1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org> 5 * Copyright (c) 2010 Luiz Otavio O Souza 6 * All rights reserved. 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 __FBSDID("$FreeBSD$"); 32 33 #include "opt_platform.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/bus.h> 38 #include <sys/gpio.h> 39 #include <sys/kernel.h> 40 #include <sys/module.h> 41 42 #ifdef FDT 43 #include <dev/fdt/fdt_common.h> 44 #include <dev/ofw/ofw_bus.h> 45 #endif 46 47 #include <dev/gpio/gpiobusvar.h> 48 #include <dev/iicbus/iiconf.h> 49 #include <dev/iicbus/iicbus.h> 50 51 #include "gpiobus_if.h" 52 #include "iicbb_if.h" 53 54 #define GPIOIIC_SCL_DFLT 0 55 #define GPIOIIC_SDA_DFLT 1 56 #define GPIOIIC_MIN_PINS 2 57 58 struct gpioiic_softc 59 { 60 device_t sc_dev; 61 device_t sc_busdev; 62 int scl_pin; 63 int sda_pin; 64 }; 65 66 static int gpioiic_probe(device_t); 67 static int gpioiic_attach(device_t); 68 69 /* iicbb interface */ 70 static void gpioiic_reset_bus(device_t); 71 static void gpioiic_setsda(device_t, int); 72 static void gpioiic_setscl(device_t, int); 73 static int gpioiic_getsda(device_t); 74 static int gpioiic_getscl(device_t); 75 static int gpioiic_reset(device_t, u_char, u_char, u_char *); 76 77 static int 78 gpioiic_probe(device_t dev) 79 { 80 struct gpiobus_ivar *devi; 81 82 #ifdef FDT 83 if (!ofw_bus_status_okay(dev)) 84 return (ENXIO); 85 if (!ofw_bus_is_compatible(dev, "gpioiic")) 86 return (ENXIO); 87 #endif 88 devi = GPIOBUS_IVAR(dev); 89 if (devi->npins < GPIOIIC_MIN_PINS) { 90 device_printf(dev, 91 "gpioiic needs at least %d GPIO pins (only %d given).\n", 92 GPIOIIC_MIN_PINS, devi->npins); 93 return (ENXIO); 94 } 95 device_set_desc(dev, "GPIO I2C bit-banging driver"); 96 97 return (BUS_PROBE_DEFAULT); 98 } 99 100 static int 101 gpioiic_attach(device_t dev) 102 { 103 device_t bitbang; 104 #ifdef FDT 105 phandle_t node; 106 pcell_t pin; 107 #endif 108 struct gpiobus_ivar *devi; 109 struct gpioiic_softc *sc; 110 111 sc = device_get_softc(dev); 112 sc->sc_dev = dev; 113 sc->sc_busdev = device_get_parent(dev); 114 if (resource_int_value(device_get_name(dev), 115 device_get_unit(dev), "scl", &sc->scl_pin)) 116 sc->scl_pin = GPIOIIC_SCL_DFLT; 117 if (resource_int_value(device_get_name(dev), 118 device_get_unit(dev), "sda", &sc->sda_pin)) 119 sc->sda_pin = GPIOIIC_SDA_DFLT; 120 121 #ifdef FDT 122 if ((node = ofw_bus_get_node(dev)) == -1) 123 return (ENXIO); 124 if (OF_getencprop(node, "scl", &pin, sizeof(pin)) > 0) 125 sc->scl_pin = (int)pin; 126 if (OF_getencprop(node, "sda", &pin, sizeof(pin)) > 0) 127 sc->sda_pin = (int)pin; 128 #endif 129 130 if (sc->scl_pin < 0 || sc->scl_pin > 1) 131 sc->scl_pin = GPIOIIC_SCL_DFLT; 132 if (sc->sda_pin < 0 || sc->sda_pin > 1) 133 sc->sda_pin = GPIOIIC_SDA_DFLT; 134 135 devi = GPIOBUS_IVAR(dev); 136 device_printf(dev, "SCL pin: %d, SDA pin: %d\n", 137 devi->pins[sc->scl_pin], devi->pins[sc->sda_pin]); 138 139 /* add generic bit-banging code */ 140 bitbang = device_add_child(dev, "iicbb", -1); 141 device_probe_and_attach(bitbang); 142 143 return (0); 144 } 145 146 /* 147 * Reset bus by setting SDA first and then SCL. 148 * Must always be called with gpio bus locked. 