Add preliminary driver for Microchip MCP48x1 family of DACs.
Needs more testing and an appropriate API for such (non-audio) DACs. For now one can set the output value using sysctl node. Also sysmon(4) will conveniently report the voltage on Vout pin of the DAC. Note that this is not an actual measured voltage, but merely calculated using equation from datasheet. Real voltage might be different and depend on analog circuitry attached to the DAC.
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rkujawa
parent
f7ca730905
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21a43d7204
@ -1,4 +1,4 @@
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# $NetBSD: files.spi,v 1.2 2006/10/07 07:21:13 gdamore Exp $
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# $NetBSD: files.spi,v 1.3 2014/02/25 20:09:37 rkujawa Exp $
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define spibus { }
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@ -25,3 +25,9 @@ file dev/spi/m25p.c m25p
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device tmp121temp: sysmon_envsys
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attach tmp121temp at spi
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file dev/spi/tmp121.c tmp121temp
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# MCP48x1 DAC
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device mcp48x1dac
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attach mcp48x1dac at spi
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file dev/spi/mcp48x1.c mcp48x1dac
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320
sys/dev/spi/mcp48x1.c
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320
sys/dev/spi/mcp48x1.c
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@ -0,0 +1,320 @@
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/* $NetBSD: mcp48x1.c,v 1.1 2014/02/25 20:09:37 rkujawa Exp $ */
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/*-
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* Copyright (c) 2014 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Radoslaw Kujawa.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: mcp48x1.c,v 1.1 2014/02/25 20:09:37 rkujawa Exp $");
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/*
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* Driver for Microchip MCP4801/MCP4811/MCP4821 DAC.
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*
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* XXX: needs more testing.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/device.h>
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#include <sys/kernel.h>
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#include <sys/types.h>
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#include <sys/sysctl.h>
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#include <dev/sysmon/sysmonvar.h>
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#include <dev/spi/spivar.h>
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#define MCP48X1DAC_DEBUG 0
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#define MCP48X1DAC_WRITE __BIT(15) /* active low */
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#define MCP48X1DAC_GAIN __BIT(13) /* active low */
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#define MCP48X1DAC_SHDN __BIT(12) /* active low */
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#define MCP48X1DAC_DATA __BITS(11,0) /* data */
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struct mcp48x1dac_model {
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const char *name;
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uint8_t resolution;
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uint8_t shift; /* data left shift during write */
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};
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struct mcp48x1dac_softc {
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device_t sc_dev;
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struct spi_handle *sc_sh;
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struct mcp48x1dac_model *sc_dm; /* struct describing DAC model */
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uint16_t sc_dac_data;
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bool sc_dac_gain;
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bool sc_dac_shutdown;
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struct sysmon_envsys *sc_sme;
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envsys_data_t sc_sm_vo; /* envsys "sensor" (Vo) */
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};
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static int mcp48x1dac_match(device_t, cfdata_t, void *);
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static void mcp48x1dac_attach(device_t, device_t, void *);
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static bool mcp48x1dac_envsys_attach(struct mcp48x1dac_softc *sc);
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static void mcp48x1dac_envsys_refresh(struct sysmon_envsys *,
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envsys_data_t *);
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static void mcp48x1dac_write(struct mcp48x1dac_softc *);
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static uint16_t mcp48x1dac_regval_to_mv(struct mcp48x1dac_softc *);
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static void mcp48x1dac_setup_sysctl(struct mcp48x1dac_softc *sc);
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static int sysctl_mcp48x1dac_data(SYSCTLFN_ARGS);
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static int sysctl_mcp48x1dac_gain(SYSCTLFN_ARGS);
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CFATTACH_DECL_NEW(mcp48x1dac, sizeof(struct mcp48x1dac_softc),
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mcp48x1dac_match, mcp48x1dac_attach, NULL, NULL);
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static struct mcp48x1dac_model mcp48x1_models[] = {
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{
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.name = "MCP4801",
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.resolution = 8,
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.shift = 4
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},
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{
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.name = "MCP4811",
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.resolution = 10,
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.shift = 2
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},
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{
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.name = "MCP4821",
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.resolution = 12,
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.shift = 0
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}
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};
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static int
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mcp48x1dac_match(device_t parent, cfdata_t cf, void *aux)
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{
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struct spi_attach_args *sa = aux;
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/* MCP48x1 is a write-only device, so no way to detect it! */
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if (spi_configure(sa->sa_handle, SPI_MODE_0, 20000000))
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return 0;
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return 1;
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}
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static void
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mcp48x1dac_attach(device_t parent, device_t self, void *aux)
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{
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struct mcp48x1dac_softc *sc;
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struct spi_attach_args *sa;
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int cf_flags;
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aprint_naive(": Digital to Analog converter\n");
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aprint_normal(": MCP48x1 DAC\n");
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sa = aux;
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sc = device_private(self);
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sc->sc_dev = self;
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sc->sc_sh = sa->sa_handle;
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cf_flags = device_cfdata(sc->sc_dev)->cf_flags;
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sc->sc_dm = &mcp48x1_models[cf_flags]; /* flag value defines model */
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if(!mcp48x1dac_envsys_attach(sc)) {
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aprint_error_dev(sc->sc_dev, "failed to attach envsys\n");
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return;
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};
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sc->sc_dac_data = 0;
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sc->sc_dac_gain = false;
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sc->sc_dac_shutdown = false;
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mcp48x1dac_write(sc);
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mcp48x1dac_setup_sysctl(sc);
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}
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static void
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mcp48x1dac_write(struct mcp48x1dac_softc *sc)
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{
