1 /* 2 * PCA9552 I2C LED blinker 3 * 4 * https://www.nxp.com/docs/en/application-note/AN264.pdf 5 * 6 * Copyright (c) 2017-2018, IBM Corporation. 7 * Copyright (c) 2020 Philippe Mathieu-Daudé 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2 or 10 * later. See the COPYING file in the top-level directory. 11 */ 12 13 #include "qemu/osdep.h" 14 #include "qemu/log.h" 15 #include "qemu/module.h" 16 #include "qemu/bitops.h" 17 #include "hw/qdev-properties.h" 18 #include "hw/gpio/pca9552.h" 19 #include "hw/gpio/pca9552_regs.h" 20 #include "hw/irq.h" 21 #include "migration/vmstate.h" 22 #include "qapi/error.h" 23 #include "qapi/visitor.h" 24 #include "trace.h" 25 #include "qom/object.h" 26 27 struct PCA955xClass { 28 /*< private >*/ 29 I2CSlaveClass parent_class; 30 /*< public >*/ 31 32 uint8_t pin_count; 33 uint8_t max_reg; 34 }; 35 typedef struct PCA955xClass PCA955xClass; 36 37 DECLARE_CLASS_CHECKERS(PCA955xClass, PCA955X, 38 TYPE_PCA955X) 39 /* 40 * Note: The LED_ON and LED_OFF configuration values for the PCA955X 41 * chips are the reverse of the PCA953X family of chips. 42 */ 43 #define PCA9552_LED_ON 0x0 44 #define PCA9552_LED_OFF 0x1 45 #define PCA9552_LED_PWM0 0x2 46 #define PCA9552_LED_PWM1 0x3 47 #define PCA9552_PIN_LOW 0x0 48 #define PCA9552_PIN_HIZ 0x1 49 50 static const char *led_state[] = {"on", "off", "pwm0", "pwm1"}; 51 52 static uint8_t pca955x_pin_get_config(PCA955xState *s, int pin) 53 { 54 uint8_t reg = PCA9552_LS0 + (pin / 4); 55 uint8_t shift = (pin % 4) << 1; 56 57 return extract32(s->regs[reg], shift, 2); 58 } 59 60 /* Return INPUT status (bit #N belongs to GPIO #N) */ 61 static uint16_t pca955x_pins_get_status(PCA955xState *s) 62 { 63 return (s->regs[PCA9552_INPUT1] << 8) | s->regs[PCA9552_INPUT0]; 64 } 65 66 static void pca955x_display_pins_status(PCA955xState *s, 67 uint16_t previous_pins_status) 68 { 69 PCA955xClass *k = PCA955X_GET_CLASS(s); 70 uint16_t pins_status, pins_changed; 71 int i; 72 73 pins_status = pca955x_pins_get_status(s); 74 pins_changed = previous_pins_status ^ pins_status; 75 if (!pins_changed) { 76 return; 77 } 78 if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_STATUS)) { 79 char *buf = g_newa(char, k->pin_count + 1); 80 81 for (i = 0; i < k->pin_count; i++) { 82 if (extract32(pins_status, i, 1)) { 83 buf[i] = '*'; 84 } else { 85 buf[i] = '.'; 86 } 87 } 88 buf[i] = '\0'; 89 trace_pca955x_gpio_status(s->description, buf); 90 } 91 if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_CHANGE)) { 92 for (i = 0; i < k->pin_count; i++) { 93 if (extract32(pins_changed, i, 1)) { 94 unsigned new_state = extract32(pins_status, i, 1); 95 96 /* 97 * We display the state using the PCA logic ("active-high"). 98 * This is not the state of the LED, which signal might be 99 * wired "active-low" on the board. 