gpioiic.c revision 1.4
1 /* $NetBSD: gpioiic.c,v 1.4 2011/08/31 12:25:05 mbalmer 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 1.4 2011/08/31 12:25:05 mbalmer 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 33 #include <dev/gpio/gpiovar.h> 34 35 #include <dev/i2c/i2cvar.h> 36 #include <dev/i2c/i2c_bitbang.h> 37 38 #define GPIOIIC_PIN_SDA 0 39 #define GPIOIIC_PIN_SCL 1 40 #define GPIOIIC_NPINS 2 41 42 #define GPIOIIC_SDA 0x01 43 #define GPIOIIC_SCL 0x02 44 45 struct gpioiic_softc { 46 void * sc_gpio; 47 struct gpio_pinmap sc_map; 48 int _map[GPIOIIC_NPINS]; 49 50 struct i2c_controller sc_i2c_tag; 51 device_t sc_i2c_dev; 52 krwlock_t sc_i2c_lock; 53 54 int sc_sda; 55 int sc_scl; 56 }; 57 58 int gpioiic_match(device_t, cfdata_t, void *); 59 void gpioiic_attach(device_t, device_t, void *); 60 int gpioiic_detach(device_t, int); 61 62 int gpioiic_i2c_acquire_bus(void *, int); 63 void gpioiic_i2c_release_bus(void *, int); 64 int gpioiic_i2c_send_start(void *, int); 65 int gpioiic_i2c_send_stop(void *, int); 66 int gpioiic_i2c_initiate_xfer(void *, i2c_addr_t, int); 67 int gpioiic_i2c_read_byte(void *, uint8_t *, int); 68 int gpioiic_i2c_write_byte(void *, uint8_t, int); 69 70 void gpioiic_bb_set_bits(void *, uint32_t); 71 void gpioiic_bb_set_dir(void *, uint32_t); 72 uint32_t gpioiic_bb_read_bits(void *); 73 74 CFATTACH_DECL_NEW(gpioiic, sizeof(struct gpioiic_softc), 75 gpioiic_match, gpioiic_attach, gpioiic_detach, NULL); 76 77 extern struct cfdriver gpioiic_cd; 78 79 static const struct i2c_bitbang_ops gpioiic_bbops = { 80 gpioiic_bb_set_bits, 81 gpioiic_bb_set_dir, 82 gpioiic_bb_read_bits, 83 { GPIOIIC_SDA, GPIOIIC_SCL, GPIOIIC_SDA, 0 } 84 }; 85 86 int 87 gpioiic_match(device_t parent, cfdata_t cf, void *aux) 88 { 89 struct gpio_attach_args *ga = aux; 90 91 if (strcmp(ga->ga_dvname, cf->cf_name)) 92 return 0; 93 94 if (ga->ga_offset == -1) 95 return 0; 96 97 /* Check that we have enough pins */ 98 if (gpio_npins(ga->ga_mask) != GPIOIIC_NPINS) { 99 aprint_debug("%s: invalid pin mask 0x%02x\n", cf->cf_name, 100 ga->ga_mask); 101 return 0; 102 } 103 return 1; 104 } 105 106 void 107 gpioiic_attach(struct device *parent, struct device *self, void *aux) 108 { 109 struct gpioiic_softc *sc = device_private(self); 110 struct gpio_attach_args *ga = aux; 111 struct i2cbus_attach_args iba; 112 int caps; 113 114 /* Map pins */ 115 sc->sc_gpio = ga->ga_gpio; 116 sc->sc_map.pm_map = sc->_map; 117 if (gpio_pin_map(sc->sc_gpio, ga->ga_offset, ga->ga_mask, 118 &sc->sc_map)) { 119 aprint_error(": can't map pins\n"); 120 return; 121 } 122 123 /* Configure SDA pin */ 124 caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA); 125 if (!