/*      $NetBSD: mcp3k.c,v 1.4 2022/01/19 05:21:44 thorpej Exp $ */

/*-
* Copyright (c) 2015 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Frank Wille.
*
* 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.
*/

/*
* Microchip MCP3x0x SAR analog to digital converters.
* The driver supports various ADCs with different resolutions, operation
* modes and number of input channels.
* The reference voltage Vref defaults to the maximum output value in mV,
* but can be changed via sysctl(3).
*
* MCP3001: http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf
* MCP3002: http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf
* MCP3004/3008: http://ww1.microchip.com/downloads/en/DeviceDoc/21295C.pdf
* MCP3201: http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf
* MCP3204/3208: http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf
* MCP3301: http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf
* MPC3302/3304: http://ww1.microchip.com/downloads/en/DeviceDoc/21697F.pdf
*/

#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 M3K_MAX_SENSORS         16              /* 8 single-ended & 8 diff. */

/* mcp3x0x model description */
struct mcp3kadc_model {
       uint32_t                name;
       uint8_t                 bits;
       uint8_t                 channels;
       uint8_t                 lead;           /* leading bits to ignore */
       uint8_t                 flags;
#define M3K_SGLDIFF             0x01            /* single-ended/differential */
#define M3K_D2D1D0              0x02            /* 3 channel select bits */
#define M3K_MSBF                0x04            /* MSBF select bit */
#define M3K_SIGNED              0x80            /* result is signed */
#define M3K_CTRL_NEEDED         (M3K_SGLDIFF | M3K_D2D1D0 | M3K_MSBF)
};

struct mcp3kadc_softc {
       device_t                sc_dev;
       struct spi_handle       *sc_sh;
       int                     sc_model;
       uint32_t                sc_adc_max;
       int32_t                 sc_vref_mv;

       struct sysmon_envsys    *sc_sme;
       envsys_data_t           sc_sensors[M3K_MAX_SENSORS];
};

static int      mcp3kadc_match(device_t, cfdata_t, void *);
static void     mcp3kadc_attach(device_t, device_t, void *);
static void     mcp3kadc_envsys_refresh(struct sysmon_envsys *,
                   envsys_data_t *);
static int      sysctl_mcp3kadc_vref(SYSCTLFN_ARGS);

CFATTACH_DECL_NEW(mcp3kadc, sizeof(struct mcp3kadc_softc),
   mcp3kadc_match,  mcp3kadc_attach, NULL, NULL);

static struct mcp3kadc_model mcp3k_models[] = {
       {
               .name = 3001,
               .bits = 10,
               .channels = 1,
               .lead = 3,
               .flags = 0
       },
       {
               .name = 3002,
               .bits = 10,
               .channels = 2,
               .lead = 2,
               .flags = M3K_SGLDIFF | M3K_MSBF
       },
       {
               .name = 3004,
               .bits = 10,
               .channels = 4,
               .lead = 2,
               .flags = M3K_SGLDIFF | M3K_D2D1D0
       },
       {
               .name = 3008,
               .bits = 10,
               .channels = 8,
               .lead = 2,
               .flags = M3K_SGLDIFF | M3K_D2D1D0
       },
       {
               .name = 3201,
               .bits = 12,
               .channels = 1,
               .lead = 3,
               .flags = 0
       },
       {
               .name = 3202,
               .bits = 12,
               .channels = 2,
               .lead = 2,
               .flags = M3K_SGLDIFF | M3K_MSBF
       },
       {
               .name = 3204,
               .bits = 12,
               .channels = 4,
               .lead = 2,
               .flags = M3K_SGLDIFF | M3K_D2D1D0
       },
       {
               .name = 3208,
               .bits = 12,
               .channels = 8,
               .lead = 2,
               .flags = M3K_SGLDIFF | M3K_D2D1D0
       },
       {
               .name = 3301,
               .bits = 13,
               .channels = 1,
               .lead = 3,
               .flags = M3K_SIGNED
       },
       {
               .name = 3302,
               .bits = 13,
               .channels = 4,
               .lead = 2,
               .flags = M3K_SIGNED | M3K_SGLDIFF | M3K_D2D1D0
       },
       {
               .name = 3304,
               .bits = 13,
               .channels = 8,
               .lead = 2,
               .flags = M3K_SIGNED | M3K_SGLDIFF | M3K_D2D1D0
       },
};

static int
mcp3kadc_match(device_t parent, cfdata_t cf, void *aux)
{

       if (strcmp(cf->cf_name, "mcp3kadc") != 0)
               return 0;

       return 1;
}

static void
mcp3kadc_attach(device_t parent, device_t self, void *aux)
{
       const struct sysctlnode *rnode, *node;
       struct spi_attach_args *sa;
       struct mcp3kadc_softc *sc;
       struct mcp3kadc_model *model;
       int error, ch, i;

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

       /* device flags define the model */
       sc->sc_model = device_cfdata(sc->sc_dev)->cf_flags;
       model = &mcp3k_models[sc->sc_model];

       aprint_naive(": Analog to Digital converter\n");
       aprint_normal(": MCP%u %u-channel %u-bit ADC\n",
           (unsigned)model->name, (unsigned)model->channels,
           (unsigned)model->bits);

       /* configure for 1MHz */
       error = spi_configure(self, sa->sa_handle, SPI_MODE_0, 1000000);
       if (error) {
               return;
       }

       /* set a default Vref in mV according to the chip's ADC resolution */
       sc->sc_vref_mv = 1 << ((model->flags & M3K_SIGNED) ?
           model->bits - 1 : model->bits);

