text: /*
   * PCA9552 I2C LED blinker
   *
   *     https://www.nxp.com/docs/en/application-note/AN264.pdf
   *
   * Copyright (c) 2017-2018, IBM Corporation.
   * Copyright (c) 2020 Philippe Mathieu-Daudé
   *
   * This work is licensed under the terms of the GNU GPL, version 2 or
   * later. See the COPYING file in the top-level directory.
   */
  
  #include "qemu/osdep.h"
  #include "qemu/log.h"
  #include "qemu/module.h"
  #include "qemu/bitops.h"
  #include "hw/qdev-properties.h"
  #include "hw/misc/pca9552.h"
  #include "hw/misc/pca9552_regs.h"
  #include "hw/irq.h"
  #include "migration/vmstate.h"
  #include "qapi/error.h"
  #include "qapi/visitor.h"
  #include "trace.h"
  #include "qom/object.h"
  
  struct PCA955xClass {
      /*< private >*/
      I2CSlaveClass parent_class;
      /*< public >*/
  
      uint8_t pin_count;
      uint8_t max_reg;
  };
  typedef struct PCA955xClass PCA955xClass;
  
  DECLARE_CLASS_CHECKERS(PCA955xClass, PCA955X,
                         TYPE_PCA955X)
  
  #define PCA9552_LED_ON   0x0
  #define PCA9552_LED_OFF  0x1
  #define PCA9552_LED_PWM0 0x2
  #define PCA9552_LED_PWM1 0x3
  
  static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};
  
  static uint8_t pca955x_pin_get_config(PCA955xState *s, int pin)
  {
      uint8_t reg   = PCA9552_LS0 + (pin / 4);
      uint8_t shift = (pin % 4) << 1;
  
      return extract32(s->regs[reg], shift, 2);
  }
  
  /* Return INPUT status (bit #N belongs to GPIO #N) */
  static uint16_t pca955x_pins_get_status(PCA955xState *s)
  {
      return (s->regs[PCA9552_INPUT1] << 8) | s->regs[PCA9552_INPUT0];
  }
  
  static void pca955x_display_pins_status(PCA955xState *s,
                                          uint16_t previous_pins_status)
  {
      PCA955xClass *k = PCA955X_GET_CLASS(s);
      uint16_t pins_status, pins_changed;
      int i;
  
      pins_status = pca955x_pins_get_status(s);
      pins_changed = previous_pins_status ^ pins_status;
      if (!pins_changed) {
          return;
      }
      if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_STATUS)) {
          char *buf = g_newa(char, k->pin_count + 1);
  
          for (i = 0; i < k->pin_count; i++) {
              if (extract32(pins_status, i, 1)) {
                  buf[i] = '*';
              } else {
                  buf[i] = '.';
              }
          }
          buf[i] = '\0';
          trace_pca955x_gpio_status(s->description, buf);
      }
      if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_CHANGE)) {
          for (i = 0; i < k->pin_count; i++) {
              if (extract32(pins_changed, i, 1)) {
                  unsigned new_state = extract32(pins_status, i, 1);
  
                  /*
                   * We display the state using the PCA logic ("active-high").
                   * This is not the state of the LED, which signal might be
                   * wired "active-low" on the board.
                   */
                  trace_pca955x_gpio_change(s->description, i,
                                            !new_state, new_state);
              }
          }
      }
  }
  
  static void pca955x_update_pin_input(PCA955xState *s)
  {
      PCA955xClass *k = PCA955X_GET_CLASS(s);
      int i;
  
      for (i = 0; i < k->pin_count; i++) {
          uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
          uint8_t input_shift = (i % 8);
          uint8_t config = pca955x_pin_get_config(s, i);
  
          switch (config) {
          case PCA9552_LED_ON:
              qemu_set_irq(s->gpio[i], 1);
              s->regs[input_reg] |= 1 << input_shift;
              break;
          case PCA9552_LED_OFF:
              qemu_set_irq(s->gpio[i], 0);
              s->regs[input_reg] &= ~(1 << input_shift);
              break;
          case PCA9552_LED_PWM0:
          case PCA9552_LED_PWM1:
              /* TODO */
          default:
              break;
          }
      }
  }
  
  static uint8_t pca955x_read(PCA955xState *s, uint8_t reg)
  {
      switch (reg) {
      case PCA9552_INPUT0:
      case PCA9552_INPUT1:
      case PCA9552_PSC0:
      case PCA9552_PWM0:
      case PCA9552_PSC1:
      case PCA9552_PWM1:
      case PCA9552_LS0:
      case PCA9552_LS1:
      case PCA9552_LS2:
      case PCA9552_LS3:
          return s->regs[reg];
      default:
          qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
                        __func__, reg);
          return 0xFF;
      }
  }
  
