gpioiic.c revision 266105
1/*- 2 * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org> 3 * Copyright (c) 2010 Luiz Otavio O Souza 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include <sys/cdefs.h> 29__FBSDID("$FreeBSD: stable/10/sys/dev/gpio/gpioiic.c 266105 2014-05-15 01:27:53Z loos $"); 30 31#include "opt_platform.h" 32 33#include <sys/param.h> 34#include <sys/systm.h> 35#include <sys/bus.h> 36#include <sys/conf.h> 37#include <sys/kernel.h> 38#include <sys/module.h> 39 40#include <sys/gpio.h> 41#include "gpiobus_if.h" 42 43#ifdef FDT 44#include <dev/ofw/ofw_bus.h> 45#include <dev/ofw/ofw_bus_subr.h> 46#include <dev/fdt/fdt_common.h> 47#endif 48 49#include <dev/iicbus/iiconf.h> 50#include <dev/iicbus/iicbus.h> 51 52#include "iicbb_if.h" 53 54#define SCL_PIN_DEFAULT 0 /* default index of SCL pin on gpiobus */ 55#define SDA_PIN_DEFAULT 1 56 57struct gpioiic_softc 58{ 59 device_t sc_dev; 60 device_t sc_busdev; 61 int scl_pin; 62 int sda_pin; 63}; 64 65static int gpioiic_probe(device_t); 66static int gpioiic_attach(device_t); 67 68/* iicbb interface */ 69static void gpioiic_reset_bus(device_t); 70static int gpioiic_callback(device_t, int, caddr_t); 71static void gpioiic_setsda(device_t, int); 72static void gpioiic_setscl(device_t, int); 73static int gpioiic_getsda(device_t); 74static int gpioiic_getscl(device_t); 75static int gpioiic_reset(device_t, u_char, u_char, u_char *); 76 77 78static int 79gpioiic_probe(device_t dev) 80{ 81 82#ifdef FDT 83 if (!ofw_bus_is_compatible(dev, "gpioiic")) 84 return (ENXIO); 85#endif 86 device_set_desc(dev, "GPIO I2C bit-banging driver"); 87 88 return (0); 89} 90 91static int 92gpioiic_attach(device_t dev) 93{ 94 struct gpioiic_softc *sc = device_get_softc(dev); 95 device_t bitbang; 96#ifdef FDT 97 phandle_t node; 98 pcell_t pin; 99#endif 100 101 sc->sc_dev = dev; 102 sc->sc_busdev = device_get_parent(dev); 103 if (resource_int_value(device_get_name(dev), 104 device_get_unit(dev), "scl", &sc->scl_pin)) 105 sc->scl_pin = SCL_PIN_DEFAULT; 106 if (resource_int_value(device_get_name(dev), 107 device_get_unit(dev), "sda", &sc->sda_pin)) 108 sc->sda_pin = SDA_PIN_DEFAULT; 109 110#ifdef FDT 111 if ((node = ofw_bus_get_node(dev)) == -1) 112 return (ENXIO); 113 if (OF_getencprop(node, "scl", &pin, sizeof(pin)) > 0) 114 sc->scl_pin = (int)pin; 115 if (OF_getencprop(node, "sda", &pin, sizeof(pin)) > 0) 116 sc->sda_pin = (int)pin; 117#endif 118 119 /* add generic bit-banging code */ 120 bitbang = device_add_child(dev, "iicbb", -1); 121 device_probe_and_attach(bitbang); 122 123 return (0); 124} 125 126/* 127 * Reset bus by setting SDA first and then SCL. 128 * Must always be called with gpio bus locked. 129 */ 130static void 131gpioiic_reset_bus(device_t dev) 132{ 133 struct gpioiic_softc *sc = device_get_softc(dev); 134 135 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 136 GPIO_PIN_INPUT); 137 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 138 GPIO_PIN_INPUT); 139} 140 141static int 142gpioiic_callback(device_t dev, int index, caddr_t data) 143{ 144 struct gpioiic_softc *sc = device_get_softc(dev); 145 int error = 0; 146 147 switch (index) { 148 case IIC_REQUEST_BUS: 149 GPIOBUS_LOCK_BUS(sc->sc_busdev); 150 GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev); 151 GPIOBUS_UNLOCK_BUS(sc->sc_busdev); 152 break; 153 case IIC_RELEASE_BUS: 154 GPIOBUS_LOCK_BUS(sc->sc_busdev); 