Commit | Line | Data |
---|---|---|
1f21d2bd BM |
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 | ||
21 | struct ds_defs *ds1603; | |
22 | ||
23 | /* HW specific register functions */ | |
24 | static void rtc_reg_write(unsigned long val) | |
25 | { | |
26 | *ds1603->reg = val; | |
27 | } | |
28 | ||
29 | static unsigned long rtc_reg_read(void) | |
30 | { | |
31 | unsigned long tmp = *ds1603->reg; | |
32 | return tmp; | |
33 | } | |
34 | ||
35 | static unsigned long rtc_datareg_read(void) | |
36 | { | |
37 | unsigned long tmp = *ds1603->data_reg; | |
38 | return tmp; | |
39 | } | |
40 | ||
41 | static void rtc_nrst_high(void) | |
42 | { | |
43 | rtc_reg_write(rtc_reg_read() | ds1603->rst); | |
44 | } | |
45 | ||
46 | static void rtc_nrst_low(void) | |
47 | { | |
48 | rtc_reg_write(rtc_reg_read() & ~ds1603->rst); | |
49 | } | |
50 | ||
51 | static 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 | ||
65 | static 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 | ||
80 | static 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 | ||
90 | static 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 | ||
100 | static 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 | ||
110 | static 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 | ||
123 | static 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 | ||
132 | static void rtc_end_op(void) | |
133 | { | |
134 | rtc_nrst_low(); | |
135 | lasat_ndelay(1000); | |
136 | } | |
137 | ||
4b550488 | 138 | unsigned long read_persistent_clock(void) |
1f21d2bd BM |
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); | |
4b550488 | 149 | |
1f21d2bd BM |
150 | return word; |
151 | } | |
152 | ||
4b550488 | 153 | int rtc_mips_set_mmss(unsigned long time) |
1f21d2bd BM |
154 | { |
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 | ||
167 | void 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 | ||
175 | void ds1603_disable(void) | |
176 | { | |
177 | ds1603_set_trimmer(TRIMMER_DISABLE_RTC); | |
178 | } | |
179 | ||
180 | void ds1603_enable(void) | |
181 | { | |
182 | ds1603_set_trimmer(TRIMMER_DEFAULT); | |
183 | } |