sys/arch/sh3/dev/adc.c

   1 /*      $NetBSD: adc.c,v 1.11 2009/04/05 00:22:27 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 1.11 2009/04/05 00:22:27 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, cfdata_t, 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, cfdata_t, const int *, void *);
  52 static int      adc_print(void *, const char *);
  53
  54
  55 static int
  56 adc_match(device_t parent, cfdata_t cf, 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             && (cpu_product != CPU_PRODUCT_7706))
  63                 return (0);
  64
  65         if (strcmp(cf->cf_name, "adc") != 0)
  66                 return (0);
  67
  68         return (1);
  69 }
  70
  71
  72 static void
  73 adc_attach(device_t parent, device_t self, void *aux)
  74 {
  75
  76         ADC_(CSR) = 0;
  77         ADC_(CR) = 0;
  78
  79         aprint_naive("\n");
  80         aprint_normal("\n");
  81
  82         config_search_ia(adc_search, self, "adc", NULL);
  83
  84         /*
  85          * XXX: TODO: provide hooks to manage power.  For now register
  86          * null hooks which is no worse than before.
  87          *
  88          * NB: ADC registers are reset by standby!
  89          */
  90         if (!pmf_device_register(self, NULL, NULL))
  91                 aprint_error_dev(self, "unable to establish power handler\n");
  92 }
  93
  94
  95 static int
  96 adc_search(device_t parent, cfdata_t cf, const int *ldesc, void *aux)
  97 {
  98
  99         if (config_match(parent, cf, NULL) > 0)
 100                 config_attach(parent, cf, NULL, adc_print);
 101
 102         return (0);
 103 }
 104
 105
 106 static int
 107 adc_print(void *aux, const char *pnp)
 108 {
 109
 110         return (pnp ? QUIET : UNCONF);
 111 }
 112
 113
 114 /*
 115  * Sample specified ADC channel.
 116  * Must be called at spltty().
 117  */
 118 int
 119 adc_sample_channel(int chan)
 120 {
 121         volatile uint8_t *hireg;
 122         volatile uint8_t *loreg;
 123         int regoff;
 124         uint8_t csr;
 125         int timo;
 126 #ifdef DIAGNOSTIC
 127         uint8_t cr;
 128         char bits[128];
 129 #endif
 130         if ((chan < 0) || (chan >= 8))
 131                 return (-1);
 132
 133         regoff = (chan & 0x03) << 2;
 134         hireg = (volatile uint8_t *)(SH7709_ADDRAH + regoff);
 135         loreg = (volatile uint8_t *)(SH7709_ADDRAL + regoff);
 136
 137         /* the loop below typically takes 27 iterations on j680 */
 138         timo = 300;
 139
 140 #ifdef DIAGNOSTIC
 141         csr = ADC_(CSR);
 142         if ((csr & SH7709_ADCSR_ADST) != 0) {
 143                 /* another conversion is in progress?! */
 144                 snprintb(bits, sizeof(buts), SH7709_ADCSR_BITS, csr);
 145                 printf("adc_sample_channel(%d): CSR=%s", chan, bits);
 146                 cr = ADC_(CR);
 147                 cr &= ~0x07;    /* three lower bits always read as 1s */
 148                 snprintb(bits, sizeof(buts), SH7709_ADCR_BITS, cr);
 149                 printf(", CR=%s\n", bits);
 150                 return (-1);
 151         }
 152 #endif
 153
 154         /* start scanning */
 155         ADC_(CSR) = chan | SH7709_ADCSR_ADST | SH7709_ADCSR_CKS;
 156
 157         do {
 158                 csr = ADC_(CSR);
 159                 if (timo-- == 0)
 160                         break;
 161         } while ((csr & SH7709_ADCSR_ADF) == 0);
 162
 163         /* stop scanning */
 164         csr &= ~(SH7709_ADCSR_ADF | SH7709_ADCSR_ADST);
 165         ADC_(CSR) = csr;
 166
 167         if (timo <= 0) {
 168                 printf("adc_sample_channel(%d): timed out\n", chan);
 169                 return (-1);
 170         }
 171
 172         /*
 173          * 10 bit of data: bits [9..2] in the high register, bits
 174          * [1..0] in the bits [7..6] of the low register.
 175          */
 176         return (((*hireg << 8) | *loreg) >> 6);
 177 }