root / hw / ds1338.c @ b67592ea
History | View | Annotate | Download (3.2 kB)
1 |
/*
|
---|---|
2 |
* MAXIM DS1338 I2C RTC+NVRAM
|
3 |
*
|
4 |
* Copyright (c) 2009 CodeSourcery.
|
5 |
* Written by Paul Brook
|
6 |
*
|
7 |
* This code is licenced under the GNU GPL v2.
|
8 |
*/
|
9 |
|
10 |
#include "i2c.h" |
11 |
|
12 |
typedef struct { |
13 |
i2c_slave i2c; |
14 |
time_t offset; |
15 |
struct tm now;
|
16 |
uint8_t nvram[56];
|
17 |
int ptr;
|
18 |
int addr_byte;
|
19 |
} DS1338State; |
20 |
|
21 |
static void ds1338_event(i2c_slave *i2c, enum i2c_event event) |
22 |
{ |
23 |
DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c); |
24 |
|
25 |
switch (event) {
|
26 |
case I2C_START_RECV:
|
27 |
qemu_get_timedate(&s->now, s->offset); |
28 |
s->nvram[0] = to_bcd(s->now.tm_sec);
|
29 |
s->nvram[1] = to_bcd(s->now.tm_min);
|
30 |
if (s->nvram[2] & 0x40) { |
31 |
s->nvram[2] = (to_bcd((s->now.tm_hour % 12)) + 1) | 0x40; |
32 |
if (s->now.tm_hour >= 12) { |
33 |
s->nvram[2] |= 0x20; |
34 |
} |
35 |
} else {
|
36 |
s->nvram[2] = to_bcd(s->now.tm_hour);
|
37 |
} |
38 |
s->nvram[3] = to_bcd(s->now.tm_wday) + 1; |
39 |
s->nvram[4] = to_bcd(s->now.tm_mday);
|
40 |
s->nvram[5] = to_bcd(s->now.tm_mon) + 1; |
41 |
s->nvram[6] = to_bcd(s->now.tm_year - 100); |
42 |
break;
|
43 |
case I2C_START_SEND:
|
44 |
s->addr_byte = 1;
|
45 |
break;
|
46 |
default:
|
47 |
break;
|
48 |
} |
49 |
} |
50 |
|
51 |
static int ds1338_recv(i2c_slave *i2c) |
52 |
{ |
53 |
DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c); |
54 |
uint8_t res; |
55 |
|
56 |
res = s->nvram[s->ptr]; |
57 |
s->ptr = (s->ptr + 1) & 0xff; |
58 |
return res;
|
59 |
} |
60 |
|
61 |
static int ds1338_send(i2c_slave *i2c, uint8_t data) |
62 |
{ |
63 |
DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c); |
64 |
if (s->addr_byte) {
|
65 |
s->ptr = data; |
66 |
s->addr_byte = 0;
|
67 |
return 0; |
68 |
} |
69 |
s->nvram[s->ptr - 8] = data;
|
70 |
if (data < 8) { |
71 |
qemu_get_timedate(&s->now, s->offset); |
72 |
switch(data) {
|
73 |
case 0: |
74 |
/* TODO: Implement CH (stop) bit. */
|
75 |
s->now.tm_sec = from_bcd(data & 0x7f);
|
76 |
break;
|
77 |
case 1: |
78 |
s->now.tm_min = from_bcd(data & 0x7f);
|
79 |
break;
|
80 |
case 2: |
81 |
if (data & 0x40) { |
82 |
if (data & 0x20) { |
83 |
data = from_bcd(data & 0x4f) + 11; |
84 |
} else {
|
85 |
data = from_bcd(data & 0x1f) - 1; |
86 |
} |
87 |
} else {
|
88 |
data = from_bcd(data); |
89 |
} |
90 |
s->now.tm_hour = data; |
91 |
break;
|
92 |
case 3: |
93 |
s->now.tm_wday = from_bcd(data & 7) - 1; |
94 |
break;
|
95 |
case 4: |
96 |
s->now.tm_mday = from_bcd(data & 0x3f);
|
97 |
break;
|
98 |
case 5: |
99 |
s->now.tm_mon = from_bcd(data & 0x1f) - 1; |
100 |
case 6: |
101 |
s->now.tm_year = from_bcd(data) + 100;
|
102 |
break;
|
103 |
case 7: |
104 |
/* Control register. Currently ignored. */
|
105 |
break;
|
106 |
} |
107 |
s->offset = qemu_timedate_diff(&s->now); |
108 |
} |
109 |
s->ptr = (s->ptr + 1) & 0xff; |
110 |
return 0; |
111 |
} |
112 |
|
113 |
static int ds1338_init(i2c_slave *i2c) |
114 |
{ |
115 |
return 0; |
116 |
} |
117 |
|
118 |
static I2CSlaveInfo ds1338_info = {
|
119 |
.qdev.name = "ds1338",
|
120 |
.qdev.size = sizeof(DS1338State),
|
121 |
.init = ds1338_init, |
122 |
.event = ds1338_event, |
123 |
.recv = ds1338_recv, |
124 |
.send = ds1338_send, |
125 |
}; |
126 |
|
127 |
static void ds1338_register_devices(void) |
128 |
{ |
129 |
i2c_register_slave(&ds1338_info); |
130 |
} |
131 |
|
132 |
device_init(ds1338_register_devices) |