1/*	$NetBSD: mpl115a.c,v 1.3 2019/12/23 14:50:43 thorpej Exp $ */
2
3/*-
4 * Copyright (c) 2013 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/*
33 * Freescale MPL115A2 miniature digital barometer driver.
34 *
35 * This driver could be split into bus-indepented driver and I2C-specific
36 * attachment, as SPI variant of this chip also exist.
37 */
38
39#include <sys/cdefs.h>
40__KERNEL_RCSID(0, "$NetBSD: mpl115a.c,v 1.3 2019/12/23 14:50:43 thorpej Exp $");
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/device.h>
45#include <sys/kernel.h>
46#include <sys/mutex.h>
47#include <sys/endian.h>
48
49#include <sys/bus.h>
50#include <dev/i2c/i2cvar.h>
51
52#include <dev/sysmon/sysmonvar.h>
53
54#include <dev/i2c/mpl115areg.h>
55
56#define MPL115A_DEBUG 1
57
58struct mpl115a_softc {
59	device_t		sc_dev;
60
61	i2c_tag_t		sc_tag;
62	i2c_addr_t		sc_addr;
63
64	/* raw coefficients */
65	int16_t			sc_a0;
66	int16_t			sc_b1;
67	int16_t			sc_b2;
68	int16_t			sc_c12;
69
70	/* envsys(4) stuff */
71	struct sysmon_envsys	*sc_sme;
72	envsys_data_t		sc_sensor;
73	kmutex_t		sc_lock;
74};
75
76
77static int	mpl115a_match(device_t, cfdata_t, void *);
78static void	mpl115a_attach(device_t, device_t, void *);
79
80static uint8_t	mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t);
81static void	mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t, uint8_t);
82
83static void	mpl115a_load_coeffs(struct mpl115a_softc *sc);
84static uint16_t	mpl115a_make_coeff(uint8_t msb, uint8_t lsb);
85static uint32_t	mpl115a_pressure(struct mpl115a_softc *sc);
86static uint32_t mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) ;
87
88static void mpl115a_envsys_register(struct mpl115a_softc *);
89static void mpl115a_envsys_refresh(struct sysmon_envsys *, envsys_data_t *);
90
91CFATTACH_DECL_NEW(mpl115a, sizeof (struct mpl115a_softc),
92    mpl115a_match, mpl115a_attach, NULL, NULL);
93
94static int
95mpl115a_match(device_t parent, cfdata_t cf, void *aux)
96{
97	struct i2c_attach_args *ia = aux;
98
99	if (ia->ia_addr == MPL115A_ADDR)
100		return I2C_MATCH_ADDRESS_ONLY;
101	return 0;
102}
103
104static void
105mpl115a_attach(device_t parent, device_t self, void *aux)
106{
107	struct mpl115a_softc *sc = device_private(self);
108	struct i2c_attach_args *ia = aux;
109
110	sc->sc_dev = self;
111	sc->sc_addr = ia->ia_addr;
112	sc->sc_tag = ia->ia_tag;
113
114	aprint_normal(": Freescale MPL115A2 Pressure Sensor\n");
115
116	/* Since coefficients do not change load them once. */
117	mpl115a_load_coeffs(sc);
118
119	mpl115a_pressure(sc);
120
121	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
122
123	mpl115a_envsys_register(sc);
124}
125
126/* Construct a coefficients from MSB and LSB bytes. */
127static uint16_t
128mpl115a_make_coeff(uint8_t msb, uint8_t lsb)
129{
130	uint16_t rv;
131
132	rv = le16toh((msb << 8) | lsb);
133
134#ifdef MPL115A_DEBUG
135	aprint_normal("msb %x, lsb %x, ret val %x\n", msb, lsb, rv);
136#endif /* MPL115A_DEBUG */
137
138	return rv;
139}
140
141static void
142mpl115a_load_coeffs(struct mpl115a_softc *sc)
143{
144	sc->sc_a0 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_A0_MSB),
145	    mpl115a_reg_read_1(sc, MPL115A_A0_LSB));
146	sc->sc_b1 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B1_MSB),
147	    mpl115a_reg_read_1(sc, MPL115A_B1_LSB));
148	sc->sc_b2 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B2_MSB),
149	    mpl115a_reg_read_1(sc, MPL115A_B2_LSB));
150	sc->sc_c12 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_C12_MSB),
151	    mpl115a_reg_read_1(sc, MPL115A_C12_LSB));
152}
153
154static void
155mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t reg, uint8_t val)
156{
157	if (iic_acquire_bus(sc->sc_tag, 0) != 0) {
158		aprint_error_dev(sc->sc_dev, "cannot acquire bus for write\n");
159		return;
160	}
161
162	if (iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr, &reg, 1,
