release/src-rt-6.x/linux/linux-2.6/arch/mips/tx4938/common/rtc_rx5c348.c

   1 /*
   2  * RTC routines for RICOH Rx5C348 SPI chip.
   3  * Copyright (C) 2000-2001 Toshiba Corporation
   4  *
   5  * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
   6  * terms of the GNU General Public License version 2. This program is
   7  * licensed "as is" without any warranty of any kind, whether express
   8  * or implied.
   9  *
  10  * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
  11  */
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/rtc.h>
  16 #include <linux/time.h>
  17 #include <linux/bcd.h>
  18 #include <asm/time.h>
  19 #include <asm/tx4938/spi.h>
  20
  21 #define EPOCH           2000
  22
  23 /* registers */
  24 #define Rx5C348_REG_SECOND      0
  25 #define Rx5C348_REG_MINUTE      1
  26 #define Rx5C348_REG_HOUR        2
  27 #define Rx5C348_REG_WEEK        3
  28 #define Rx5C348_REG_DAY 4
  29 #define Rx5C348_REG_MONTH       5
  30 #define Rx5C348_REG_YEAR        6
  31 #define Rx5C348_REG_ADJUST      7
  32 #define Rx5C348_REG_ALARM_W_MIN 8
  33 #define Rx5C348_REG_ALARM_W_HOUR        9
  34 #define Rx5C348_REG_ALARM_W_WEEK        10
  35 #define Rx5C348_REG_ALARM_D_MIN 11
  36 #define Rx5C348_REG_ALARM_D_HOUR        12
  37 #define Rx5C348_REG_CTL1        14
  38 #define Rx5C348_REG_CTL2        15
  39
  40 /* register bits */
  41 #define Rx5C348_BIT_PM  0x20    /* REG_HOUR */
  42 #define Rx5C348_BIT_Y2K 0x80    /* REG_MONTH */
  43 #define Rx5C348_BIT_24H 0x20    /* REG_CTL1 */
  44 #define Rx5C348_BIT_XSTP        0x10    /* REG_CTL2 */
  45
  46 /* commands */
  47 #define Rx5C348_CMD_W(addr)     (((addr) << 4) | 0x08)  /* single write */
  48 #define Rx5C348_CMD_R(addr)     (((addr) << 4) | 0x0c)  /* single read */
  49 #define Rx5C348_CMD_MW(addr)    (((addr) << 4) | 0x00)  /* burst write */
  50 #define Rx5C348_CMD_MR(addr)    (((addr) << 4) | 0x04)  /* burst read */
  51
  52 static struct spi_dev_desc srtc_dev_desc = {
  53         .baud           = 1000000,      /* 1.0Mbps @ Vdd 2.0V */
  54         .tcss           = 31,
  55         .tcsh           = 1,
  56         .tcsr           = 62,
  57         /* 31us for Tcss (62us for Tcsr) is required for carry operation) */
  58         .byteorder      = 1,            /* MSB-First */
  59         .polarity       = 0,            /* High-Active */
  60         .phase          = 1,            /* Shift-Then-Sample */
  61
  62 };
  63 static int srtc_chipid;
  64 static int srtc_24h;
  65
  66 static inline int
  67 spi_rtc_io(unsigned char *inbuf, unsigned char *outbuf, unsigned int count)
  68 {
  69         unsigned char *inbufs[1], *outbufs[1];
  70         unsigned int incounts[2], outcounts[2];
  71         inbufs[0] = inbuf;
  72         incounts[0] = count;
  73         incounts[1] = 0;
  74         outbufs[0] = outbuf;
  75         outcounts[0] = count;
  76         outcounts[1] = 0;
  77         return txx9_spi_io(srtc_chipid, &srtc_dev_desc,
  78                            inbufs, incounts, outbufs, outcounts, 0);
  79 }
  80
  81 /* RTC-dependent code for time.c */
  82
  83 static int
  84 rtc_rx5c348_set_time(unsigned long t)
  85 {
  86         unsigned char inbuf[8];
  87         struct rtc_time tm;
  88         u8 year, month, day, hour, minute, second, century;
  89
  90         /* convert */
  91         to_tm(t, &tm);
  92
  93         year = tm.tm_year % 100;
