text: /*
   * Maxim MAX1110/1111 ADC chip emulation.
   *
   * Copyright (c) 2006 Openedhand Ltd.
   * Written by Andrzej Zaborowski <balrog@zabor.org>
   *
   * This code is licensed under the GNU GPLv2.
   *
   * Contributions after 2012-01-13 are licensed under the terms of the
   * GNU GPL, version 2 or (at your option) any later version.
   */
  
  #include "hw/ssi.h"
  
  typedef struct {
      SSISlave parent_obj;
  
      qemu_irq interrupt;
      uint8_t tb1, rb2, rb3;
      int cycle;
  
      uint8_t input[8];
      int inputs, com;
  } MAX111xState;
  
  #define TYPE_MAX_111X "max111x"
  
  #define MAX_111X(obj) \
      OBJECT_CHECK(MAX111xState, (obj), TYPE_MAX_111X)
  
  #define TYPE_MAX_1110 "max1110"
  #define TYPE_MAX_1111 "max1111"
  
  /* Control-byte bitfields */
  #define CB_PD0		(1 << 0)
  #define CB_PD1		(1 << 1)
  #define CB_SGL		(1 << 2)
  #define CB_UNI		(1 << 3)
  #define CB_SEL0		(1 << 4)
  #define CB_SEL1		(1 << 5)
  #define CB_SEL2		(1 << 6)
  #define CB_START	(1 << 7)
  
  #define CHANNEL_NUM(v, b0, b1, b2)	\
  			((((v) >> (2 + (b0))) & 4) |	\
  			 (((v) >> (3 + (b1))) & 2) |	\
  			 (((v) >> (4 + (b2))) & 1))
  
  static uint32_t max111x_read(MAX111xState *s)
  {
      if (!s->tb1)
          return 0;
  
      switch (s->cycle ++) {
      case 1:
          return s->rb2;
      case 2:
          return s->rb3;
      }
  
      return 0;
  }
  
  /* Interpret a control-byte */
  static void max111x_write(MAX111xState *s, uint32_t value)
  {
      int measure, chan;
  
      /* Ignore the value if START bit is zero */
      if (!(value & CB_START))
          return;
  
      s->cycle = 0;
  
      if (!(value & CB_PD1)) {
          s->tb1 = 0;
          return;
      }
  
      s->tb1 = value;
  
      if (s->inputs == 8)
          chan = CHANNEL_NUM(value, 1, 0, 2);
      else
          chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);
  
      if (value & CB_SGL)
          measure = s->input[chan] - s->com;
      else
          measure = s->input[chan] - s->input[chan ^ 1];
  
      if (!(value & CB_UNI))
          measure ^= 0x80;
  
      s->rb2 = (measure >> 2) & 0x3f;
      s->rb3 = (measure << 6) & 0xc0;
  
      /* FIXME: When should the IRQ be lowered?  */
      qemu_irq_raise(s->interrupt);
  }
  
  static uint32_t max111x_transfer(SSISlave *dev, uint32_t value)
  {
      MAX111xState *s = MAX_111X(dev);
      max111x_write(s, value);
      return max111x_read(s);
  }
  
  static const VMStateDescription vmstate_max111x = {
      .name = "max111x",
      .version_id = 1,
      .minimum_version_id = 1,
      .fields = (VMStateField[]) {
          VMSTATE_SSI_SLAVE(parent_obj, MAX111xState),
          VMSTATE_UINT8(tb1, MAX111xState),
          VMSTATE_UINT8(rb2, MAX111xState),
          VMSTATE_UINT8(rb3, MAX111xState),
          VMSTATE_INT32_EQUAL(inputs, MAX111xState),
          VMSTATE_INT32(com, MAX111xState),
          VMSTATE_ARRAY_INT32_UNSAFE(input, MAX111xState, inputs,
                                     vmstate_info_uint8, uint8_t),
          VMSTATE_END_OF_LIST()
      }
  };
  
  static int max111x_init(SSISlave *d, int inputs)
  {
      DeviceState *dev = DEVICE(d);
      MAX111xState *s = MAX_111X(dev);
  
      qdev_init_gpio_out(dev, &s->interrupt, 1);
  
      s->inputs = inputs;
      /* TODO: add a user interface for setting these */
      s->input[0] = 0xf0;
      s->input[1] = 0xe0;
      s->input[2] = 0xd0;
      s->input[3] = 0xc0;
      s->input[4] = 0xb0;
      s->input[5] = 0xa0;
      s->input[6] = 0x90;
      s->input[7] = 0x80;
      s->com = 0;
  
      vmstate_register(dev, -1, &vmstate_max111x, s);
      return 0;
  }
  
  static int max1110_init(SSISlave *dev)
  {
      return max111x_init(dev, 8);
  }
  
  static int max1111_init(SSISlave *dev)
  {
      return max111x_init(dev, 4);
  }
  
  void max111x_set_input(DeviceState *dev, int line, uint8_t value)
  {
      MAX111xState *s = MAX_111X(dev);
      assert(line >= 0 && line < s->inputs);
      s->input[line] = value;
  }
  
  static void max111x_class_init(ObjectClass *klass, void *data)
  {
      SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
  
      k->transfer = max111x_transfer;
  }
  
  static const TypeInfo max111x_info = {
      .name          = TYPE_MAX_111X,
      .parent        = TYPE_SSI_SLAVE,
      .instance_size = sizeof(MAX111xState),
      .class_init    = max111x_class_init,
      .abstract      = true,
  };
  
  static void max1110_class_init(ObjectClass *klass, void *data)
  {
      SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
  
      k->init = max1110_init;
  }
  
  static const TypeInfo max1110_info = {
      .name          = TYPE_MAX_1110,
      .parent        = TYPE_MAX_111X,
      .class_init    = max1110_class_init,
  };
  
  static void max1111_class_init(ObjectClass *klass, void *data)
  {
      SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
  
      k->init = max1111_init;
  }
  
  static const TypeInfo max1111_info = {
      .name          = TYPE_MAX_1111,
      .parent        = TYPE_MAX_111X,
      .class_init    = max1111_class_init,
  };
  
  static void max111x_register_types(void)
  {
      type_register_static(&max111x_info);
      type_register_static(&max1110_info);
      type_register_static(&max1111_info);
  }
  
  type_init(max111x_register_types)
  