pcf8591_ofw.c revision 1.1 
1/*	$OpenBSD: pcf8591_ofw.c,v 1.1 2006/02/10 05:28:56 djm 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
29struct pcfadc_channel {
30	u_int		chan_num;
31	struct sensor	chan_sensor;
32};
33
34struct 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};
42
43int	pcfadc_match(struct device *, void *, void *);
44void	pcfadc_attach(struct device *, struct device *, void *);
45void	pcfadc_refresh(void *);
46
47struct cfattach pcfadc_ca = {
48	sizeof(struct pcfadc_softc), pcfadc_match, pcfadc_attach
49};
50
51struct cfdriver pcfadc_cd = {
52	NULL, "pcfadc", DV_DULL
53};
54
55int
56pcfadc_match(struct device *parent, void *match, void *aux)
57{
58	struct i2c_attach_args *ia = aux;
59
60	if (strcmp(ia->ia_name, "i2cpcf,8591") != 0)
61		return (0);
62
63	return (1);
64}
65
66void
67pcfadc_attach(struct device *parent, struct device *self, void *aux)
68{
69	struct pcfadc_softc *sc = (struct pcfadc_softc *)self;
70	u_char chanuse[PCF8591_CHANNELS * 4], desc[PCF8591_CHANNELS * 32];
71	u_char *cp;
72	u_int8_t junk[PCF8591_CHANNELS + 1];
73	u_int32_t transinfo[PCF8591_CHANNELS * 4];
74	struct i2c_attach_args *ia = aux;
75	int dlen, clen, tlen, node = *(int *)ia->ia_cookie;
76	u_int i;
77
78	if ((dlen = OF_getprop(node, "channels-description", desc,
79	    sizeof(desc))) < 0) {
80		printf(": couldn't find \"channels-description\" property\n");
81		return;
82	}
83	if (dlen > sizeof(desc) || desc[dlen - 1] != '\0') {
84		printf(": bad \"channels-description\" property\n");
85		return;
86	}
87	if ((clen = OF_getprop(node, "channels-in-use", chanuse,
88	    sizeof(chanuse))) < 0) {
89		printf(": couldn't find \"channels-in-use\" property\n");
90		return;
91	}
92	if ((clen % 4) != 0) {
93		printf(": invalid \"channels-in-use\" length %d\n", clen);
94		return;
95	}
96	sc->sc_nchan = clen / 4;
97	if (sc->sc_nchan > PCF8591_CHANNELS) {
98		printf(": invalid number of channels (%d)\n", sc->sc_nchan);
99		return;
100	}
101
102	if ((tlen = OF_getprop(node, "tables", sc->sc_xlate,
103	    sizeof(sc->sc_xlate))) < 0) {
104		printf(": couldn't find \"tables\" property\n");
105		return;
106	}
107	/* We only support complete, single width tables */
108	if (tlen != 256) {
109		printf(": invalid \"tables\" length %d\n", tlen);
110		return;
111	}
112
113	if ((tlen = OF_getprop(node, "translation", transinfo,
114	    sizeof(transinfo))) < 0) {
115		printf(": couldn't find \"translation\" property\n");
116		return;
117	}
118	if (tlen != (sc->sc_nchan * 4 * 4)) {
119		printf(": invalid \"translation\" length %d\n", tlen);
120		return;
121	}
122
123	cp = desc;
124	for (i = 0; i < sc->sc_nchan; i++) {
125		struct pcfadc_channel *chp = &sc->sc_channels[i];
126
127		bzero(&chp->chan_sensor, sizeof(chp->chan_sensor));
128		strlcpy(chp->chan_sensor.device, sc->sc_dev.dv_xname,
129		    sizeof(chp->chan_sensor.device));
130		chp->chan_sensor.type = SENSOR_TEMP;
131
132		if (cp >= desc + dlen) {
133			printf(": invalid \"channels-description\"\n");
134			return;
135		}
136		strlcpy(chp->chan_sensor.desc, cp,
137		    sizeof(chp->chan_sensor.desc));
138		cp += strlen(cp) + 1;
139
140		/*
141		 * We only support input temperature channels, with
142		 * valid channel numbers, and basic (unscaled) translation
143		 *
144		 * XXX TODO: support voltage (type 2) channels and type 4
145		 * (scaled) translation tables
146		 */
147		if (chanuse[(i * 4)] > PCF8591_CHANNELS || /* channel # */
148		    chanuse[(i * 4) + 1] != 0 ||	/* dir == input */
149		    chanuse[(i * 4) + 2] != 1 ||	/* type == temp */
150		    transinfo[(i * 4)] != 3 ||		/* xlate == table */
151		    transinfo[(i * 4) + 2] != 0 ||	/* no xlate offset */
152		    transinfo[(i * 4) + 3] != 0x100) {	/* xlate tbl length */
153			printf(": unsupported sensor %d\n", i);
154			return;
155		}
156		chp->chan_num = chanuse[(i * 4)];
157	}
158
159	sc->sc_tag = ia->ia_tag;
160	sc->sc_addr = ia->ia_addr;
161
162	iic_acquire_bus(sc->sc_tag, 0);
163
164	/* Try a read now, so we can fail if it doesn't work */
165	if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
166	    NULL, 0, junk, sc->sc_nchan + 1, 0)) {
167		printf(": read failed\n");
168		iic_release_bus(sc->sc_tag, 0);
169		return;
170	}
171
172	iic_release_bus(sc->sc_tag, 0);
173
174	/* Initialize sensor data. */
175	for (i = 0; i < sc->sc_nchan; i++)
176		if (!(sc->sc_channels[i].chan_sensor.flags & SENSOR_FINVALID))
177			sensor_add(&sc->sc_channels[i].chan_sensor);
178
179	if (sensor_task_register(sc, pcfadc_refresh, 5)) {
180		printf(": unable to register update task\n");
181		return;
182	}
183
184	printf("\n");
185}
186
187void
188pcfadc_refresh(void *arg)
189{
190	struct pcfadc_softc *sc = arg;
191	u_int i;
192	u_int8_t data[PCF8591_CHANNELS + 1];
193
194	iic_acquire_bus(sc->sc_tag, 0);
195	/* NB: first byte out is stale, so read num_channels + 1 */
196	if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
197	    NULL, 0, data, PCF8591_CHANNELS + 1, 0)) {
198		iic_release_bus(sc->sc_tag, 0);
199		return;
200	}
201	iic_release_bus(sc->sc_tag, 0);
202
203	/* XXX: so far this only supports temperature channels */
204	for (i = 0; i < sc->sc_nchan; i++) {
205		struct pcfadc_channel *chp = &sc->sc_channels[i];
206
207		if ((chp->chan_sensor.flags & SENSOR_FINVALID) != 0)
208			continue;
209		chp->chan_sensor.value = 273150000 + 1000000 *
210		    sc->sc_xlate[data[1 + chp->chan_num]];
211	}
212}
213
214