2 * QEMU I2C bus interface.
4 * Copyright (c) 2007 CodeSourcery.
5 * Written by Paul Brook
7 * This code is licensed under the LGPL.
15 I2CSlave
*current_dev
;
17 uint8_t saved_address
;
20 static Property i2c_props
[] = {
21 DEFINE_PROP_UINT8("address", struct I2CSlave
, address
, 0),
22 DEFINE_PROP_END_OF_LIST(),
25 static struct BusInfo i2c_bus_info
= {
27 .size
= sizeof(i2c_bus
),
30 static void i2c_bus_pre_save(void *opaque
)
32 i2c_bus
*bus
= opaque
;
34 bus
->saved_address
= bus
->current_dev
? bus
->current_dev
->address
: -1;
37 static int i2c_bus_post_load(void *opaque
, int version_id
)
39 i2c_bus
*bus
= opaque
;
41 /* The bus is loaded before attached devices, so load and save the
42 current device id. Devices will check themselves as loaded. */
43 bus
->current_dev
= NULL
;
47 static const VMStateDescription vmstate_i2c_bus
= {
50 .minimum_version_id
= 1,
51 .minimum_version_id_old
= 1,
52 .pre_save
= i2c_bus_pre_save
,
53 .post_load
= i2c_bus_post_load
,
54 .fields
= (VMStateField
[]) {
55 VMSTATE_UINT8(saved_address
, i2c_bus
),
60 /* Create a new I2C bus. */
61 i2c_bus
*i2c_init_bus(DeviceState
*parent
, const char *name
)
65 bus
= FROM_QBUS(i2c_bus
, qbus_create(&i2c_bus_info
, parent
, name
));
66 vmstate_register(NULL
, -1, &vmstate_i2c_bus
, bus
);
70 void i2c_set_slave_address(I2CSlave
*dev
, uint8_t address
)
72 dev
->address
= address
;
75 /* Return nonzero if bus is busy. */
76 int i2c_bus_busy(i2c_bus
*bus
)
78 return bus
->current_dev
!= NULL
;
81 /* Returns non-zero if the address is not valid. */
82 /* TODO: Make this handle multiple masters. */
83 int i2c_start_transfer(i2c_bus
*bus
, uint8_t address
, int recv
)
86 I2CSlave
*slave
= NULL
;
89 QTAILQ_FOREACH(qdev
, &bus
->qbus
.children
, sibling
) {
90 I2CSlave
*candidate
= I2C_SLAVE_FROM_QDEV(qdev
);
91 if (candidate
->address
== address
) {
101 sc
= I2C_SLAVE_GET_CLASS(slave
);
102 /* If the bus is already busy, assume this is a repeated
104 bus
->current_dev
= slave
;
106 sc
->event(slave
, recv
? I2C_START_RECV
: I2C_START_SEND
);
111 void i2c_end_transfer(i2c_bus
*bus
)
113 I2CSlave
*dev
= bus
->current_dev
;
120 sc
= I2C_SLAVE_GET_CLASS(dev
);
122 sc
->event(dev
, I2C_FINISH
);
125 bus
->current_dev
= NULL
;
128 int i2c_send(i2c_bus
*bus
, uint8_t data
)
130 I2CSlave
*dev
= bus
->current_dev
;
137 sc
= I2C_SLAVE_GET_CLASS(dev
);
139 return sc
->send(dev
, data
);
145 int i2c_recv(i2c_bus
*bus
)
147 I2CSlave
*dev
= bus
->current_dev
;
154 sc
= I2C_SLAVE_GET_CLASS(dev
);
156 return sc
->recv(dev
);
162 void i2c_nack(i2c_bus
*bus
)
164 I2CSlave
*dev
= bus
->current_dev
;
171 sc
= I2C_SLAVE_GET_CLASS(dev
);
173 sc
->event(dev
, I2C_NACK
);
177 static int i2c_slave_post_load(void *opaque
, int version_id
)
179 I2CSlave
*dev
= opaque
;
181 bus
= FROM_QBUS(i2c_bus
, qdev_get_parent_bus(&dev
->qdev
));
182 if (bus
->saved_address
== dev
->address
) {
183 bus
->current_dev
= dev
;
188 const VMStateDescription vmstate_i2c_slave
= {
191 .minimum_version_id
= 1,
192 .minimum_version_id_old
= 1,
193 .post_load
= i2c_slave_post_load
,
194 .fields
= (VMStateField
[]) {
195 VMSTATE_UINT8(address
, I2CSlave
),
196 VMSTATE_END_OF_LIST()
200 static int i2c_slave_qdev_init(DeviceState
*dev
)
202 I2CSlave
*s
= I2C_SLAVE_FROM_QDEV(dev
);
203 I2CSlaveClass
*sc
= I2C_SLAVE_GET_CLASS(s
);
208 DeviceState
*i2c_create_slave(i2c_bus
*bus
, const char *name
, uint8_t addr
)
212 dev
= qdev_create(&bus
->qbus
, name
);
213 qdev_prop_set_uint8(dev
, "address", addr
);
214 qdev_init_nofail(dev
);
218 static void i2c_slave_class_init(ObjectClass
*klass
, void *data
)
220 DeviceClass
*k
= DEVICE_CLASS(klass
);
221 k
->init
= i2c_slave_qdev_init
;
222 k
->bus_info
= &i2c_bus_info
;
223 k
->props
= i2c_props
;
226 static TypeInfo i2c_slave_type_info
= {
227 .name
= TYPE_I2C_SLAVE
,
228 .parent
= TYPE_DEVICE
,
229 .instance_size
= sizeof(I2CSlave
),
231 .class_size
= sizeof(I2CSlaveClass
),
232 .class_init
= i2c_slave_class_init
,
235 static void i2c_slave_register_types(void)
237 type_register_static(&i2c_slave_type_info
);
240 type_init(i2c_slave_register_types
)