149 */ 150 static void 151 gpioiic_reset_bus(device_t dev) 152 { 153 struct gpioiic_softc *sc = device_get_softc(dev); 154 155 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 156 GPIO_PIN_INPUT); 157 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 158 GPIO_PIN_INPUT); 159 } 160 161 static void 162 gpioiic_setsda(device_t dev, int val) 163 { 164 struct gpioiic_softc *sc = device_get_softc(dev); 165 166 if (val == 0) { 167 GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 0); 168 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 169 GPIO_PIN_OUTPUT); 170 } else { 171 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 172 GPIO_PIN_INPUT); 173 } 174 } 175 176 static void 177 gpioiic_setscl(device_t dev, int val) 178 { 179 struct gpioiic_softc *sc = device_get_softc(dev); 180 181 if (val == 0) { 182 GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 0); 183 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 184 GPIO_PIN_OUTPUT); 185 } else { 186 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 187 GPIO_PIN_INPUT); 188 } 189 } 190 191 static int 192 gpioiic_getscl(device_t dev) 193 { 194 struct gpioiic_softc *sc = device_get_softc(dev); 195 unsigned int val; 196 197 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 198 GPIO_PIN_INPUT); 199 GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, sc->scl_pin, &val); 200 201 return ((int)val); 202 } 203 204 static int 205 gpioiic_getsda(device_t dev) 206 { 207 struct gpioiic_softc *sc = device_get_softc(dev); 208 unsigned int val; 209 210 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 211 GPIO_PIN_INPUT); 212 GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, sc->sda_pin, &val); 213 214 return ((int)val); 215 } 216 217 static int 218 gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr) 219 { 220 struct gpioiic_softc *sc; 221 222 sc = device_get_softc(dev); 223 gpioiic_reset_bus(sc->sc_dev); 224 225 return (IIC_ENOADDR); 226 } 227 228 #ifdef FDT 229 static phandle_t 230 gpioiic_get_node(device_t bus, device_t dev) 231 { 232 233 /* We only have one child, the iicbb, which needs our own node. */ 234 return (ofw_bus_get_node(bus)); 235 } 236 #endif 237 238 static devclass_t gpioiic_devclass; 239 240 static device_method_t gpioiic_methods[] = { 241 /* Device interface */ 242 DEVMETHOD(device_probe, gpioiic_probe), 243 DEVMETHOD(device_attach, gpioiic_attach), 244 DEVMETHOD(device_detach, bus_generic_detach), 245 246 /* iicbb interface */ 247 DEVMETHOD(iicbb_setsda, gpioiic_setsda), 248 DEVMETHOD(iicbb_setscl, gpioiic_setscl), 249 DEVMETHOD(iicbb_getsda, gpioiic_getsda), 250 DEVMETHOD(iicbb_getscl, gpioiic_getscl), 251 DEVMETHOD(iicbb_reset, gpioiic_reset), 252 253 #ifdef FDT 254 /* OFW bus interface */ 255 DEVMETHOD(ofw_bus_get_node, gpioiic_get_node), 256 #endif 257 258 DEVMETHOD_END 259 }; 260 261 static driver_t gpioiic_driver = { 262 "gpioiic", 263 gpioiic_methods, 264 sizeof(struct gpioiic_softc), 265 }; 266 267 DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, gpioiic_devclass, 0, 0); 268 DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, iicbb_devclass, 0, 0); 269 MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER); 270 MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1); 271