Driver for analog->digital converter in sh7709.
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uwe
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/* $NetBSD: adc.c,v 1.1 2003/10/18 01:27:18 uwe Exp $ */
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/*
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* Copyright (c) 2003 Valeriy E. Ushakov
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* All rights reserved.
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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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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/device.h>
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#include <sys/malloc.h>
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#include <sys/systm.h>
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#ifdef GPROF
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#include <sys/gmon.h>
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#endif
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#include <sh3/adcreg.h>
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#define ADC_(x) (*((volatile uint8_t *)SH7709_AD ## x))
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struct adc_softc {
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struct device sc_dev;
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};
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static int adc_match(struct device *, struct cfdata *, void *);
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static void adc_attach(struct device *, struct device *, void *);
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CFATTACH_DECL(adc, sizeof(struct adc_softc),
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adc_match, adc_attach, NULL, NULL);
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static int adc_search(struct device *, struct cfdata *, void *);
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static int adc_print(void *, const char *);
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extern int adc_sample_channel(int); /* XXX: adcvar.h */
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static int
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adc_match(struct device *parent, struct cfdata *cfp, void *aux)
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{
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/* REMINDER: also in 7727 and 7729 */
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if ((cpu_product != CPU_PRODUCT_7709)
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&& (cpu_product != CPU_PRODUCT_7709A))
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return (0);
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if (strcmp(cfp->cf_name, "adc") != 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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adc_attach(struct device *parent, struct device *self, void *aux)
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{
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/* struct adc_softc *sc = (struct adc_softc *)self; */
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ADC_(CSR) = 0;
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ADC_(CR) = 0;
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printf("\n");
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config_search(adc_search, self, NULL);
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}
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static int
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adc_search(struct device *parent, struct cfdata *cf, void *aux)
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{
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if (config_match(parent, cf, NULL) > 0)
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config_attach(parent, cf, NULL, adc_print);
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return (0);
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}
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static int
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adc_print(void *aux, const char *pnp)
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{
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return (pnp ? QUIET : UNCONF);
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}
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/*
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* Sample specified ADC channel.
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* Must be called at spltty().
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*/
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int
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adc_sample_channel(int chan)
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{
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volatile uint8_t *hireg;
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volatile uint8_t *loreg;
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int regoff;
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uint8_t csr;
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int timo;
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#ifdef DIAGNOSTIC
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uint8_t cr;
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char bits[128];
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#endif
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if ((chan < 0) || (chan >= 8))
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return (-1);
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regoff = (chan & 0x03) << 2;
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hireg = (volatile uint8_t *)(SH7709_ADDRAH + regoff);
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loreg = (volatile uint8_t *)(SH7709_ADDRAL + regoff);
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/* the loop below typically takes 27 iterations on j680 */
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timo = 300;
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#ifdef DIAGNOSTIC
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csr = ADC_(CSR);
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if ((csr & SH7709_ADCSR_ADST) != 0) {
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/* another conversion is in progress?! */
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printf("adc_sample_channel(%d): CSR=%s", chan,
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bitmask_snprintf(csr, SH7709_ADCSR_BITS,
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bits, sizeof(bits)));
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cr = ADC_(CR);
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cr &= ~0x07; /* three lower bits always read as 1s */
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printf(", CR=%s\n",
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bitmask_snprintf(cr, SH7709_ADCR_BITS,
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bits, sizeof(bits)));
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return (-1);
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}
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#endif
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/* start scanning */
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ADC_(CSR) = chan | SH7709_ADCSR_ADST | SH7709_ADCSR_CKS;
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do {
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csr = ADC_(CSR);
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if (timo-- == 0)
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break;
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} while ((csr & SH7709_ADCSR_ADF) == 0);
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/* stop scanning */
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csr &= ~(SH7709_ADCSR_ADF | SH7709_ADCSR_ADST);
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ADC_(CSR) = csr;
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if (timo <= 0) {
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printf("adc_sample_channel(%d): timed out\n", chan);
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return (-1);
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}
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/*
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* 10 bit of data: bits [9..2] in the high register, bits
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* [1..0] in the bits [7..6] of the low register.
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*/
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return (((*hireg << 8) | *loreg) >> 6);
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}
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