mcp48x1.c revision 1.5
1 /* $NetBSD: mcp48x1.c,v 1.5 2025/09/11 14:12:38 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2014 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Radoslaw Kujawa. 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 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: mcp48x1.c,v 1.5 2025/09/11 14:12:38 thorpej Exp $"); 34 35 /* 36 * Driver for Microchip MCP4801/MCP4811/MCP4821 DAC. 37 * 38 * XXX: needs more testing. 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/device.h> 44 #include <sys/kernel.h> 45 #include <sys/types.h> 46 #include <sys/sysctl.h> 47 48 #include <dev/sysmon/sysmonvar.h> 49 50 #include <dev/spi/spivar.h> 51 52 #define MCP48X1DAC_DEBUG 0 53 54 #define MCP48X1DAC_WRITE __BIT(15) /* active low */ 55 #define MCP48X1DAC_GAIN __BIT(13) /* active low */ 56 #define MCP48X1DAC_SHDN __BIT(12) /* active low */ 57 #define MCP48X1DAC_DATA __BITS(11,0) /* data */ 58 59 struct mcp48x1dac_model { 60 const char *name; 61 uint8_t resolution; 62 uint8_t shift; /* data left shift during write */ 63 }; 64 65 struct mcp48x1dac_softc { 66 device_t sc_dev; 67 struct spi_handle *sc_sh; 68 69 struct mcp48x1dac_model *sc_dm; /* struct describing DAC model */ 70 71 uint16_t sc_dac_data; 72 bool sc_dac_gain; 73 bool sc_dac_shutdown; 74 75 struct sysmon_envsys *sc_sme; 76 envsys_data_t sc_sm_vo; /* envsys "sensor" (Vo) */ 77 }; 78 79 static int mcp48x1dac_match(device_t, cfdata_t, void *); 80 static void mcp48x1dac_attach(device_t, device_t, void *); 81 82 static bool mcp48x1dac_envsys_attach(struct mcp48x1dac_softc *sc); 83 static void mcp48x1dac_envsys_refresh(struct sysmon_envsys *, 84 envsys_data_t *); 85 86 static void mcp48x1dac_write(struct mcp48x1dac_softc *); 87 static uint16_t mcp48x1dac_regval_to_mv(struct mcp48x1dac_softc *); 88 89 static void mcp48x1dac_setup_sysctl(struct mcp48x1dac_softc *sc); 90 static int sysctl_mcp48x1dac_data(SYSCTLFN_ARGS); 91 static int sysctl_mcp48x1dac_gain(SYSCTLFN_ARGS); 92 93 CFATTACH_DECL_NEW(mcp48x1dac, sizeof(struct mcp48x1dac_softc), 94 mcp48x1dac_match, mcp48x1dac_attach, NULL, NULL); 95 96 static struct mcp48x1dac_model mcp48x1_models[] = { 97 { 98 .name = "MCP4801", 99 .resolution = 8, 100 .shift = 4 101 }, 102 { 103 .name = "MCP4811", 104 .resolution = 10, 105 .shift = 2 106 }, 107 { 108 .name = "MCP4821", 109 .resolution = 12, 110 .shift = 0 111 } 112 }; 113 114 115 static int 116 mcp48x1dac_match(device_t parent, cfdata_t cf, void *aux) 117 { 118 return SPI_MATCH_DEFAULT; 119 } 120 121 static void 122 mcp48x1dac_attach(device_t parent, device_t self, void *aux) 123 { 124 struct mcp48x1dac_softc *sc; 125 struct spi_attach_args *sa; 126 int error, cf_flags; 127 128 aprint_naive(": Digital to Analog converter\n"); 129 aprint_normal(": MCP48x1 DAC\n"); 130 131 sa = aux; 132 sc = device_private(self); 133 sc->sc_dev = self; 134 sc->sc_sh = sa->sa_handle; 135 cf_flags = device_cfdata(sc->sc_dev)->cf_flags; 136 137 sc->sc_dm = &mcp48x1_models[cf_flags]; /* flag value defines model */ 138 139 error = spi_configure(self, sa->sa_handle, SPI_MODE_0, 140 SPI_FREQ_MHz(20)); 141 if (error) { 142 return; 143 } 144 145 if(!mcp48x1dac_envsys_attach(sc)) { 146 aprint_error_dev(sc->sc_dev, "failed to attach envsys\n"); 147 return; 148 }; 149 150 sc->sc_dac_data = 0; 151 sc->sc_dac_gain = false; 152 sc->sc_dac_shutdown = false; 153 mcp48x1dac_write(sc); 154 155 mcp48x1dac_setup_sysctl(sc); 156 } 157 158 static void 159 mcp48x1dac_write(struct mcp48x1dac_softc *sc) 160 { 161 int rv; 162 uint16_t reg, regbe; 163 164 reg = 0; 165 166 if (!(sc->sc_dac_gain)) 167 reg |= MCP48X1DAC_GAIN; 168 169 if (!