summaryrefslogtreecommitdiffstats
path: root/doc/driver-model/UDM-rtc.txt
blob: 6aaeb86f2710bd09b6e6b2e03a8543c2296bd914 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
=============================
RTC device subsystem analysis
=============================

Tomas Hlavacek <tmshlvck@gmail.com>
2012-03-10

I) Overview
-----------

U-Boot currently implements one common API for RTC devices. The interface
is defined in include/rtc.h and comprises of functions and structures:

    struct rtc_time {
        int tm_sec;
        int tm_min;
        int tm_hour;
        int tm_mday;
        int tm_mon;
        int tm_year;
        int tm_wday;
        int tm_yday;
        int tm_isdst;
    };

    int rtc_get (struct rtc_time *);
    int rtc_set (struct rtc_time *);
    void rtc_reset (void);

The functions are implemented by a proper device driver in drivers/rtc
directory and the driver to be compiled in is selected in a Makefile.
Drivers are mutually exclusive.

Drivers depends on date code in drivers/rtc/date.c and naturally on board
specific data.

II) Approach
------------

  1) New API
  ----------
  In the UDM each rtc driver would register itself by a function

    int rtc_device_register(struct instance *i,
                            struct rtc_device_ops *o);

  The structure being defined as follows:

    struct rtc_device_ops {
        int  (*get_time)(struct instance *i, struct rtc_time *t);
        int  (*set_time)(struct instance *i, struct rtc_time *t);
        int  (*reset)(struct instance *i);
    };


  2) Conversion thougths
  ----------------------
  U-Boot RTC drivers exports the same functions and therefore the conversion
  of the drivers is straight-forward. There is no initialization needed.


III) Analysis of in-tree drivers
--------------------------------

  1) drivers/rtc/rv3029.c
  -----------------------
  The driver is standard rtc. Simple conversion is possible.


  2) drivers/rtc/s3c24x0_rtc.c
  ----------------------------
  The driver is standard rtc. Simple conversion is possible.


  3) drivers/rtc/pt7c4338.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  4) drivers/rtc/mvrtc.c
  ----------------------
  The driver is standard rtc. Simple conversion is possible.


  5) drivers/rtc/ftrtc010.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  6) drivers/rtc/mpc5xxx.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  7) drivers/rtc/ds164x.c
  -----------------------
  The driver is standard rtc. Simple conversion is possible.


  8) drivers/rtc/rs5c372.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  9) drivers/rtc/m41t94.c
  -----------------------
  The driver is standard rtc. Simple conversion is possible.


  10) drivers/rtc/mc13xxx-rtc.c
  -----------------------------
  The driver is standard rtc. Simple conversion is possible.


  11) drivers/rtc/mcfrtc.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  12) drivers/rtc/davinci.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  13) drivers/rtc/rx8025.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  14) drivers/rtc/bfin_rtc.c
  --------------------------
  The driver is standard rtc. Simple conversion is possible.


  15) drivers/rtc/m41t62.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  16) drivers/rtc/ds1306.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  17) drivers/rtc/mpc8xx.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  18) drivers/rtc/ds3231.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  19) drivers/rtc/ds12887.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  20) drivers/rtc/ds1302.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  21) drivers/rtc/ds1374.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  22) drivers/rtc/ds174x.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  23) drivers/rtc/m41t60.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  24) drivers/rtc/m48t35ax.c
  --------------------------
  The driver is standard rtc. Simple conversion is possible.


  25) drivers/rtc/pl031.c
  -----------------------
  The driver is standard rtc. Simple conversion is possible.


  26) drivers/rtc/x1205.c
  -----------------------
  The driver is standard rtc. Simple conversion is possible.


  27) drivers/rtc/m41t11.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  28) drivers/rtc/pcf8563.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  29) drivers/rtc/mk48t59.c
  -------------------------
  Macros needs cleanup. Besides that the driver is standard rtc.
  Simple conversion is possible.


  30) drivers/rtc/mxsrtc.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  31) drivers/rtc/ds1307.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  32) drivers/rtc/ds1556.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  33) drivers/rtc/rtc4543.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  34) drivers/rtc/ds1337.c
  ------------------------
  The driver is standard rtc. Simple conversion is possible.


  35) drivers/rtc/isl1208.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  36) drivers/rtc/max6900.c
  -------------------------
  The driver is standard rtc. Simple conversion is possible.


  37) drivers/rtc/mc146818.c
  --------------------------
  The driver is standard rtc. Simple conversion is possible.


  38) drivers/rtc/at91sam9_rtt.c
  ------------------------------
  The driver is standard rtc. Simple conversion is possible.
OpenPOWER on IntegriCloud