1 /*
2 * Maxim MAX1110/1111 ADC chip emulation.
3 *
4 * Copyright (c) 2006 Openedhand Ltd.
5 * Written by Andrzej Zaborowski <balrog@zabor.org>
6 *
7 * This code is licensed under the GNU GPLv2.
8 *
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.
11 */
12
13 #include "qemu/osdep.h"
14 #include "hw/irq.h"
15 #include "hw/ssi/ssi.h"
16 #include "migration/vmstate.h"
17 #include "qemu/module.h"
18
19 typedef struct {
20 SSISlave parent_obj;
21
22 qemu_irq interrupt;
23 uint8_t tb1, rb2, rb3;
24 int cycle;
25
26 uint8_t input[8];
27 int inputs, com;
28 } MAX111xState;
29
30 #define TYPE_MAX_111X "max111x"
31
32 #define MAX_111X(obj) \
33 OBJECT_CHECK(MAX111xState, (obj), TYPE_MAX_111X)
34
35 #define TYPE_MAX_1110 "max1110"
36 #define TYPE_MAX_1111 "max1111"
37
38 /* Control-byte bitfields */
39 #define CB_PD0 (1 << 0)
40 #define CB_PD1 (1 << 1)
41 #define CB_SGL (1 << 2)
42 #define CB_UNI (1 << 3)
43 #define CB_SEL0 (1 << 4)
44 #define CB_SEL1 (1 << 5)
45 #define CB_SEL2 (1 << 6)
46 #define CB_START (1 << 7)
47
48 #define CHANNEL_NUM(v, b0, b1, b2) \
49 ((((v) >> (2 + (b0))) & 4) | \
50 (((v) >> (3 + (b1))) & 2) | \
51 (((v) >> (4 + (b2))) & 1))
52
max111x_read(MAX111xState * s)53 static uint32_t max111x_read(MAX111xState *s)
54 {
55 if (!s->tb1)
56 return 0;
57
58 switch (s->cycle ++) {
59 case 1:
60 return s->rb2;
61 case 2:
62 return s->rb3;
63 }
64
65 return 0;
66 }
67
68 /* Interpret a control-byte */
max111x_write(MAX111xState * s,uint32_t value)69 static void max111x_write(MAX111xState *s, uint32_t value)
70 {
71 int measure, chan;
72
73 /* Ignore the value if START bit is zero */
74 if (!(value & CB_START))
75 return;
76
77 s->cycle = 0;
78
79 if (!(value & CB_PD1)) {
80 s->tb1 = 0;
81 return;
82 }
83
84 s->tb1 = value;
85
86 if (s->inputs == 8)
87 chan = CHANNEL_NUM(value, 1, 0, 2);
88 else
89 chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);
90
91 if (value & CB_SGL)
92 measure = s->input[chan] - s->com;
93 else
94 measure = s->input[chan] - s->input[chan ^ 1];
95
96 if (!(value & CB_UNI))
97 measure ^= 0x80;
98
99 s->rb2 = (measure >> 2) & 0x3f;
100 s->rb3 = (measure << 6) & 0xc0;
101
102 /* FIXME: When should the IRQ be lowered? */
103 qemu_irq_raise(s->interrupt);
104 }
105
max111x_transfer(SSISlave * dev,uint32_t value)106 static uint32_t max111x_transfer(SSISlave *dev, uint32_t value)
107 {
108 MAX111xState *s = MAX_111X(dev);
109 max111x_write(s, value);
110 return max111x_read(s);
111 }
112
113 static const VMStateDescription vmstate_max111x = {
114 .name = "max111x",
115 .version_id = 1,
116 .minimum_version_id = 1,
117 .fields = (VMStateField[]) {
118 VMSTATE_SSI_SLAVE(parent_obj, MAX111xState),
119 VMSTATE_UINT8(tb1, MAX111xState),
120 VMSTATE_UINT8(rb2, MAX111xState),
121 VMSTATE_UINT8(rb3, MAX111xState),
122 VMSTATE_INT32_EQUAL(inputs, MAX111xState, NULL),
123 VMSTATE_INT32(com, MAX111xState),
124 VMSTATE_ARRAY_INT32_UNSAFE(input, MAX111xState, inputs,
125 vmstate_info_uint8, uint8_t),
126 VMSTATE_END_OF_LIST()
127 }
128 };
129
max111x_init(SSISlave * d,int inputs)130 static int max111x_init(SSISlave *d, int inputs)
131 {
132 DeviceState *dev = DEVICE(d);
133 MAX111xState *s = MAX_111X(dev);
134
135 qdev_init_gpio_out(dev, &s->interrupt, 1);
136
137 s->inputs = inputs;
138 /* TODO: add a user interface for setting these */
139 s->input[0] = 0xf0;
140 s->input[1] = 0xe0;
141 s->input[2] = 0xd0;
142 s->input[3] = 0xc0;
143 s->input[4] = 0xb0;
144 s->input[5] = 0xa0;
145 s->input[6] = 0x90;
146 s->input[7] = 0x80;
147 s->com = 0;
148
149 vmstate_register(dev, -1, &vmstate_max111x, s);
150 return 0;
151 }
152
max1110_realize(SSISlave * dev,Error ** errp)153 static void max1110_realize(SSISlave *dev, Error **errp)
154 {
155 max111x_init(dev, 8);
156 }
157
max1111_realize(SSISlave * dev,Error ** errp)158 static void max1111_realize(SSISlave *dev, Error **errp)
159 {
160 max111x_init(dev, 4);
161 }
162
max111x_set_input(DeviceState * dev,int line,uint8_t value)163 void max111x_set_input(DeviceState *dev, int line, uint8_t value)
164 {
165 MAX111xState *s = MAX_111X(dev);
166 assert(line >= 0 && line < s->inputs);
167 s->input[line] = value;
168 }
169
max111x_class_init(ObjectClass * klass,void * data)170 static void max111x_class_init(ObjectClass *klass, void *data)
171 {
172 SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
173
174 k->transfer = max111x_transfer;
175 }
176
177 static const TypeInfo max111x_info = {
178 .name = TYPE_MAX_111X,
179 .parent = TYPE_SSI_SLAVE,
180 .instance_size = sizeof(MAX111xState),
181 .class_init = max111x_class_init,
182 .abstract = true,
183 };
184
max1110_class_init(ObjectClass * klass,void * data)185 static void max1110_class_init(ObjectClass *klass, void *data)
186 {
187 SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
188
189 k->realize = max1110_realize;
190 }
191
192 static const TypeInfo max1110_info = {
193 .name = TYPE_MAX_1110,
194 .parent = TYPE_MAX_111X,
195 .class_init = max1110_class_init,
196 };
197
max1111_class_init(ObjectClass * klass,void * data)198 static void max1111_class_init(ObjectClass *klass, void *data)
199 {
200 SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
201
202 k->realize = max1111_realize;
203 }
204
205 static const TypeInfo max1111_info = {
206 .name = TYPE_MAX_1111,
207 .parent = TYPE_MAX_111X,
208 .class_init = max1111_class_init,
209 };
210
max111x_register_types(void)211 static void max111x_register_types(void)
212 {
213 type_register_static(&max111x_info);
214 type_register_static(&max1110_info);
215 type_register_static(&max1111_info);
216 }
217
218 type_init(max111x_register_types)
219