gpio.c revision 1.2
1 /* $NetBSD: gpio.c,v 1.2 2011/10/08 08:46:40 mbalmer Exp $ */ 2 3 /* 4 * Copyright (c) 2011 Marc Balmer <marc (at) msys.ch> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 /* GPIO interface for Lua */ 29 30 #include <errno.h> 31 #include <fcntl.h> 32 #include <stdarg.h> 33 #include <stdio.h> 34 #include <string.h> 35 #include <ctype.h> 36 #include <stdlib.h> 37 #include <unistd.h> 38 39 #include <lua.h> 40 #include <lauxlib.h> 41 #include <lualib.h> 42 43 #include <sys/gpio.h> 44 #include <sys/ioctl.h> 45 46 #define GPIO_METATABLE "GPIO object methods" 47 48 static void 49 gpio_error(lua_State *L, const char *fmt, ...) 50 { 51 va_list ap; 52 int len; 53 char *msg; 54 55 va_start(ap, fmt); 56 len = vasprintf(&msg, fmt, ap); 57 va_end(ap); 58 59 if (len != -1) { 60 lua_pushstring(L, msg); 61 free(msg); 62 } else 63 lua_pushstring(L, "vasprintf failed"); 64 lua_error(L); 65 } 66 67 static int 68 gpio_open(lua_State *L) 69 { 70 int *fd; 71 72 fd = lua_newuserdata(L, sizeof(int)); 73 *fd = open(luaL_checkstring(L, -2), O_RDWR); 74 if (*fd == -1) { 75 gpio_error(L, "%s", strerror(errno)); 76 /* NOTREACHED */ 77 return 0; 78 } 79 luaL_getmetatable(L, GPIO_METATABLE); 80 lua_setmetatable(L, -2); 81 return 1; 82 } 83 84 static int 85 gpio_close(lua_State *L) 86 { 87 int *fd; 88 89 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 90 if (*fd != -1) { 91 close(*fd); 92 *fd = -1; 93 } 94 return 0; 95 } 96 97 static int 98 gpio_info(lua_State *L) 99 { 100 struct gpio_info info; 101 int *fd; 102 103 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 104 if (ioctl(*fd, GPIOINFO, &info) == -1) 105 gpio_error(L, "GPIOINFO"); 106 lua_pushinteger(L, info.gpio_npins); 107 return 1; 108 } 109 110 static void 111 gpio_get_pin(lua_State *L, int n, struct gpio_req *req) 112 { 113 switch (lua_type(L, n)) { 114 case LUA_TNUMBER: 115 req->gp_pin = lua_tointeger(L, n) - 1; /* 1 based! */ 116 break; 117 case LUA_TSTRING: 118 strlcpy(req->gp_name, lua_tostring(L, n), sizeof(req->gp_name)); 119 break; 120 default: 121 luaL_argerror(L, n, "expected string or integer"); 122 /* NOTREACHED */ 123 } 124 } 125 126 static int 127 gpio_set(lua_State *L) 128 { 129 struct gpio_set set; 130 int *fd; 131 132 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 133 memset(&set, 0, sizeof(set)); 134 gpio_get_pin(L, 2, (struct gpio_req *)&set); 135 set.gp_flags = luaL_checkinteger(L, 3); 136 if (ioctl(*fd, GPIOSET, &set) == -1) 137 gpio_error(L, "GPIOSET"); 138 return 0; 139 } 140 141 static int 142 gpio_unset(lua_State *L) 143 { 144 struct gpio_set set; 145 int *fd; 146 147 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 148 memset(&set, 0, sizeof(set)); 149 gpio_get_pin(L, 2, (struct gpio_req *)&set); 150 if (ioctl(*fd, GPIOUNSET, &set) == -1) 151 gpio_error(L, "GPIOUNSET"); 152 return 