1 /* $NetBSD: gpioiic.c,v 1.13 2025/09/15 13:23:03 thorpej Exp $ */ 2 /* $OpenBSD: gpioiic.c,v 1.8 2008/11/24 12:12:12 mbalmer Exp $ */ 3 4 /* 5 * Copyright (c) 2006 Alexander Yurchenko <grange (at) openbsd.org> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include <sys/cdefs.h> 21 __KERNEL_RCSID(0, "$NetBSD: gpioiic.c,v 1.13 2025/09/15 13:23:03 thorpej Exp $"); 22 23 /* 24 * I2C bus bit-banging through GPIO pins. 25 */ 26 27 #include <sys/param.h> 28 #include <sys/systm.h> 29 #include <sys/device.h> 30 #include <sys/gpio.h> 31 #include <sys/rwlock.h> 32 #include <sys/module.h> 33 34 #include <dev/gpio/gpiovar.h> 35 36 #include <dev/i2c/i2cvar.h> 37 #include <dev/i2c/i2c_bitbang.h> 38 39 #include "ioconf.h" 40 41 #define GPIOIIC_PIN_SDA 0 42 #define GPIOIIC_PIN_SCL 1 43 #define GPIOIIC_NPINS 2 44 45 #define GPIOIIC_SDA 0x01 46 #define GPIOIIC_SCL 0x02 47 48 #define GPIOIIC_PIN_REVERSE 0x01 49 50 struct gpioiic_softc { 51 void * sc_gpio; 52 struct gpio_pinmap sc_map; 53 int _map[GPIOIIC_NPINS]; 54 55 struct i2c_controller sc_i2c_tag; 56 device_t sc_i2c_dev; 57 58 int sc_pin_sda; 59 int sc_pin_scl; 60 61 int sc_sda; 62 int sc_scl; 63 }; 64 65 int gpioiic_match(device_t, cfdata_t, void *); 66 void gpioiic_attach(device_t, device_t, void *); 67 int gpioiic_detach(device_t, int); 68 69 int gpioiic_i2c_send_start(void *, int); 70 int gpioiic_i2c_send_stop(void *, int); 71 int gpioiic_i2c_initiate_xfer(void *, i2c_addr_t, int); 72 int gpioiic_i2c_read_byte(void *, uint8_t *, int); 73 int gpioiic_i2c_write_byte(void *, uint8_t, int); 74 75 void gpioiic_bb_set_bits(void *, uint32_t); 76 void gpioiic_bb_set_dir(void *, uint32_t); 77 uint32_t gpioiic_bb_read_bits(void *); 78 79 CFATTACH_DECL_NEW(gpioiic, sizeof(struct gpioiic_softc), 80 gpioiic_match, gpioiic_attach, gpioiic_detach, NULL); 81 82 static const struct i2c_bitbang_ops gpioiic_bbops = { 83 gpioiic_bb_set_bits, 84 gpioiic_bb_set_dir, 85 gpioiic_bb_read_bits, 86 { GPIOIIC_SDA, GPIOIIC_SCL, GPIOIIC_SDA, 0 } 87 }; 88 89 int 90 gpioiic_match(device_t parent, cfdata_t cf, void *aux) 91 { 92 struct gpio_attach_args *ga = aux; 93 94 if (strcmp(ga->ga_dvname, cf->cf_name)) 95 return 0; 96 97 if (ga->ga_offset == -1) 98 return 0; 99 100 /* Check that we have enough pins */ 101 if (gpio_npins(ga->ga_mask) != GPIOIIC_NPINS) { 102 aprint_debug("%s: invalid pin mask 0x%02x\n", cf->cf_name, 103 ga->ga_mask); 104 return 0; 105 } 106 return 1; 107 } 108 109 void 110 gpioiic_attach(device_t parent, device_t self, void *aux) 111 { 112 struct gpioiic_softc *sc = device_private(self); 113 struct gpio_attach_args *ga = aux; 114 int caps; 115 116 /* Map pins */ 117 sc->sc_gpio = ga->ga_gpio; 118 sc->sc_map.pm_map = sc->_map; 119 120 121 if (gpio_pin_map(sc->sc_gpio, ga->ga_offset, ga->ga_mask, 122 &sc->sc_map)) { 123 aprint_error(": can't map pins\n"); 124 return; 125 } 126 127 if (ga->ga_flags & GPIOIIC_PIN_REVERSE) { 128 sc->sc_pin_sda = GPIOIIC_PIN_SCL; 129 sc->sc_pin_scl = GPIOIIC_PIN_SDA; 130 } else { 131 sc->sc_pin_sda = GPIOIIC_PIN_SDA; 132 sc->sc_pin_scl = GPIOIIC_PIN_SCL; 133 } 134 135 /* Configure SDA pin */ 136 caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, sc->sc_pin_sda); 137 if (!