  static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
  {
      uint16_t pins_status;
  
      switch (reg) {
      case PCA9552_PSC0:
      case PCA9552_PWM0:
      case PCA9552_PSC1:
      case PCA9552_PWM1:
          s->regs[reg] = data;
          break;
  
      case PCA9552_LS0:
      case PCA9552_LS1:
      case PCA9552_LS2:
      case PCA9552_LS3:
          pins_status = pca955x_pins_get_status(s);
          s->regs[reg] = data;
          pca955x_update_pin_input(s);
          pca955x_display_pins_status(s, pins_status);
          break;
  
      case PCA9552_INPUT0:
      case PCA9552_INPUT1:
      default:
          qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
                        __func__, reg);
      }
  }
  
  /*
   * When Auto-Increment is on, the register address is incremented
   * after each byte is sent to or received by the device. The index
   * rollovers to 0 when the maximum register address is reached.
   */
  static void pca955x_autoinc(PCA955xState *s)
  {
      PCA955xClass *k = PCA955X_GET_CLASS(s);
  
      if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
          uint8_t reg = s->pointer & 0xf;
  
          reg = (reg + 1) % (k->max_reg + 1);
          s->pointer = reg | PCA9552_AUTOINC;
      }
  }
  
  static uint8_t pca955x_recv(I2CSlave *i2c)
  {
      PCA955xState *s = PCA955X(i2c);
      uint8_t ret;
  
      ret = pca955x_read(s, s->pointer & 0xf);
  
      /*
       * From the Specs:
       *
       *     Important Note: When a Read sequence is initiated and the
       *     AI bit is set to Logic Level 1, the Read Sequence MUST
       *     start by a register different from 0.
       *
       * I don't know what should be done in this case, so throw an
       * error.
       */
      if (s->pointer == PCA9552_AUTOINC) {
          qemu_log_mask(LOG_GUEST_ERROR,
                        "%s: Autoincrement read starting with register 0\n",
                        __func__);
      }
  
      pca955x_autoinc(s);
  
      return ret;
  }
  
  static int pca955x_send(I2CSlave *i2c, uint8_t data)
  {
      PCA955xState *s = PCA955X(i2c);
  
      /* First byte sent by is the register address */
      if (s->len == 0) {
          s->pointer = data;
          s->len++;
      } else {
          pca955x_write(s, s->pointer & 0xf, data);
  
          pca955x_autoinc(s);
      }
  
      return 0;
  }
  
  static int pca955x_event(I2CSlave *i2c, enum i2c_event event)
  {
      PCA955xState *s = PCA955X(i2c);
  
      s->len = 0;
      return 0;
  }
  
  static void pca955x_get_led(Object *obj, Visitor *v, const char *name,
                              void *opaque, Error **errp)
  {
      PCA955xClass *k = PCA955X_GET_CLASS(obj);
      PCA955xState *s = PCA955X(obj);
      int led, rc, reg;
      uint8_t state;
  
      rc = sscanf(name, "led%2d", &led);
      if (rc != 1) {
          error_setg(errp, "%s: error reading %s", __func__, name);
          return;
      }
      if (led < 0 || led > k->pin_count) {
          error_setg(errp, "%s invalid led %s", __func__, name);
          return;
      }
      /*
       * Get the LSx register as the qom interface should expose the device
       * state, not the modeled 'input line' behaviour which would come from
       * reading the INPUTx reg
       */
      reg = PCA9552_LS0 + led / 4;
      state = (pca955x_read(s, reg) >> (led % 8)) & 0x3;
      visit_type_str(v, name, (char **)&led_state[state], errp);
  }
  
  /*
   * Return an LED selector register value based on an existing one, with
   * the appropriate 2-bit state value set for the given LED number (0-3).
   */
  static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
  {
          return (oldval & (~(0x3 << (led_num << 1)))) |
                  ((state & 0x3) << (led_num << 1));
  }
  
  static void pca955x_set_led(Object *obj, Visitor *v, const char *name,
                              void *opaque, Error **errp)
  {
      PCA955xClass *k = PCA955X_GET_CLASS(obj);
      PCA955xState *s = PCA955X(obj);
      int led, rc, reg, val;
      uint8_t state;
      char *state_str;
  
