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adc.c revision 1.3 
      1 /*	$NetBSD: adc.c,v 1.3 2003/10/22 23:52:46 uwe Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2003 Valeriy E. Ushakov
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. The name of the author may not be used to endorse or promote products
     16  *    derived from this software without specific prior written permission
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 #include <sys/cdefs.h>
     31 __KERNEL_RCSID(0, "$NetBSD: adc.c,v 1.3 2003/10/22 23:52:46 uwe Exp $");
     32 
     33 #include <sys/param.h>
     34 #include <sys/kernel.h>
     35 #include <sys/device.h>
     36 #include <sys/malloc.h>
     37 #include <sys/systm.h>
     38 #ifdef GPROF
     39 #include <sys/gmon.h>
     40 #endif
     41 
     42 #include <sh3/adcreg.h>
     43 #include <sh3/dev/adcvar.h>
     44 
     45 #define ADC_(x)    (*((volatile uint8_t *)SH7709_AD ## x))
     46 
     47 
     48 struct adc_softc {
     49 	struct device sc_dev;
     50 };
     51 
     52 static int	adc_match(struct device *, struct cfdata *, void *);
     53 static void	adc_attach(struct device *, struct device *, void *);
     54 
     55 CFATTACH_DECL(adc, sizeof(struct adc_softc),
     56     adc_match, adc_attach, NULL, NULL);
     57 
     58 static int	adc_search(struct device *, struct cfdata *, void *);
     59 static int	adc_print(void *, const char *);
     60 
     61 
     62 static int
     63 adc_match(struct device *parent, struct cfdata *cfp, void *aux)
     64 {
     65 
     66 	/* REMINDER: also in 7727 and 7729 */
     67 	if ((cpu_product != CPU_PRODUCT_7709)
     68 	    && (cpu_product != CPU_PRODUCT_7709A))
     69 		return (0);
     70 
     71 	if (strcmp(cfp->cf_name, "adc") != 0)
     72 		return (0);
     73 
     74 	return (1);
     75 }
     76 
     77 
     78 static void
     79 adc_attach(struct device *parent, struct device *self, void *aux)
     80 {
     81 	/* struct adc_softc *sc = (struct adc_softc *)self; */
     82 
     83 	ADC_(CSR) = 0;
     84 	ADC_(CR) = 0;
     85 
     86 	printf("\n");
     87 	config_search(adc_search, self, NULL);
     88 }
     89 
     90 
     91 static int
     92 adc_search(struct device *parent, struct cfdata *cf, void *aux)
     93 {
     94 
     95 	if (config_match(parent, cf, NULL) > 0)
     96 		config_attach(parent, cf, NULL, adc_print);
     97 
     98 	return (0);
     99 }
    100 
    101 
    102 static int
    103 adc_print(void *aux, const char *pnp)
    104 {
    105 
    106 	return (pnp ? QUIET : UNCONF);
    107 }
    108 
    109 
    110 /*
    111  * Sample specified ADC channel.
    112  * Must be called at spltty().
    113  */
    114 int
    115 adc_sample_channel(int chan)
    116 {
    117 	volatile uint8_t *hireg;
    118 	volatile uint8_t *loreg;
    119 	int regoff;
    120 	uint8_t csr;
    121 	int timo;
    122 #ifdef DIAGNOSTIC
    123 	uint8_t cr;
    124 	char bits[128];
    125 #endif
    126 	if ((chan < 0) || (chan >= 8))
    127 		return (-1);
    128 
    129 	regoff = (chan & 0x03) << 2;
    130 	hireg = (volatile uint8_t *)(SH7709_ADDRAH + regoff);
    131 	loreg = (volatile uint8_t *)(SH7709_ADDRAL + regoff);
    132 
    133 	/* the loop below typically takes 27 iterations on j680 */
    134 	timo = 300;
    135 
    136 #ifdef DIAGNOSTIC
    137 	csr = ADC_(CSR);
    138 	if ((csr & SH7709_ADCSR_ADST) != 0) {
    139 		/* another conversion is in progress?! */
    140 		printf("adc_sample_channel(%d): CSR=%s", chan,
    141 		       bitmask_snprintf(csr, SH7709_ADCSR_BITS,
    142 					bits, sizeof(bits)));
    143 		cr = ADC_(CR);
    144 		cr &= ~0x07;	/* three lower bits always read as 1s */
    145 		printf(", CR=%s\n",
    146 		       bitmask_snprintf(cr, SH7709_ADCR_BITS,
    147 					bits, sizeof(bits)));
    148 		return (-1);
    149 	}
    150 #endif
    151 
    152 	/* start scanning */
    153 	ADC_(CSR) = chan | SH7709_ADCSR_ADST | SH7709_ADCSR_CKS;
    154 
    155 	do {
    156 		csr = ADC_(CSR);
    157 		if (timo-- == 0)
    158 			break;
    159 	} while ((csr & SH7709_ADCSR_ADF) == 0);
    160 
    161 	/* stop scanning */
    162 	csr &= ~(SH7709_ADCSR_ADF | SH7709_ADCSR_ADST);
    163 	ADC_(CSR) = csr;
    164 
    165 	if (timo <= 0) {
    166 		printf("adc_sample_channel(%d): timed out\n", chan);
    167 		return (-1);
    168 	}
    169 
    170 	/*
    171 	 * 10 bit of data: bits [9..2] in the high register, bits
    172 	 * [1..0] in the bits [7..6] of the low register.
    173 	 */
    174 	return (((*hireg << 8) | *loreg) >> 6);
    175 }
    176