(sc->sc_dac_shutdown)) 170 reg |= MCP48X1DAC_SHDN; 171 172 reg |= sc->sc_dac_data << sc->sc_dm->shift; 173 174 regbe = htobe16(reg); 175 176 #ifdef MCP48X1DAC_DEBUG 177 aprint_normal_dev(sc->sc_dev, "sending %x over SPI\n", regbe); 178 #endif /* MCP48X1DAC_DEBUG */ 179 180 rv = spi_send(sc->sc_sh, 2, (uint8_t*) ®be); /* XXX: ugly cast */ 181 182 if (rv != 0) 183 aprint_error_dev(sc->sc_dev, "error sending data over SPI\n"); 184 } 185 186 static bool 187 mcp48x1dac_envsys_attach(struct mcp48x1dac_softc *sc) 188 { 189 190 sc->sc_sme = sysmon_envsys_create(); 191 sc->sc_sm_vo.units = ENVSYS_SVOLTS_DC; 192 sc->sc_sm_vo.state = ENVSYS_SINVALID; 193 strlcpy(sc->sc_sm_vo.desc, device_xname(sc->sc_dev), 194 sizeof(sc->sc_sm_vo.desc)); 195 if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sm_vo)) { 196 sysmon_envsys_destroy(sc->sc_sme); 197 return false; 198 } 199 200 sc->sc_sme->sme_name = device_xname(sc->sc_dev); 201 sc->sc_sme->sme_refresh = mcp48x1dac_envsys_refresh; 202 sc->sc_sme->sme_cookie = sc; 203 204 if (sysmon_envsys_register(sc->sc_sme)) { 205 aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n"); 206 sysmon_envsys_destroy(sc->sc_sme); 207 } 208 209 return true; 210 } 211 212 static uint16_t 213 mcp48x1dac_regval_to_mv(struct mcp48x1dac_softc *sc) 214 { 215 uint16_t mv; 216 217 mv = (2048 * sc->sc_dac_data / (1 << sc->sc_dm->resolution)); 218 219 if (sc->sc_dac_gain) 220 mv *= 2; 221 222 return mv; 223 } 224 225 static void 226 mcp48x1dac_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata) 227 { 228 struct mcp48x1dac_softc *sc; 229 230 sc = sme->sme_cookie; 231 232 edata->value_cur = mcp48x1dac_regval_to_mv(sc); 233 edata->state = ENVSYS_SVALID; 234 } 235 236 static void 237 mcp48x1dac_setup_sysctl(struct mcp48x1dac_softc *sc) 238 { 239 const struct sysctlnode *me = NULL, *node = NULL; 240 241 sysctl_createv(NULL, 0, NULL, &me, 242 CTLFLAG_READWRITE, 243 CTLTYPE_NODE, device_xname(sc->sc_dev), NULL, 244 NULL, 0, NULL, 0, 245 CTL_MACHDEP, CTL_CREATE, CTL_EOL); 246 247 sysctl_createv(NULL, 0, NULL, &node, 248 CTLFLAG_READWRITE | CTLFLAG_OWNDESC, 249 CTLTYPE_INT, "data", "Digital value to convert to analog", 250 sysctl_mcp48x1dac_data, 1, (void *)sc, 0, 251 CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL); 252 253 sysctl_createv(NULL, 0, NULL, &node, 254 CTLFLAG_READWRITE | CTLFLAG_OWNDESC, 255 CTLTYPE_INT, "gain", "Gain 2x enable", 256 sysctl_mcp48x1dac_gain, 1, (void *)sc, 0, 257 CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL); 258 259 } 260 261 262 SYSCTL_SETUP(sysctl_mcp48x1dac_setup, "sysctl mcp48x1dac subtree setup") 263 { 264 sysctl_createv(NULL, 0, NULL, NULL, CTLFLAG_PERMANENT, 265 CTLTYPE_NODE, "machdep", NULL, NULL, 0, NULL, 0, 266 CTL_MACHDEP, CTL_EOL); 267 } 268 269 270 static int 271 sysctl_mcp48x1dac_data(SYSCTLFN_ARGS) 272 { 273 struct sysctlnode node = *rnode; 274 struct mcp48x1dac_softc *sc = node.sysctl_data; 275 int newdata, err; 276 277 node.sysctl_data = &sc->sc_dac_data; 278 if ((err = (sysctl_lookup(SYSCTLFN_CALL(&node)))) != 0) 279 return err; 280 281 if (newp) { 282 newdata = *(int *)node.sysctl_data; 283 if (newdata > (1 << sc->sc_dm->resolution)) 284 return EINVAL; 285 sc->sc_dac_data = (uint16_t) newdata; 286 mcp48x1dac_write(sc); 287 return 0; 288 } else { 289 /* nothing to do, since we can't read from DAC */ 290 node.sysctl_size = 4; 291 } 292 293 return err; 294 } 295 296 static int 297 sysctl_mcp48x1dac_gain(SYSCTLFN_ARGS) 298 { 299 struct sysctlnode node = *rnode; 300 struct mcp48x1dac_softc *sc = node.sysctl_data; 301 int newgain, err; 302 303 node.sysctl_data = &sc->sc_dac_gain; 304 if ((err = (sysctl_lookup(SYSCTLFN_CALL(&node)))) != 0) 305 return err; 306 307 if (newp) { 308 newgain = *(int *)node.sysctl_data; 309 sc->sc_dac_gain = (bool) newgain; 310 mcp48x1dac_write(sc); 311 return 0; 312 } else { 313 /* nothing to do, since we can't read from DAC */ 314 node.sysctl_size = 4; 315 } 316 317 return err; 318 } 319 320
Indexes created Fri Sep 26 20:09:58 GMT 2025