pcf8591_ofw.c revision 1.3 
1/*	$OpenBSD: pcf8591_ofw.c,v 1.3 2007/03/22 16:55:31 deraadt 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 ksensor	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	struct ksensordev	sc_sensordev;
42};
43
44int	pcfadc_match(struct device *, void *, void *);
45void	pcfadc_attach(struct device *, struct device *, void *);
46void	pcfadc_refresh(void *);
47
48struct cfattach pcfadc_ca = {
49	sizeof(struct pcfadc_softc), pcfadc_match, pcfadc_attach
50};
51
52struct cfdriver pcfadc_cd = {
53	NULL, "pcfadc", DV_DULL
54};
55
56int
57pcfadc_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
67void
68pcfadc_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		if (!(sc->sc_channels[i].chan_sensor.flags & SENSOR_FINVALID))
178			sensor_attach(&sc->sc_sensordev,
179			    &sc->sc_channels[i].chan_sensor);
180
181	if (sensor_task_register(sc, pcfadc_refresh, 5)) {
182		printf(": unable to register update task\n");
183		return;
184	}
185
186	sensordev_install(&sc->sc_sensordev);
187
188	printf("\n");
189}
190
191void
192pcfadc_refresh(void *arg)
193{
194	struct pcfadc_softc *sc = arg;
195	u_int i;
196	u_int8_t data[PCF8591_CHANNELS + 1];
197
198	iic_acquire_bus(sc->sc_tag, 0);
199	/* NB: first byte out is stale, so read num_channels + 1 */
200	if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
201	    NULL, 0, data, PCF8591_CHANNELS + 1, 0)) {
202		iic_release_bus(sc->sc_tag, 0);
203		return;
204	}
205	iic_release_bus(sc->sc_tag, 0);
206
207	/* XXX: so far this only supports temperature channels */
208	for (i = 0; i < sc->sc_nchan; i++) {
209		struct pcfadc_channel *chp = &sc->sc_channels[i];
210
211		if ((chp->chan_sensor.flags & SENSOR_FINVALID) != 0)
212			continue;
213		chp->chan_sensor.value = 273150000 + 1000000 *
214		    sc->sc_xlate[data[1 + chp->chan_num]];
215	}
216}
217
218