0; 153 } 154 155 static int 156 gpio_read(lua_State *L) 157 { 158 struct gpio_req req; 159 int *fd; 160 161 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 162 memset(&req, 0, sizeof(req)); 163 gpio_get_pin(L, 2, &req); 164 if (ioctl(*fd, GPIOREAD, &req) == -1) 165 gpio_error(L, "GPIOREAD"); 166 lua_pushinteger(L, req.gp_value); 167 return 1; 168 } 169 170 171 static int 172 gpio_write(lua_State *L) 173 { 174 struct gpio_req req; 175 int *fd, val; 176 177 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 178 val = luaL_checkinteger(L, 3); 179 if (val != GPIO_PIN_HIGH && val != GPIO_PIN_LOW) 180 gpio_error(L, "%d: invalid value", val); 181 memset(&req, 0, sizeof(req)); 182 gpio_get_pin(L, 2, &req); 183 req.gp_value = val; 184 if (ioctl(*fd, GPIOWRITE, &req) == -1) 185 gpio_error(L, "GPIOWRITE"); 186 lua_pushinteger(L, req.gp_value); 187 return 1; 188 } 189 190 static int 191 gpio_toggle(lua_State *L) 192 { 193 struct gpio_req req; 194 int *fd, val; 195 196 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 197 memset(&req, 0, sizeof(req)); 198 gpio_get_pin(L, 2, &req); 199 if (ioctl(*fd, GPIOTOGGLE, &req) == -1) 200 gpio_error(L, "GPIOTOGGLE"); 201 lua_pushinteger(L, req.gp_value); 202 return 1; 203 } 204 205 static int 206 gpio_attach(lua_State *L) 207 { 208 struct gpio_attach attach; 209 int *fd; 210 211 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 212 memset(&attach, 0, sizeof(attach)); 213 strlcpy(attach.ga_dvname, luaL_checkstring(L, 2), 214 sizeof(attach.ga_dvname)); 215 attach.ga_offset = luaL_checkinteger(L, 3); 216 attach.ga_mask = luaL_checkinteger(L, 4); 217 if (lua_gettop(L) > 4) 218 attach.ga_flags = luaL_checkinteger(L, 5); 219 else 220 attach.ga_flags = 0; 221 222 if (ioctl(*fd, GPIOATTACH, &attach) == -1) 223 gpio_error(L, "GPIOATTACH"); 224 return 0; 225 } 226 227 static int 228 gpio_pulse(lua_State *L) 229 { 230 struct gpio_pulse pulse; 231 suseconds_t period, on, off; 232 double freq, dc; 233 int *fd; 234 235 fd = luaL_checkudata(L, 1, GPIO_METATABLE); 236 freq = luaL_checknumber(L, 3); 237 dc = luaL_checknumber(L, 4); 238 239 if (freq < 0.0 || (dc < 0.0 || dc >= 100.0)) 240 gpio_error(L, "%.f Hz, %.f%% duty cycle: invalid value", 241 freq, dc); 242 243 memset(&pulse, 0, sizeof(pulse)); 244 gpio_get_pin(L, 2, (struct gpio_req *)&pulse); 245 246 if (freq > 0.0 && dc > 0.0) { 247 period = 1000000 / freq; 248 on = period * dc / 100; 249 off = period - on; 250 251 if (on >= 1000000) { 252 pulse.gp_pulse_on.tv_sec = on / 1000000; 253 on -= pulse.gp_pulse_on.tv_sec * 1000000; 254 pulse.gp_pulse_on.tv_usec = on; 255 } else { 256 pulse.gp_pulse_on.tv_sec = 0; 257 pulse.gp_pulse_on.tv_usec = on; 258 } 259 if (off >= 1000000) { 260 pulse.gp_pulse_off.tv_sec = off / 1000000; 261 off -= pulse.gp_pulse_off.tv_sec * 1000000; 262 pulse.gp_pulse_off.tv_usec = off; 263 } else { 264 pulse.gp_pulse_off.tv_sec = 0; 265 pulse.gp_pulse_off.tv_usec = off; 266 } 267 } else { /* gpio(4) defaults */ 268 freq = 1.0; 269 dc = 50.0; 270 } 271 272 if (ioctl(*fd, GPIOPULSE, &pulse) == -1) 273 gpio_error(L, "GPIOPULSE"); 274 } 275 276 struct constant { 277 char *name; 278 int value; 279 }; 280 281 static struct constant gpio_constant[] = { 282 /* GPIO pin states */ 283 { "PIN_LOW", GPIO_PIN_LOW }, 284 { "PIN_HIGH", GPIO_PIN_HIGH }, 285 { "PIN_PULSE", GPIO_PIN_PULSE }, 286 287 /* GPIO pin configuration flags */ 288 { "PIN_INPUT", GPIO_PIN_INPUT }, 289 { "PIN_OUTPUT", GPIO_PIN_OUTPUT }, 290 { "PIN_INOUT", GPIO_PIN_INOUT }, 291 { "PIN_OPENDRAIN", GPIO_PIN_OPENDRAIN }, 292 { "PIN_PUSHPULL", GPIO_PIN_PUSHPULL }, 293 { "PIN_TRISTATE", GPIO_PIN_TRISTATE }, 294 { "PIN_PULLUP", GPIO_PIN_PULLUP }, 295 { "PIN_PULLDOWN", GPIO_PIN_PULLDOWN }, 296 { "PIN_INVIN", GPIO_PIN_INVIN }, 297 { "PIN_INVOUT", GPIO_PIN_INVOUT }, 298 { "PIN_USER", GPIO_PIN_USER }, 299 { "PIN_PULSATE", GPIO_PIN_PULSATE }, 300 { "PIN_INTR", GPIO_PIN_INTR }, 301 { "PIN_INTR_HIGH", GPIO_PIN_INTR_HIGH }, 302 { "PIN_SET", GPIO_PIN_SET }, 303 { NULL, 0 } 304 }; 305 306 static void 307 gpio_set_info(lua_State *L) 308 { 309 lua_pushliteral(L, "_COPYRIGHT"); 310 lua_pushliteral(L, "Copyright (C) 2011 Marc Balmer <marc (at) msys.ch>"); 311 lua_settable(L, -3); 312 lua_pushliteral(L, "_DESCRIPTION"); 313 lua_pushliteral(L, "GPIO interface for Lua"); 314 lua_settable(L, -3); 315 lua_pushliteral(L, "_VERSION"); 316 lua_pushliteral(L, "gpio 1.0.0"); 317 lua_settable(L, -3); 318 } 319 320 int 321 luaopen_gpio(lua_State* L) 322 { 323 static const struct luaL_Reg methods[] = { 324 { "open", gpio_open }, 325 { NULL, NULL } 326 }; 327 static const struct luaL_Reg gpio_methods[] = { 328 { "info", gpio_info }, 329 { "close", gpio_close }, 330 { "set", gpio_set }, 331 { "unset", gpio_unset }, 332 { "read", gpio_read }, 333 { "write", gpio_write }, 334 { "toggle", gpio_toggle }, 335 { "attach", gpio_attach }, 336 { "pulse", gpio_pulse }, 337 { NULL, NULL } 338 }; 339 int n; 340 341 luaL_register(L, "gpio", methods); 342 gpio_set_info(L); 343 344 /* The gpio metatable */ 345 if (luaL_newmetatable(L, GPIO_METATABLE)) { 346 luaL_register(L, NULL, gpio_methods); 347 348 lua_pushliteral(L, "__gc"); 349 lua_pushcfunction(L, gpio_close); 350 lua_settable(L, -3); 351 352 lua_pushliteral(L, "__index"); 353 lua_pushvalue(L, -2); 354 lua_settable(L, -3); 355 356 lua_pushliteral(L, "__metatable"); 357 lua_pushliteral(L, "must not access this metatable"); 358 lua_settable(L, -3); 359 } 360 lua_pop(L, 1); 361 362 for (n = 0; gpio_constant[n].name != NULL; n++) { 363 lua_pushinteger(L, gpio_constant[n].value); 364 lua_setfield(L, -2, gpio_constant[n].name); 365 }; 366 return 1; 367 } 368
Indexes created Thu Sep 25 06:09:39 GMT 2025