      if (!visit_type_str(v, name, &state_str, errp)) {
          return;
      }
      rc = sscanf(name, "led%2d", &led);
      if (rc != 1) {
          error_setg(errp, "%s: error reading %s", __func__, name);
          return;
      }
      if (led < 0 || led > k->pin_count) {
          error_setg(errp, "%s invalid led %s", __func__, name);
          return;
      }
  
      for (state = 0; state < ARRAY_SIZE(led_state); state++) {
          if (!strcmp(state_str, led_state[state])) {
              break;
          }
      }
      if (state >= ARRAY_SIZE(led_state)) {
          error_setg(errp, "%s invalid led state %s", __func__, state_str);
          return;
      }
  
      reg = PCA9552_LS0 + led / 4;
      val = pca955x_read(s, reg);
      val = pca955x_ledsel(val, led % 4, state);
      pca955x_write(s, reg, val);
  }
  
  static const VMStateDescription pca9552_vmstate = {
      .name = "PCA9552",
      .version_id = 0,
      .minimum_version_id = 0,
      .fields = (VMStateField[]) {
          VMSTATE_UINT8(len, PCA955xState),
          VMSTATE_UINT8(pointer, PCA955xState),
          VMSTATE_UINT8_ARRAY(regs, PCA955xState, PCA955X_NR_REGS),
          VMSTATE_I2C_SLAVE(i2c, PCA955xState),
          VMSTATE_END_OF_LIST()
      }
  };
  
  static void pca9552_reset(DeviceState *dev)
  {
      PCA955xState *s = PCA955X(dev);
  
      s->regs[PCA9552_PSC0] = 0xFF;
      s->regs[PCA9552_PWM0] = 0x80;
      s->regs[PCA9552_PSC1] = 0xFF;
      s->regs[PCA9552_PWM1] = 0x80;
      s->regs[PCA9552_LS0] = 0x55; /* all OFF */
      s->regs[PCA9552_LS1] = 0x55;
      s->regs[PCA9552_LS2] = 0x55;
      s->regs[PCA9552_LS3] = 0x55;
  
      pca955x_update_pin_input(s);
  
      s->pointer = 0xFF;
      s->len = 0;
  }
  
  static void pca955x_initfn(Object *obj)
  {
      PCA955xClass *k = PCA955X_GET_CLASS(obj);
      int led;
  
      assert(k->pin_count <= PCA955X_PIN_COUNT_MAX);
      for (led = 0; led < k->pin_count; led++) {
          char *name;
  
          name = g_strdup_printf("led%d", led);
          object_property_add(obj, name, "bool", pca955x_get_led, pca955x_set_led,
                              NULL, NULL);
          g_free(name);
      }
  }
  
  static void pca955x_realize(DeviceState *dev, Error **errp)
  {
      PCA955xClass *k = PCA955X_GET_CLASS(dev);
      PCA955xState *s = PCA955X(dev);
  
      if (!s->description) {
          s->description = g_strdup("pca-unspecified");
      }
  
      qdev_init_gpio_out(dev, s->gpio, k->pin_count);
  }
  
  static Property pca955x_properties[] = {
      DEFINE_PROP_STRING("description", PCA955xState, description),
      DEFINE_PROP_END_OF_LIST(),
  };
  
  static void pca955x_class_init(ObjectClass *klass, void *data)
  {
      DeviceClass *dc = DEVICE_CLASS(klass);
      I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
  
      k->event = pca955x_event;
      k->recv = pca955x_recv;
      k->send = pca955x_send;
      dc->realize = pca955x_realize;
      device_class_set_props(dc, pca955x_properties);
  }
  
  static const TypeInfo pca955x_info = {
      .name          = TYPE_PCA955X,
      .parent        = TYPE_I2C_SLAVE,
      .instance_init = pca955x_initfn,
      .instance_size = sizeof(PCA955xState),
      .class_init    = pca955x_class_init,
      .class_size    = sizeof(PCA955xClass),
      .abstract      = true,
  };
  
  static void pca9552_class_init(ObjectClass *oc, void *data)
  {
      DeviceClass *dc = DEVICE_CLASS(oc);
      PCA955xClass *pc = PCA955X_CLASS(oc);
  
      dc->reset = pca9552_reset;
      dc->vmsd = &pca9552_vmstate;
      pc->max_reg = PCA9552_LS3;
      pc->pin_count = 16;
  }
  
  static const TypeInfo pca9552_info = {
      .name          = TYPE_PCA9552,
      .parent        = TYPE_PCA955X,
      .class_init    = pca9552_class_init,
  };
  
  static void pca955x_register_types(void)
  {
      type_register_static(&pca955x_info);
      type_register_static(&pca9552_info);
  }
  
  type_init(pca955x_register_types)
  