370 lines
9.7 KiB
C
370 lines
9.7 KiB
C
/* $NetBSD: mcp3k.c,v 1.4 2022/01/19 05:21:44 thorpej Exp $ */
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/*-
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* Copyright (c) 2015 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 Frank Wille.
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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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/*
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* Microchip MCP3x0x SAR analog to digital converters.
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* The driver supports various ADCs with different resolutions, operation
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* modes and number of input channels.
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* The reference voltage Vref defaults to the maximum output value in mV,
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* but can be changed via sysctl(3).
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*
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* MCP3001: http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf
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* MCP3002: http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf
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* MCP3004/3008: http://ww1.microchip.com/downloads/en/DeviceDoc/21295C.pdf
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* MCP3201: http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf
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* MCP3204/3208: http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf
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* MCP3301: http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf
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* MPC3302/3304: http://ww1.microchip.com/downloads/en/DeviceDoc/21697F.pdf
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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 M3K_MAX_SENSORS 16 /* 8 single-ended & 8 diff. */
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/* mcp3x0x model description */
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struct mcp3kadc_model {
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uint32_t name;
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uint8_t bits;
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uint8_t channels;
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uint8_t lead; /* leading bits to ignore */
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uint8_t flags;
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#define M3K_SGLDIFF 0x01 /* single-ended/differential */
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#define M3K_D2D1D0 0x02 /* 3 channel select bits */
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#define M3K_MSBF 0x04 /* MSBF select bit */
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#define M3K_SIGNED 0x80 /* result is signed */
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#define M3K_CTRL_NEEDED (M3K_SGLDIFF | M3K_D2D1D0 | M3K_MSBF)
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};
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struct mcp3kadc_softc {
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device_t sc_dev;
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struct spi_handle *sc_sh;
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int sc_model;
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uint32_t sc_adc_max;
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int32_t sc_vref_mv;
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struct sysmon_envsys *sc_sme;
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envsys_data_t sc_sensors[M3K_MAX_SENSORS];
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};
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static int mcp3kadc_match(device_t, cfdata_t, void *);
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static void mcp3kadc_attach(device_t, device_t, void *);
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static void mcp3kadc_envsys_refresh(struct sysmon_envsys *,
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envsys_data_t *);
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static int sysctl_mcp3kadc_vref(SYSCTLFN_ARGS);
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CFATTACH_DECL_NEW(mcp3kadc, sizeof(struct mcp3kadc_softc),
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mcp3kadc_match, mcp3kadc_attach, NULL, NULL);
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static struct mcp3kadc_model mcp3k_models[] = {
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{
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.name = 3001,
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.bits = 10,
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.channels = 1,
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.lead = 3,
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.flags = 0
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},
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{
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.name = 3002,
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.bits = 10,
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.channels = 2,
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.lead = 2,
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.flags = M3K_SGLDIFF | M3K_MSBF
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},
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{
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.name = 3004,
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.bits = 10,
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.channels = 4,
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.lead = 2,
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.flags = M3K_SGLDIFF | M3K_D2D1D0
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},
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{
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.name = 3008,
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.bits = 10,
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.channels = 8,
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.lead = 2,
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.flags = M3K_SGLDIFF | M3K_D2D1D0
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},
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{
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.name = 3201,
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.bits = 12,
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.channels = 1,
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.lead = 3,
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.flags = 0
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},
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{
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.name = 3202,
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.bits = 12,
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.channels = 2,
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.lead = 2,
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.flags = M3K_SGLDIFF | M3K_MSBF
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},
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{
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.name = 3204,
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.bits = 12,
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.channels = 4,
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.lead = 2,
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.flags = M3K_SGLDIFF | M3K_D2D1D0
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},
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{
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.name = 3208,
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.bits = 12,
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.channels = 8,
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.lead = 2,
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.flags = M3K_SGLDIFF | M3K_D2D1D0
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},
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{
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.name = 3301,
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.bits = 13,
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.channels = 1,
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.lead = 3,
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.flags = M3K_SIGNED
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},
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{
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.name = 3302,
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.bits = 13,
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.channels = 4,
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.lead = 2,
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.flags = M3K_SIGNED | M3K_SGLDIFF | M3K_D2D1D0
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},
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{
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.name = 3304,
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.bits = 13,
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.channels = 8,
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.lead = 2,
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.flags = M3K_SIGNED | M3K_SGLDIFF | M3K_D2D1D0
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},
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};
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static int
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mcp3kadc_match(device_t parent, cfdata_t cf, void *aux)
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{
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if (strcmp(cf->cf_name, "mcp3kadc") != 0)
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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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mcp3kadc_attach(device_t parent, device_t self, void *aux)
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{
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const struct sysctlnode *rnode, *node;
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struct spi_attach_args *sa;
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struct mcp3kadc_softc *sc;
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struct mcp3kadc_model *model;
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int error, ch, i;
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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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/* device flags define the model */
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sc->sc_model = device_cfdata(sc->sc_dev)->cf_flags;
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model = &mcp3k_models[sc->sc_model];
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aprint_naive(": Analog to Digital converter\n");
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aprint_normal(": MCP%u %u-channel %u-bit ADC\n",
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(unsigned)model->name, (unsigned)model->channels,
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(unsigned)model->bits);
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/* configure for 1MHz */
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error = spi_configure(self, sa->sa_handle, SPI_MODE_0, 1000000);
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if (error) {
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return;
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}
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/* set a default Vref in mV according to the chip's ADC resolution */
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sc->sc_vref_mv = 1 << ((model->flags & M3K_SIGNED) ?
