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78c71af8 PM |
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" | |
0b8fa32f | 21 | #include "qemu/module.h" |
78c71af8 | 22 | #include "hw/i2c/i2c.h" |
a27bd6c7 | 23 | #include "hw/qdev-properties.h" |
d6454270 | 24 | #include "migration/vmstate.h" |
6306cae2 | 25 | #include "hw/display/i2c-ddc.h" |
78c71af8 PM |
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 | } \ | |
2562755e | 35 | } while (0) |
78c71af8 | 36 | |
78c71af8 PM |
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 | ||
d307c28c | 45 | static int i2c_ddc_event(I2CSlave *i2c, enum i2c_event event) |
78c71af8 PM |
46 | { |
47 | I2CDDCState *s = I2CDDC(i2c); | |
48 | ||
49 | if (event == I2C_START_SEND) { | |
50 | s->firstbyte = true; | |
51 | } | |
d307c28c CM |
52 | |
53 | return 0; | |
78c71af8 PM |
54 | } |
55 | ||
2ac4c5f4 | 56 | static uint8_t i2c_ddc_rx(I2CSlave *i2c) |
78c71af8 PM |
57 | { |
58 | I2CDDCState *s = I2CDDC(i2c); | |
59 | ||
60 | int value; | |
b05b2678 | 61 | value = s->edid_blob[s->reg % sizeof(s->edid_blob)]; |
78c71af8 PM |
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); | |
839a2b28 | 73 | return 0; |
78c71af8 PM |
74 | } |
75 | ||
76 | /* Ignore all writes */ | |
77 | s->reg++; | |
839a2b28 | 78 | return 0; |
78c71af8 PM |
79 | } |
80 | ||
81 | static void i2c_ddc_init(Object *obj) | |
82 | { | |
83 | I2CDDCState *s = I2CDDC(obj); | |
715eb05b GH |
84 | |
85 | qemu_edid_generate(s->edid_blob, sizeof(s->edid_blob), &s->edid_info); | |
78c71af8 PM |
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 | ||
715eb05b GH |
98 | static Property i2c_ddc_properties[] = { |
99 | DEFINE_EDID_PROPERTIES(I2CDDCState, edid_info), | |
100 | DEFINE_PROP_END_OF_LIST(), | |
101 | }; | |
102 | ||
78c71af8 PM |
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; | |
715eb05b | 110 | dc->props = i2c_ddc_properties; |
78c71af8 PM |
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); |