1 /*
2 * ds1302.c - Support for the Dallas Semiconductor DS1302 Timekeeping Chip
3 *
4 * Rex G. Feany <rfeany@zumanetworks.com>
5 *
6 */
7
8 #include <common.h>
9 #include <command.h>
10 #include <rtc.h>
11 #include <linux/delay.h>
12
13 /* GPP Pins */
14 #define DATA 0x200
15 #define SCLK 0x400
16 #define RST 0x800
17
18 /* Happy Fun Defines(tm) */
19 #define RESET rtc_go_low(RST), rtc_go_low(SCLK)
20 #define N_RESET rtc_go_high(RST), rtc_go_low(SCLK)
21
22 #define CLOCK_HIGH rtc_go_high(SCLK)
23 #define CLOCK_LOW rtc_go_low(SCLK)
24
25 #define DATA_HIGH rtc_go_high(DATA)
26 #define DATA_LOW rtc_go_low(DATA)
27 #define DATA_READ (GTREGREAD(GPP_VALUE) & DATA)
28
29 #undef RTC_DEBUG
30
31 #ifdef RTC_DEBUG
32 # define DPRINTF(x,args...) printf("ds1302: " x , ##args)
DUMP(const char * ptr,int num)33 static inline void DUMP(const char *ptr, int num)
34 {
35 while (num--) printf("%x ", *ptr++);
36 printf("]\n");
37 }
38 #else
39 # define DPRINTF(x,args...)
40 # define DUMP(ptr, num)
41 #endif
42
43 /* time data format for DS1302 */
44 struct ds1302_st
45 {
46 unsigned char CH:1; /* clock halt 1=stop 0=start */
47 unsigned char sec10:3;
48 unsigned char sec:4;
49
50 unsigned char zero0:1;
51 unsigned char min10:3;
52 unsigned char min:4;
53
54 unsigned char fmt:1; /* 1=12 hour 0=24 hour */
55 unsigned char zero1:1;
56 unsigned char hr10:2; /* 10 (0-2) or am/pm (am/pm, 0-1) */
57 unsigned char hr:4;
58
59 unsigned char zero2:2;
60 unsigned char date10:2;
61 unsigned char date:4;
62
63 unsigned char zero3:3;
64 unsigned char month10:1;
65 unsigned char month:4;
66
67 unsigned char zero4:5;
68 unsigned char day:3; /* day of week */
69
70 unsigned char year10:4;
71 unsigned char year:4;
72
73 unsigned char WP:1; /* write protect 1=protect 0=unprot */
74 unsigned char zero5:7;
75 };
76
77 static int ds1302_initted=0;
78
79 /* Pin control */
80 static inline void
rtc_go_high(unsigned int mask)81 rtc_go_high(unsigned int mask)
82 {
83 unsigned int f = GTREGREAD(GPP_VALUE) | mask;
84
85 GT_REG_WRITE(GPP_VALUE, f);
86 }
87
88 static inline void
rtc_go_low(unsigned int mask)89 rtc_go_low(unsigned int mask)
90 {
91 unsigned int f = GTREGREAD(GPP_VALUE) & ~mask;
92
93 GT_REG_WRITE(GPP_VALUE, f);
94 }
95
96 static inline void
rtc_go_input(unsigned int mask)97 rtc_go_input(unsigned int mask)
98 {
99 unsigned int f = GTREGREAD(GPP_IO_CONTROL) & ~mask;
100
101 GT_REG_WRITE(GPP_IO_CONTROL, f);
102 }
103
104 static inline void
rtc_go_output(unsigned int mask)105 rtc_go_output(unsigned int mask)
106 {
107 unsigned int f = GTREGREAD(GPP_IO_CONTROL) | mask;
108
109 GT_REG_WRITE(GPP_IO_CONTROL, f);
110 }
111
112 /* Access data in RTC */
113
114 static void
write_byte(unsigned char b)115 write_byte(unsigned char b)
116 {
117 int i;
118 unsigned char mask=1;
119
120 for(i=0;i<8;i++) {
121 CLOCK_LOW; /* Lower clock */
122 (b&mask)?DATA_HIGH:DATA_LOW; /* set data */
123 udelay(1);
124 CLOCK_HIGH; /* latch data with rising clock */
125 udelay(1);
126 mask=mask<<1;
127 }
128 }
129
130 static unsigned char
read_byte(void)131 read_byte(void)
132 {
133 int i;
134 unsigned char mask=1;
135 unsigned char b=0;
136
137 for(i=0;i<8;i++) {
138 CLOCK_LOW;
139 udelay(1);
140 if (DATA_READ) b|=mask; /* if this bit is high, set in b */
141 CLOCK_HIGH; /* clock out next bit */
142 udelay(1);
143 mask=mask<<1;
144 }
145 return b;
146 }
147
148 static void
read_ser_drv(unsigned char addr,unsigned char * buf,int count)149 read_ser_drv(unsigned char addr, unsigned char *buf, int count)
150 {
151 int i;
152 #ifdef RTC_DEBUG
153 char *foo = buf;
154 #endif
155
156 DPRINTF("READ 0x%x bytes @ 0x%x [ ", count, addr);
157
158 addr|=1; /* READ */
159 N_RESET;
160 udelay(4);
161 write_byte(addr);
162 rtc_go_input(DATA); /* Put gpp pin into input mode */
163 udelay(1);
164 for(i=0;i<count;i++) *(buf++)=read_byte();
165 RESET;
