Source-Changes-HG archive
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
[src/trunk]: src/sys/dev/i2c Preliminary support for MPL115A2 pressure sensor...
details: https://anonhg.NetBSD.org/src/rev/5bc63bb6ebfe
branches: trunk
changeset: 789815:5bc63bb6ebfe
user: rkujawa <rkujawa%NetBSD.org@localhost>
date: Sun Sep 08 14:59:42 2013 +0000
description:
Preliminary support for MPL115A2 pressure sensor. It works, but accurracy is
awful.
I should add presure as a new type of sensor to envsys at some point...
diffstat:
sys/dev/i2c/files.i2c | 8 +-
sys/dev/i2c/mpl115a.c | 303 +++++++++++++++++++++++++++++++++++++++++++++++
sys/dev/i2c/mpl115areg.h | 51 +++++++
3 files changed, 361 insertions(+), 1 deletions(-)
diffs (truncated from 381 to 300 lines):
diff -r 5e6d99fc3338 -r 5bc63bb6ebfe sys/dev/i2c/files.i2c
--- a/sys/dev/i2c/files.i2c Sun Sep 08 14:27:39 2013 +0000
+++ b/sys/dev/i2c/files.i2c Sun Sep 08 14:59:42 2013 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: files.i2c,v 1.51 2013/09/06 00:56:12 matt Exp $
+# $NetBSD: files.i2c,v 1.52 2013/09/08 14:59:42 rkujawa Exp $
obsolete defflag opt_i2cbus.h I2C_SCAN
define i2cbus { }
@@ -198,3 +198,9 @@
device w83795g: gpiobus, sysmon_envsys, sysmon_wdog
attach w83795g at iic
file dev/i2c/w83795g.c w83795g
+
+# Freescale MPL115A2
+device mpl115a: sysmon_envsys
+attach mpl115a at iic
+file dev/i2c/mpl115a.c mpl115a
+
diff -r 5e6d99fc3338 -r 5bc63bb6ebfe sys/dev/i2c/mpl115a.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/dev/i2c/mpl115a.c Sun Sep 08 14:59:42 2013 +0000
@@ -0,0 +1,303 @@
+/* $NetBSD: mpl115a.c,v 1.1 2013/09/08 14:59:42 rkujawa Exp $ */
+
+/*-
+ * Copyright (c) 2013 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Radoslaw Kujawa.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Freescale MPL115A2 miniature digital barometer driver.
+ *
+ * This driver could be split into bus-indepented driver and I2C-specific
+ * attachment, as SPI variant of this chip also exist.
+ */
+
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: mpl115a.c,v 1.1 2013/09/08 14:59:42 rkujawa Exp $");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/kernel.h>
+#include <sys/mutex.h>
+#include <sys/endian.h>
+
+#include <sys/bus.h>
+#include <dev/i2c/i2cvar.h>
+
+#include <dev/sysmon/sysmonvar.h>
+
+#include <dev/i2c/mpl115areg.h>
+
+#define MPL115A_DEBUG 1
+
+struct mpl115a_softc {
+ device_t sc_dev;
+
+ i2c_tag_t sc_tag;
+ i2c_addr_t sc_addr;
+
+ /* raw coefficients */
+ int16_t sc_a0;
+ int16_t sc_b1;
+ int16_t sc_b2;
+ int16_t sc_c12;
+
+ /* envsys(4) stuff */
+ struct sysmon_envsys *sc_sme;
+ envsys_data_t sc_sensor;
+ kmutex_t sc_lock;
+};
+
+
+static int mpl115a_match(device_t, cfdata_t, void *);
+static void mpl115a_attach(device_t, device_t, void *);
+
+static uint8_t mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t);
+static void mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t, uint8_t);
+
+static void mpl115a_load_coeffs(struct mpl115a_softc *sc);
+static uint16_t mpl115a_make_coeff(uint8_t msb, uint8_t lsb);
+static uint32_t mpl115a_pressure(struct mpl115a_softc *sc);
+static uint32_t mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) ;
+
+static void mpl115a_envsys_register(struct mpl115a_softc *);
+static void mpl115a_envsys_refresh(struct sysmon_envsys *, envsys_data_t *);
+
+CFATTACH_DECL_NEW(mpl115a, sizeof (struct mpl115a_softc),
+ mpl115a_match, mpl115a_attach, NULL, NULL);
+
+static int
+mpl115a_match(device_t parent, cfdata_t cf, void *aux)
+{
+ struct i2c_attach_args *ia = aux;
+
+ if (ia->ia_addr == MPL115A_ADDR)
+ return 1;
+ return 0;
+}
+
+static void
+mpl115a_attach(device_t parent, device_t self, void *aux)
+{
+ struct mpl115a_softc *sc = device_private(self);
+ struct i2c_attach_args *ia = aux;
+
+ sc->sc_dev = self;
+ sc->sc_addr = ia->ia_addr;
+ sc->sc_tag = ia->ia_tag;
+
+ aprint_normal(": Freescale MPL115A2 Pressure Sensor\n");
+
+ /* Since coefficients do not change load them once. */
+ mpl115a_load_coeffs(sc);
+
+ mpl115a_pressure(sc);
+
+ mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
+
+ mpl115a_envsys_register(sc);
+}
+
+/* Construct a coefficients from MSB and LSB bytes. */
