mcp3k.c revision 1.7
1 /* $NetBSD: mcp3k.c,v 1.7 2025/09/11 14:19:05 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2015 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Frank Wille. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Microchip MCP3x0x SAR analog to digital converters. 34 * The driver supports various ADCs with different resolutions, operation 35 * modes and number of input channels. 36 * The reference voltage Vref defaults to the maximum output value in mV, 37 * but can be changed via sysctl(3). 38 * 39 * MCP3001: http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf 40 * MCP3002: http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf 41 * MCP3004/3008: http://ww1.microchip.com/downloads/en/DeviceDoc/21295C.pdf 42 * MCP3201: http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf 43 * MCP3204/3208: http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf 44 * MCP3301: http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf 45 * MPC3302/3304: http://ww1.microchip.com/downloads/en/DeviceDoc/21697F.pdf 46 */ 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/device.h> 51 #include <sys/kernel.h> 52 #include <sys/types.h> 53 #include <sys/sysctl.h> 54 55 #include <dev/sysmon/sysmonvar.h> 56 #include <dev/spi/spivar.h> 57 58 #define M3K_MAX_SENSORS 16 /* 8 single-ended & 8 diff. */ 59 60 /* mcp3x0x model description */ 61 struct mcp3kadc_model { 62 uint32_t name; 63 uint8_t bits; 64 uint8_t channels; 65 uint8_t lead; /* leading bits to ignore */ 66 uint8_t flags; 67 #define M3K_SGLDIFF 0x01 /* single-ended/differential */ 68 #define M3K_D2D1D0 0x02 /* 3 channel select bits */ 69 #define M3K_MSBF 0x04 /* MSBF select bit */ 70 #define M3K_SIGNED 0x80 /* result is signed */ 71 #define M3K_CTRL_NEEDED (M3K_SGLDIFF | M3K_D2D1D0 | M3K_MSBF) 72 }; 73 74 struct mcp3kadc_softc { 75 device_t sc_dev; 76 struct spi_handle *sc_sh; 77 const struct mcp3kadc_model *sc_model; 78 uint32_t sc_adc_max; 79 int32_t sc_vref_mv; 80 81 struct sysmon_envsys *sc_sme; 82 envsys_data_t sc_sensors[M3K_MAX_SENSORS]; 83 }; 84 85 static int mcp3kadc_match(device_t, cfdata_t, void *); 86 static void mcp3kadc_attach(device_t, device_t, void *); 87 static void mcp3kadc_envsys_refresh(struct sysmon_envsys *, 88 envsys_data_t *); 89 static int sysctl_mcp3kadc_vref(SYSCTLFN_ARGS); 90 91 CFATTACH_DECL_NEW(mcp3kadc, sizeof(struct mcp3kadc_softc), 92 mcp3kadc_match, mcp3kadc_attach, NULL, NULL); 93 94 static const struct mcp3kadc_model mcp3001 = { 95 .name = 3001, 96 .bits = 10, 97 .channels = 1, 98 .lead = 3, 99 .flags = 0 100 }; 101 102 static const struct mcp3kadc_model mcp3002 = { 103 .name = 3002, 104 .bits = 10, 105 .channels = 2, 106 .lead = 2, 107 .flags = M3K_SGLDIFF | M3K_MSBF 108 }; 109 110 static const struct mcp3kadc_model mcp3004 = { 111 .name = 3004, 112 .bits = 10, 113 .channels = 4, 114 .lead = 2, 115 .flags = M3K_SGLDIFF | M3K_D2D1D0 116 }; 117 118 static const struct mcp3kadc_model mcp3008 = { 119 .name = 3008, 120 .bits = 10, 121 .channels = 8, 122 .lead = 2, 123 .flags = M3K_SGLDIFF | M3K_D2D1D0 124 }; 125 126 static const struct mcp3kadc_model mcp3201 = { 127 .name = 3201, 128 .bits = 12, 129 .channels = 1, 130 .lead = 3, 131 .flags = 0 132 }; 133 134 static const struct mcp3kadc_model mcp3202 = { 135 .name = 3202, 136 .bits = 12, 137 .channels = 2, 138 .lead = 2, 139 .flags = M3K_SGLDIFF | M3K_MSBF 140 }; 141 142 static const struct mcp3kadc_model mcp3204 = { 143 .name = 3204, 144 .bits = 12, 145 .channels = 4, 146 .lead = 2, 147 .flags = M3K_SGLDIFF | M3K_D2D1D0 148 }; 149 150 static const struct mcp3kadc_model mcp3208 = { 151 .name = 3208, 152 .bits = 12, 153 .channels = 8, 154 .lead = 2, 155 .flags = M3K_SGLDIFF | M3K_D2D1D0 156 }; 157 158 static const struct mcp3kadc_model mcp3301 = { 159 .name = 3301, 160 .bits = 13, 161 .channels = 1, 162 .lead = 3, 163 .flags = M3K_SIGNED 164 }; 165 166 static const struct mcp3kadc_model mcp3302 = { 167 .name = 3302, 168 .bits = 13, 169 .channels = 4, 170 .lead = 2, 171 .flags = M3K_SIGNED | M3K_SGLDIFF | M3K_D2D1D0 172 }; 173 174 static const struct mcp3kadc_model mcp3304 = { 175 .name = 3304, 176 .bits = 13, 177 .channels = 8, 178 .lead = 2, 179 .flags = M3K_SIGNED | M3K_SGLDIFF | M3K_D2D1D0 180 }; 181 182 /* 183 * N.B. The order of this table is important! It matches the order 184 * of the legacy mcp3k_models[] array, which is used to manually 185 * select the device type in the kernel configuration file when 186 * direct configuration is not available. 187 */ 188 static const struct device_compatible_entry compat_data[] = { 189 { .compat = "microchip,mcp3001", .data = &mcp3001 }, 190 { .compat = "microchip,mcp3002", .data = &mcp3002 }, 191 { .compat = "microchip,mcp3004", .data = &mcp3004 }, 192 { .compat = "microchip,mcp3008", .data = &mcp3008 }, 193 { .compat = "microchip,mcp3201", .data = &mcp3201 }, 194 { .compat = "microchip,mcp3202", .data = &mcp3202 }, 195 { .compat = "microchip,mcp3204", .data = &mcp3204 }, 196 { .compat = "microchip,mcp3208", .data = &mcp3208 }, 197 { .compat = "microchip,mcp3301", .data = &mcp3301 }, 198 { .compat = "microchip,mcp3302", .data = &mcp3302 }, 199 { .compat = "microchip,mcp3304", .data = &mcp3304 }, 200 201 #if 0 /* We should also add support for these: */ 202 { .compat = "microchip,mcp3550-50" }, 203 { .compat = "microchip,mcp3550-60" }, 204 { .compat = "microchip,mcp3551" }, 205 { .compat = "microchip,mcp3553" }, 206 #endif 207 208 DEVICE_COMPAT_EOL 209 }; 210 static const int mcp3k_nmodels = __arraycount(compat_data) - 1; 211 212 static const struct mcp3kadc_model * 213 mcp3kadc_lookup(const struct spi_attach_args *sa, const cfdata_t cf) 214 { 215 if (sa->sa_ncompat > 0) { 216 const struct device_compatible_entry *dce = 217 spi_compatible_lookup(sa, compat_data); 218 if (dce == NULL) { 219 return NULL; 220 } 221 return dce->data; 222 } else { 223 if (cf->cf_flags < 0 || cf->cf_flags >= mcp3k_nmodels) { 224 return NULL; 225 } 226 return compat_data[cf->cf_flags].data; 227 } 228 } 229 230 static int 231 mcp3kadc_match(device_t parent, cfdata_t cf, void *aux) 232 { 233 struct spi_attach_args *sa = aux; 234 int match_result; 235 236 if (spi_use_direct_match(sa, compat_data, &match_result)) { 237 return match_result; 238 } 239 240 /* 241 * If we're doing indirect config, the user must 242 * have specified a valid model. 