ads7846.c (4626B)
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" 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 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 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 } 118 119 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 = (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 }; 142 143 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(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_ads7846, s); 162 } 163 164 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 }; 180 181 static void ads7846_register_types(void) 182 { 183 type_register_static(&ads7846_info); 184 } 185 186 type_init(ads7846_register_types)