blob: 52cb1436a12aff59908461f87f9ea114d44c1f63 [file] [log] [blame]
Brian Murphy1f21d2b2007-08-21 22:34:16 +02001/*
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
Ralf Baechle4b550482007-10-11 23:46:08 +0100138unsigned long read_persistent_clock(void)
Brian Murphy1f21d2b2007-08-21 22:34:16 +0200139{
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);
Ralf Baechle4b550482007-10-11 23:46:08 +0100149
Brian Murphy1f21d2b2007-08-21 22:34:16 +0200150 return word;
151}
152
Ralf Baechle4b550482007-10-11 23:46:08 +0100153int rtc_mips_set_mmss(unsigned long time)
Brian Murphy1f21d2b2007-08-21 22:34:16 +0200154{
155 unsigned long flags;
156
157 spin_lock_irqsave(&rtc_lock, flags);
158 rtc_init_op();
159 rtc_write_byte(SET_TIME_CMD);
160 rtc_write_word(time);
161 rtc_end_op();
162 spin_unlock_irqrestore(&rtc_lock, flags);
163
164 return 0;
165}
166
167void ds1603_set_trimmer(unsigned int trimval)
168{
169 rtc_init_op();
170 rtc_write_byte(((trimval << TRIMMER_SHIFT) & TRIMMER_VALUE_MASK)
171 | (TRIMMER_SET_CMD));
172 rtc_end_op();
173}
174
175void ds1603_disable(void)
176{
177 ds1603_set_trimmer(TRIMMER_DISABLE_RTC);
178}
179
180void ds1603_enable(void)
181{
182 ds1603_set_trimmer(TRIMMER_DEFAULT);
183}