1 /* $OpenBSD: pcf8591_ofw.c,v 1.6 2021/10/24 17:05:03 mpi Exp $ */
2
3 /*
4 * Copyright (c) 2006 Damien Miller <djm@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <sys/param.h>
20 #include <sys/systm.h>
21 #include <sys/device.h>
22 #include <sys/sensors.h>
23
24 #include <dev/ofw/openfirm.h>
25 #include <dev/i2c/i2cvar.h>
26
27 #define PCF8591_CHANNELS 4
28
29 struct pcfadc_channel {
30 u_int chan_num;
31 struct ksensor chan_sensor;
32 };
33
34 struct pcfadc_softc {
35 struct device sc_dev;
36 i2c_tag_t sc_tag;
37 i2c_addr_t sc_addr;
38 u_char sc_xlate[256];
39 u_int sc_nchan;
40 struct pcfadc_channel sc_channels[PCF8591_CHANNELS];
41 struct ksensordev sc_sensordev;
42 };
43
44 int pcfadc_match(struct device *, void *, void *);
45 void pcfadc_attach(struct device *, struct device *, void *);
46 void pcfadc_refresh(void *);
47
48 const struct cfattach pcfadc_ca = {
49 sizeof(struct pcfadc_softc), pcfadc_match, pcfadc_attach
50 };
51
52 struct cfdriver pcfadc_cd = {
53 NULL, "pcfadc", DV_DULL
54 };
55
56 int
pcfadc_match(struct device * parent,void * match,void * aux)57 pcfadc_match(struct device *parent, void *match, void *aux)
58 {
59 struct i2c_attach_args *ia = aux;
60
61 if (strcmp(ia->ia_name, "i2cpcf,8591") != 0)
62 return (0);
63
64 return (1);
65 }
66
67 void
pcfadc_attach(struct device * parent,struct device * self,void * aux)68 pcfadc_attach(struct device *parent, struct device *self, void *aux)
69 {
70 struct pcfadc_softc *sc = (struct pcfadc_softc *)self;
71 u_char chanuse[PCF8591_CHANNELS * 4], desc[PCF8591_CHANNELS * 32];
72 u_char *cp;
73 u_int8_t junk[PCF8591_CHANNELS + 1];
74 u_int32_t transinfo[PCF8591_CHANNELS * 4];
75 struct i2c_attach_args *ia = aux;
76 int dlen, clen, tlen, node = *(int *)ia->ia_cookie;
77 u_int i;
78
79 if ((dlen = OF_getprop(node, "channels-description", desc,
80 sizeof(desc))) < 0) {
81 printf(": couldn't find \"channels-description\" property\n");
82 return;
83 }
84 if (dlen > sizeof(desc) || desc[dlen - 1] != '\0') {
85 printf(": bad \"channels-description\" property\n");
86 return;
87 }
88 if ((clen = OF_getprop(node, "channels-in-use", chanuse,
89 sizeof(chanuse))) < 0) {
90 printf(": couldn't find \"channels-in-use\" property\n");
91 return;
92 }
93 if ((clen % 4) != 0) {
94 printf(": invalid \"channels-in-use\" length %d\n", clen);
95 return;
96 }
97 sc->sc_nchan = clen / 4;
98 if (sc->sc_nchan > PCF8591_CHANNELS) {
99 printf(": invalid number of channels (%d)\n", sc->sc_nchan);
100 return;
101 }
102
103 if ((tlen = OF_getprop(node, "tables", sc->sc_xlate,
104 sizeof(sc->sc_xlate))) < 0) {
105 printf(": couldn't find \"tables\" property\n");
106 return;
107 }
108 /* We only support complete, single width tables */
109 if (tlen != 256) {
110 printf(": invalid \"tables\" length %d\n", tlen);
111 return;
112 }
113
114 if ((tlen = OF_getprop(node, "translation", transinfo,
115 sizeof(transinfo))) < 0) {
116 printf(": couldn't find \"translation\" property\n");
117 return;
118 }
119 if (tlen != (sc->sc_nchan * 4 * 4)) {
120 printf(": invalid \"translation\" length %d\n", tlen);
121 return;
122 }
123
124 cp = desc;
125 for (i = 0; i < sc->sc_nchan; i++) {
126 struct pcfadc_channel *chp = &sc->sc_channels[i];
127
128 chp->chan_sensor.type = SENSOR_TEMP;
129
130 if (cp >= desc + dlen) {
131 printf(": invalid \"channels-description\"\n");
132 return;
133 }
134 strlcpy(chp->chan_sensor.desc, cp,
135 sizeof(chp->chan_sensor.desc));
136 cp += strlen(cp) + 1;
137
138 /*
139 * We only support input temperature channels, with
140 * valid channel numbers, and basic (unscaled) translation
141 *
142 * XXX TODO: support voltage (type 2) channels and type 4
143 * (scaled) translation tables
144 */
145 if (chanuse[(i * 4)] > PCF8591_CHANNELS || /* channel # */
146 chanuse[(i * 4) + 1] != 0 || /* dir == input */
147 chanuse[(i * 4) + 2] != 1 || /* type == temp */
148 transinfo[(i * 4)] != 3 || /* xlate == table */
149 transinfo[(i * 4) + 2] != 0 || /* no xlate offset */
150 transinfo[(i * 4) + 3] != 0x100) { /* xlate tbl length */
151 printf(": unsupported sensor %d\n", i);
152 return;
153 }
154 chp->chan_num = chanuse[(i * 4)];
155 }
156
157 sc->sc_tag = ia->ia_tag;
158 sc->sc_addr = ia->ia_addr;
159
160 iic_acquire_bus(sc->sc_tag, 0);
161
162 /* Try a read now, so we can fail if it doesn't work */
163 if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
164 NULL, 0, junk, sc->sc_nchan + 1, 0)) {
165 printf(": read failed\n");
166 iic_release_bus(sc->sc_tag, 0);
167 return;
168 }
169
170 iic_release_bus(sc->sc_tag, 0);
171
172 /* Initialize sensor data. */
173 strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
174 sizeof(sc->sc_sensordev.xname));
175
176 for (i = 0; i < sc->sc_nchan; i++)
177 sensor_attach(&sc->sc_sensordev,
178 &sc->sc_channels[i].chan_sensor);
179
180 if (sensor_task_register(sc, pcfadc_refresh, 5) == NULL) {
181 printf(": unable to register update task\n");
182 return;
183 }
184
185 sensordev_install(&sc->sc_sensordev);
186
187 printf("\n");
188 }
189
190 void
pcfadc_refresh(void * arg)191 pcfadc_refresh(void *arg)
192 {
193 struct pcfadc_softc *sc = arg;
194 u_int i;
195 u_int8_t data[PCF8591_CHANNELS + 1];
196
197 iic_acquire_bus(sc->sc_tag, 0);
198 /* NB: first byte out is stale, so read num_channels + 1 */
199 if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
200 NULL, 0, data, PCF8591_CHANNELS + 1, 0)) {
201 iic_release_bus(sc->sc_tag, 0);
202 return;
203 }
204 iic_release_bus(sc->sc_tag, 0);
205
206 /* XXX: so far this only supports temperature channels */
207 for (i = 0; i < sc->sc_nchan; i++) {
208 struct pcfadc_channel *chp = &sc->sc_channels[i];
209
210 chp->chan_sensor.value = 273150000 + 1000000 *
211 sc->sc_xlate[data[1 + chp->chan_num]];
212 }
213 }
214
215