1/* $NetBSD: adc.c,v 1.12 2009/04/30 05:20:30 nonaka 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 1.12 2009/04/30 05:20:30 nonaka 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 45static int adc_match(device_t, cfdata_t, void *); 46static void adc_attach(device_t, device_t, void *); 47 48CFATTACH_DECL_NEW(adc, 0, 49 adc_match, adc_attach, NULL, NULL); 50 51static int adc_search(device_t, cfdata_t, const int *, void *); 52static int adc_print(void *, const char *); 53 54 55static int 56adc_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 72static void 73adc_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 95static int 96adc_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 106static int 107adc_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 */ 118int 119adc_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(bits), 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(bits), 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} 178