(caps & GPIO_PIN_OUTPUT)) { 138 aprint_error(": SDA pin is unable to drive output\n"); 139 goto fail; 140 } 141 if (!(caps & GPIO_PIN_INPUT)) { 142 aprint_error(": SDA pin is unable to read input\n"); 143 goto fail; 144 } 145 aprint_normal(": SDA[%d]", sc->sc_map.pm_map[sc->sc_pin_sda]); 146 sc->sc_sda = GPIO_PIN_OUTPUT; 147 if (caps & GPIO_PIN_OPENDRAIN) { 148 aprint_normal(" open-drain"); 149 sc->sc_sda |= GPIO_PIN_OPENDRAIN; 150 } else if ((caps & GPIO_PIN_PUSHPULL) && (caps & GPIO_PIN_TRISTATE)) { 151 aprint_normal(" push-pull tri-state"); 152 sc->sc_sda |= GPIO_PIN_PUSHPULL; 153 } 154 if (caps & GPIO_PIN_PULLUP) { 155 aprint_normal(" pull-up"); 156 sc->sc_sda |= GPIO_PIN_PULLUP; 157 } 158 gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, sc->sc_pin_sda, sc->sc_sda); 159 160 /* Configure SCL pin */ 161 caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, sc->sc_pin_scl); 162 if (!(caps & GPIO_PIN_OUTPUT)) { 163 aprint_error(": SCL pin is unable to drive output\n"); 164 goto fail; 165 } 166 aprint_normal(", SCL[%d]", sc->sc_map.pm_map[sc->sc_pin_scl]); 167 sc->sc_scl = GPIO_PIN_OUTPUT; 168 if (caps & GPIO_PIN_OPENDRAIN) { 169 aprint_normal(" open-drain"); 170 sc->sc_scl |= GPIO_PIN_OPENDRAIN; 171 if (caps & GPIO_PIN_PULLUP) { 172 aprint_normal(" pull-up"); 173 sc->sc_scl |= GPIO_PIN_PULLUP; 174 } 175 } else if (caps & GPIO_PIN_PUSHPULL) { 176 aprint_normal(" push-pull"); 177 sc->sc_scl |= GPIO_PIN_PUSHPULL; 178 } 179 gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, sc->sc_pin_scl, sc->sc_scl); 180 181 aprint_normal("\n"); 182 183 /* Attach I2C bus */ 184 iic_tag_init(&sc->sc_i2c_tag); 185 sc->sc_i2c_tag.ic_cookie = sc; 186 sc->sc_i2c_tag.ic_send_start = gpioiic_i2c_send_start; 187 sc->sc_i2c_tag.ic_send_stop = gpioiic_i2c_send_stop; 188 sc->sc_i2c_tag.ic_initiate_xfer = gpioiic_i2c_initiate_xfer; 189 sc->sc_i2c_tag.ic_read_byte = gpioiic_i2c_read_byte; 190 sc->sc_i2c_tag.ic_write_byte = gpioiic_i2c_write_byte; 191 192 sc->sc_i2c_dev = iicbus_attach(self, &sc->sc_i2c_tag); 193 194 if (!pmf_device_register(self, NULL, NULL)) 195 aprint_error("%s: could not establish power handler\n", 196 device_xname(self)); 197 return; 198 199 fail: 200 gpio_pin_unmap(sc->sc_gpio, &sc->sc_map); 201 } 202 203 int 204 gpioiic_detach(device_t self, int flags) 205 { 206 struct gpioiic_softc *sc = device_private(self); 207 int error; 208 209 error = config_detach_children(self, flags); 210 if (error) 211 return error; 212 213 iic_tag_fini(&sc->sc_i2c_tag); 214 gpio_pin_unmap(sc->sc_gpio, &sc->sc_map); 215 