root / hw / ads7846.c @ bde7600c
History | View | Annotate | Download (3.9 kB)
1 |
/*
|
---|---|
2 |
* TI ADS7846 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 <vl.h> |
11 |
|
12 |
struct ads7846_state_s {
|
13 |
qemu_irq interrupt; |
14 |
|
15 |
int input[8]; |
16 |
int pressure;
|
17 |
int noise;
|
18 |
|
19 |
int cycle;
|
20 |
int output;
|
21 |
}; |
22 |
|
23 |
/* Control-byte bitfields */
|
24 |
#define CB_PD0 (1 << 0) |
25 |
#define CB_PD1 (1 << 1) |
26 |
#define CB_SER (1 << 2) |
27 |
#define CB_MODE (1 << 3) |
28 |
#define CB_A0 (1 << 4) |
29 |
#define CB_A1 (1 << 5) |
30 |
#define CB_A2 (1 << 6) |
31 |
#define CB_START (1 << 7) |
32 |
|
33 |
#define X_AXIS_DMAX 3470 |
34 |
#define X_AXIS_MIN 290 |
35 |
#define Y_AXIS_DMAX 3450 |
36 |
#define Y_AXIS_MIN 200 |
37 |
|
38 |
#define ADS_VBAT 2000 |
39 |
#define ADS_VAUX 2000 |
40 |
#define ADS_TEMP0 2000 |
41 |
#define ADS_TEMP1 3000 |
42 |
#define ADS_XPOS(x, y) (X_AXIS_MIN + ((X_AXIS_DMAX * (x)) >> 15)) |
43 |
#define ADS_YPOS(x, y) (Y_AXIS_MIN + ((Y_AXIS_DMAX * (y)) >> 15)) |
44 |
#define ADS_Z1POS(x, y) 600 |
45 |
#define ADS_Z2POS(x, y) (600 + 6000 / ADS_XPOS(x, y)) |
46 |
|
47 |
static void ads7846_int_update(struct ads7846_state_s *s) |
48 |
{ |
49 |
if (s->interrupt)
|
50 |
qemu_set_irq(s->interrupt, s->pressure == 0);
|
51 |
} |
52 |
|
53 |
uint32_t ads7846_read(void *opaque)
|
54 |
{ |
55 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
56 |
|
57 |
return s->output;
|
58 |
} |
59 |
|
60 |
void ads7846_write(void *opaque, uint32_t value) |
61 |
{ |
62 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
63 |
|
64 |
switch (s->cycle ++) {
|
65 |
case 0: |
66 |
if (!(value & CB_START)) {
|
67 |
s->cycle = 0;
|
68 |
break;
|
69 |
} |
70 |
|
71 |
s->output = s->input[(value >> 4) & 7]; |
72 |
|
73 |
/* Imitate the ADC noise, some drivers expect this. */
|
74 |
s->noise = (s->noise + 3) & 7; |
75 |
switch ((value >> 4) & 7) { |
76 |
case 1: s->output += s->noise ^ 2; break; |
77 |
case 3: s->output += s->noise ^ 0; break; |
78 |
case 4: s->output += s->noise ^ 7; break; |
79 |
case 5: s->output += s->noise ^ 5; break; |
80 |
} |
81 |
|
82 |
if (value & CB_MODE)
|
83 |
s->output >>= 4; /* 8 bits instead of 12 */ |
84 |
|
85 |
break;
|
86 |
case 1: |
87 |
s->cycle = 0;
|
88 |
break;
|
89 |
} |
90 |
} |
91 |
|
92 |
static void ads7846_ts_event(void *opaque, |
93 |
int x, int y, int z, int buttons_state) |
94 |
{ |
95 |
struct ads7846_state_s *s = opaque;
|
96 |
|
97 |
if (buttons_state) {
|
98 |
x = 0x7fff - x;
|
99 |
s->input[1] = ADS_XPOS(x, y);
|
100 |
s->input[3] = ADS_Z1POS(x, y);
|
101 |
s->input[4] = ADS_Z2POS(x, y);
|
102 |
s->input[5] = ADS_YPOS(x, y);
|
103 |
} |
104 |
|
105 |
if (s->pressure == !buttons_state) {
|
106 |
s->pressure = !!buttons_state; |
107 |
|
108 |
ads7846_int_update(s); |
109 |
} |
110 |
} |
111 |
|
112 |
static void ads7846_save(QEMUFile *f, void *opaque) |
113 |
{ |
114 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
115 |
int i;
|
116 |
|
117 |
for (i = 0; i < 8; i ++) |
118 |
qemu_put_be32(f, s->input[i]); |
119 |
qemu_put_be32(f, s->noise); |
120 |
qemu_put_be32(f, s->cycle); |
121 |
qemu_put_be32(f, s->output); |
122 |
} |
123 |
|
124 |
static int ads7846_load(QEMUFile *f, void *opaque, int version_id) |
125 |
{ |
126 |
struct ads7846_state_s *s = (struct ads7846_state_s *) opaque; |
127 |
int i;
|
128 |
|
129 |
for (i = 0; i < 8; i ++) |
130 |
s->input[i] = qemu_get_be32(f); |
131 |
s->noise = qemu_get_be32(f); |
132 |
s->cycle = qemu_get_be32(f); |
133 |
s->output = qemu_get_be32(f); |
134 |
|
135 |
s->pressure = 0;
|
136 |
ads7846_int_update(s); |
137 |
|
138 |
return 0; |
139 |
} |
140 |
|
141 |
static int ads7846_iid = 0; |
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", ads7846_iid ++, 0, |
164 |
ads7846_save, ads7846_load, s); |
165 |
|
166 |
return s;
|
167 |
} |