/*      $NetBSD: mcp48x1.c,v 1.3 2022/01/19 05:21:44 thorpej Exp $ */

/*-
* Copyright (c) 2014 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mcp48x1.c,v 1.3 2022/01/19 05:21:44 thorpej Exp $");

/*
* Driver for Microchip MCP4801/MCP4811/MCP4821 DAC.
*
* XXX: needs more testing.
*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/sysctl.h>

#include <dev/sysmon/sysmonvar.h>

#include <dev/spi/spivar.h>

#define MCP48X1DAC_DEBUG 0

#define MCP48X1DAC_WRITE        __BIT(15)       /* active low */
#define MCP48X1DAC_GAIN         __BIT(13)       /* active low */
#define MCP48X1DAC_SHDN         __BIT(12)       /* active low */
#define MCP48X1DAC_DATA         __BITS(11,0)    /* data */

struct mcp48x1dac_model {
       const char *name;
       uint8_t resolution;
       uint8_t shift;                  /* data left shift during write */
};

struct mcp48x1dac_softc {
       device_t sc_dev;
       struct spi_handle *sc_sh;

       struct mcp48x1dac_model *sc_dm; /* struct describing DAC model */

       uint16_t sc_dac_data;
       bool sc_dac_gain;
       bool sc_dac_shutdown;

       struct sysmon_envsys *sc_sme;
       envsys_data_t sc_sm_vo;         /* envsys "sensor" (Vo) */
};

static int      mcp48x1dac_match(device_t, cfdata_t, void *);
static void     mcp48x1dac_attach(device_t, device_t, void *);

static bool     mcp48x1dac_envsys_attach(struct mcp48x1dac_softc *sc);
static void     mcp48x1dac_envsys_refresh(struct sysmon_envsys *,
                   envsys_data_t *);

static void     mcp48x1dac_write(struct mcp48x1dac_softc *);
static uint16_t mcp48x1dac_regval_to_mv(struct mcp48x1dac_softc *);

static void     mcp48x1dac_setup_sysctl(struct mcp48x1dac_softc *sc);
static int      sysctl_mcp48x1dac_data(SYSCTLFN_ARGS);
static int      sysctl_mcp48x1dac_gain(SYSCTLFN_ARGS);

CFATTACH_DECL_NEW(mcp48x1dac, sizeof(struct mcp48x1dac_softc),
   mcp48x1dac_match, mcp48x1dac_attach, NULL, NULL);

static struct mcp48x1dac_model mcp48x1_models[] = {
       {
               .name = "MCP4801",
               .resolution = 8,
               .shift = 4
       },
       {
               .name = "MCP4811",
               .resolution = 10,
               .shift = 2
       },
       {
               .name = "MCP4821",
               .resolution = 12,
               .shift = 0
       }
};


static int
mcp48x1dac_match(device_t parent, cfdata_t cf, void *aux)
{

       /* MCP48x1 is a write-only device, so no way to detect it! */

       return 1;
}

static void
mcp48x1dac_attach(device_t parent, device_t self, void *aux)
{
       struct mcp48x1dac_softc *sc;
       struct spi_attach_args *sa;
       int error, cf_flags;

       aprint_naive(": Digital to Analog converter\n");
       aprint_normal(": MCP48x1 DAC\n");

       sa = aux;
       sc = device_private(self);
       sc->sc_dev = self;
       sc->sc_sh = sa->sa_handle;
       cf_flags = device_cfdata(sc->sc_dev)->cf_flags;

       sc->sc_dm = &mcp48x1_models[cf_flags]; /* flag value defines model */

       error = spi_configure(self, sa->sa_handle, SPI_MODE_0, 20000000);
       if (error) {
               return;
       }

       if(!mcp48x1dac_envsys_attach(sc)) {
               aprint_error_dev(sc->sc_dev, "failed to attach envsys\n");
               return;
       };

       sc->sc_dac_data = 0;
       sc->sc_dac_gain = false;
       sc->sc_dac_shutdown = false;
       mcp48x1dac_write(sc);

       mcp48x1dac_setup_sysctl(sc);
}

static void
mcp48x1dac_write(struct mcp48x1dac_softc *sc)
{
       int rv;
       uint16_t reg, regbe;

       reg = 0;

       if (!(sc->sc_dac_gain))
               reg |= MCP48X1DAC_GAIN;

       if (!(sc->sc_dac_shutdown))
               reg |= MCP48X1DAC_SHDN;

       reg |= sc->sc_dac_data << sc->sc_dm->shift;

       regbe = htobe16(reg);