100 */ 101 trace_pca955x_gpio_change(s->description, i, 102 !new_state, new_state); 103 } 104 } 105 } 106 } 107 108 static void pca955x_update_pin_input(PCA955xState *s) 109 { 110 PCA955xClass *k = PCA955X_GET_CLASS(s); 111 int i; 112 113 for (i = 0; i < k->pin_count; i++) { 114 uint8_t input_reg = PCA9552_INPUT0 + (i / 8); 115 uint8_t bit_mask = 1 << (i % 8); 116 uint8_t config = pca955x_pin_get_config(s, i); 117 uint8_t old_value = s->regs[input_reg] & bit_mask; 118 uint8_t new_value; 119 120 switch (config) { 121 case PCA9552_LED_ON: 122 /* Pin is set to 0V to turn on LED */ 123 s->regs[input_reg] &= ~bit_mask; 124 break; 125 case PCA9552_LED_OFF: 126 /* 127 * Pin is set to Hi-Z to turn off LED and 128 * pullup sets it to a logical 1 unless 129 * external device drives it low. 130 */ 131 if (s->ext_state[i] == PCA9552_PIN_LOW) { 132 s->regs[input_reg] &= ~bit_mask; 133 } else { 134 s->regs[input_reg] |= bit_mask; 135 } 136 break; 137 case PCA9552_LED_PWM0: 138 case PCA9552_LED_PWM1: 139 /* TODO */ 140 default: 141 break; 142 } 143 144 /* update irq state only if pin state changed */ 145 new_value = s->regs[input_reg] & bit_mask; 146 if (new_value != old_value) { 147 qemu_set_irq(s->gpio_out[i], !!new_value); 148 } 149 } 150 } 151 152 static uint8_t pca955x_read(PCA955xState *s, uint8_t reg) 153 { 154 switch (reg) { 155 case PCA9552_INPUT0: 156 case PCA9552_INPUT1: 157 case PCA9552_PSC0: 158 case PCA9552_PWM0: 159 case PCA9552_PSC1: 160 case PCA9552_PWM1: 161 case PCA9552_LS0: 162 case PCA9552_LS1: 163 case PCA9552_LS2: 164 case PCA9552_LS3: 165 return s->regs[reg]; 166 default: 167 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n", 168 __func__, reg); 169 return 0xFF; 170 } 171 } 172 173 static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data) 174 { 175 uint16_t pins_status; 176 177 switch (reg) { 178 case PCA9552_PSC0: 179 case PCA9552_PWM0: 180 case PCA9552_PSC1: 181 case PCA9552_PWM1: 182 s->regs[reg] = data; 183 break; 184 185 case PCA9552_LS0: 186 case PCA9552_LS1: 187 case PCA9552_LS2: 188 case PCA9552_LS3: 189 pins_status = pca955x_pins_get_status(s); 190 s->regs[reg] = data; 191 pca955x_update_pin_input(s); 192 pca955x_display_pins_status(s, pins_status); 193 break; 194 195 case PCA9552_INPUT0: 196 case PCA9552_INPUT1: 197 default: 198 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n", 199 __func__, reg); 200 } 201 } 202 203 /* 204 * When Auto-Increment is on, the register address is incremented 205 * after each byte is sent to or received by the device. The index 206 * rollovers to 0 when the maximum register address is reached. 207 */ 208 static void pca955x_autoinc(PCA955xState *s) 209 { 210 PCA955xClass *k = PCA955X_GET_CLASS(s); 211 212 if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) { 213 uint8_t reg = s->pointer & 0xf; 214 215 reg = (reg + 1) % (k->max_reg + 1); 216 s->pointer = reg | PCA9552_AUTOINC; 217 } 218 } 219 220 static uint8_t pca955x_recv(I2CSlave *i2c) 221 { 222 PCA955xState *s = PCA955X(i2c); 223 uint8_t ret; 224 225 ret = pca955x_read(s, s->pointer & 0xf); 226 227 /* 228 * From the Specs: 229 * 230 * Important Note: When a Read sequence is initiated and the 231 * AI bit is set to Logic Level 1, the Read Sequence MUST 232 * start by a register different from 0. 233 * 234 * I don't know what should be done in this case, so throw an 235 * error. 