+static uint16_t
+mpl115a_make_coeff(uint8_t msb, uint8_t lsb)
+{
+ uint16_t rv;
+
+ rv = le16toh((msb << 8) | lsb);
+
+#ifdef MPL115A_DEBUG
+ aprint_normal("msb %x, lsb %x, ret val %x\n", msb, lsb, rv);
+#endif /* MPL115A_DEBUG */
+
+ return rv;
+}
+
+static void
+mpl115a_load_coeffs(struct mpl115a_softc *sc)
+{
+ sc->sc_a0 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_A0_MSB),
+ mpl115a_reg_read_1(sc, MPL115A_A0_LSB));
+ sc->sc_b1 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B1_MSB),
+ mpl115a_reg_read_1(sc, MPL115A_B1_LSB));
+ sc->sc_b2 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B2_MSB),
+ mpl115a_reg_read_1(sc, MPL115A_B2_LSB));
+ sc->sc_c12 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_C12_MSB),
+ mpl115a_reg_read_1(sc, MPL115A_C12_LSB));
+}
+
+static void
+mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t reg, uint8_t val)
+{
+ if (iic_acquire_bus(sc->sc_tag, I2C_F_POLL) != 0) {
+ aprint_error_dev(sc->sc_dev, "cannot acquire bus for write\n");
+ return;
+ }
+
+ if (iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr, ®, 1,
+ &val, 1, I2C_F_POLL)) {
+ aprint_error_dev(sc->sc_dev, "cannot execute write\n");
+ }
+ iic_release_bus(sc->sc_tag, I2C_F_POLL);
+}
+
+static uint8_t
+mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t reg)
+{
+ uint8_t rv, wbuf[2];
+
+ if (iic_acquire_bus(sc->sc_tag, I2C_F_POLL) != 0) {
+#ifdef MPL115A_DEBUG
+ aprint_error_dev(sc->sc_dev, "cannot acquire bus for read\n");
+#endif /* MPL115A_DEBUG */
+ return 0;
+ }
+
+ wbuf[0] = reg;
+
+ if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, wbuf,
+ 1, &rv, 1, I2C_F_POLL)) {
+ aprint_error_dev(sc->sc_dev, "cannot execute read\n");
+ iic_release_bus(sc->sc_tag, I2C_F_POLL);
+ return 0;
+ }
+ iic_release_bus(sc->sc_tag, I2C_F_POLL);
+
+ return rv;
+}
+
+
+
+/* Get pressure in pascals. */
+static uint32_t
+mpl115a_pressure(struct mpl115a_softc *sc)
+{
+ uint32_t rv;
+
+ uint16_t padc, tadc;
+
+ rv = 0;
+
+ mpl115a_reg_write_1(sc, MPL115A_CONVERT, 1);
+ delay(20); /* even 3 should be enough */
+
+ padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB),
+ mpl115a_reg_read_1(sc, MPL115A_PADC_LSB)); /* XXX, this fails */
+ padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB),
+ mpl115a_reg_read_1(sc, MPL115A_PADC_LSB));
+
+ tadc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_TADC_MSB),
+ mpl115a_reg_read_1(sc, MPL115A_TADC_LSB));
+
+#ifdef MPL115A_DEBUG
+ aprint_normal_dev(sc->sc_dev, "padc %x, tadc %x\n", padc, tadc);
+#endif /* MPL115A_DEBUG */
+
+ rv = mpl115a_calc(sc, padc, tadc);
+
+#ifdef MPL115A_DEBUG
+ aprint_normal_dev(sc->sc_dev, "%d Pa\n", rv);
+#endif /* MPL115A_DEBUG */
+
+ return rv;
+}
+
+/* The following calculation routine was suggested by Matt Thomas. */
+static uint32_t
+mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc)
+{
+ int32_t fp_a0, fp_b1, fp_b2, fp_c12, fp_padc, fp_tadc;
+ int32_t c12x2, a1, a1x2, y1, a2x2, pcomp;
+ uint32_t pre_kpa1, pre_kpa2, pa;
+
+ /* convert coefficients to common fixed point format */
+ fp_a0 = sc->sc_a0 << 13; /* 12.3 -> 15.16 */
+ fp_b1 = sc->sc_b1 << 3; /* 2.13 -> 15.16 */
+ fp_b2 = sc->sc_b2 << 2; /* 1.14 -> 15.16 */
+ fp_c12 = sc->sc_c12 >> 2; /* 0.22 */
+
+ fp_padc = padc >> 6;
+ fp_tadc = tadc >> 6;
+
+ c12x2 = (fp_c12 * fp_tadc + 0x3f) >> 6;
+ a1 = fp_b1 + c12x2;
+ a1x2 = a1 * fp_padc;
+ y1 = fp_a0 + a1x2;
+ a2x2 = fp_b2 * fp_tadc;
+ pcomp = y1 + a2x2;
+
+ /* pre_kpa has 16 fractional digits so it's accurate to 1/65536 kPa */
+ pre_kpa1 = pcomp * (115 - 50);
+ pre_kpa2 = pre_kpa1 / 1023 + (50 << 16);
+
+ /* but the real accuracy of the sensor is around +/- 1 kPa... */
+ pa = ((pre_kpa2 + 32768) >> 16) * 1000;
+
+ return pa;
+}
+
+static void
+mpl115a_envsys_register(struct mpl115a_softc *sc)
+{
+ sc->sc_sme = sysmon_envsys_create();
+
+ strlcpy(sc->sc_sensor.desc, "Absolute pressure",
+ sizeof(sc->sc_sensor.desc));
+ /* sc->sc_sensor.units = ENVSYS_SPRESSURE; */
+ sc->sc_sensor.units = ENVSYS_INTEGER;
+ sc->sc_sensor.state = ENVSYS_SINVALID;
+
+ if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
+ aprint_error_dev(sc->sc_dev,
+ "error attaching sensor\n");
Home |
Main Index |
Thread Index |
Old Index