2 * Dallas Semiconductors 1603 RTC driver
4 * Brian Murphy <brian@murphy.dk>
7 #include <linux/kernel.h>
8 #include <asm/lasat/lasat.h>
9 #include <linux/delay.h>
10 #include <asm/lasat/ds1603.h>
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
21 struct ds_defs
*ds1603
;
23 /* HW specific register functions */
24 static void rtc_reg_write(unsigned long val
)
29 static unsigned long rtc_reg_read(void)
31 unsigned long tmp
= *ds1603
->reg
;
35 static unsigned long rtc_datareg_read(void)
37 unsigned long tmp
= *ds1603
->data_reg
;
41 static void rtc_nrst_high(void)
43 rtc_reg_write(rtc_reg_read() | ds1603
->rst
);
46 static void rtc_nrst_low(void)
48 rtc_reg_write(rtc_reg_read() & ~ds1603
->rst
);
51 static void rtc_cycle_clock(unsigned long data
)
56 if (ds1603
->data_reversed
)
57 data
&= ~ds1603
->data
;
62 lasat_ndelay(250 + ds1603
->huge_delay
);
65 static void rtc_write_databit(unsigned int bit
)
67 unsigned long data
= rtc_reg_read();
68 if (ds1603
->data_reversed
)
73 data
&= ~ds1603
->data
;
76 lasat_ndelay(50 + ds1603
->huge_delay
);
77 rtc_cycle_clock(data
);
80 static unsigned int rtc_read_databit(void)
84 data
= (rtc_datareg_read() & (1 << ds1603
->data_read_shift
))
85 >> ds1603
->data_read_shift
;
86 rtc_cycle_clock(rtc_reg_read());
90 static void rtc_write_byte(unsigned int byte
)
94 for (i
= 0; i
<= 7; i
++) {
95 rtc_write_databit(byte
& 1L);
100 static void rtc_write_word(unsigned long word
)
104 for (i
= 0; i
<= 31; i
++) {
105 rtc_write_databit(word
& 1L);
110 static unsigned long rtc_read_word(void)
113 unsigned long word
= 0;
114 unsigned long shift
= 0;
116 for (i
= 0; i
<= 31; i
++) {
117 word
|= rtc_read_databit() << shift
;
123 static void rtc_init_op(void)
127 rtc_reg_write(rtc_reg_read() & ~ds1603
->clk
);
132 static void rtc_end_op(void)
138 void read_persistent_clock(struct timespec
*ts
)
143 spin_lock_irqsave(&rtc_lock
, flags
);
145 rtc_write_byte(READ_TIME_CMD
);
146 word
= rtc_read_word();
148 spin_unlock_irqrestore(&rtc_lock
, flags
);
154 int rtc_mips_set_mmss(unsigned long time
)
158 spin_lock_irqsave(&rtc_lock
, flags
);
160 rtc_write_byte(SET_TIME_CMD
);
161 rtc_write_word(time
);
163 spin_unlock_irqrestore(&rtc_lock
, flags
);
168 void ds1603_set_trimmer(unsigned int trimval
)
171 rtc_write_byte(((trimval
<< TRIMMER_SHIFT
) & TRIMMER_VALUE_MASK
)
172 | (TRIMMER_SET_CMD
));
176 void ds1603_disable(void)
178 ds1603_set_trimmer(TRIMMER_DISABLE_RTC
);
181 void ds1603_enable(void)
183 ds1603_set_trimmer(TRIMMER_DEFAULT
);
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