243 */ 244 if (sa->sa_ncompat == 0 && mcp3kadc_lookup(sa, cf) == NULL) { 245 return 0; 246 } 247 248 return SPI_MATCH_DEFAULT; 249 } 250 251 static void 252 mcp3kadc_attach(device_t parent, device_t self, void *aux) 253 { 254 const struct sysctlnode *rnode, *node; 255 struct spi_attach_args *sa = aux; 256 struct mcp3kadc_softc *sc = device_private(self);; 257 const struct mcp3kadc_model *model; 258 int error, ch, i; 259 260 sc->sc_dev = self; 261 sc->sc_sh = sa->sa_handle; 262 263 model = mcp3kadc_lookup(sa, device_cfdata(self)); 264 KASSERT(model != NULL); 265 266 sc->sc_model = model; 267 268 aprint_naive(": Analog to Digital converter\n"); 269 aprint_normal(": MCP%u %u-channel %u-bit ADC\n", 270 (unsigned)model->name, (unsigned)model->channels, 271 (unsigned)model->bits); 272 273 /* configure for 1MHz */ 274 error = spi_configure(self, sa->sa_handle, SPI_MODE_0, SPI_FREQ_MHz(1)); 275 if (error) { 276 aprint_error_dev(self, "spi_configure failed (error = %d)\n", 277 error); 278 return; 279 } 280 281 /* set a default Vref in mV according to the chip's ADC resolution */ 282 sc->sc_vref_mv = 1 << ((model->flags & M3K_SIGNED) ? 283 model->bits - 1 : model->bits); 284 285 /* remember maximum value for this ADC - also used for masking */ 286 sc->sc_adc_max = (1 << model->bits) - 1; 287 288 /* attach voltage sensors to envsys */ 289 sc->sc_sme = sysmon_envsys_create(); 290 291 /* adc difference from two neighbouring channels */ 292 for (ch = 0; ch < model->channels; ch++) { 293 KASSERT(ch < M3K_MAX_SENSORS); 294 sc->sc_sensors[ch].units = ENVSYS_SVOLTS_DC; 295 sc->sc_sensors[ch].state = ENVSYS_SINVALID; 296 if (model->channels == 1) 297 strlcpy(sc->sc_sensors[ch].desc, "adc diff ch0", 298 sizeof(sc->sc_sensors[ch].desc)); 299 else 300 snprintf(sc->sc_sensors[ch].desc, 301 sizeof(sc->sc_sensors[ch].desc), 302 "adc diff ch%d-ch%d", ch, ch ^ 1); 303 sc->sc_sensors[ch].private = ch; 304 sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensors[ch]); 305 } 306 307 if (model->flags & M3K_SGLDIFF) { 308 /* adc from single ended channels */ 309 for (i = 0; i < model->channels; i++, ch++) { 310 KASSERT(ch < M3K_MAX_SENSORS); 311 sc->sc_sensors[ch].units = ENVSYS_SVOLTS_DC; 312 sc->sc_sensors[ch].state = ENVSYS_SINVALID; 313 snprintf(sc->sc_sensors[ch].desc, 314 sizeof(sc->sc_sensors[ch].desc), 315 "adc single ch%d", i); 316 sc->sc_sensors[ch].private = ch; 317 sysmon_envsys_sensor_attach(sc->sc_sme, 318 &sc->sc_sensors[ch]); 319 } 320 } 321 322 sc->sc_sme->sme_name = device_xname(self); 323 sc->sc_sme->sme_refresh = mcp3kadc_envsys_refresh; 324 sc->sc_sme->sme_cookie = sc; 325 if (sysmon_envsys_register(sc->sc_sme)) { 