root / hw / i2c.c @ 5b7f5327
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1 | 5fafdf24 | ths | /*
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2 | 0ff596d0 | pbrook | * QEMU I2C bus interface.
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3 | 0ff596d0 | pbrook | *
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4 | 0ff596d0 | pbrook | * Copyright (c) 2007 CodeSourcery.
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5 | 0ff596d0 | pbrook | * Written by Paul Brook
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6 | 0ff596d0 | pbrook | *
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7 | 0ff596d0 | pbrook | * This code is licenced under the LGPL.
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8 | 0ff596d0 | pbrook | */
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9 | 0ff596d0 | pbrook | |
10 | 87ecb68b | pbrook | #include "i2c.h" |
11 | 0ff596d0 | pbrook | |
12 | 0ff596d0 | pbrook | struct i2c_bus
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13 | 0ff596d0 | pbrook | { |
14 | 02e2da45 | Paul Brook | BusState qbus; |
15 | 0ff596d0 | pbrook | i2c_slave *current_dev; |
16 | 0ff596d0 | pbrook | i2c_slave *dev; |
17 | 5b7f5327 | Juan Quintela | uint8_t saved_address; |
18 | 0ff596d0 | pbrook | }; |
19 | 0ff596d0 | pbrook | |
20 | 10c4c98a | Gerd Hoffmann | static struct BusInfo i2c_bus_info = { |
21 | 10c4c98a | Gerd Hoffmann | .name = "I2C",
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22 | 10c4c98a | Gerd Hoffmann | .size = sizeof(i2c_bus),
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23 | ee6847d1 | Gerd Hoffmann | .props = (Property[]) { |
24 | 5b7f5327 | Juan Quintela | DEFINE_PROP_UINT8("address", struct i2c_slave, address, 0), |
25 | 368eb5d4 | Gerd Hoffmann | DEFINE_PROP_END_OF_LIST(), |
26 | ee6847d1 | Gerd Hoffmann | } |
27 | 10c4c98a | Gerd Hoffmann | }; |
28 | 10c4c98a | Gerd Hoffmann | |
29 | c701b35b | pbrook | static void i2c_bus_save(QEMUFile *f, void *opaque) |
30 | c701b35b | pbrook | { |
31 | c701b35b | pbrook | i2c_bus *bus = (i2c_bus *)opaque; |
32 | 5b7f5327 | Juan Quintela | bus->saved_address = bus->current_dev ? bus->current_dev->address : -1;
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33 | c701b35b | pbrook | |
34 | 5b7f5327 | Juan Quintela | qemu_put_8s(f, &bus->saved_address); |
35 | c701b35b | pbrook | } |
36 | c701b35b | pbrook | |
37 | c701b35b | pbrook | static int i2c_bus_load(QEMUFile *f, void *opaque, int version_id) |
38 | c701b35b | pbrook | { |
39 | c701b35b | pbrook | i2c_bus *bus = (i2c_bus *)opaque; |
40 | c701b35b | pbrook | |
41 | c701b35b | pbrook | if (version_id != 1) |
42 | c701b35b | pbrook | return -EINVAL;
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43 | c701b35b | pbrook | |
44 | c701b35b | pbrook | /* The bus is loaded before attached devices, so load and save the
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45 | c701b35b | pbrook | current device id. Devices will check themselves as loaded. */
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46 | 5b7f5327 | Juan Quintela | qemu_get_8s(f, &bus->saved_address); |
47 | c701b35b | pbrook | bus->current_dev = NULL;
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48 | c701b35b | pbrook | |
49 | c701b35b | pbrook | return 0; |
50 | c701b35b | pbrook | } |
51 | c701b35b | pbrook | |
52 | 0ff596d0 | pbrook | /* Create a new I2C bus. */
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53 | 02e2da45 | Paul Brook | i2c_bus *i2c_init_bus(DeviceState *parent, const char *name) |
54 | 0ff596d0 | pbrook | { |
55 | 0ff596d0 | pbrook | i2c_bus *bus; |
56 | 0ff596d0 | pbrook | |
57 | 10c4c98a | Gerd Hoffmann | bus = FROM_QBUS(i2c_bus, qbus_create(&i2c_bus_info, parent, name)); |