236 */ 237 if (s->pointer == PCA9552_AUTOINC) { 238 qemu_log_mask(LOG_GUEST_ERROR, 239 "%s: Autoincrement read starting with register 0\n", 240 __func__); 241 } 242 243 pca955x_autoinc(s); 244 245 return ret; 246 } 247 248 static int pca955x_send(I2CSlave *i2c, uint8_t data) 249 { 250 PCA955xState *s = PCA955X(i2c); 251 252 /* First byte sent by is the register address */ 253 if (s->len == 0) { 254 s->pointer = data; 255 s->len++; 256 } else { 257 pca955x_write(s, s->pointer & 0xf, data); 258 259 pca955x_autoinc(s); 260 } 261 262 return 0; 263 } 264 265 static int pca955x_event(I2CSlave *i2c, enum i2c_event event) 266 { 267 PCA955xState *s = PCA955X(i2c); 268 269 s->len = 0; 270 return 0; 271 } 272 273 static void pca955x_get_led(Object *obj, Visitor *v, const char *name, 274 void *opaque, Error **errp) 275 { 276 PCA955xClass *k = PCA955X_GET_CLASS(obj); 277 PCA955xState *s = PCA955X(obj); 278 int led, rc, reg; 279 uint8_t state; 280 281 rc = sscanf(name, "led%2d", &led); 282 if (rc != 1) { 283 error_setg(errp, "%s: error reading %s", __func__, name); 284 return; 285 } 286 if (led < 0 || led > k->pin_count) { 287 error_setg(errp, "%s invalid led %s", __func__, name); 288 return; 289 } 290 /* 291 * Get the LSx register as the qom interface should expose the device 292 * state, not the modeled 'input line' behaviour which would come from 293 * reading the INPUTx reg 294 */ 295 reg = PCA9552_LS0 + led / 4; 296 state = (pca955x_read(s, reg) >> ((led % 4) * 2)) & 0x3; 297 visit_type_str(v, name, (char **)&led_state[state], errp); 298 } 299 300 /* 301 * Return an LED selector register value based on an existing one, with 302 * the appropriate 2-bit state value set for the given LED number (0-3). 303 */ 304 static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state) 305 { 306 return (oldval & (~(0x3 << (led_num << 1)))) | 307 ((state & 0x3) << (led_num << 1)); 308 } 309 310 static void pca955x_set_led(Object *obj, Visitor *v, const char *name, 311 void *opaque, Error **errp) 312 { 313 PCA955xClass *k = PCA955X_GET_CLASS(obj); 314 PCA955xState *s = PCA955X(obj); 315 int led, rc, reg, val; 316 uint8_t state; 317 char *state_str; 318 319 if (!visit_type_str(v, name, &state_str, errp)) { 320 return; 321 } 322 rc = sscanf(name, "led%2d", &led); 323 if (rc != 1) { 324 error_setg(errp, "%s: error reading %s", __func__, name); 325 return; 326 } 327 if (led < 0 || led > k->pin_count) { 328 error_setg(errp, "%s invalid led %s", __func__, name); 329 return; 330 } 331 332 for (state = 0; state < ARRAY_SIZE(led_state); state++) { 333 if (!strcmp(state_str, led_state[state])) { 334 break; 335 } 336 } 337 if (state >= ARRAY_SIZE(led_state)) { 338 error_setg(errp, "%s invalid led state %s", __func__, state_str); 339 return; 340 } 341 342 reg = PCA9552_LS0 + led / 4; 343 val = pca955x_read(s, reg); 344 val = pca955x_ledsel(val, led % 4, state); 345 pca955x_write(s, reg, val); 346 } 347 348 static const VMStateDescription pca9552_vmstate = { 349 .name = "PCA9552", 350 .version_id = 0, 351 .minimum_version_id = 0, 352 .fields = (const VMStateField[]) { 353 VMSTATE_UINT8(len, PCA955xState), 354 VMSTATE_UINT8(pointer, PCA955xState), 355 VMSTATE_UINT8_ARRAY(regs, PCA955xState, PCA955X_NR_REGS), 356 VMSTATE_UINT8_ARRAY(ext_state, PCA955xState, PCA955X_PIN_COUNT_MAX), 357 VMSTATE_I2C_SLAVE(i2c, PCA955xState), 358 VMSTATE_END_OF_LIST() 359 } 360 }; 361 362 static void pca9552_reset(DeviceState *dev) 363 { 364 PCA955xState *s = PCA955X(dev); 365 