1/*	$OpenBSD: owsbm.c,v 1.11 2022/04/06 18:59:29 naddy Exp $	*/
2
3/*
4 * Copyright (c) 2007 Aaron Linville <aaron@linville.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/*
20 * 1-Wire Smart Battery Monitor family type device driver.
21 * Provides on-board temperature, an A/D converter for voltage/current,
22 * current accumulator, elapsed time metter, and 40 bytes of nonvolatile
23 * memory.
24 */
25
26#include <sys/param.h>
27#include <sys/systm.h>
28#include <sys/device.h>
29#include <sys/rwlock.h>
30#include <sys/sensors.h>
31
32#include <dev/onewire/onewiredevs.h>
33#include <dev/onewire/onewirereg.h>
34#include <dev/onewire/onewirevar.h>
35
36/* Commands */
37#define	DSSBM_CMD_READ_SCRATCHPAD	0xbe
38#define	DSSBM_CMD_WRITE_SCRATCHPAD	0x4e
39#define	DSSBM_CMD_COPY_SCRATCHPAD	0x48
40
41#define	DSSBM_CMD_RECALL_MEMORY		0xb8
42
43#define	DSSBM_CMD_CONVERT_T		0x44
44#define	DSSBM_CMD_CONVERT_V		0xb4
45
46/* Scratchpad layout */
47#define DS2438_SP_STATUS		0
48#define DS2438_SP_TEMP_LSB		1
49#define DS2438_SP_TEMP_MSB		2
50#define DS2438_SP_VOLT_LSB		3
51#define DS2438_SP_VOLT_MSB		4
52#define DS2438_SP_CURRENT_LSB		5
53#define DS2438_SP_CURRENT_MSB		6
54#define DS2438_SP_THRESHOLD		7
55#define DS2438_SP_CRC			8
56
57struct owsbm_softc {
58	struct device		sc_dev;
59
60	void *			sc_onewire;
61	u_int64_t		sc_rom;
62
63	struct ksensordev	sc_sensordev;
64
65	struct ksensor		sc_temp;
66	struct ksensor		sc_voltage_vdd; /* Battery, AD = 1*/
67	struct ksensor		sc_voltage_vad; /* General purpose, AD = 0 */
68	struct ksensor		sc_voltage_cr; /* Current Register */
69
70	struct sensor_task	*sc_sensortask;
71
72	struct rwlock		sc_lock;
73};
74
75int	owsbm_match(struct device *, void *, void *);
76void	owsbm_attach(struct device *, struct device *, void *);
77int	owsbm_detach(struct device *, int);
78int	owsbm_activate(struct device *, int);
79
80void	owsbm_update(void *);
81
82const struct cfattach owsbm_ca = {
83	sizeof(struct owsbm_softc),
84	owsbm_match,
85	owsbm_attach,
86	owsbm_detach,
87	owsbm_activate
88};
89
90struct cfdriver owsbm_cd = {
91	NULL, "owsbm", DV_DULL
92};
93
94static const struct onewire_matchfam owsbm_fams[] = {
95	{ ONEWIRE_FAMILY_DS2438 }
96};
97
98int
99owsbm_match(struct device *parent, void *match, void *aux)
100{
101	return (onewire_matchbyfam(aux, owsbm_fams, nitems(owsbm_fams)));
102}
103
104void
105owsbm_attach(struct device *parent, struct device *self, void *aux)
106{
107	struct owsbm_softc *sc = (struct owsbm_softc *)self;
108	struct onewire_attach_args *oa = aux;
109
110	sc->sc_onewire = oa->oa_onewire;
111	sc->sc_rom = oa->oa_rom;
112
113	/* Initialize temp sensor */
114	strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
115	    sizeof(sc->sc_sensordev.xname));
116	sc->sc_temp.type = SENSOR_TEMP;
117	snprintf(sc->sc_temp.desc, sizeof(sc->sc_temp.desc), "sn %012llx",
118	    ONEWIRE_ROM_SN(oa->oa_rom));
119	sensor_attach(&sc->sc_sensordev, &sc->sc_temp);
120
121	/* Initialize voltage sensor */
122	sc->sc_voltage_vdd.type = SENSOR_VOLTS_DC;
123	strlcpy(sc->sc_voltage_vdd.desc, "VDD", sizeof(sc->sc_voltage_vdd.desc));
124	sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_vdd);
125
126	/* Initialize voltage sensor */
127	sc->sc_voltage_vad.type = SENSOR_VOLTS_DC;
128	strlcpy(sc->sc_voltage_vad.desc, "VAD", sizeof(sc->sc_voltage_vad.desc));
129	sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_vad);
130
131	/* Initialize the current sensor */
132	sc->sc_voltage_cr.type = SENSOR_VOLTS_DC;
133	strlcpy(sc->sc_voltage_cr.desc, "CR", sizeof(sc->sc_voltage_cr.desc));
134	sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_cr);
135
136	sc->sc_sensortask = sensor_task_register(sc, owsbm_update, 10);
137	if (sc->sc_sensortask == NULL) {
138		printf(": unable to register update task\n");
139		return;
140	}
141
142	sensordev_install(&sc->sc_sensordev);
143
144	rw_init(&sc->sc_lock, sc->sc_dev.dv_xname);