58 | c701b35b | pbrook | register_savevm("i2c_bus", -1, 1, i2c_bus_save, i2c_bus_load, bus); |
59 | 0ff596d0 | pbrook | return bus;
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60 | 0ff596d0 | pbrook | } |
61 | 0ff596d0 | pbrook | |
62 | 5b7f5327 | Juan Quintela | void i2c_set_slave_address(i2c_slave *dev, uint8_t address)
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63 | 0ff596d0 | pbrook | { |
64 | 0ff596d0 | pbrook | dev->address = address; |
65 | 0ff596d0 | pbrook | } |
66 | 0ff596d0 | pbrook | |
67 | 0ff596d0 | pbrook | /* Return nonzero if bus is busy. */
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68 | 0ff596d0 | pbrook | int i2c_bus_busy(i2c_bus *bus)
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69 | 0ff596d0 | pbrook | { |
70 | 0ff596d0 | pbrook | return bus->current_dev != NULL; |
71 | 0ff596d0 | pbrook | } |
72 | 0ff596d0 | pbrook | |
73 | 4a2c8ac2 | balrog | /* Returns non-zero if the address is not valid. */
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74 | 0ff596d0 | pbrook | /* TODO: Make this handle multiple masters. */
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75 | 5b7f5327 | Juan Quintela | int i2c_start_transfer(i2c_bus *bus, uint8_t address, int recv) |
76 | 0ff596d0 | pbrook | { |
77 | 02e2da45 | Paul Brook | DeviceState *qdev; |
78 | 02e2da45 | Paul Brook | i2c_slave *slave = NULL;
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79 | 0ff596d0 | pbrook | |
80 | 72cf2d4f | Blue Swirl | QLIST_FOREACH(qdev, &bus->qbus.children, sibling) { |
81 | 02e2da45 | Paul Brook | slave = I2C_SLAVE_FROM_QDEV(qdev); |
82 | 02e2da45 | Paul Brook | if (slave->address == address)
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83 | 0ff596d0 | pbrook | break;
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84 | 0ff596d0 | pbrook | } |
85 | 0ff596d0 | pbrook | |
86 | 02e2da45 | Paul Brook | if (!slave)
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87 | 0ff596d0 | pbrook | return 1; |
88 | 0ff596d0 | pbrook | |
89 | 0ff596d0 | pbrook | /* If the bus is already busy, assume this is a repeated
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90 | 0ff596d0 | pbrook | start condition. */
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91 | 02e2da45 | Paul Brook | bus->current_dev = slave; |
92 | 02e2da45 | Paul Brook | slave->info->event(slave, recv ? I2C_START_RECV : I2C_START_SEND); |
93 | 0ff596d0 | pbrook | return 0; |
94 | 0ff596d0 | pbrook | } |
95 | 0ff596d0 | pbrook | |
96 | 0ff596d0 | pbrook | void i2c_end_transfer(i2c_bus *bus)
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97 | 0ff596d0 | pbrook | { |
98 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
99 | 0ff596d0 | pbrook | |
100 | 0ff596d0 | pbrook | if (!dev)
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101 | 0ff596d0 | pbrook | return;
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102 | 0ff596d0 | pbrook | |
103 | fe8de492 | Paul Brook | dev->info->event(dev, I2C_FINISH); |
104 | 0ff596d0 | pbrook | |
105 | 0ff596d0 | pbrook | bus->current_dev = NULL;
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106 | 0ff596d0 | pbrook | } |
107 | 0ff596d0 | pbrook | |
108 | 0ff596d0 | pbrook | int i2c_send(i2c_bus *bus, uint8_t data)
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109 | 0ff596d0 | pbrook | { |
110 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
111 | 0ff596d0 | pbrook | |
112 | 0ff596d0 | pbrook | if (!dev)
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113 | 0ff596d0 | pbrook | return -1; |
114 | 0ff596d0 | pbrook | |
115 | fe8de492 | Paul Brook | return dev->info->send(dev, data);
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116 | 0ff596d0 | pbrook | } |
117 | 0ff596d0 | pbrook | |