  94         month = tm.tm_mon+1;    /* tm_mon starts from 0 to 11 */
  95         day = tm.tm_mday;
  96         hour = tm.tm_hour;
  97         minute = tm.tm_min;
  98         second = tm.tm_sec;
  99         century = tm.tm_year / 100;
 100
 101         inbuf[0] = Rx5C348_CMD_MW(Rx5C348_REG_SECOND);
 102         BIN_TO_BCD(second);
 103         inbuf[1] = second;
 104         BIN_TO_BCD(minute);
 105         inbuf[2] = minute;
 106
 107         if (srtc_24h) {
 108                 BIN_TO_BCD(hour);
 109                 inbuf[3] = hour;
 110         } else {
 111                 /* hour 0 is AM12, noon is PM12 */
 112                 inbuf[3] = 0;
 113                 if (hour >= 12)
 114                         inbuf[3] = Rx5C348_BIT_PM;
 115                 hour = (hour + 11) % 12 + 1;
 116                 BIN_TO_BCD(hour);
 117                 inbuf[3] |= hour;
 118         }
 119         inbuf[4] = 0;   /* ignore week */
 120         BIN_TO_BCD(day);
 121         inbuf[5] = day;
 122         BIN_TO_BCD(month);
 123         inbuf[6] = month;
 124         if (century >= 20)
 125                 inbuf[6] |= Rx5C348_BIT_Y2K;
 126         BIN_TO_BCD(year);
 127         inbuf[7] = year;
 128         /* write in one transfer to avoid data inconsistency */
 129         return spi_rtc_io(inbuf, NULL, 8);
 130 }
 131
 132 static unsigned long
 133 rtc_rx5c348_get_time(void)
 134 {
 135         unsigned char inbuf[8], outbuf[8];
 136         unsigned int year, month, day, hour, minute, second;
 137
 138         inbuf[0] = Rx5C348_CMD_MR(Rx5C348_REG_SECOND);
 139         memset(inbuf + 1, 0, 7);
 140         /* read in one transfer to avoid data inconsistency */
 141         if (spi_rtc_io(inbuf, outbuf, 8))
 142                 return 0;
 143         second = outbuf[1];
 144         BCD_TO_BIN(second);
 145         minute = outbuf[2];
 146         BCD_TO_BIN(minute);
 147         if (srtc_24h) {
 148                 hour = outbuf[3];
 149                 BCD_TO_BIN(hour);
 150         } else {
 151                 hour = outbuf[3] & ~Rx5C348_BIT_PM;
 152                 BCD_TO_BIN(hour);
 153                 hour %= 12;
 154                 if (outbuf[3] & Rx5C348_BIT_PM)
 155                         hour += 12;
 156         }
 157         day = outbuf[5];
 158         BCD_TO_BIN(day);
 159         month = outbuf[6] & ~Rx5C348_BIT_Y2K;
 160         BCD_TO_BIN(month);
 161         year = outbuf[7];
 162         BCD_TO_BIN(year);
 163         year += EPOCH;
 164
 165         return mktime(year, month, day, hour, minute, second);
 166 }
 167
 168 void __init
 169 rtc_rx5c348_init(int chipid)
 170 {
 171         unsigned char inbuf[2], outbuf[2];
 172         srtc_chipid = chipid;
 173         /* turn on RTC if it is not on */
 174         inbuf[0] = Rx5C348_CMD_R(Rx5C348_REG_CTL2);
 175         inbuf[1] = 0;
 176         spi_rtc_io(inbuf, outbuf, 2);
 177         if (outbuf[1] & Rx5C348_BIT_XSTP) {
 178                 inbuf[0] = Rx5C348_CMD_W(Rx5C348_REG_CTL2);
 179                 inbuf[1] = 0;
 180                 spi_rtc_io(inbuf, NULL, 2);
 181         }
 182
 183         inbuf[0] = Rx5C348_CMD_R(Rx5C348_REG_CTL1);
 184         inbuf[1] = 0;
 185         spi_rtc_io(inbuf, outbuf, 2);
 186         if (outbuf[1] & Rx5C348_BIT_24H)
 187                 srtc_24h = 1;
 188
 189         /* set the function pointers */
 190         rtc_mips_get_time = rtc_rx5c348_get_time;
 191         rtc_mips_set_time = rtc_rx5c348_set_time;
 192 }