2 * MAXIM DS1338 I2C RTC+NVRAM
4 * Copyright (c) 2009 CodeSourcery.
5 * Written by Paul Brook
7 * This code is licensed under the GNU GPL v2.
9 * Contributions after 2012-01-13 are licensed under the terms of the
10 * GNU GPL, version 2 or (at your option) any later version.
13 #include "qemu/osdep.h"
14 #include "hw/i2c/i2c.h"
16 /* Size of NVRAM including both the user-accessible area and the
17 * secondary register area.
21 /* Flags definitions */
22 #define SECONDS_CH 0x80
27 #define TYPE_DS1338 "ds1338"
28 #define DS1338(obj) OBJECT_CHECK(DS1338State, (obj), TYPE_DS1338)
30 typedef struct DS1338State
{
35 uint8_t nvram
[NVRAM_SIZE
];
40 static const VMStateDescription vmstate_ds1338
= {
43 .minimum_version_id
= 1,
44 .fields
= (VMStateField
[]) {
45 VMSTATE_I2C_SLAVE(parent_obj
, DS1338State
),
46 VMSTATE_INT64(offset
, DS1338State
),
47 VMSTATE_UINT8_V(wday_offset
, DS1338State
, 2),
48 VMSTATE_UINT8_ARRAY(nvram
, DS1338State
, NVRAM_SIZE
),
49 VMSTATE_INT32(ptr
, DS1338State
),
50 VMSTATE_BOOL(addr_byte
, DS1338State
),
55 static void capture_current_time(DS1338State
*s
)
57 /* Capture the current time into the secondary registers
58 * which will be actually read by the data transfer operation.
61 qemu_get_timedate(&now
, s
->offset
);
62 s
->nvram
[0] = to_bcd(now
.tm_sec
);
63 s
->nvram
[1] = to_bcd(now
.tm_min
);
64 if (s
->nvram
[2] & HOURS_12
) {
65 int tmp
= now
.tm_hour
;
70 s
->nvram
[2] = HOURS_12
| to_bcd(tmp
);
72 s
->nvram
[2] = HOURS_12
| HOURS_PM
| to_bcd(tmp
- 12);
75 s
->nvram
[2] = to_bcd(now
.tm_hour
);
77 s
->nvram
[3] = (now
.tm_wday
+ s
->wday_offset
) % 7 + 1;
78 s
->nvram
[4] = to_bcd(now
.tm_mday
);
79 s
->nvram
[5] = to_bcd(now
.tm_mon
+ 1);
80 s
->nvram
[6] = to_bcd(now
.tm_year
- 100);
83 static void inc_regptr(DS1338State
*s
)
85 /* The register pointer wraps around after 0x3F; wraparound
86 * causes the current time/date to be retransferred into
87 * the secondary registers.
89 s
->ptr
= (s
->ptr
+ 1) & (NVRAM_SIZE
- 1);
91 capture_current_time(s
);
95 static void ds1338_event(I2CSlave
*i2c
, enum i2c_event event
)
97 DS1338State
*s
= DS1338(i2c
);
101 /* In h/w, capture happens on any START condition, not just a
102 * START_RECV, but there is no need to actually capture on
103 * START_SEND, because the guest can't get at that data
104 * without going through a START_RECV which would overwrite it.
106 capture_current_time(s
);
116 static int ds1338_recv(I2CSlave
*i2c
)
118 DS1338State
*s
= DS1338(i2c
);
121 res
= s
->nvram
[s
->ptr
];
126 static int ds1338_send(I2CSlave
*i2c
, uint8_t data
)
128 DS1338State
*s
= DS1338(i2c
);
131 s
->ptr
= data
& (NVRAM_SIZE
- 1);
132 s
->addr_byte
= false;
138 qemu_get_timedate(&now
, s
->offset
);
141 /* TODO: Implement CH (stop) bit. */
142 now
.tm_sec
= from_bcd(data
& 0x7f);
145 now
.tm_min
= from_bcd(data
& 0x7f);
148 if (data
& HOURS_12
) {
149 int tmp
= from_bcd(data
& (HOURS_PM
- 1));
150 if (data
& HOURS_PM
) {
158 now
.tm_hour
= from_bcd(data
& (HOURS_12
- 1));
163 /* The day field is supposed to contain a value in
164 the range 1-7. Otherwise behavior is undefined.
166 int user_wday
= (data
& 7) - 1;
167 s
->wday_offset
= (user_wday
- now
.tm_wday
+ 7) % 7;
171 now
.tm_mday
= from_bcd(data
& 0x3f);
174 now
.tm_mon
= from_bcd(data
& 0x1f) - 1;
177 now
.tm_year
= from_bcd(data
) + 100;
180 s
->offset
= qemu_timedate_diff(&now
);
181 } else if (s
->ptr
== 7) {
182 /* Control register. */
184 /* Ensure bits 2, 3 and 6 will read back as zero. */
187 /* Attempting to write the OSF flag to logic 1 leaves the
189 data
= (data
& ~CTRL_OSF
) | (data
& s
->nvram
[s
->ptr
] & CTRL_OSF
);
191 s
->nvram
[s
->ptr
] = data
;
193 s
->nvram
[s
->ptr
] = data
;
199 static int ds1338_init(I2CSlave
*i2c
)
204 static void ds1338_reset(DeviceState
*dev
)
206 DS1338State
*s
= DS1338(dev
);
208 /* The clock is running and synchronized with the host */
211 memset(s
->nvram
, 0, NVRAM_SIZE
);
213 s
->addr_byte
= false;
216 static void ds1338_class_init(ObjectClass
*klass
, void *data
)
218 DeviceClass
*dc
= DEVICE_CLASS(klass
);
219 I2CSlaveClass
*k
= I2C_SLAVE_CLASS(klass
);
221 k
->init
= ds1338_init
;
222 k
->event
= ds1338_event
;
223 k
->recv
= ds1338_recv
;
224 k
->send
= ds1338_send
;
225 dc
->reset
= ds1338_reset
;
226 dc
->vmsd
= &vmstate_ds1338
;
229 static const TypeInfo ds1338_info
= {
231 .parent
= TYPE_I2C_SLAVE
,
232 .instance_size
= sizeof(DS1338State
),
233 .class_init
= ds1338_class_init
,
236 static void ds1338_register_types(void)
238 type_register_static(&ds1338_info
);
241 type_init(ds1338_register_types
)