321 lines
8.0 KiB
C
321 lines
8.0 KiB
C
/* $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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