aboutsummaryrefslogtreecommitdiff
path: root/hw/max111x.c
blob: 15392a21fca362971ac25797f13cbbc77a8d39f7 (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
/*
 * Maxim MAX1110/1111 ADC chip emulation.
 *
 * Copyright (c) 2006 Openedhand Ltd.
 * Written by Andrzej Zaborowski <balrog@zabor.org>
 *
 * This code is licensed under the GNU GPLv2.
 */

#include "hw.h"
#include "i2c.h"

struct max111x_s {
    qemu_irq interrupt;
    uint8_t tb1, rb2, rb3;
    int cycle;

    int input[8];
    int inputs, com;
};

/* Control-byte bitfields */
#define CB_PD0		(1 << 0)
#define CB_PD1		(1 << 1)
#define CB_SGL		(1 << 2)
#define CB_UNI		(1 << 3)
#define CB_SEL0		(1 << 4)
#define CB_SEL1		(1 << 5)
#define CB_SEL2		(1 << 6)
#define CB_START	(1 << 7)

#define CHANNEL_NUM(v, b0, b1, b2)	\
			((((v) >> (2 + (b0))) & 4) |	\
			 (((v) >> (3 + (b1))) & 2) |	\
			 (((v) >> (4 + (b2))) & 1))

uint32_t max111x_read(void *opaque)
{
    struct max111x_s *s = (struct max111x_s *) opaque;

    if (!s->tb1)
        return 0;

    switch (s->cycle ++) {
    case 1:
        return s->rb2;
    case 2:
        return s->rb3;
    }

    return 0;
}

/* Interpret a control-byte */
void max111x_write(void *opaque, uint32_t value)
{
    struct max111x_s *s = (struct max111x_s *) opaque;
    int measure, chan;

    /* Ignore the value if START bit is zero */
    if (!(value & CB_START))
        return;

    s->cycle = 0;

    if (!(value & CB_PD1)) {
        s->tb1 = 0;
        return;
    }

    s->tb1 = value;

    if (s->inputs == 8)
        chan = CHANNEL_NUM(value, 1, 0, 2);
    else
        chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);

    if (value & CB_SGL)
        measure = s->input[chan] - s->com;
    else
        measure = s->input[chan] - s->input[chan ^ 1];

    if (!(value & CB_UNI))
        measure ^= 0x80;

    s->rb2 = (measure >> 2) & 0x3f;
    s->rb3 = (measure << 6) & 0xc0;

    if (s->interrupt)
        qemu_irq_raise(s->interrupt);
}

static void max111x_save(QEMUFile *f, void *opaque)
{
    struct max111x_s *s = (struct max111x_s *) opaque;
    int i;

    qemu_put_8s(f, &s->tb1);
    qemu_put_8s(f, &s->rb2);
    qemu_put_8s(f, &s->rb3);
    qemu_put_be32(f, s->inputs);
    qemu_put_be32(f, s->com);
    for (i = 0; i < s->inputs; i ++)
        qemu_put_byte(f, s->input[i]);
}

static int max111x_load(QEMUFile *f, void *opaque, int version_id)
{
    struct max111x_s *s = (struct max111x_s *) opaque;
    int i;

    qemu_get_8s(f, &s->tb1);
    qemu_get_8s(f, &s->rb2);
    qemu_get_8s(f, &s->rb3);
    if (s->inputs != qemu_get_be32(f))
        return -EINVAL;
    s->com = qemu_get_be32(f);
    for (i = 0; i < s->inputs; i ++)
        s->input[i] = qemu_get_byte(f);

    return 0;
}

static struct max111x_s *max111x_init(qemu_irq cb)
{
    struct max111x_s *s;
    s = (struct max111x_s *)
            qemu_mallocz(sizeof(struct max111x_s));
    memset(s, 0, sizeof(struct max111x_s));

    s->interrupt = cb;

    /* TODO: add a user interface for setting these */
    s->input[0] = 0xf0;
    s->input[1] = 0xe0;
    s->input[2] = 0xd0;
    s->input[3] = 0xc0;
    s->input[4] = 0xb0;
    s->input[5] = 0xa0;
    s->input[6] = 0x90;
    s->input[7] = 0x80;
    s->com = 0;

    register_savevm("max111x", -1, 0, max111x_save, max111x_load, s);

    return s;
}

struct max111x_s *max1110_init(qemu_irq cb)
{
    struct max111x_s *s = max111x_init(cb);
    s->inputs = 8;
    return s;
}

struct max111x_s *max1111_init(qemu_irq cb)
{
    struct max111x_s *s = max111x_init(cb);
    s->inputs = 4;
    return s;
}

void max111x_set_input(struct max111x_s *s, int line, uint8_t value)
{
    if (line >= s->inputs) {
        printf("%s: There's no input %i\n", __FUNCTION__, line);
        return;
    }

    s->input[line] = value;
}