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int rv;
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uint16_t reg, regbe;
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reg = 0;
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if (!(sc->sc_dac_gain))
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reg |= MCP48X1DAC_GAIN;
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if (!(sc->sc_dac_shutdown))
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reg |= MCP48X1DAC_SHDN;
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reg |= sc->sc_dac_data << sc->sc_dm->shift;
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regbe = htobe16(reg);
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#ifdef MCP48X1DAC_DEBUG
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aprint_normal_dev(sc->sc_dev, "sending %x over SPI\n", regbe);
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#endif /* MCP48X1DAC_DEBUG */
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rv = spi_send(sc->sc_sh, 2, (uint8_t*) ®be); /* XXX: ugly cast */
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if (rv != 0)
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aprint_error_dev(sc->sc_dev, "error sending data over SPI\n");
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}
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static bool
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mcp48x1dac_envsys_attach(struct mcp48x1dac_softc *sc)
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{
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sc->sc_sme = sysmon_envsys_create();
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sc->sc_sm_vo.units = ENVSYS_SVOLTS_DC;
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sc->sc_sm_vo.state = ENVSYS_SINVALID;
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strlcpy(sc->sc_sm_vo.desc, device_xname(sc->sc_dev),
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sizeof(sc->sc_sm_vo.desc));
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if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sm_vo)) {
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sysmon_envsys_destroy(sc->sc_sme);
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return false;
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}
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sc->sc_sme->sme_name = device_xname(sc->sc_dev);
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sc->sc_sme->sme_refresh = mcp48x1dac_envsys_refresh;
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sc->sc_sme->sme_cookie = sc;
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if (sysmon_envsys_register(sc->sc_sme)) {
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aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n");
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sysmon_envsys_destroy(sc->sc_sme);
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}
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return true;
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}
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static uint16_t
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mcp48x1dac_regval_to_mv(struct mcp48x1dac_softc *sc)
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{
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uint16_t mv;
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mv = (2048 * sc->sc_dac_data / (1 << sc->sc_dm->resolution));
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if (sc->sc_dac_gain)
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mv *= 2;
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return mv;
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}
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static void
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mcp48x1dac_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
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{
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struct mcp48x1dac_softc *sc;
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sc = sme->sme_cookie;
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edata->value_cur = mcp48x1dac_regval_to_mv(sc);
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edata->state = ENVSYS_SVALID;
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}
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static void
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mcp48x1dac_setup_sysctl(struct mcp48x1dac_softc *sc)
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{
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const struct sysctlnode *me = NULL, *node = NULL;
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sysctl_createv(NULL, 0, NULL, &me,
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CTLFLAG_READWRITE,
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CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
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NULL, 0, NULL, 0,
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CTL_MACHDEP, CTL_CREATE, CTL_EOL);
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sysctl_createv(NULL, 0, NULL, &node,
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CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
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CTLTYPE_INT, "data", "Digital value to convert to analog",
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sysctl_mcp48x1dac_data, 1, (void *)sc, 0,
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CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL);
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sysctl_createv(NULL, 0, NULL, &node,
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CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
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CTLTYPE_INT, "gain", "Gain 2x enable",
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sysctl_mcp48x1dac_gain, 1, (void *)sc, 0,
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CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL);
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}
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SYSCTL_SETUP(sysctl_mcp48x1dac_setup, "sysctl mcp48x1dac subtree setup")
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{
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sysctl_createv(NULL, 0, NULL, NULL, CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "machdep", NULL, NULL, 0, NULL, 0,
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CTL_MACHDEP, CTL_EOL);
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}
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static int
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sysctl_mcp48x1dac_data(SYSCTLFN_ARGS)
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{
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struct sysctlnode node = *rnode;
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struct mcp48x1dac_softc *sc = node.sysctl_data;
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int newdata, err;
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node.sysctl_data = &sc->sc_dac_data;
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if ((err = (sysctl_lookup(SYSCTLFN_CALL(&node)))) != 0)
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return err;
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if (newp) {
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newdata = *(int *)node.sysctl_data;
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if (newdata > (1 << sc->sc_dm->resolution))
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return EINVAL;
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sc->sc_dac_data = (uint16_t) newdata;
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mcp48x1dac_write(sc);
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return 0;
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} else {
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/* nothing to do, since we can't read from DAC */
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node.sysctl_size = 4;
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}
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return err;
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}
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static int
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sysctl_mcp48x1dac_gain(SYSCTLFN_ARGS)
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{
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struct sysctlnode node = *rnode;
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struct mcp48x1dac_softc *sc = node.sysctl_data;
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int newgain, err;
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node.sysctl_data = &sc->sc_dac_gain;
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if ((err = (sysctl_lookup(SYSCTLFN_CALL(&node)))) != 0)
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return err;
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if (newp) {
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newgain = *(int *)node.sysctl_data;
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sc->sc_dac_gain = (bool) newgain;
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mcp48x1dac_write(sc);
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return 0;
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} else {
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/* nothing to do, since we can't read from DAC */
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node.sysctl_size = 4;
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}
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return err;
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}
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