166 rtc_go_output(DATA);/* Reset gpp for output */
167 udelay(4);
168
169 DUMP(foo, count);
170 }
171
172 static void
write_ser_drv(unsigned char addr,unsigned char * buf,int count)173 write_ser_drv(unsigned char addr, unsigned char *buf, int count)
174 {
175 int i;
176
177 DPRINTF("WRITE 0x%x bytes @ 0x%x [ ", count, addr);
178 DUMP(buf, count);
179
180 addr&=~1; /* WRITE */
181 N_RESET;
182 udelay(4);
183 write_byte(addr);
184 for(i=0;i<count;i++) write_byte(*(buf++));
185 RESET;
186 udelay(4);
187
188 }
189
190 void
rtc_init(void)191 rtc_init(void)
192 {
193 struct ds1302_st bbclk;
194 unsigned char b;
195 int mod;
196
197 DPRINTF("init\n");
198
199 rtc_go_output(DATA|SCLK|RST);
200
201 /* disable write protect */
202 b = 0;
203 write_ser_drv(0x8e,&b,1);
204
205 /* enable trickle */
206 b = 0xa5; /* 1010.0101 */
207 write_ser_drv(0x90,&b,1);
208
209 /* read burst */
210 read_ser_drv(0xbe, (unsigned char *)&bbclk, 8);
211
212 /* Sanity checks */
213 mod = 0;
214 if (bbclk.CH) {
215 printf("ds1302: Clock was halted, starting clock\n");
216 bbclk.CH=0;
217 mod=1;
218 }
219
220 if (bbclk.fmt) {
221 printf("ds1302: Clock was in 12 hour mode, fixing\n");
222 bbclk.fmt=0;
223 mod=1;
224 }
225
226 if (bbclk.year>9) {
227 printf("ds1302: Year was corrupted, fixing\n");
228 bbclk.year10=100/10; /* 2000 - why not? ;) */
229 bbclk.year=0;
230 mod=1;
231 }
232
233 /* Write out the changes if needed */
234 if (mod) {
235 /* enable write protect */
236 bbclk.WP = 1;
237 write_ser_drv(0xbe,(unsigned char *)&bbclk,8);
238 } else {
239 /* Else just turn write protect on */
240 b = 0x80;
241 write_ser_drv(0x8e,&b,1);
242 }
243 DPRINTF("init done\n");
244
245 ds1302_initted=1;
246 }
247
248 void
rtc_reset(void)249 rtc_reset(void)
250 {
251 if(!ds1302_initted) rtc_init();
252 /* TODO */
253 }
254
255 int
rtc_get(struct rtc_time * tmp)256 rtc_get(struct rtc_time *tmp)
257 {
258 int rel = 0;
259 struct ds1302_st bbclk;
260
261 if(!ds1302_initted) rtc_init();
262
263 read_ser_drv(0xbe,(unsigned char *)&bbclk, 8); /* read burst */
264
265 if (bbclk.CH) {
266 printf("ds1302: rtc_get: Clock was halted, clock probably "
267 "corrupt\n");
268 rel = -1;
269 }
270
271 tmp->tm_sec=10*bbclk.sec10+bbclk.sec;
272 tmp->tm_min=10*bbclk.min10+bbclk.min;
273 tmp->tm_hour=10*bbclk.hr10+bbclk.hr;
274 tmp->tm_wday=bbclk.day;
275 tmp->tm_mday=10*bbclk.date10+bbclk.date;
276 tmp->tm_mon=10*bbclk.month10+bbclk.month;
277 tmp->tm_year=10*bbclk.year10+bbclk.year + 1900;
278
279 tmp->tm_yday = 0;
280 tmp->tm_isdst= 0;
281
282 DPRINTF("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
283 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
284 tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
285
286 return rel;
287 }
288
rtc_set(struct rtc_time * tmp)289 int rtc_set(struct rtc_time *tmp)
290 {
291 struct ds1302_st bbclk;
292 unsigned char b=0;
293
294 if(!ds1302_initted) rtc_init();
295
296 DPRINTF("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
297 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
298 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
299
300 memset(&bbclk,0,sizeof(bbclk));
301 bbclk.CH=0; /* dont halt */
302 bbclk.WP=1; /* write protect when we're done */
303
304 bbclk.sec10=tmp->tm_sec/10;
305 bbclk.sec=tmp->tm_sec%10;
306
307 bbclk.min10=tmp->tm_min/10;
308 bbclk.min=tmp->tm_min%10;
309
310 bbclk.hr10=tmp->tm_hour/10;
311 bbclk.hr=tmp->tm_hour%10;
312
313 bbclk.day=tmp->tm_wday;
314
315 bbclk.date10=tmp->tm_mday/10;
316 bbclk.date=tmp->tm_mday%10;
317
318 bbclk.month10=tmp->tm_mon/10;
319 bbclk.month=tmp->tm_mon%10;
320
321 tmp->tm_year -= 1900;
322 bbclk.year10=tmp->tm_year/10;
323 bbclk.year=tmp->tm_year%10;
324
325 write_ser_drv(0x8e,&b,1); /* disable write protect */
326 write_ser_drv(0xbe,(unsigned char *)&bbclk, 8); /* write burst */
327
328 return 0;
329 }
330