1 /*
2 * TI ADS7846 / TSC2046 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 GPL v2.
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 #include "ui/console.h"
19 #include "qom/object.h"
20
21 struct ADS7846State {
22 SSIPeripheral ssidev;
23 qemu_irq interrupt;
24
25 int input[8];
26 int pressure;
27 int noise;
28
29 int cycle;
30 int output;
31 };
32
33 #define TYPE_ADS7846 "ads7846"
OBJECT_DECLARE_SIMPLE_TYPE(ADS7846State,ADS7846)34 OBJECT_DECLARE_SIMPLE_TYPE(ADS7846State, ADS7846)
35
36 /* Control-byte bitfields */
37 #define CB_PD0 (1 << 0)
38 #define CB_PD1 (1 << 1)
39 #define CB_SER (1 << 2)
40 #define CB_MODE (1 << 3)
41 #define CB_A0 (1 << 4)
42 #define CB_A1 (1 << 5)
43 #define CB_A2 (1 << 6)
44 #define CB_START (1 << 7)
45
46 #define X_AXIS_DMAX 3470
47 #define X_AXIS_MIN 290
48 #define Y_AXIS_DMAX 3450
49 #define Y_AXIS_MIN 200
50
51 #define ADS_VBAT 2000
52 #define ADS_VAUX 2000
53 #define ADS_TEMP0 2000
54 #define ADS_TEMP1 3000
55 #define ADS_XPOS(x, y) (X_AXIS_MIN + ((X_AXIS_DMAX * (x)) >> 15))
56 #define ADS_YPOS(x, y) (Y_AXIS_MIN + ((Y_AXIS_DMAX * (y)) >> 15))
57 #define ADS_Z1POS(x, y) 600
58 #define ADS_Z2POS(x, y) (600 + 6000 / ADS_XPOS(x, y))
59
60 static void ads7846_int_update(ADS7846State *s)
61 {
62 if (s->interrupt)
63 qemu_set_irq(s->interrupt, s->pressure == 0);
64 }
65
ads7846_transfer(SSIPeripheral * dev,uint32_t value)66 static uint32_t ads7846_transfer(SSIPeripheral *dev, uint32_t value)
67 {
68 ADS7846State *s = ADS7846(dev);
69
70 switch (s->cycle ++) {
71 case 0:
72 if (!(value & CB_START)) {
73 s->cycle = 0;
74 break;
75 }
76
77 s->output = s->input[(value >> 4) & 7];
78
79 /* Imitate the ADC noise, some drivers expect this. */
80 s->noise = (s->noise + 3) & 7;
81 switch ((value >> 4) & 7) {
82 case 1: s->output += s->noise ^ 2; break;
83 case 3: s->output += s->noise ^ 0; break;
84 case 4: s->output += s->noise ^ 7; break;
85 case 5: s->output += s->noise ^ 5; break;
86 }
87
88 if (value & CB_MODE)
89 s->output >>= 4; /* 8 bits instead of 12 */
90
91 break;
92 case 1:
93 s->cycle = 0;
94 break;
95 }
96 return s->output;
97 }
98
ads7846_ts_event(void * opaque,int x,int y,int z,int buttons_state)99 static void ads7846_ts_event(void *opaque,
100 int x, int y, int z, int buttons_state)
101 {
102 ADS7846State *s = opaque;
103
104 if (buttons_state) {
105 x = 0x7fff - x;
106 s->input[1] = ADS_XPOS(x, y);
107 s->input[3] = ADS_Z1POS(x, y);
108 s->input[4] = ADS_Z2POS(x, y);
109 s->input[5] = ADS_YPOS(x, y);
110 }
111
112 if (s->pressure == !buttons_state) {
113 s->pressure = !!buttons_state;
114
115 ads7846_int_update(s);
116 }
117 }
118
ads7856_post_load(void * opaque,int version_id)119 static int ads7856_post_load(void *opaque, int version_id)
120 {
121 ADS7846State *s = opaque;
122
123 s->pressure = 0;
124 ads7846_int_update(s);
125 return 0;
126 }
127
128 static const VMStateDescription vmstate_ads7846 = {
129 .name = "ads7846",
130 .version_id = 1,
131 .minimum_version_id = 1,
132 .post_load = ads7856_post_load,
133 .fields = (const VMStateField[]) {
134 VMSTATE_SSI_PERIPHERAL(ssidev, ADS7846State),
135 VMSTATE_INT32_ARRAY(input, ADS7846State, 8),
136 VMSTATE_INT32(noise, ADS7846State),
137 VMSTATE_INT32(cycle, ADS7846State),
138 VMSTATE_INT32(output, ADS7846State),
139 VMSTATE_END_OF_LIST()
140 }
141 };
142
ads7846_realize(SSIPeripheral * d,Error ** errp)143 static void ads7846_realize(SSIPeripheral *d, Error **errp)
144 {
145 DeviceState *dev = DEVICE(d);
146 ADS7846State *s = ADS7846(d);
147
148 qdev_init_gpio_out(dev, &s->interrupt, 1);
149
150 s->input[0] = ADS_TEMP0; /* TEMP0 */
151 s->input[2] = ADS_VBAT; /* VBAT */
152 s->input[6] = ADS_VAUX; /* VAUX */
153 s->input[7] = ADS_TEMP1; /* TEMP1 */
154
155 /* We want absolute coordinates */
156 qemu_add_mouse_event_handler(ads7846_ts_event, s, 1,
157 "QEMU ADS7846-driven Touchscreen");
158
159 ads7846_int_update(s);
160
161 vmstate_register_any(NULL, &vmstate_ads7846, s);
162 }
163
ads7846_class_init(ObjectClass * klass,void * data)164 static void ads7846_class_init(ObjectClass *klass, void *data)
165 {
166 DeviceClass *dc = DEVICE_CLASS(klass);
167 SSIPeripheralClass *k = SSI_PERIPHERAL_CLASS(klass);
168
169 k->realize = ads7846_realize;
170 k->transfer = ads7846_transfer;
171 set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
172 }
173
174 static const TypeInfo ads7846_info = {
175 .name = TYPE_ADS7846,
176 .parent = TYPE_SSI_PERIPHERAL,
177 .instance_size = sizeof(ADS7846State),
178 .class_init = ads7846_class_init,
179 };
180
ads7846_register_types(void)181 static void ads7846_register_types(void)
182 {
183 type_register_static(&ads7846_info);
184 }
185
186 type_init(ads7846_register_types)
187