145	printf("\n");
146}
147
148int
149owsbm_detach(struct device *self, int flags)
150{
151	struct owsbm_softc *sc = (struct owsbm_softc *)self;
152
153	rw_enter_write(&sc->sc_lock);
154	sensordev_deinstall(&sc->sc_sensordev);
155	if (sc->sc_sensortask != NULL)
156		sensor_task_unregister(sc->sc_sensortask);
157	rw_exit_write(&sc->sc_lock);
158
159	return (0);
160}
161
162int
163owsbm_activate(struct device *self, int act)
164{
165	return (0);
166}
167
168void
169owsbm_update(void *arg)
170{
171	struct owsbm_softc *sc = arg;
172	u_int8_t data[9];
173
174	rw_enter_write(&sc->sc_lock);
175	onewire_lock(sc->sc_onewire, 0);
176	if (onewire_reset(sc->sc_onewire) != 0)
177		goto done;
178
179	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
180	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_T);
181	if (onewire_reset(sc->sc_onewire) != 0)
182		goto done;
183
184	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
185	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_V);
186	if (onewire_reset(sc->sc_onewire) != 0)
187		goto done;
188
189	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
190	/* Issue Recall Memory page 00h cmd */
191	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_RECALL_MEMORY);
192	onewire_write_byte(sc->sc_onewire, 0);
193
194	if (onewire_reset(sc->sc_onewire) != 0)
195		goto done;
196
197	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
198	/* Read page 0 of Memory Map from Scratchpad */
199	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_READ_SCRATCHPAD);
200	onewire_write_byte(sc->sc_onewire, 0);
201	onewire_read_block(sc->sc_onewire, data, 9);
202	if (onewire_crc(data, 8) == data[DS2438_SP_CRC]) {
203		sc->sc_temp.value = 273150000 +
204		     (int)(((u_int16_t)data[DS2438_SP_TEMP_MSB] << 5) |
205		     ((u_int16_t)data[DS2438_SP_TEMP_LSB] >> 3)) * 31250;
206		sc->sc_voltage_vdd.value =
207		     (int)(((u_int16_t)data[DS2438_SP_VOLT_MSB] << 8) |
208		     data[DS2438_SP_VOLT_LSB]) * 10000;
209
210		sc->sc_voltage_cr.value =
211		    (int)(((u_int16_t)data[DS2438_SP_CURRENT_MSB] << 8) |
212		    data[DS2438_SP_CURRENT_LSB]) * 244;
213	}
214
215	/* Reconfigure DS2438 to measure VAD */
216
217	if (onewire_reset(sc->sc_onewire) != 0)
218		goto done;
219
220	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
221	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_WRITE_SCRATCHPAD);
222	onewire_write_byte(sc->sc_onewire, 0);
223	onewire_write_byte(sc->sc_onewire, 0x7); /* AD = 0 */
224
225	if (onewire_reset(sc->sc_onewire) != 0)
226		goto done;
227
228	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
229	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_V);
230	if (onewire_reset(sc->sc_onewire) != 0)
231		goto done;
232
233	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
234	/* Issue Recall Memory page 00h cmd */
235	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_RECALL_MEMORY);
236	onewire_write_byte(sc->sc_onewire, 0);
237
238	if (onewire_reset(sc->sc_onewire) != 0)
239		goto done;
240
241	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
242	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_READ_SCRATCHPAD);
243	onewire_write_byte(sc->sc_onewire, 0);
244	onewire_read_block(sc->sc_onewire, data, 9);
245	if (onewire_crc(data, 8) == data[8]) {
246		sc->sc_voltage_vad.value =
247		    (int)(((u_int16_t)data[DS2438_SP_VOLT_MSB] << 8) |
248		    data[DS2438_SP_VOLT_LSB]) * 10000;
249	}
250
251	/* Reconfigure back DS2438 to measure VDD (default) */
252
253	if (onewire_reset(sc->sc_onewire) != 0)
254		goto done;
255
256	onewire_matchrom(sc->sc_onewire, sc->sc_rom);
257	onewire_write_byte(sc->sc_onewire, DSSBM_CMD_WRITE_SCRATCHPAD);
258	onewire_write_byte(sc->sc_onewire, 0);
259	onewire_write_byte(sc->sc_onewire, 0xf); /* AD = 1 */
260	onewire_reset(sc->sc_onewire);
261
262done:
263	onewire_unlock(sc->sc_onewire);
264	rw_exit_write(&sc->sc_lock);
265}
266