163	    &val, 1, 0)) {
164		aprint_error_dev(sc->sc_dev, "cannot execute write\n");
165	}
166	iic_release_bus(sc->sc_tag, 0);
167}
168
169static uint8_t
170mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t reg)
171{
172	uint8_t rv, wbuf[2];
173
174	if (iic_acquire_bus(sc->sc_tag, 0) != 0) {
175#ifdef MPL115A_DEBUG
176		aprint_error_dev(sc->sc_dev, "cannot acquire bus for read\n");
177#endif /* MPL115A_DEBUG */
178		return 0;
179	}
180
181	wbuf[0] = reg;
182
183	if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, wbuf,
184	    1, &rv, 1, 0)) {
185		iic_release_bus(sc->sc_tag, 0);
186		aprint_error_dev(sc->sc_dev, "cannot execute read\n");
187		return 0;
188	}
189	iic_release_bus(sc->sc_tag, 0);
190
191	return rv;
192}
193
194
195
196/* Get pressure in pascals. */
197static uint32_t
198mpl115a_pressure(struct mpl115a_softc *sc)
199{
200	uint32_t rv;
201
202	uint16_t padc, tadc;
203
204	rv = 0;
205
206	mpl115a_reg_write_1(sc, MPL115A_CONVERT, 1);
207	delay(20); /* even 3 should be enough */
208
209	padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB),
210	    mpl115a_reg_read_1(sc, MPL115A_PADC_LSB)); /* XXX, this fails */
211	padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB),
212	    mpl115a_reg_read_1(sc, MPL115A_PADC_LSB));
213
214	tadc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_TADC_MSB),
215	    mpl115a_reg_read_1(sc, MPL115A_TADC_LSB));
216
217#ifdef MPL115A_DEBUG
218	aprint_normal_dev(sc->sc_dev, "padc %x, tadc %x\n", padc, tadc);
219#endif /* MPL115A_DEBUG */
220
221	rv = mpl115a_calc(sc, padc, tadc);
222
223#ifdef MPL115A_DEBUG
224	aprint_normal_dev(sc->sc_dev, "%d Pa\n", rv);
225#endif /* MPL115A_DEBUG */
226
227	return rv;
228}
229
230/* The following calculation routine was suggested by Matt Thomas. */
231static uint32_t
232mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc)
233{
234	int32_t fp_a0, fp_b1, fp_b2, fp_c12, fp_padc, fp_tadc;
235	int32_t c12x2, a1, a1x2, y1, a2x2, pcomp;
236	uint32_t pre_kpa1, pre_kpa2, pa;
237
238	/* convert coefficients to common fixed point format */
239	fp_a0 = sc->sc_a0 << 13;	/* 12.3 -> 15.16 */
240	fp_b1 = sc->sc_b1 << 3;		/* 2.13 -> 15.16 */
241	fp_b2 = sc->sc_b2 << 2;		/* 1.14 -> 15.16 */
242	fp_c12 = sc->sc_c12 >> 2;	/* 0.22 */
243
244	fp_padc = padc >> 6;
245	fp_tadc = tadc >> 6;
246
247	c12x2 = (fp_c12 * fp_tadc + 0x3f) >> 6;
248	a1 = fp_b1 + c12x2;
249	a1x2 = a1 * fp_padc;
250	y1 = fp_a0 + a1x2;
251	a2x2 = fp_b2 * fp_tadc;
252	pcomp = y1 + a2x2;
253
254	/* pre_kpa has 16 fractional digits so it's accurate to 1/65536 kPa */
255	pre_kpa1 = pcomp * (115 - 50);
256	pre_kpa2 = pre_kpa1 / 1023 + (50 << 16);
257
258	/* but the real accuracy of the sensor is around +/- 1 kPa... */
259	pa = ((pre_kpa2 + 32768) >> 16) * 1000;
260
261	return pa;
262}
263
264static void
265mpl115a_envsys_register(struct mpl115a_softc *sc)
266{
267	sc->sc_sme = sysmon_envsys_create();
268
269	strlcpy(sc->sc_sensor.desc, "Absolute pressure",
270	    sizeof(sc->sc_sensor.desc));
271	/* sc->sc_sensor.units = ENVSYS_SPRESSURE; */
272	sc->sc_sensor.units = ENVSYS_INTEGER;
273	sc->sc_sensor.state = ENVSYS_SINVALID;
274
275	if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
276		aprint_error_dev(sc->sc_dev,
277		    "error attaching sensor\n");
278		return;
279	}
280
281	sc->sc_sme->sme_name = device_xname(sc->sc_dev);
282	sc->sc_sme->sme_cookie = sc;
283	sc->sc_sme->sme_refresh = mpl115a_envsys_refresh;
284
285	if (sysmon_envsys_register(sc->sc_sme)) {
286		aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n");
287		sysmon_envsys_destroy(sc->sc_sme);
288	}
289}
290
291static void
292mpl115a_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
293{
294	struct mpl115a_softc *sc = sme->sme_cookie;
295
296	mutex_enter(&sc->sc_lock);
297
298	edata->value_cur = mpl115a_pressure(sc);
299	edata->state = ENVSYS_SVALID;
300
301	mutex_exit(&sc->sc_lock);
302}
303
304