366 s->regs[PCA9552_PSC0] = 0xFF; 367 s->regs[PCA9552_PWM0] = 0x80; 368 s->regs[PCA9552_PSC1] = 0xFF; 369 s->regs[PCA9552_PWM1] = 0x80; 370 s->regs[PCA9552_LS0] = 0x55; /* all OFF */ 371 s->regs[PCA9552_LS1] = 0x55; 372 s->regs[PCA9552_LS2] = 0x55; 373 s->regs[PCA9552_LS3] = 0x55; 374 375 memset(s->ext_state, PCA9552_PIN_HIZ, PCA955X_PIN_COUNT_MAX); 376 pca955x_update_pin_input(s); 377 378 s->pointer = 0xFF; 379 s->len = 0; 380 } 381 382 static void pca955x_initfn(Object *obj) 383 { 384 PCA955xClass *k = PCA955X_GET_CLASS(obj); 385 int led; 386 387 assert(k->pin_count <= PCA955X_PIN_COUNT_MAX); 388 for (led = 0; led < k->pin_count; led++) { 389 char *name; 390 391 name = g_strdup_printf("led%d", led); 392 object_property_add(obj, name, "bool", pca955x_get_led, pca955x_set_led, 393 NULL, NULL); 394 g_free(name); 395 } 396 } 397 398 static void pca955x_set_ext_state(PCA955xState *s, int pin, int level) 399 { 400 if (s->ext_state[pin] != level) { 401 uint16_t pins_status = pca955x_pins_get_status(s); 402 s->ext_state[pin] = level; 403 pca955x_update_pin_input(s); 404 pca955x_display_pins_status(s, pins_status); 405 } 406 } 407 408 static void pca955x_gpio_in_handler(void *opaque, int pin, int level) 409 { 410 411 PCA955xState *s = PCA955X(opaque); 412 PCA955xClass *k = PCA955X_GET_CLASS(s); 413 414 assert((pin >= 0) && (pin < k->pin_count)); 415 pca955x_set_ext_state(s, pin, level); 416 } 417 418 static void pca955x_realize(DeviceState *dev, Error **errp) 419 { 420 PCA955xClass *k = PCA955X_GET_CLASS(dev); 421 PCA955xState *s = PCA955X(dev); 422 423 if (!s->description) { 424 s->description = g_strdup("pca-unspecified"); 425 } 426 427 qdev_init_gpio_out(dev, s->gpio_out, k->pin_count); 428 qdev_init_gpio_in(dev, pca955x_gpio_in_handler, k->pin_count); 429 } 430 431 static Property pca955x_properties[] = { 432 DEFINE_PROP_STRING("description", PCA955xState, description), 433 DEFINE_PROP_END_OF_LIST(), 434 }; 435 436 static void pca955x_class_init(ObjectClass *klass, void *data) 437 { 438 DeviceClass *dc = DEVICE_CLASS(klass); 439 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass); 440 441 k->event = pca955x_event; 442 k->recv = pca955x_recv; 443 k->send = pca955x_send; 444 dc->realize = pca955x_realize; 445 device_class_set_props(dc, pca955x_properties); 446 } 447 448 static const TypeInfo pca955x_info = { 449 .name = TYPE_PCA955X, 450 .parent = TYPE_I2C_SLAVE, 451 .instance_init = pca955x_initfn, 452 .instance_size = sizeof(PCA955xState), 453 .class_init = pca955x_class_init, 454 .class_size = sizeof(PCA955xClass), 455 .abstract = true, 456 }; 457 458 static void pca9552_class_init(ObjectClass *oc, void *data) 459 { 460 DeviceClass *dc = DEVICE_CLASS(oc); 461 PCA955xClass *pc = PCA955X_CLASS(oc); 462 463 dc->reset = pca9552_reset; 464 dc->vmsd = &pca9552_vmstate; 465 pc->max_reg = PCA9552_LS3; 466 pc->pin_count = 16; 467 } 468 469 static const TypeInfo pca9552_info = { 470 .name = TYPE_PCA9552, 471 .parent = TYPE_PCA955X, 472 .class_init = pca9552_class_init, 473 }; 474 475 static void pca955x_register_types(void) 476 { 477 type_register_static(&pca955x_info); 478 type_register_static(&pca9552_info); 479 } 480 481 type_init(pca955x_register_types) 482