       /* remember maximum value for this ADC - also used for masking */
       sc->sc_adc_max = (1 << model->bits) - 1;

       /* attach voltage sensors to envsys */
       sc->sc_sme = sysmon_envsys_create();

       /* adc difference from two neighbouring channels */
       for (ch = 0; ch < model->channels; ch++) {
               KASSERT(ch < M3K_MAX_SENSORS);
               sc->sc_sensors[ch].units = ENVSYS_SVOLTS_DC;
               sc->sc_sensors[ch].state = ENVSYS_SINVALID;
               if (model->channels == 1)
                       strlcpy(sc->sc_sensors[ch].desc, "adc diff ch0",
                           sizeof(sc->sc_sensors[ch].desc));
               else
                       snprintf(sc->sc_sensors[ch].desc,
                           sizeof(sc->sc_sensors[ch].desc),
                           "adc diff ch%d-ch%d", ch, ch ^ 1);
               sc->sc_sensors[ch].private = ch;
               sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensors[ch]);
       }

       if (model->flags & M3K_SGLDIFF) {
               /* adc from single ended channels */
               for (i = 0; i < model->channels; i++, ch++) {
                       KASSERT(ch < M3K_MAX_SENSORS);
                       sc->sc_sensors[ch].units = ENVSYS_SVOLTS_DC;
                       sc->sc_sensors[ch].state = ENVSYS_SINVALID;
                       snprintf(sc->sc_sensors[ch].desc,
                           sizeof(sc->sc_sensors[ch].desc),
                           "adc single ch%d", i);
                       sc->sc_sensors[ch].private = ch;
                       sysmon_envsys_sensor_attach(sc->sc_sme,
                           &sc->sc_sensors[ch]);
               }
       }

       sc->sc_sme->sme_name = device_xname(self);
       sc->sc_sme->sme_refresh = mcp3kadc_envsys_refresh;
       sc->sc_sme->sme_cookie = sc;
       if (sysmon_envsys_register(sc->sc_sme)) {
               aprint_error_dev(self, "unable to register with sysmon\n");
               sysmon_envsys_destroy(sc->sc_sme);
       }

       /* create a sysctl node for adjusting the ADC's reference voltage */
       rnode = node = NULL;
       sysctl_createv(NULL, 0, NULL, &rnode,
           CTLFLAG_READWRITE,
           CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
           NULL, 0, NULL, 0,
           CTL_HW, CTL_CREATE, CTL_EOL);

       if (rnode != NULL)
               sysctl_createv(NULL, 0, NULL, &node,
                   CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
                   CTLTYPE_INT, "vref",
                   SYSCTL_DESCR("ADC reference voltage"),
                   sysctl_mcp3kadc_vref, 0, (void *)sc, 0,
                   CTL_HW, rnode->sysctl_num, CTL_CREATE, CTL_EOL);
}

static void
mcp3kadc_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
{
       struct mcp3kadc_softc *sc;
       struct mcp3kadc_model *model;
       uint8_t buf[2], ctrl;
       int32_t val, scale;

       sc = sme->sme_cookie;
       model = &mcp3k_models[sc->sc_model];
       scale = sc->sc_adc_max + 1;

       if (model->flags & M3K_CTRL_NEEDED) {
               /* we need to send some control bits first */
               ctrl = 1;       /* start bit */

               if (model->flags & M3K_SGLDIFF) {
                       /* bit set to select single-ended mode */
                       ctrl <<= 1;
                       ctrl |= edata->private >= model->channels;
               }

               if (model->flags & M3K_D2D1D0) {
                       /* 3 bits select the channel */
                       ctrl <<= 3;
                       ctrl |= edata->private & (model->channels - 1);
               } else {
                       /* 1 bit selects between two channels */
                       ctrl <<= 1;
                       ctrl |= edata->private & 1;
               }

               if (model->flags & M3K_MSBF) {
                       /* bit select MSB first format */
                       ctrl <<= 1;
                       ctrl |= 1;
               }

               /* send control bits, receive ADC data */
               if (spi_send_recv(sc->sc_sh, 1, &ctrl, 2, buf) != 0) {
                       edata->state = ENVSYS_SINVALID;
                       return;
               }
       } else {

               /* just read data from the ADC */
               if (spi_recv(sc->sc_sh, 2, buf) != 0) {
                       edata->state = ENVSYS_SINVALID;
                       return;
               }
       }

       /* extract big-endian ADC data from buffer */
       val = (buf[0] << 8) | buf[1];
       val = (val >> (16 - (model->bits + model->lead))) & sc->sc_adc_max;

       /* sign-extend the result, when needed */
       if (model->flags & M3K_SIGNED) {
               if (val & (1 << (model->bits - 1)))
                       val -= sc->sc_adc_max + 1;
               scale >>= 1;    /* MSB is the sign */
       }

       /* scale the value for Vref and convert to mV */
       edata->value_cur = (sc->sc_vref_mv * val / scale) * 1000;
       edata->state = ENVSYS_SVALID;
}

static int
sysctl_mcp3kadc_vref(SYSCTLFN_ARGS)
{
       struct sysctlnode node;
       struct mcp3kadc_softc *sc;
       int32_t t;
       int error;

       node = *rnode;
       sc = node.sysctl_data;

       t = sc->sc_vref_mv;
       node.sysctl_data = &t;

       error = sysctl_lookup(SYSCTLFN_CALL(&node));
       if (error || newp == NULL)
               return error;
       if (t <= 0)
               return EINVAL;

       sc->sc_vref_mv = t;
       return 0;
}

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