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fd5a3b33 1/*
87283515 2 * TI ADS7846 / TSC2046 chip emulation.
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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
a984a69e 10#include "ssi.h"
87ecb68b 11#include "console.h"
fd5a3b33 12
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13typedef struct {
14 SSISlave ssidev;
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15 qemu_irq interrupt;
16
17 int input[8];
18 int pressure;
19 int noise;
20
21 int cycle;
22 int output;
a984a69e 23} ADS7846State;
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24
25/* Control-byte bitfields */
26#define CB_PD0 (1 << 0)
27#define CB_PD1 (1 << 1)
28#define CB_SER (1 << 2)
29#define CB_MODE (1 << 3)
30#define CB_A0 (1 << 4)
31#define CB_A1 (1 << 5)
32#define CB_A2 (1 << 6)
33#define CB_START (1 << 7)
34
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35#define X_AXIS_DMAX 3470
36#define X_AXIS_MIN 290
37#define Y_AXIS_DMAX 3450
38#define Y_AXIS_MIN 200
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39
40#define ADS_VBAT 2000
41#define ADS_VAUX 2000
42#define ADS_TEMP0 2000
43#define ADS_TEMP1 3000
44#define ADS_XPOS(x, y) (X_AXIS_MIN + ((X_AXIS_DMAX * (x)) >> 15))
45#define ADS_YPOS(x, y) (Y_AXIS_MIN + ((Y_AXIS_DMAX * (y)) >> 15))
46#define ADS_Z1POS(x, y) 600
47#define ADS_Z2POS(x, y) (600 + 6000 / ADS_XPOS(x, y))
48
bc24a225 49static void ads7846_int_update(ADS7846State *s)
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50{
51 if (s->interrupt)
52 qemu_set_irq(s->interrupt, s->pressure == 0);
53}
54
a984a69e 55static uint32_t ads7846_transfer(SSISlave *dev, uint32_t value)
fd5a3b33 56{
a984a69e 57 ADS7846State *s = FROM_SSI_SLAVE(ADS7846State, dev);
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58
59 switch (s->cycle ++) {
60 case 0:
61 if (!(value & CB_START)) {
62 s->cycle = 0;
63 break;
64 }
65
66 s->output = s->input[(value >> 4) & 7];
67
68 /* Imitate the ADC noise, some drivers expect this. */
69 s->noise = (s->noise + 3) & 7;
70 switch ((value >> 4) & 7) {
71 case 1: s->output += s->noise ^ 2; break;
72 case 3: s->output += s->noise ^ 0; break;
73 case 4: s->output += s->noise ^ 7; break;
74 case 5: s->output += s->noise ^ 5; break;
75 }
76
77 if (value & CB_MODE)
78 s->output >>= 4; /* 8 bits instead of 12 */
79
80 break;
81 case 1:
82 s->cycle = 0;
83 break;
84 }
a984a69e 85 return s->output;
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86}
87
88static void ads7846_ts_event(void *opaque,
89 int x, int y, int z, int buttons_state)
90{
bc24a225 91 ADS7846State *s = opaque;
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92
93 if (buttons_state) {
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94 x = 0x7fff - x;
95 s->input[1] = ADS_XPOS(x, y);
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96 s->input[3] = ADS_Z1POS(x, y);
97 s->input[4] = ADS_Z2POS(x, y);
611d7189 98 s->input[5] = ADS_YPOS(x, y);
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99 }
100
101 if (s->pressure == !buttons_state) {
102 s->pressure = !!buttons_state;
103
aa941b94 104 ads7846_int_update(s);
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105 }
106}
107
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108static void ads7846_save(QEMUFile *f, void *opaque)
109{
bc24a225 110 ADS7846State *s = (ADS7846State *) opaque;
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111 int i;
112
113 for (i = 0; i < 8; i ++)
114 qemu_put_be32(f, s->input[i]);
115 qemu_put_be32(f, s->noise);
116 qemu_put_be32(f, s->cycle);
117 qemu_put_be32(f, s->output);
118}
119
120static int ads7846_load(QEMUFile *f, void *opaque, int version_id)
121{
bc24a225 122 ADS7846State *s = (ADS7846State *) opaque;
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123 int i;
124
125 for (i = 0; i < 8; i ++)
126 s->input[i] = qemu_get_be32(f);
127 s->noise = qemu_get_be32(f);
128 s->cycle = qemu_get_be32(f);
129 s->output = qemu_get_be32(f);
130
131 s->pressure = 0;
132 ads7846_int_update(s);
133
134 return 0;
135}
136
81a322d4 137static int ads7846_init(SSISlave *dev)
fd5a3b33 138{
a984a69e 139 ADS7846State *s = FROM_SSI_SLAVE(ADS7846State, dev);
fd5a3b33 140
a984a69e 141 qdev_init_gpio_out(&dev->qdev, &s->interrupt, 1);
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142
143 s->input[0] = ADS_TEMP0; /* TEMP0 */
144 s->input[2] = ADS_VBAT; /* VBAT */
145 s->input[6] = ADS_VAUX; /* VAUX */
146 s->input[7] = ADS_TEMP1; /* TEMP1 */
147
148 /* We want absolute coordinates */
149 qemu_add_mouse_event_handler(ads7846_ts_event, s, 1,
150 "QEMU ADS7846-driven Touchscreen");
151
152 ads7846_int_update(s);
aa941b94 153
0be71e32 154 register_savevm(NULL, "ads7846", -1, 0, ads7846_save, ads7846_load, s);
81a322d4 155 return 0;
a984a69e 156}
aa941b94 157
a984a69e 158static SSISlaveInfo ads7846_info = {
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159 .qdev.name ="ads7846",
160 .qdev.size = sizeof(ADS7846State),
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161 .init = ads7846_init,
162 .transfer = ads7846_transfer
163};
164
165static void ads7846_register_devices(void)
166{
074f2fff 167 ssi_register_slave(&ads7846_info);
fd5a3b33 168}
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169
170device_init(ads7846_register_devices)