#ifdef MCP48X1DAC_DEBUG
       aprint_normal_dev(sc->sc_dev, "sending %x over SPI\n", regbe);
#endif /* MCP48X1DAC_DEBUG */

       rv = spi_send(sc->sc_sh, 2, (uint8_t*) &regbe); /* XXX: ugly cast */

       if (rv != 0)
               aprint_error_dev(sc->sc_dev, "error sending data over SPI\n");
}

static bool
mcp48x1dac_envsys_attach(struct mcp48x1dac_softc *sc)
{

       sc->sc_sme = sysmon_envsys_create();
       sc->sc_sm_vo.units = ENVSYS_SVOLTS_DC;
       sc->sc_sm_vo.state = ENVSYS_SINVALID;
       strlcpy(sc->sc_sm_vo.desc, device_xname(sc->sc_dev),
           sizeof(sc->sc_sm_vo.desc));
       if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sm_vo)) {
               sysmon_envsys_destroy(sc->sc_sme);
               return false;
       }

       sc->sc_sme->sme_name = device_xname(sc->sc_dev);
       sc->sc_sme->sme_refresh = mcp48x1dac_envsys_refresh;
       sc->sc_sme->sme_cookie = sc;

       if (sysmon_envsys_register(sc->sc_sme)) {
               aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n");
               sysmon_envsys_destroy(sc->sc_sme);
       }

       return true;
}

static uint16_t
mcp48x1dac_regval_to_mv(struct mcp48x1dac_softc *sc)
{
       uint16_t mv;

       mv = (2048 * sc->sc_dac_data / (1 << sc->sc_dm->resolution));

       if (sc->sc_dac_gain)
               mv *= 2;

       return mv;
}

static void
mcp48x1dac_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
{
       struct mcp48x1dac_softc *sc;

       sc = sme->sme_cookie;

       edata->value_cur = mcp48x1dac_regval_to_mv(sc);
       edata->state = ENVSYS_SVALID;
}

static void
mcp48x1dac_setup_sysctl(struct mcp48x1dac_softc *sc)
{
       const struct sysctlnode *me = NULL, *node = NULL;

       sysctl_createv(NULL, 0, NULL, &me,
           CTLFLAG_READWRITE,
           CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
           NULL, 0, NULL, 0,
           CTL_MACHDEP, CTL_CREATE, CTL_EOL);

       sysctl_createv(NULL, 0, NULL, &node,
           CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
           CTLTYPE_INT, "data", "Digital value to convert to analog",
           sysctl_mcp48x1dac_data, 1, (void *)sc, 0,
           CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL);

       sysctl_createv(NULL, 0, NULL, &node,
           CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
           CTLTYPE_INT, "gain", "Gain 2x enable",
           sysctl_mcp48x1dac_gain, 1, (void *)sc, 0,
           CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL);

}


SYSCTL_SETUP(sysctl_mcp48x1dac_setup, "sysctl mcp48x1dac subtree setup")
{
       sysctl_createv(NULL, 0, NULL, NULL, CTLFLAG_PERMANENT,
           CTLTYPE_NODE, "machdep", NULL, NULL, 0, NULL, 0,
           CTL_MACHDEP, CTL_EOL);
}


static int
sysctl_mcp48x1dac_data(SYSCTLFN_ARGS)
{
       struct sysctlnode node = *rnode;
       struct mcp48x1dac_softc *sc = node.sysctl_data;
       int newdata, err;

       node.sysctl_data = &sc->sc_dac_data;
       if ((err = (sysctl_lookup(SYSCTLFN_CALL(&node)))) != 0)
               return err;

       if (newp) {
               newdata = *(int *)node.sysctl_data;
               if (newdata > (1 << sc->sc_dm->resolution))
                       return EINVAL;
               sc->sc_dac_data = (uint16_t) newdata;
               mcp48x1dac_write(sc);
               return 0;
       } else {
               /* nothing to do, since we can't read from DAC */
               node.sysctl_size = 4;
       }

       return err;
}

static int
sysctl_mcp48x1dac_gain(SYSCTLFN_ARGS)
{
       struct sysctlnode node = *rnode;
       struct mcp48x1dac_softc *sc = node.sysctl_data;
       int newgain, err;

       node.sysctl_data = &sc->sc_dac_gain;
       if ((err = (sysctl_lookup(SYSCTLFN_CALL(&node)))) != 0)
               return err;

       if (newp) {
               newgain = *(int *)node.sysctl_data;
               sc->sc_dac_gain = (bool) newgain;
               mcp48x1dac_write(sc);
               return 0;
       } else {
               /* nothing to do, since we can't read from DAC */
               node.sysctl_size = 4;
       }

       return err;
}

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.