1/* 2 * Dallas Semiconductors 1603 RTC driver 3 * 4 * Brian Murphy <brian@murphy.dk> 5 * 6 */ 7#include <linux/kernel.h> 8#include <asm/lasat/lasat.h> 9#include <linux/delay.h> 10#include <asm/lasat/ds1603.h> 11#include <asm/time.h> 12 13#include "ds1603.h" 14 15#define READ_TIME_CMD 0x81 16#define SET_TIME_CMD 0x80 17#define TRIMMER_SET_CMD 0xC0 18#define TRIMMER_VALUE_MASK 0x38 19#define TRIMMER_SHIFT 3 20 21struct ds_defs *ds1603; 22 23/* HW specific register functions */ 24static void rtc_reg_write(unsigned long val) 25{ 26 *ds1603->reg = val; 27} 28 29static unsigned long rtc_reg_read(void) 30{ 31 unsigned long tmp = *ds1603->reg; 32 return tmp; 33} 34 35static unsigned long rtc_datareg_read(void) 36{ 37 unsigned long tmp = *ds1603->data_reg; 38 return tmp; 39} 40 41static void rtc_nrst_high(void) 42{ 43 rtc_reg_write(rtc_reg_read() | ds1603->rst); 44} 45 46static void rtc_nrst_low(void) 47{ 48 rtc_reg_write(rtc_reg_read() & ~ds1603->rst); 49} 50 51static void rtc_cycle_clock(unsigned long data) 52{ 53 data |= ds1603->clk; 54 rtc_reg_write(data); 55 lasat_ndelay(250); 56 if (ds1603->data_reversed) 57 data &= ~ds1603->data; 58 else 59 data |= ds1603->data; 60 data &= ~ds1603->clk; 61 rtc_reg_write(data); 62 lasat_ndelay(250 + ds1603->huge_delay); 63} 64 65static void rtc_write_databit(unsigned int bit) 66{ 67 unsigned long data = rtc_reg_read(); 68 if (ds1603->data_reversed) 69 bit = !bit; 70 if (bit) 71 data |= ds1603->data; 72 else 73 data &= ~ds1603->data; 74 75 rtc_reg_write(data); 76 lasat_ndelay(50 + ds1603->huge_delay); 77 rtc_cycle_clock(data); 78} 79 80static unsigned int rtc_read_databit(void) 81{ 82 unsigned int data; 83 84 data = (rtc_datareg_read() & (1 << ds1603->data_read_shift)) 85 >> ds1603->data_read_shift; 86 rtc_cycle_clock(rtc_reg_read()); 87 return data; 88} 89 90static void rtc_write_byte(unsigned int byte) 91{ 92 int i; 93 94 for (i = 0; i <= 7; i++) { 95 rtc_write_databit(byte & 1L); 96 byte >>= 1; 97 } 98} 99 100static void rtc_write_word(unsigned long word) 101{ 102 int i; 103 104 for (i = 0; i <= 31; i++) { 105 rtc_write_databit(word & 1L); 106 word >>= 1; 107 } 108} 109 110static unsigned long rtc_read_word(void) 111{ 112 int i; 113 unsigned long word = 0; 114 unsigned long shift = 0; 115 116 for (i = 0; i <= 31; i++) { 117 word |= rtc_read_databit() << shift; 118 shift++; 119 } 120 return word; 121} 122 123static void rtc_init_op(void) 124{ 125 rtc_nrst_high(); 126 127 rtc_reg_write(rtc_reg_read() & ~ds1603->clk); 128 129 lasat_ndelay(50); 130} 131 132static void rtc_end_op(void) 133{ 134 rtc_nrst_low(); 135 lasat_ndelay(1000); 136} 137 138void read_persistent_clock(struct timespec *ts) 139{ 140 unsigned long word; 141 unsigned long flags; 142 143 spin_lock_irqsave(&rtc_lock, flags); 144 rtc_init_op(); 145 rtc_write_byte(READ_TIME_CMD); 146 word = rtc_read_word(); 147 rtc_end_op(); 148 spin_unlock_irqrestore(&rtc_lock, flags); 149 150 ts->tv_sec = word; 151 ts->tv_nsec = 0; 152} 153 154int rtc_mips_set_mmss(unsigned long time) 155{ 156 unsigned long flags; 157 158 spin_lock_irqsave(&rtc_lock, flags); 159 rtc_init_op(); 160 rtc_write_byte(SET_TIME_CMD); 161 rtc_write_word(time); 162 rtc_end_op(); 163 spin_unlock_irqrestore(&rtc_lock, flags); 164 165 return 0; 166} 167 168void ds1603_set_trimmer(unsigned int trimval) 169{ 170 rtc_init_op(); 171 rtc_write_byte(((trimval << TRIMMER_SHIFT) & TRIMMER_VALUE_MASK) 172 | (TRIMMER_SET_CMD)); 173 rtc_end_op(); 174} 175 176void ds1603_disable(void) 177{ 178 ds1603_set_trimmer(TRIMMER_DISABLE_RTC); 179} 180 181void ds1603_enable(void) 182{ 183 ds1603_set_trimmer(TRIMMER_DEFAULT); 184} 185