(devname, unit, "sda", &sdanum)) != 0) 171 sdanum = GPIOIIC_SDA_DFLT; 172 else if (sdanum < 0 || sdanum >= numpins) { 173 device_printf(sc->dev, "invalid sda hint %d\n", sdanum); 174 return (EINVAL); 175 } 176 177 /* Allocate gpiobus_pin structs for the pins we found above. */ 178 if ((err = gpio_pin_get_by_child_index(sc->dev, sclnum, 179 &sc->sclpin)) != 0) 180 return (err); 181 if ((err = gpio_pin_get_by_child_index(sc->dev, sdanum, 182 &sc->sdapin)) != 0) 183 return (err); 184 185 return (0); 186 } 187 188 static void 189 gpioiic_setsda(device_t dev, int val) 190 { 191 struct gpioiic_softc *sc = device_get_softc(dev); 192 193 if (val) { 194 gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT); 195 } else { 196 gpio_pin_setflags(sc->sdapin, 197 GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN); 198 gpio_pin_set_active(sc->sdapin, 0); 199 } 200 } 201 202 static void 203 gpioiic_setscl(device_t dev, int val) 204 { 205 struct gpioiic_softc *sc = device_get_softc(dev); 206 207 if (val) { 208 gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT); 209 } else { 210 gpio_pin_setflags(sc->sclpin, 211 GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN); 212 gpio_pin_set_active(sc->sclpin, 0); 213 } 214 } 215 216 static int 217 gpioiic_getscl(device_t dev) 218 { 219 struct gpioiic_softc *sc = device_get_softc(dev); 220 bool val; 221 222 gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT); 223 gpio_pin_is_active(sc->sclpin, &val); 224 return (val); 225 } 226 227 static int 228 gpioiic_getsda(device_t dev) 229 { 230 struct gpioiic_softc *sc = device_get_softc(dev); 231 bool val; 232 233 gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT); 234 gpio_pin_is_active(sc->sdapin, &val); 235 return (val); 236 } 237 238 static int 239 gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr) 240 { 241 struct gpioiic_softc *sc = device_get_softc(dev); 242 243 /* Stop driving the bus pins. */ 244 gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT); 245 gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT); 246 247 /* Indicate that we have no slave address (master mode). */ 248 return (IIC_ENOADDR); 249 } 250 251 static void 252 gpioiic_cleanup(struct gpioiic_softc *sc) 253 { 254 255 device_delete_children(sc->dev); 256 257 if (sc->sclpin != NULL) 258 gpio_pin_release(sc->sclpin); 259 260 if (sc->sdapin != NULL) 261 gpio_pin_release(sc->sdapin); 262 } 263 264 static int 265 gpioiic_probe(device_t dev) 266 { 267 int rv; 268 269 /* 270 * By default we only bid to attach if specifically added by our parent 271 * (usually via hint.gpioiic.#.at=busname). On FDT systems we bid as 272 * the default driver based on being configured in the FDT data. 273 */ 274 rv = BUS_PROBE_NOWILDCARD; 275 276 #ifdef FDT 277 if (ofw_bus_status_okay(dev) && 278 ofw_bus_search_compatible(dev, compat_data)->ocd_data) 279 rv = BUS_PROBE_DEFAULT; 280 #endif 281 282 device_set_desc(dev, "GPIO I2C"); 283 284 return (rv); 285 } 286 287 static int 288 gpioiic_attach(device_t dev) 289 { 290 struct gpioiic_softc *sc = device_get_softc(dev); 291 int err; 292 293 sc->dev = dev; 294 295 /* Acquire our gpio pins. */ 296 err = gpioiic_setup_hinted_pins(sc); 297 #ifdef FDT 298 if (err != 0) 299 err = gpioiic_setup_fdt_pins(sc); 300 #endif 301 if (err != 0) { 302 device_printf(sc->dev, "no pins configured\n"); 303 gpioiic_cleanup(sc); 304 return (ENXIO); 305 } 306 307 /* 308 * Say what we came up with for pin config. 309 * NB: in the !FDT case the controller driver might not be set up enough 310 * for GPIO_GET_BUS() to work. Also, our parent is the only gpiobus 311 * that can provide our pins. 312 */ 313 device_printf(dev, "SCL pin: %s:%d, SDA pin: %s:%d\n", 314 #ifdef FDT 315 device_get_nameunit(GPIO_GET_BUS(sc->sclpin->dev)), sc->sclpin->pin, 316 device_get_nameunit(GPIO_GET_BUS(sc->sdapin->dev)), sc->sdapin->pin); 317 #else 318 device_get_nameunit(device_get_parent(dev)), sc->sclpin->pin, 319 device_get_nameunit(device_get_parent(dev)), sc->sdapin->pin); 320 #endif 321 322 /* Add the bitbang driver as our only child; it will add iicbus. */ 323 device_add_child(sc->dev, "iicbb", DEVICE_UNIT_ANY); 324 bus_attach_children(dev); 325 return (0); 326 } 327 328 static int 329 gpioiic_detach(device_t dev) 330 { 331 struct gpioiic_softc *sc = device_get_softc(dev); 332 int err; 333 334 if ((err = bus_generic_detach(dev)) != 0) 335 return (err); 336 337 gpioiic_cleanup(sc); 338 339 return (0); 340 } 341 342 static device_method_t gpioiic_methods[] = { 343 /* Device interface */ 344 DEVMETHOD(device_probe, gpioiic_probe), 345 DEVMETHOD(device_attach, gpioiic_attach), 346 DEVMETHOD(device_detach, gpioiic_detach), 347 348 /* iicbb interface */ 349 DEVMETHOD(iicbb_setsda, gpioiic_setsda), 350 DEVMETHOD(iicbb_setscl, gpioiic_setscl), 351 DEVMETHOD(iicbb_getsda, gpioiic_getsda), 352 DEVMETHOD(iicbb_getscl, gpioiic_getscl), 353 DEVMETHOD(iicbb_reset, gpioiic_reset), 354 355 #ifdef FDT 356 /* OFW bus interface */ 357 DEVMETHOD(ofw_bus_get_node, gpioiic_get_node), 358 #endif 359 360 DEVMETHOD_END 361 }; 362 363 static driver_t gpioiic_driver = { 364 "gpioiic", 365 gpioiic_methods, 366 sizeof(struct gpioiic_softc), 367 }; 368 369 DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, 0, 0); 370 DRIVER_MODULE(gpioiic, simplebus, gpioiic_driver, 0, 0); 371 DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, 0, 0); 372 MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER); 373 MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1); 374