326 aprint_error_dev(self, "unable to register with sysmon\n"); 327 sysmon_envsys_destroy(sc->sc_sme); 328 } 329 330 /* create a sysctl node for adjusting the ADC's reference voltage */ 331 rnode = node = NULL; 332 sysctl_createv(NULL, 0, NULL, &rnode, 333 CTLFLAG_READWRITE, 334 CTLTYPE_NODE, device_xname(sc->sc_dev), NULL, 335 NULL, 0, NULL, 0, 336 CTL_HW, CTL_CREATE, CTL_EOL); 337 338 if (rnode != NULL) 339 sysctl_createv(NULL, 0, NULL, &node, 340 CTLFLAG_READWRITE | CTLFLAG_OWNDESC, 341 CTLTYPE_INT, "vref", 342 SYSCTL_DESCR("ADC reference voltage"), 343 sysctl_mcp3kadc_vref, 0, (void *)sc, 0, 344 CTL_HW, rnode->sysctl_num, CTL_CREATE, CTL_EOL); 345 } 346 347 static void 348 mcp3kadc_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata) 349 { 350 struct mcp3kadc_softc *sc; 351 const struct mcp3kadc_model *model; 352 uint8_t buf[2], ctrl; 353 int32_t val, scale; 354 355 sc = sme->sme_cookie; 356 model = sc->sc_model; 357 scale = sc->sc_adc_max + 1; 358 359 if (model->flags & M3K_CTRL_NEEDED) { 360 /* we need to send some control bits first */ 361 ctrl = 1; /* start bit */ 362 363 if (model->flags & M3K_SGLDIFF) { 364 /* bit set to select single-ended mode */ 365 ctrl <<= 1; 366 ctrl |= edata->private >= model->channels; 367 } 368 369 if (model->flags & M3K_D2D1D0) { 370 /* 3 bits select the channel */ 371 ctrl <<= 3; 372 ctrl |= edata->private & (model->channels - 1); 373 } else { 374 /* 1 bit selects between two channels */ 375 ctrl <<= 1; 376 ctrl |= edata->private & 1; 377 } 378 379 if (model->flags & M3K_MSBF) { 380 /* bit select MSB first format */ 381 ctrl <<= 1; 382 ctrl |= 1; 383 } 384 385 /* send control bits, receive ADC data */ 386 if (spi_send_recv(sc->sc_sh, 1, &ctrl, 2, buf) != 0) { 387 edata->state = ENVSYS_SINVALID; 388 return; 389 } 390 } else { 391 392 /* just read data from the ADC */ 393 if (spi_recv(sc->sc_sh, 2, buf) != 0) { 394 edata->state = ENVSYS_SINVALID; 395 return; 396 } 397 } 398 399 /* extract big-endian ADC data from buffer */ 400 val = (buf[0] << 8) | buf[1]; 401 val = (val >> (16 - (model->bits + model->lead))) & sc->sc_adc_max; 402 403 /* sign-extend the result, when needed */ 404 if (model->flags & M3K_SIGNED) { 405 if (val & (1 << (model->bits - 1))) 406 val -= sc->sc_adc_max + 1; 407 scale >>= 1; /* MSB is the sign */ 408 } 409 410 /* scale the value for Vref and convert to mV */ 411 edata->value_cur = (sc->sc_vref_mv * val / scale) * 1000; 412 edata->state = ENVSYS_SVALID; 413 } 414 415 static int 416 sysctl_mcp3kadc_vref(SYSCTLFN_ARGS) 417 { 418 struct sysctlnode node; 419 struct mcp3kadc_softc *sc; 420 int32_t t; 421 int error; 422 423 node = *rnode; 424 sc = node.sysctl_data; 425 426 t = sc->sc_vref_mv; 427 node.sysctl_data = &t; 428 429 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 430 if (error || newp == NULL) 431 return error; 432 if (t <= 0) 433 return EINVAL; 434 435 sc->sc_vref_mv = t; 436 return 0; 437 } 438
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