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model->bits - 1 : model->bits);
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/* remember maximum value for this ADC - also used for masking */
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sc->sc_adc_max = (1 << model->bits) - 1;
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/* attach voltage sensors to envsys */
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sc->sc_sme = sysmon_envsys_create();
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/* adc difference from two neighbouring channels */
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for (ch = 0; ch < model->channels; ch++) {
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KASSERT(ch < M3K_MAX_SENSORS);
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sc->sc_sensors[ch].units = ENVSYS_SVOLTS_DC;
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sc->sc_sensors[ch].state = ENVSYS_SINVALID;
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if (model->channels == 1)
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strlcpy(sc->sc_sensors[ch].desc, "adc diff ch0",
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sizeof(sc->sc_sensors[ch].desc));
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else
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snprintf(sc->sc_sensors[ch].desc,
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sizeof(sc->sc_sensors[ch].desc),
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"adc diff ch%d-ch%d", ch, ch ^ 1);
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sc->sc_sensors[ch].private = ch;
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sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensors[ch]);
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}
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if (model->flags & M3K_SGLDIFF) {
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/* adc from single ended channels */
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for (i = 0; i < model->channels; i++, ch++) {
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KASSERT(ch < M3K_MAX_SENSORS);
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sc->sc_sensors[ch].units = ENVSYS_SVOLTS_DC;
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sc->sc_sensors[ch].state = ENVSYS_SINVALID;
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snprintf(sc->sc_sensors[ch].desc,
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sizeof(sc->sc_sensors[ch].desc),
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"adc single ch%d", i);
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sc->sc_sensors[ch].private = ch;
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sysmon_envsys_sensor_attach(sc->sc_sme,
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&sc->sc_sensors[ch]);
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}
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}
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sc->sc_sme->sme_name = device_xname(self);
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sc->sc_sme->sme_refresh = mcp3kadc_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(self, "unable to register with sysmon\n");
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sysmon_envsys_destroy(sc->sc_sme);
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}
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/* create a sysctl node for adjusting the ADC's reference voltage */
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rnode = node = NULL;
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sysctl_createv(NULL, 0, NULL, &rnode,
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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_HW, CTL_CREATE, CTL_EOL);
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if (rnode != NULL)
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sysctl_createv(NULL, 0, NULL, &node,
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CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
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CTLTYPE_INT, "vref",
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SYSCTL_DESCR("ADC reference voltage"),
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sysctl_mcp3kadc_vref, 0, (void *)sc, 0,
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CTL_HW, rnode->sysctl_num, CTL_CREATE, CTL_EOL);
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}
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static void
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mcp3kadc_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
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{
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struct mcp3kadc_softc *sc;
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struct mcp3kadc_model *model;
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uint8_t buf[2], ctrl;
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int32_t val, scale;
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sc = sme->sme_cookie;
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model = &mcp3k_models[sc->sc_model];
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scale = sc->sc_adc_max + 1;
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if (model->flags & M3K_CTRL_NEEDED) {
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/* we need to send some control bits first */
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ctrl = 1; /* start bit */
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if (model->flags & M3K_SGLDIFF) {
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/* bit set to select single-ended mode */
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ctrl <<= 1;
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ctrl |= edata->private >= model->channels;
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}
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if (model->flags & M3K_D2D1D0) {
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/* 3 bits select the channel */
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ctrl <<= 3;
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ctrl |= edata->private & (model->channels - 1);
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} else {
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/* 1 bit selects between two channels */
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ctrl <<= 1;
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ctrl |= edata->private & 1;
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}
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if (model->flags & M3K_MSBF) {
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/* bit select MSB first format */
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ctrl <<= 1;
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ctrl |= 1;
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}
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/* send control bits, receive ADC data */
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if (spi_send_recv(sc->sc_sh, 1, &ctrl, 2, buf) != 0) {
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edata->state = ENVSYS_SINVALID;
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return;
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}
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} else {
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/* just read data from the ADC */
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if (spi_recv(sc->sc_sh, 2, buf) != 0) {
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edata->state = ENVSYS_SINVALID;
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return;
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}
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}
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/* extract big-endian ADC data from buffer */
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val = (buf[0] << 8) | buf[1];
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val = (val >> (16 - (model->bits + model->lead))) & sc->sc_adc_max;
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/* sign-extend the result, when needed */
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if (model->flags & M3K_SIGNED) {
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if (val & (1 << (model->bits - 1)))
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val -= sc->sc_adc_max + 1;
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scale >>= 1; /* MSB is the sign */
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}
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/* scale the value for Vref and convert to mV */
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edata->value_cur = (sc->sc_vref_mv * val / scale) * 1000;
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edata->state = ENVSYS_SVALID;
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}
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static int
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sysctl_mcp3kadc_vref(SYSCTLFN_ARGS)
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{
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struct sysctlnode node;
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struct mcp3kadc_softc *sc;
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int32_t t;
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int error;
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node = *rnode;
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sc = node.sysctl_data;
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t = sc->sc_vref_mv;
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node.sysctl_data = &t;
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error = sysctl_lookup(SYSCTLFN_CALL(&node));
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if (error || newp == NULL)
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return error;
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if (t <= 0)
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return EINVAL;
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sc->sc_vref_mv = t;
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return 0;
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}
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