118 | 0ff596d0 | pbrook | int i2c_recv(i2c_bus *bus)
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119 | 0ff596d0 | pbrook | { |
120 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
121 | 0ff596d0 | pbrook | |
122 | 0ff596d0 | pbrook | if (!dev)
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123 | 0ff596d0 | pbrook | return -1; |
124 | 0ff596d0 | pbrook | |
125 | fe8de492 | Paul Brook | return dev->info->recv(dev);
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126 | 0ff596d0 | pbrook | } |
127 | 0ff596d0 | pbrook | |
128 | 0ff596d0 | pbrook | void i2c_nack(i2c_bus *bus)
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129 | 0ff596d0 | pbrook | { |
130 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
131 | 0ff596d0 | pbrook | |
132 | 0ff596d0 | pbrook | if (!dev)
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133 | 0ff596d0 | pbrook | return;
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134 | 0ff596d0 | pbrook | |
135 | fe8de492 | Paul Brook | dev->info->event(dev, I2C_NACK); |
136 | 0ff596d0 | pbrook | } |
137 | 0ff596d0 | pbrook | |
138 | aa941b94 | balrog | void i2c_slave_save(QEMUFile *f, i2c_slave *dev)
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139 | aa941b94 | balrog | { |
140 | 5b7f5327 | Juan Quintela | qemu_put_8s(f, &dev->address); |
141 | aa941b94 | balrog | } |
142 | aa941b94 | balrog | |
143 | aa941b94 | balrog | void i2c_slave_load(QEMUFile *f, i2c_slave *dev)
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144 | aa941b94 | balrog | { |
145 | fe8de492 | Paul Brook | i2c_bus *bus; |
146 | 02e2da45 | Paul Brook | bus = FROM_QBUS(i2c_bus, qdev_get_parent_bus(&dev->qdev)); |
147 | 5b7f5327 | Juan Quintela | qemu_get_8s(f, &dev->address); |
148 | fe8de492 | Paul Brook | if (bus->saved_address == dev->address) {
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149 | fe8de492 | Paul Brook | bus->current_dev = dev; |
150 | fe8de492 | Paul Brook | } |
151 | fe8de492 | Paul Brook | } |
152 | fe8de492 | Paul Brook | |
153 | 81a322d4 | Gerd Hoffmann | static int i2c_slave_qdev_init(DeviceState *dev, DeviceInfo *base) |
154 | fe8de492 | Paul Brook | { |
155 | 02e2da45 | Paul Brook | I2CSlaveInfo *info = container_of(base, I2CSlaveInfo, qdev); |
156 | fe8de492 | Paul Brook | i2c_slave *s = I2C_SLAVE_FROM_QDEV(dev); |
157 | fe8de492 | Paul Brook | |
158 | fe8de492 | Paul Brook | s->info = info; |
159 | fe8de492 | Paul Brook | |
160 | 81a322d4 | Gerd Hoffmann | return info->init(s);
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161 | fe8de492 | Paul Brook | } |
162 | fe8de492 | Paul Brook | |
163 | 074f2fff | Gerd Hoffmann | void i2c_register_slave(I2CSlaveInfo *info)
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164 | fe8de492 | Paul Brook | { |
165 | 074f2fff | Gerd Hoffmann | assert(info->qdev.size >= sizeof(i2c_slave));
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166 | 02e2da45 | Paul Brook | info->qdev.init = i2c_slave_qdev_init; |
167 | 10c4c98a | Gerd Hoffmann | info->qdev.bus_info = &i2c_bus_info; |
168 | 074f2fff | Gerd Hoffmann | qdev_register(&info->qdev); |
169 | fe8de492 | Paul Brook | } |
170 | fe8de492 | Paul Brook | |
171 | 5b7f5327 | Juan Quintela | DeviceState *i2c_create_slave(i2c_bus *bus, const char *name, uint8_t addr) |
172 | fe8de492 | Paul Brook | { |
173 | fe8de492 | Paul Brook | DeviceState *dev; |
174 | fe8de492 | Paul Brook | |
175 | 02e2da45 | Paul Brook | dev = qdev_create(&bus->qbus, name); |
176 | 5b7f5327 | Juan Quintela | qdev_prop_set_uint8(dev, "address", addr);
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177 | fe8de492 | Paul Brook | qdev_init(dev); |
178 | fe8de492 | Paul Brook | return dev;
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179 | aa941b94 | balrog | } |