1 /* 2 * PCA9554 I/O port 3 * 4 * Copyright (c) 2023, IBM Corporation. 5 * 6 * SPDX-License-Identifier: GPL-2.0-or-later 7 */ 8 9 #include "qemu/osdep.h" 10 #include "qemu/log.h" 11 #include "qemu/module.h" 12 #include "qemu/bitops.h" 13 #include "hw/qdev-properties.h" 14 #include "hw/gpio/pca9554.h" 15 #include "hw/gpio/pca9554_regs.h" 16 #include "hw/irq.h" 17 #include "migration/vmstate.h" 18 #include "qapi/error.h" 19 #include "qapi/visitor.h" 20 #include "trace.h" 21 #include "qom/object.h" 22 23 struct PCA9554Class { 24 /*< private >*/ 25 I2CSlaveClass parent_class; 26 /*< public >*/ 27 }; 28 typedef struct PCA9554Class PCA9554Class; 29 30 DECLARE_CLASS_CHECKERS(PCA9554Class, PCA9554, 31 TYPE_PCA9554) 32 33 #define PCA9554_PIN_LOW 0x0 34 #define PCA9554_PIN_HIZ 0x1 35 36 static const char *pin_state[] = {"low", "high"}; 37 38 static void pca9554_update_pin_input(PCA9554State *s) 39 { 40 int i; 41 uint8_t config = s->regs[PCA9554_CONFIG]; 42 uint8_t output = s->regs[PCA9554_OUTPUT]; 43 uint8_t internal_state = config | output; 44 45 for (i = 0; i < PCA9554_PIN_COUNT; i++) { 46 uint8_t bit_mask = 1 << i; 47 uint8_t internal_pin_state = (internal_state >> i) & 0x1; 48 uint8_t old_value = s->regs[PCA9554_INPUT] & bit_mask; 49 uint8_t new_value; 50 51 switch (internal_pin_state) { 52 case PCA9554_PIN_LOW: 53 s->regs[PCA9554_INPUT] &= ~bit_mask; 54 break; 55 case PCA9554_PIN_HIZ: 56 /* 57 * pullup sets it to a logical 1 unless 58 * external device drives it low. 59 */ 60 if (s->ext_state[i] == PCA9554_PIN_LOW) { 61 s->regs[PCA9554_INPUT] &= ~bit_mask; 62 } else { 63 s->regs[PCA9554_INPUT] |= bit_mask; 64 } 65 break; 66 default: 67 break; 68 } 69 70 /* update irq state only if pin state changed */ 71 new_value = s->regs[PCA9554_INPUT] & bit_mask; 72 if (new_value != old_value) { 73 if (new_value) { 74 /* changed from 0 to 1 */ 75 qemu_set_irq(s->gpio_out[i], 1); 76 } else { 77 /* changed from 1 to 0 */ 78 qemu_set_irq(s->gpio_out[i], 0); 79 } 80 } 81 } 82 } 83 84 static uint8_t pca9554_read(PCA9554State *s, uint8_t reg) 85 { 86 switch (reg) { 87 case PCA9554_INPUT: 88 return s->regs[PCA9554_INPUT] ^ s->regs[PCA9554_POLARITY]; 89 case PCA9554_OUTPUT: 90 case PCA9554_POLARITY: 91 case PCA9554_CONFIG: 92 return s->regs[reg]; 93 default: 94 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n", 95 __func__, reg); 96 return 0xFF; 97 } 98 } 99 100 static void pca9554_write(PCA9554State *s, uint8_t reg, uint8_t data) 101 { 102 switch (reg) { 103 case PCA9554_OUTPUT: 104 case PCA9554_CONFIG: 105 s->regs[reg] = data; 106 pca9554_update_pin_input(s); 107 break; 108 case PCA9554_POLARITY: 109 s->regs[reg] = data; 110 break; 111 case PCA9554_INPUT: 112 default: 113 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n", 114 __func__, reg); 115 } 116 } 117 118 static uint8_t pca9554_recv(I2CSlave *i2c) 119 { 120 PCA9554State *s = PCA9554(i2c); 121 uint8_t ret; 122 123 ret = pca9554_read(s, s->pointer & 0x3); 124 125 return ret; 126 } 127 128 static int pca9554_send(I2CSlave *i2c, uint8_t data) 129 { 130 PCA9554State *s = PCA9554(i2c); 131 132 /* First byte sent by is the register address */ 133 if (s->len == 0) { 134 s->pointer = data; 135 s->len++; 136 } else { 137 pca9554_write(s, s->pointer & 0x3, data); 138 } 139 140 return 0; 141 } 142 143 static int pca9554_event(I2CSlave *i2c, enum i2c_event event) 144 { 145 PCA9554State *s = PCA9554(i2c); 146 147 s->len = 0; 148 return 0; 149 } 150 151 static void pca9554_get_pin(Object *obj, Visitor *v, const char *name, 152 void *opaque, Error **errp) 153 { 154 PCA9554State *s = PCA9554(obj); 155 int pin, rc; 156 uint8_t state; 157 158 rc = sscanf(name, "pin%2d", &pin); 159 if (rc != 1) { 160 error_setg(errp, "%s: error reading %s", __func__, name); 161 return; 162 } 163 if (pin < 0 || pin >= PCA9554_PIN_COUNT) { 164 error_setg(errp, "%s invalid pin %s", __func__, name); 165 return; 166 } 167 168 state = pca9554_read(s, PCA9554_CONFIG); 169 state |= pca9554_read(s, PCA9554_OUTPUT); 170 state = (state >> pin) & 0x1; 171 visit_type_str(v, name, (char **)&pin_state[state], errp); 172 } 173 174 static void pca9554_set_pin(Object *obj, Visitor *v, const char *name, 175 void *opaque, Error **errp) 176 { 177 PCA9554State *s = PCA9554(obj); 178 int pin, rc, val; 179 uint8_t state, mask; 180 char *state_str; 181 182 if (!visit_type_str(v, name, &state_str, errp)) { 183 return; 184 } 185 rc = sscanf(name, "pin%2d", &pin); 186 if (rc != 1) { 187 error_setg(errp, "%s: error reading %s", __func__, name); 188 return; 189 } 190 if (pin < 0 || pin >= PCA9554_PIN_COUNT) { 191 error_setg(errp, "%s invalid pin %s", __func__, name); 192 return; 193 } 194 195 for (state = 0; state < ARRAY_SIZE(pin_state); state++) { 196 if (!strcmp(state_str, pin_state[state])) { 197 break; 198 } 199 } 200 if (state >= ARRAY_SIZE(pin_state)) { 201 error_setg(errp, "%s invalid pin state %s", __func__, state_str); 202 return; 203 } 204 205 /* First, modify the output register bit */ 206 val = pca9554_read(s, PCA9554_OUTPUT); 207 mask = 0x1 << pin; 208 if (state == PCA9554_PIN_LOW) { 209 val &= ~(mask); 210 } else { 211 val |= mask; 212 } 213 pca9554_write(s, PCA9554_OUTPUT, val); 214 215 /* Then, clear the config register bit for output mode */ 216 val = pca9554_read(s, PCA9554_CONFIG); 217 val &= ~mask; 218 pca9554_write(s, PCA9554_CONFIG, val); 219 } 220 221 static const VMStateDescription pca9554_vmstate = { 222 .name = "PCA9554", 223 .version_id = 0, 224 .minimum_version_id = 0, 225 .fields = (VMStateField[]) { 226 VMSTATE_UINT8(len, PCA9554State), 227 VMSTATE_UINT8(pointer, PCA9554State), 228 VMSTATE_UINT8_ARRAY(regs, PCA9554State, PCA9554_NR_REGS), 229 VMSTATE_UINT8_ARRAY(ext_state, PCA9554State, PCA9554_PIN_COUNT), 230 VMSTATE_I2C_SLAVE(i2c, PCA9554State), 231 VMSTATE_END_OF_LIST() 232 } 233 }; 234 235 static void pca9554_reset(DeviceState *dev) 236 { 237 PCA9554State *s = PCA9554(dev); 238 239 s->regs[PCA9554_INPUT] = 0xFF; 240 s->regs[PCA9554_OUTPUT] = 0xFF; 241 s->regs[PCA9554_POLARITY] = 0x0; /* No pins are inverted */ 242 s->regs[PCA9554_CONFIG] = 0xFF; /* All pins are inputs */ 243 244 memset(s->ext_state, PCA9554_PIN_HIZ, PCA9554_PIN_COUNT); 245 pca9554_update_pin_input(s); 246 247 s->pointer = 0x0; 248 s->len = 0; 249 } 250 251 static void pca9554_initfn(Object *obj) 252 { 253 int pin; 254 255 for (pin = 0; pin < PCA9554_PIN_COUNT; pin++) { 256 char *name; 257 258 name = g_strdup_printf("pin%d", pin); 259 object_property_add(obj, name, "bool", pca9554_get_pin, pca9554_set_pin, 260 NULL, NULL); 261 g_free(name); 262 } 263 } 264 265 static void pca9554_set_ext_state(PCA9554State *s, int pin, int level) 266 { 267 if (s->ext_state[pin] != level) { 268 s->ext_state[pin] = level; 269 pca9554_update_pin_input(s); 270 } 271 } 272 273 static void pca9554_gpio_in_handler(void *opaque, int pin, int level) 274 { 275 276 PCA9554State *s = PCA9554(opaque); 277 278 assert((pin >= 0) && (pin < PCA9554_PIN_COUNT)); 279 pca9554_set_ext_state(s, pin, level); 280 } 281 282 static void pca9554_realize(DeviceState *dev, Error **errp) 283 { 284 PCA9554State *s = PCA9554(dev); 285 286 if (!s->description) { 287 s->description = g_strdup("pca9554"); 288 } 289 290 qdev_init_gpio_out(dev, s->gpio_out, PCA9554_PIN_COUNT); 291 qdev_init_gpio_in(dev, pca9554_gpio_in_handler, PCA9554_PIN_COUNT); 292 } 293 294 static Property pca9554_properties[] = { 295 DEFINE_PROP_STRING("description", PCA9554State, description), 296 DEFINE_PROP_END_OF_LIST(), 297 }; 298 299 static void pca9554_class_init(ObjectClass *klass, void *data) 300 { 301 DeviceClass *dc = DEVICE_CLASS(klass); 302 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass); 303 304 k->event = pca9554_event; 305 k->recv = pca9554_recv; 306 k->send = pca9554_send; 307 dc->realize = pca9554_realize; 308 device_class_set_legacy_reset(dc, pca9554_reset); 309 dc->vmsd = &pca9554_vmstate; 310 device_class_set_props(dc, pca9554_properties); 311 } 312 313 static const TypeInfo pca9554_info = { 314 .name = TYPE_PCA9554, 315 .parent = TYPE_I2C_SLAVE, 316 .instance_init = pca9554_initfn, 317 .instance_size = sizeof(PCA9554State), 318 .class_init = pca9554_class_init, 319 .class_size = sizeof(PCA9554Class), 320 .abstract = false, 321 }; 322 323 static void pca9554_register_types(void) 324 { 325 type_register_static(&pca9554_info); 326 } 327 328 type_init(pca9554_register_types) 329