1 | /* A simple I2C slave for returning monitor EDID data via DDC. |
2 | * |
3 | * Copyright (c) 2011 Linaro Limited |
4 | * Written by Peter Maydell |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify |
7 | * it under the terms of the GNU General Public License version 2 as |
8 | * published by the Free Software Foundation. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | * GNU General Public License for more details. |
14 | * |
15 | * You should have received a copy of the GNU General Public License along |
16 | * with this program; if not, see <http://www.gnu.org/licenses/>. |
17 | */ |
18 | |
19 | #include "qemu/osdep.h" |
20 | #include "qemu/log.h" |
21 | #include "qemu/module.h" |
22 | #include "hw/i2c/i2c.h" |
23 | #include "hw/qdev-properties.h" |
24 | #include "migration/vmstate.h" |
25 | #include "hw/display/i2c-ddc.h" |
26 | |
27 | #ifndef DEBUG_I2CDDC |
28 | #define DEBUG_I2CDDC 0 |
29 | #endif |
30 | |
31 | #define DPRINTF(fmt, ...) do { \ |
32 | if (DEBUG_I2CDDC) { \ |
33 | qemu_log("i2c-ddc: " fmt , ## __VA_ARGS__); \ |
34 | } \ |
35 | } while (0) |
36 | |
37 | static void i2c_ddc_reset(DeviceState *ds) |
38 | { |
39 | I2CDDCState *s = I2CDDC(ds); |
40 | |
41 | s->firstbyte = false; |
42 | s->reg = 0; |
43 | } |
44 | |
45 | static int i2c_ddc_event(I2CSlave *i2c, enum i2c_event event) |
46 | { |
47 | I2CDDCState *s = I2CDDC(i2c); |
48 | |
49 | if (event == I2C_START_SEND) { |
50 | s->firstbyte = true; |
51 | } |
52 | |
53 | return 0; |
54 | } |
55 | |
56 | static uint8_t i2c_ddc_rx(I2CSlave *i2c) |
57 | { |
58 | I2CDDCState *s = I2CDDC(i2c); |
59 | |
60 | int value; |
61 | value = s->edid_blob[s->reg % sizeof(s->edid_blob)]; |
62 | s->reg++; |
63 | return value; |
64 | } |
65 | |
66 | static int i2c_ddc_tx(I2CSlave *i2c, uint8_t data) |
67 | { |
68 | I2CDDCState *s = I2CDDC(i2c); |
69 | if (s->firstbyte) { |
70 | s->reg = data; |
71 | s->firstbyte = false; |
72 | DPRINTF("[EDID] Written new pointer: %u\n" , data); |
73 | return 0; |
74 | } |
75 | |
76 | /* Ignore all writes */ |
77 | s->reg++; |
78 | return 0; |
79 | } |
80 | |
81 | static void i2c_ddc_init(Object *obj) |
82 | { |
83 | I2CDDCState *s = I2CDDC(obj); |
84 | |
85 | qemu_edid_generate(s->edid_blob, sizeof(s->edid_blob), &s->edid_info); |
86 | } |
87 | |
88 | static const VMStateDescription vmstate_i2c_ddc = { |
89 | .name = TYPE_I2CDDC, |
90 | .version_id = 1, |
91 | .fields = (VMStateField[]) { |
92 | VMSTATE_BOOL(firstbyte, I2CDDCState), |
93 | VMSTATE_UINT8(reg, I2CDDCState), |
94 | VMSTATE_END_OF_LIST() |
95 | } |
96 | }; |
97 | |
98 | static Property i2c_ddc_properties[] = { |
99 | DEFINE_EDID_PROPERTIES(I2CDDCState, edid_info), |
100 | DEFINE_PROP_END_OF_LIST(), |
101 | }; |
102 | |
103 | static void i2c_ddc_class_init(ObjectClass *oc, void *data) |
104 | { |
105 | DeviceClass *dc = DEVICE_CLASS(oc); |
106 | I2CSlaveClass *isc = I2C_SLAVE_CLASS(oc); |
107 | |
108 | dc->reset = i2c_ddc_reset; |
109 | dc->vmsd = &vmstate_i2c_ddc; |
110 | dc->props = i2c_ddc_properties; |
111 | isc->event = i2c_ddc_event; |
112 | isc->recv = i2c_ddc_rx; |
113 | isc->send = i2c_ddc_tx; |
114 | } |
115 | |
116 | static TypeInfo i2c_ddc_info = { |
117 | .name = TYPE_I2CDDC, |
118 | .parent = TYPE_I2C_SLAVE, |
119 | .instance_size = sizeof(I2CDDCState), |
120 | .instance_init = i2c_ddc_init, |
121 | .class_init = i2c_ddc_class_init |
122 | }; |
123 | |
124 | static void ddc_register_devices(void) |
125 | { |
126 | type_register_static(&i2c_ddc_info); |
127 | } |
128 | |
129 | type_init(ddc_register_devices); |
130 | |