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adc.c revision 1.8 
      1 /*	$NetBSD: adc.c,v 1.8 2008/03/27 00:23:40 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 1.8 2008/03/27 00:23:40 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 
     39 #include <sh3/adcreg.h>
     40 #include <sh3/dev/adcvar.h>
     41 
     42 #define ADC_(x)    (*((volatile uint8_t *)SH7709_AD ## x))
     43 
     44 
     45 static int	adc_match(device_t, struct cfdata *, void *);
     46 static void	adc_attach(device_t, device_t, void *);
     47 
     48 CFATTACH_DECL_NEW(adc, 0,
     49     adc_match, adc_attach, NULL, NULL);
     50 
     51 static int	adc_search(device_t, struct cfdata *, const int *, void *);
     52 static int	adc_print(void *, const char *);
     53 
     54 
     55 static int
     56 adc_match(device_t parent, struct cfdata *cfp, void *aux)
     57 {
     58 
     59 	/* REMINDER: also in 7727 and 7729 */
     60 	if ((cpu_product != CPU_PRODUCT_7709)
     61 	    && (cpu_product != CPU_PRODUCT_7709A))
     62 		return (0);
     63 
     64 	if (strcmp(cfp->cf_name, "adc") != 0)
     65 		return (0);
     66 
     67 	return (1);
     68 }
     69 
     70 
     71 static void
     72 adc_attach(device_t parent, device_t self, void *aux)
     73 {
     74 
     75 	ADC_(CSR) = 0;
     76 	ADC_(CR) = 0;
     77 
     78 	printf("\n");
     79 	config_search_ia(adc_search, self, "adc", NULL);
     80 }
     81 
     82 
     83 static int
     84 adc_search(device_t parent, struct cfdata *cf,
     85 	   const int *ldesc, void *aux)
     86 {
     87 
     88 	if (config_match(parent, cf, NULL) > 0)
     89 		config_attach(parent, cf, NULL, adc_print);
     90 
     91 	return (0);
     92 }
     93 
     94 
     95 static int
     96 adc_print(void *aux, const char *pnp)
     97 {
     98 
     99 	return (pnp ? QUIET : UNCONF);
    100 }
    101 
    102 
    103 /*
    104  * Sample specified ADC channel.
    105  * Must be called at spltty().
    106  */
    107 int
    108 adc_sample_channel(int chan)
    109 {
    110 	volatile uint8_t *hireg;
    111 	volatile uint8_t *loreg;
    112 	int regoff;
    113 	uint8_t csr;
    114 	int timo;
    115 #ifdef DIAGNOSTIC
    116 	uint8_t cr;
    117 	char bits[128];
    118 #endif
    119 	if ((chan < 0) || (chan >= 8))
    120 		return (-1);
    121 
    122 	regoff = (chan & 0x03) << 2;
    123 	hireg = (volatile uint8_t *)(SH7709_ADDRAH + regoff);
    124 	loreg = (volatile uint8_t *)(SH7709_ADDRAL + regoff);
    125 
    126 	/* the loop below typically takes 27 iterations on j680 */
    127 	timo = 300;
    128 
    129 #ifdef DIAGNOSTIC
    130 	csr = ADC_(CSR);
    131 	if ((csr & SH7709_ADCSR_ADST) != 0) {
    132 		/* another conversion is in progress?! */
    133 		printf("adc_sample_channel(%d): CSR=%s", chan,
    134 		       bitmask_snprintf(csr, SH7709_ADCSR_BITS,
    135 					bits, sizeof(bits)));
    136 		cr = ADC_(CR);
    137 		cr &= ~0x07;	/* three lower bits always read as 1s */
    138 		printf(", CR=%s\n",
    139 		       bitmask_snprintf(cr, SH7709_ADCR_BITS,
    140 					bits, sizeof(bits)));
    141 		return (-1);
    142 	}
    143 #endif
    144 
    145 	/* start scanning */
    146 	ADC_(CSR) = chan | SH7709_ADCSR_ADST | SH7709_ADCSR_CKS;
    147 
    148 	do {
    149 		csr = ADC_(CSR);
    150 		if (timo-- == 0)
    151 			break;
    152 	} while ((csr & SH7709_ADCSR_ADF) == 0);
    153 
    154 	/* stop scanning */
    155 	csr &= ~(SH7709_ADCSR_ADF | SH7709_ADCSR_ADST);
    156 	ADC_(CSR) = csr;
    157 
    158 	if (timo <= 0) {
    159 		printf("adc_sample_channel(%d): timed out\n", chan);
    160 		return (-1);
    161 	}
    162 
    163 	/*
    164 	 * 10 bit of data: bits [9..2] in the high register, bits
    165 	 * [1..0] in the bits [7..6] of the low register.
    166 	 */
    167 	return (((*hireg << 8) | *loreg) >> 6);
    168 }
    169