pmf_device_deregister(self); 216 return 0; 217 } 218 219 int 220 gpioiic_i2c_send_start(void *cookie, int flags) 221 { 222 return i2c_bitbang_send_start(cookie, flags, &gpioiic_bbops); 223 } 224 225 int 226 gpioiic_i2c_send_stop(void *cookie, int flags) 227 { 228 return i2c_bitbang_send_stop(cookie, flags, &gpioiic_bbops); 229 } 230 231 int 232 gpioiic_i2c_initiate_xfer(void *cookie, i2c_addr_t addr, int flags) 233 { 234 return i2c_bitbang_initiate_xfer(cookie, addr, flags, &gpioiic_bbops); 235 } 236 237 int 238 gpioiic_i2c_read_byte(void *cookie, uint8_t *bytep, int flags) 239 { 240 return i2c_bitbang_read_byte(cookie, bytep, flags, &gpioiic_bbops); 241 } 242 243 int 244 gpioiic_i2c_write_byte(void *cookie, uint8_t byte, int flags) 245 { 246 return i2c_bitbang_write_byte(cookie, byte, flags, &gpioiic_bbops); 247 } 248 249 void 250 gpioiic_bb_set_bits(void *cookie, uint32_t bits) 251 { 252 struct gpioiic_softc *sc = cookie; 253 254 gpio_pin_write(sc->sc_gpio, &sc->sc_map, sc->sc_pin_sda, 255 bits & GPIOIIC_SDA ? GPIO_PIN_HIGH : GPIO_PIN_LOW); 256 gpio_pin_write(sc->sc_gpio, &sc->sc_map, sc->sc_pin_scl, 257 bits & GPIOIIC_SCL ? GPIO_PIN_HIGH : GPIO_PIN_LOW); 258 } 259 260 void 261 gpioiic_bb_set_dir(void *cookie, uint32_t bits) 262 { 263 struct gpioiic_softc *sc = cookie; 264 int sda = sc->sc_sda; 265 266 sda &= ~(GPIO_PIN_INPUT | GPIO_PIN_OUTPUT | GPIO_PIN_TRISTATE); 267 sda |= (bits & GPIOIIC_SDA ? GPIO_PIN_OUTPUT : GPIO_PIN_INPUT); 268 if ((sda & GPIO_PIN_PUSHPULL) && !(bits & GPIOIIC_SDA)) 269 sda |= GPIO_PIN_TRISTATE; 270 if (sc->sc_sda != sda) { 271 sc->sc_sda = sda; 272 gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, sc->sc_pin_sda, 273 sc->sc_sda); 274 } 275 } 276 277 uint32_t 278 gpioiic_bb_read_bits(void *cookie) 279 { 280 struct gpioiic_softc *sc = cookie; 281 uint32_t bits = 0; 282 283 if (gpio_pin_read(sc->sc_gpio, &sc->sc_map, 284 sc->sc_pin_sda) == GPIO_PIN_HIGH) 285 bits |= GPIOIIC_SDA; 286 if (gpio_pin_read(sc->sc_gpio, &sc->sc_map, 287 sc->sc_pin_scl) == GPIO_PIN_HIGH) 288 bits |= GPIOIIC_SCL; 289 290 return bits; 291 } 292 293 MODULE(MODULE_CLASS_DRIVER, gpioiic, "gpio,iic"); 294 295 #ifdef _MODULE 296 #include "ioconf.c" 297 #endif 298 299 static int 300 gpioiic_modcmd(modcmd_t cmd, void *opaque) 301 { 302 int error; 303 304 error = 0; 305 switch (cmd) { 306 case MODULE_CMD_INIT: 307 #ifdef _MODULE 308 error = config_init_component(cfdriver_ioconf_gpioiic, 309 cfattach_ioconf_gpioiic, cfdata_ioconf_gpioiic); 310 if (error) 311 aprint_error("%s: unable to init component\n", 312 gpioiic_cd.cd_name); 313 #endif 314 break; 315 case MODULE_CMD_FINI: 316 #ifdef _MODULE 317 config_fini_component(cfdriver_ioconf_gpioiic, 318 cfattach_ioconf_gpioiic, cfdata_ioconf_gpioiic); 319 #endif 320 break; 321 default: 322 error = ENOTTY; 323 } 324 return error; 325 } 326
Indexes created Tue Sep 23 07:09:52 GMT 2025