(caps & GPIO_PIN_OUTPUT)) { 126 aprint_error(": SDA pin is unable to drive output\n"); 127 goto fail; 128 } 129 if (!(caps & GPIO_PIN_INPUT)) { 130 aprint_error(": SDA pin is unable to read input\n"); 131 goto fail; 132 } 133 aprint_normal(": SDA[%d]", sc->sc_map.pm_map[GPIOIIC_PIN_SDA]); 134 sc->sc_sda = GPIO_PIN_OUTPUT; 135 if (caps & GPIO_PIN_OPENDRAIN) { 136 aprint_normal(" open-drain"); 137 sc->sc_sda |= GPIO_PIN_OPENDRAIN; 138 } else if ((caps & GPIO_PIN_PUSHPULL) && (caps & GPIO_PIN_TRISTATE)) { 139 aprint_normal(" push-pull tri-state"); 140 sc->sc_sda |= GPIO_PIN_PUSHPULL; 141 } 142 if (caps & GPIO_PIN_PULLUP) { 143 aprint_normal(" pull-up"); 144 sc->sc_sda |= GPIO_PIN_PULLUP; 145 } 146 gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA, sc->sc_sda); 147 148 /* Configure SCL pin */ 149 caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL); 150 if (!(caps & GPIO_PIN_OUTPUT)) { 151 aprint_error(": SCL pin is unable to drive output\n"); 152 goto fail; 153 } 154 aprint_normal(", SCL[%d]", sc->sc_map.pm_map[GPIOIIC_PIN_SCL]); 155 sc->sc_scl = GPIO_PIN_OUTPUT; 156 if (caps & GPIO_PIN_OPENDRAIN) { 157 aprint_normal(" open-drain"); 158 sc->sc_scl |= GPIO_PIN_OPENDRAIN; 159 if (caps & GPIO_PIN_PULLUP) { 160 aprint_normal(" pull-up"); 161 sc->sc_scl |= GPIO_PIN_PULLUP; 162 } 163 } else if (caps & GPIO_PIN_PUSHPULL) { 164 aprint_normal(" push-pull"); 165 sc->sc_scl |= GPIO_PIN_PUSHPULL; 166 } 167 gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL, sc->sc_scl); 168 169 aprint_normal("\n"); 170 171 /* Attach I2C bus */ 172 rw_init(&sc->sc_i2c_lock); 173 sc->sc_i2c_tag.ic_cookie = sc; 174 sc->sc_i2c_tag.ic_acquire_bus = gpioiic_i2c_acquire_bus; 175 sc->sc_i2c_tag.ic_release_bus = gpioiic_i2c_release_bus; 176 sc->sc_i2c_tag.ic_send_start = gpioiic_i2c_send_start; 177 sc->sc_i2c_tag.ic_send_stop = gpioiic_i2c_send_stop; 178 sc->sc_i2c_tag.ic_initiate_xfer = gpioiic_i2c_initiate_xfer; 179 sc->sc_i2c_tag.ic_read_byte = gpioiic_i2c_read_byte; 180 sc->sc_i2c_tag.ic_write_byte = gpioiic_i2c_write_byte; 181 sc->sc_i2c_tag.ic_exec = NULL; 182 183 memset(&iba, 0, sizeof(iba)); 184 iba.iba_type = I2C_TYPE_SMBUS; 185 iba.iba_tag = &sc->sc_i2c_tag; 186 sc->sc_i2c_dev = config_found(self, &iba, iicbus_print); 187 188 if (!pmf_device_register(self, NULL, NULL)) 189 aprint_error("%s: could not establish power handler\n", 190 device_xname(self)); 191 return; 192 193 fail: 194 gpio_pin_unmap(sc->sc_gpio, &sc->sc_map); 195 } 196 197 int 198 gpioiic_detach(struct device *self, int flags) 199 { 200 struct gpioiic_softc *sc = device_private(self); 201 int rv = 0; 202 203 if (sc->sc_i2c_dev != NULL) 204 rv = config_detach(sc->sc_i2c_dev, flags); 205 206 if (!rv) { 207 gpio_pin_unmap(sc->sc_gpio, &sc->sc_map); 208 pmf_device_deregister(self); 209 } 210 return rv; 211 } 212 213 int 214 gpioiic_i2c_acquire_bus(void *cookie, int flags) 215 { 216 struct gpioiic_softc *sc = cookie; 217 218 if (flags & I2C_F_POLL) 219 return 0; 220 221 rw_enter(&sc->sc_i2c_lock, RW_WRITER); 222 return 1; 223 } 224 225 void 226 gpioiic_i2c_release_bus(void *cookie, int flags) 227 { 228 struct gpioiic_softc *sc = cookie; 229 230 if (flags & I2C_F_POLL) 231 return; 232 233 rw_exit(&sc->sc_i2c_lock); 234 } 235 236 int 237 gpioiic_i2c_send_start(void *cookie, int flags) 238 { 239 return i2c_bitbang_send_start(cookie, flags, &gpioiic_bbops); 240 } 241 242 int 243 gpioiic_i2c_send_stop(void *cookie, int flags) 244 { 245 return i2c_bitbang_send_stop(cookie, flags, &gpioiic_bbops); 246 } 247 248 int 249 gpioiic_i2c_initiate_xfer(void *cookie, i2c_addr_t addr, int flags) 250 { 251 return i2c_bitbang_initiate_xfer(cookie, addr, flags, &gpioiic_bbops); 252 } 253 254 int 255 gpioiic_i2c_read_byte(void *cookie, uint8_t *bytep, int flags) 256 { 257 return i2c_bitbang_read_byte(cookie, bytep, flags, &gpioiic_bbops); 258 } 259 260 int 261 gpioiic_i2c_write_byte(void *cookie, uint8_t byte, int flags) 262 { 263 return i2c_bitbang_write_byte(cookie, byte, flags, &gpioiic_bbops); 264 } 265 266 void 267 gpioiic_bb_set_bits(void *cookie, uint32_t bits) 268 { 269 struct gpioiic_softc *sc = cookie; 270 271 gpio_pin_write(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA, 272 bits & GPIOIIC_SDA ? GPIO_PIN_HIGH : GPIO_PIN_LOW); 273 gpio_pin_write(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL, 274 bits & GPIOIIC_SCL ? GPIO_PIN_HIGH : GPIO_PIN_LOW); 275 } 276 277 void 278 gpioiic_bb_set_dir(void *cookie, uint32_t bits) 279 { 280 struct gpioiic_softc *sc = cookie; 281 int sda = sc->sc_sda; 282 283 sda &= ~(GPIO_PIN_INPUT | GPIO_PIN_OUTPUT | GPIO_PIN_TRISTATE); 284 sda |= (bits & GPIOIIC_SDA ? GPIO_PIN_OUTPUT : GPIO_PIN_INPUT); 285 if ((sda & GPIO_PIN_PUSHPULL) && !(bits & GPIOIIC_SDA)) 286 sda |= GPIO_PIN_TRISTATE; 287 if (sc->sc_sda != sda) { 288 sc->sc_sda = sda; 289 gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA, 290 sc->sc_sda); 291 } 292 } 293 294 uint32_t 295 gpioiic_bb_read_bits(void *cookie) 296 { 297 struct gpioiic_softc *sc = cookie; 298 uint32_t bits = 0; 299 300 if (gpio_pin_read(sc->sc_gpio, &sc->sc_map, 301 GPIOIIC_PIN_SDA) == GPIO_PIN_HIGH) 302 bits |= GPIOIIC_SDA; 303 if (gpio_pin_read(sc->sc_gpio, &sc->sc_map, 304 GPIOIIC_PIN_SCL) == GPIO_PIN_HIGH) 305 bits |= GPIOIIC_SCL; 306 307 return bits; 308 } 309
Indexes created Wed Sep 24 05:09:52 GMT 2025