155 GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev); 156 GPIOBUS_UNLOCK_BUS(sc->sc_busdev); 157 break; 158 default: 159 error = EINVAL; 160 } 161 162 return (error); 163} 164 165static void 166gpioiic_setsda(device_t dev, int val) 167{ 168 struct gpioiic_softc *sc = device_get_softc(dev); 169 170 if (val == 0) { 171 GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 0); 172 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 173 GPIO_PIN_OUTPUT); 174 } else { 175 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 176 GPIO_PIN_INPUT); 177 } 178} 179 180static void 181gpioiic_setscl(device_t dev, int val) 182{ 183 struct gpioiic_softc *sc = device_get_softc(dev); 184 185 if (val == 0) { 186 GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 0); 187 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 188 GPIO_PIN_OUTPUT); 189 } else { 190 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 191 GPIO_PIN_INPUT); 192 } 193} 194 195static int 196gpioiic_getscl(device_t dev) 197{ 198 struct gpioiic_softc *sc = device_get_softc(dev); 199 unsigned int val; 200 201 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 202 GPIO_PIN_INPUT); 203 GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, sc->scl_pin, &val); 204 205 return ((int)val); 206} 207 208static int 209gpioiic_getsda(device_t dev) 210{ 211 struct gpioiic_softc *sc = device_get_softc(dev); 212 unsigned int val; 213 214 GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 215 GPIO_PIN_INPUT); 216 GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, sc->sda_pin, &val); 217 218 return ((int)val); 219} 220 221static int 222gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr) 223{ 224 struct gpioiic_softc *sc = device_get_softc(dev); 225 226 GPIOBUS_LOCK_BUS(sc->sc_busdev); 227 GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev); 228 229 gpioiic_reset_bus(sc->sc_dev); 230 231 GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev); 232 GPIOBUS_UNLOCK_BUS(sc->sc_busdev); 233 234 return (IIC_ENOADDR); 235} 236 237#ifdef FDT 238static phandle_t 239gpioiic_get_node(device_t bus, device_t dev) 240{ 241 242 /* We only have one child, the iicbb, which needs our own node. */ 243 return (ofw_bus_get_node(bus)); 244} 245#endif 246 247static devclass_t gpioiic_devclass; 248 249static device_method_t gpioiic_methods[] = { 250 /* Device interface */ 251 DEVMETHOD(device_probe, gpioiic_probe), 252 DEVMETHOD(device_attach, gpioiic_attach), 253 DEVMETHOD(device_detach, bus_generic_detach), 254 255 /* iicbb interface */ 256 DEVMETHOD(iicbb_callback, gpioiic_callback), 257 DEVMETHOD(iicbb_setsda, gpioiic_setsda), 258 DEVMETHOD(iicbb_setscl, gpioiic_setscl), 259 DEVMETHOD(iicbb_getsda, gpioiic_getsda), 260 DEVMETHOD(iicbb_getscl, gpioiic_getscl), 261 DEVMETHOD(iicbb_reset, gpioiic_reset), 262 263#ifdef FDT 264 /* OFW bus interface */ 265 DEVMETHOD(ofw_bus_get_node, gpioiic_get_node), 266#endif 267 268 { 0, 0 } 269}; 270 271static driver_t gpioiic_driver = { 272 "gpioiic", 273 gpioiic_methods, 274 sizeof(struct gpioiic_softc), 275}; 276 277DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, gpioiic_devclass, 0, 0); 278DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, iicbb_devclass, 0, 0); 279MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER); 280MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1); 281