arch/mips/sibyte/swarm/rtc_xicor1241.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2000, 2001 Broadcom Corporation
   4  *
   5  * Copyright (C) 2002 MontaVista Software Inc.
   6  * Author: jsun@mvista.com or jsun@junsun.net
   7  */
   8 #include <linux/bcd.h>
   9 #include <linux/types.h>
  10 #include <linux/time.h>
  11
  12 #include <asm/time.h>
  13 #include <asm/addrspace.h>
  14 #include <asm/io.h>
  15
  16 #include <asm/sibyte/sb1250.h>
  17 #include <asm/sibyte/sb1250_regs.h>
  18 #include <asm/sibyte/sb1250_smbus.h>
  19
  20
  21 /* Xicor 1241 definitions */
  22
  23 /*
  24  * Register bits
  25  */
  26
  27 #define X1241REG_SR_BAT 0x80            /* currently on battery power */
  28 #define X1241REG_SR_RWEL 0x04           /* r/w latch is enabled, can write RTC */
  29 #define X1241REG_SR_WEL 0x02            /* r/w latch is unlocked, can enable r/w now */
  30 #define X1241REG_SR_RTCF 0x01           /* clock failed */
  31 #define X1241REG_BL_BP2 0x80            /* block protect 2 */
  32 #define X1241REG_BL_BP1 0x40            /* block protect 1 */
  33 #define X1241REG_BL_BP0 0x20            /* block protect 0 */
  34 #define X1241REG_BL_WD1 0x10
  35 #define X1241REG_BL_WD0 0x08
  36 #define X1241REG_HR_MIL 0x80            /* military time format */
  37
  38 /*
  39  * Register numbers
  40  */
  41
  42 #define X1241REG_BL     0x10            /* block protect bits */
  43 #define X1241REG_INT    0x11            /*  */
  44 #define X1241REG_SC     0x30            /* Seconds */
  45 #define X1241REG_MN     0x31            /* Minutes */
  46 #define X1241REG_HR     0x32            /* Hours */
  47 #define X1241REG_DT     0x33            /* Day of month */
  48 #define X1241REG_MO     0x34            /* Month */
  49 #define X1241REG_YR     0x35            /* Year */
  50 #define X1241REG_DW     0x36            /* Day of Week */
  51 #define X1241REG_Y2K    0x37            /* Year 2K */
  52 #define X1241REG_SR     0x3F            /* Status register */
  53
  54 #define X1241_CCR_ADDRESS       0x6F
  55
  56 #define SMB_CSR(reg)    IOADDR(A_SMB_REGISTER(1, reg))
  57
  58 static int xicor_read(uint8_t addr)
  59 {
  60         while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
  61                 ;
  62
  63         __raw_writeq((addr >> 8) & 0x7, SMB_CSR(R_SMB_CMD));
  64         __raw_writeq(addr & 0xff, SMB_CSR(R_SMB_DATA));
  65         __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR2BYTE,
  66                      SMB_CSR(R_SMB_START));
  67
  68         while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
  69                 ;
  70
  71         __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_RD1BYTE,
  72                      SMB_CSR(R_SMB_START));
  73
  74         while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
  75                 ;
  76
  77         if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
  78                 /* Clear error bit by writing a 1 */
  79                 __raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
  80                 return -1;
  81         }
  82
  83         return __raw_readq(SMB_CSR(R_SMB_DATA)) & 0xff;
  84 }
  85
  86 static int xicor_write(uint8_t addr, int b)
  87 {
  88         while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
  89                 ;
  90
  91         __raw_writeq(addr, SMB_CSR(R_SMB_CMD));
  92         __raw_writeq((addr & 0xff) | ((b & 0xff) << 8), SMB_CSR(R_SMB_DATA));
  93         __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR3BYTE,
  94                      SMB_CSR(R_SMB_START));
  95
