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NetBSD/sys/dev/spi/mcp3k.c

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/* $NetBSD: mcp3k.c,v 1.2 2016/11/20 12:38:04 phx 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)
{
struct spi_attach_args *sa = aux;
if (strcmp(cf->cf_name, "mcp3kadc") != 0)
return 0;
/* configure for 1MHz */
if (spi_configure(sa->sa_handle, SPI_MODE_0, 1000000))
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 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);
/* 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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