1 /* $NetBSD: adc.c,v 1.14 2021/04/24 23:36:48 thorpej 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 1.14 2021/04/24 23:36:48 thorpej 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(self, NULL, 83 CFARG_SEARCH, adc_search, 84 CFARG_EOL); 85 86 /* 87 * XXX: TODO: provide hooks to manage power. For now register 88 * null hooks which is no worse than before. 89 * 90 * NB: ADC registers are reset by standby! 91 */ 92 if (!pmf_device_register(self, NULL, NULL)) 93 aprint_error_dev(self, "unable to establish power handler\n"); 94 } 95 96 97 static int 98 adc_search(device_t parent, cfdata_t cf, const int *ldesc, void *aux) 99 { 100 101 if (config_probe(parent, cf, NULL)) 102 config_attach(parent, cf, NULL, adc_print, CFARG_EOL); 103 104 return (0); 105 } 106 107 108 static int 109 adc_print(void *aux, const char *pnp) 110 { 111 112 return (pnp ? QUIET : UNCONF); 113 } 114 115 116 /* 117 * Sample specified ADC channel. 118 * Must be called at spltty(). 119 */ 120 int 121 adc_sample_channel(int chan) 122 { 123 volatile uint8_t *hireg; 124 volatile uint8_t *loreg; 125 int regoff; 126 uint8_t csr; 127 int timo; 128 #ifdef DIAGNOSTIC 129 uint8_t cr; 130 char bits[128]; 131 #endif 132 if ((chan < 0) || (chan >= 8)) 133 return (-1); 134 135 regoff = (chan & 0x03) << 2; 136 hireg = (volatile uint8_t *)(SH7709_ADDRAH + regoff); 137 loreg = (volatile uint8_t *)(SH7709_ADDRAL + regoff); 138 139 /* the loop below typically takes 27 iterations on j680 */ 140 timo = 300; 141 142 #ifdef DIAGNOSTIC 143 csr = ADC_(CSR); 144 if ((csr & SH7709_ADCSR_ADST) != 0) { 145 /* another conversion is in progress?! */ 146 snprintb(bits, sizeof(bits), SH7709_ADCSR_BITS, csr); 147 printf("adc_sample_channel(%d): CSR=%s", chan, bits); 148 cr = ADC_(CR); 149 cr &= ~0x07; /* three lower bits always read as 1s */ 150 snprintb(bits, sizeof(bits), SH7709_ADCR_BITS, cr); 151 printf(", CR=%s\n", bits); 152 return (-1); 153 } 154 #endif 155 156 /* start scanning */ 157 ADC_(CSR) = chan | SH7709_ADCSR_ADST | SH7709_ADCSR_CKS; 158 159 do { 160 csr = ADC_(CSR); 161 if (timo-- == 0) 162 break; 163 } while ((csr & SH7709_ADCSR_ADF) == 0); 164 165 /* stop scanning */ 166 csr &= ~(SH7709_ADCSR_ADF | SH7709_ADCSR_ADST); 167 ADC_(CSR) = csr; 168 169 if (timo <= 0) { 170 printf("adc_sample_channel(%d): timed out\n", chan); 171 return (-1); 172 } 173 174 /* 175 * 10 bit of data: bits [9..2] in the high register, bits 176 * [1..0] in the bits [7..6] of the low register. 177 */ 178 return (((*hireg << 8) | *loreg) >> 6); 179 } 180