  96         while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
  97                 ;
  98
  99         if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
 100                 /* Clear error bit by writing a 1 */
 101                 __raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
 102                 return -1;
 103         } else {
 104                 return 0;
 105         }
 106 }
 107
 108 int xicor_set_time(time64_t t)
 109 {
 110         struct rtc_time tm;
 111         int tmp;
 112         unsigned long flags;
 113
 114         rtc_time64_to_tm(t, &tm);
 115         tm.tm_year += 1900;
 116
 117         spin_lock_irqsave(&rtc_lock, flags);
 118         /* unlock writes to the CCR */
 119         xicor_write(X1241REG_SR, X1241REG_SR_WEL);
 120         xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);
 121
 122         /* trivial ones */
 123         tm.tm_sec = bin2bcd(tm.tm_sec);
 124         xicor_write(X1241REG_SC, tm.tm_sec);
 125
 126         tm.tm_min = bin2bcd(tm.tm_min);
 127         xicor_write(X1241REG_MN, tm.tm_min);
 128
 129         tm.tm_mday = bin2bcd(tm.tm_mday);
 130         xicor_write(X1241REG_DT, tm.tm_mday);
 131
 132         /* tm_mon starts from 0, *ick* */
 133         tm.tm_mon ++;
 134         tm.tm_mon = bin2bcd(tm.tm_mon);
 135         xicor_write(X1241REG_MO, tm.tm_mon);
 136
 137         /* year is split */
 138         tmp = tm.tm_year / 100;
 139         tm.tm_year %= 100;
 140         xicor_write(X1241REG_YR, tm.tm_year);
 141         xicor_write(X1241REG_Y2K, tmp);
 142
 143         /* hour is the most tricky one */
 144         tmp = xicor_read(X1241REG_HR);
 145         if (tmp & X1241REG_HR_MIL) {
 146                 /* 24 hour format */
 147                 tm.tm_hour = bin2bcd(tm.tm_hour);
 148                 tmp = (tmp & ~0x3f) | (tm.tm_hour & 0x3f);
 149         } else {
 150                 /* 12 hour format, with 0x2 for pm */
 151                 tmp = tmp & ~0x3f;
 152                 if (tm.tm_hour >= 12) {
 153                         tmp |= 0x20;
 154                         tm.tm_hour -= 12;
 155                 }
 156                 tm.tm_hour = bin2bcd(tm.tm_hour);
 157                 tmp |= tm.tm_hour;
 158         }
 159         xicor_write(X1241REG_HR, tmp);
 160
 161         xicor_write(X1241REG_SR, 0);
 162         spin_unlock_irqrestore(&rtc_lock, flags);
 163
 164         return 0;
 165 }
 166
 167 time64_t xicor_get_time(void)
 168 {
 169         unsigned int year, mon, day, hour, min, sec, y2k;
 170         unsigned long flags;
 171
 172         spin_lock_irqsave(&rtc_lock, flags);
 173         sec = xicor_read(X1241REG_SC);
 174         min = xicor_read(X1241REG_MN);
 175         hour = xicor_read(X1241REG_HR);
 176
 177         if (hour & X1241REG_HR_MIL) {
 178                 hour &= 0x3f;
 179         } else {
 180                 if (hour & 0x20)
 181                         hour = (hour & 0xf) + 0x12;
 182         }
 183
 184         day = xicor_read(X1241REG_DT);
 185         mon = xicor_read(X1241REG_MO);
 186         year = xicor_read(X1241REG_YR);
 187         y2k = xicor_read(X1241REG_Y2K);
 188         spin_unlock_irqrestore(&rtc_lock, flags);
 189
 190         sec = bcd2bin(sec);
 191         min = bcd2bin(min);
 192         hour = bcd2bin(hour);
 193         day = bcd2bin(day);
 194         mon = bcd2bin(mon);
 195         year = bcd2bin(year);
 196         y2k = bcd2bin(y2k);
 197
 198         year += (y2k * 100);
 199
 200         return mktime64(year, mon, day, hour, min, sec);
 201 }
 202
 203 int xicor_probe(void)
 204 {
 205         return xicor_read(X1241REG_SC) != -1;
 206 }