root / hw / ads7846.c @ c190ea07
History | View | Annotate | Download (3.8 kB)
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 |
|
10 |
#include "hw.h" |
11 |
#include "devices.h" |
12 |
#include "console.h" |
13 |
|
14 |
struct ads7846_state_s {
|
15 |
qemu_irq interrupt; |
16 |
|
17 |
int input[8]; |
18 |
int pressure;
|
19 |
int noise;
|
20 |
|
21 |
int cycle;
|
22 |
int output;
|
23 |
}; |
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 |
|
35 |
#define X_AXIS_DMAX 3470 |
36 |
#define X_AXIS_MIN 290 |
37 |
#define Y_AXIS_DMAX 3450 |
38 |
#define Y_AXIS_MIN 200 |
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 |
|
49 |
static void ads7846_int_update(struct ads7846_state_s *s) |
50 |
{ |
51 |
if (s->interrupt)
|
52 |
qemu_set_irq(s->interrupt, s->pressure == 0);
|
53 |
} |
54 |
|
55 |
uint32_t ads7846_read(void *opaque)
|
56 |
{ |
57 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
58 |
|
59 |
return s->output;
|
60 |
} |
61 |
|
62 |
void ads7846_write(void *opaque, uint32_t value) |
63 |
{ |
64 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
65 |
|
66 |
switch (s->cycle ++) {
|
67 |
case 0: |
68 |
if (!(value & CB_START)) {
|
69 |
s->cycle = 0;
|
70 |
break;
|
71 |
} |
72 |
|
73 |
s->output = s->input[(value >> 4) & 7]; |
74 |
|
75 |
/* Imitate the ADC noise, some drivers expect this. */
|
76 |
s->noise = (s->noise + 3) & 7; |
77 |
switch ((value >> 4) & 7) { |
78 |
case 1: s->output += s->noise ^ 2; break; |
79 |
case 3: s->output += s->noise ^ 0; break; |
80 |
case 4: s->output += s->noise ^ 7; break; |
81 |
case 5: s->output += s->noise ^ 5; break; |
82 |
} |
83 |
|
84 |
if (value & CB_MODE)
|
85 |
s->output >>= 4; /* 8 bits instead of 12 */ |
86 |
|
87 |
break;
|
88 |
case 1: |
89 |
s->cycle = 0;
|
90 |
break;
|
91 |
} |
92 |
} |
93 |
|
94 |
static void ads7846_ts_event(void *opaque, |
95 |
int x, int y, int z, int buttons_state) |
96 |
{ |
97 |
struct ads7846_state_s *s = opaque;
|
98 |
|
99 |
if (buttons_state) {
|
100 |
x = 0x7fff - x;
|
101 |
s->input[1] = ADS_XPOS(x, y);
|
102 |
s->input[3] = ADS_Z1POS(x, y);
|
103 |
s->input[4] = ADS_Z2POS(x, y);
|
104 |
s->input[5] = ADS_YPOS(x, y);
|
105 |
} |
106 |
|
107 |
if (s->pressure == !buttons_state) {
|
108 |
s->pressure = !!buttons_state; |
109 |
|
110 |
ads7846_int_update(s); |
111 |
} |
112 |
} |
113 |
|
114 |
static void ads7846_save(QEMUFile *f, void *opaque) |
115 |
{ |
116 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
117 |
int i;
|
118 |
|
119 |
for (i = 0; i < 8; i ++) |
120 |
qemu_put_be32(f, s->input[i]); |
121 |
qemu_put_be32(f, s->noise); |
122 |
qemu_put_be32(f, s->cycle); |
123 |
qemu_put_be32(f, s->output); |
124 |
} |
125 |
|
126 |
static int ads7846_load(QEMUFile *f, void *opaque, int version_id) |
127 |
{ |
128 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
129 |
int i;
|
130 |
|
131 |
for (i = 0; i < 8; i ++) |
132 |
s->input[i] = qemu_get_be32(f); |
133 |
s->noise = qemu_get_be32(f); |
134 |
s->cycle = qemu_get_be32(f); |
135 |
s->output = qemu_get_be32(f); |
136 |
|
137 |
s->pressure = 0;
|
138 |
ads7846_int_update(s); |
139 |
|
140 |
return 0; |
141 |
} |
142 |
|
143 |
struct ads7846_state_s *ads7846_init(qemu_irq penirq)
|
144 |
{ |
145 |
struct ads7846_state_s *s;
|
146 |
s = (struct ads7846_state_s *)
|
147 |
qemu_mallocz(sizeof(struct ads7846_state_s)); |
148 |
memset(s, 0, sizeof(struct ads7846_state_s)); |
149 |
|
150 |
s->interrupt = penirq; |
151 |
|
152 |
s->input[0] = ADS_TEMP0; /* TEMP0 */ |
153 |
s->input[2] = ADS_VBAT; /* VBAT */ |
154 |
s->input[6] = ADS_VAUX; /* VAUX */ |
155 |
s->input[7] = ADS_TEMP1; /* TEMP1 */ |
156 |
|
157 |
/* We want absolute coordinates */
|
158 |
qemu_add_mouse_event_handler(ads7846_ts_event, s, 1,
|
159 |
"QEMU ADS7846-driven Touchscreen");
|
160 |
|
161 |
ads7846_int_update(s); |
162 |
|
163 |
register_savevm("ads7846", -1, 0, ads7846_save, ads7846_load, s); |
164 |
|
165 |
return s;
|
166 |
} |