root / hw / max111x.c @ 75b0646f
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/*
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* Maxim MAX1110/1111 ADC chip emulation.
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*
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* Copyright (c) 2006 Openedhand Ltd.
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* Written by Andrzej Zaborowski <balrog@zabor.org>
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*
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* This code is licensed under the GNU GPLv2.
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*/
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#include "ssi.h" |
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typedef struct { |
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SSISlave ssidev; |
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qemu_irq interrupt; |
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uint8_t tb1, rb2, rb3; |
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int cycle;
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uint8_t input[8];
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int inputs, com;
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} MAX111xState; |
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/* Control-byte bitfields */
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#define CB_PD0 (1 << 0) |
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#define CB_PD1 (1 << 1) |
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#define CB_SGL (1 << 2) |
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#define CB_UNI (1 << 3) |
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#define CB_SEL0 (1 << 4) |
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#define CB_SEL1 (1 << 5) |
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#define CB_SEL2 (1 << 6) |
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#define CB_START (1 << 7) |
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#define CHANNEL_NUM(v, b0, b1, b2) \
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((((v) >> (2 + (b0))) & 4) | \ |
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(((v) >> (3 + (b1))) & 2) | \ |
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(((v) >> (4 + (b2))) & 1)) |
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static uint32_t max111x_read(MAX111xState *s)
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{ |
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if (!s->tb1)
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return 0; |
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switch (s->cycle ++) {
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case 1: |
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return s->rb2;
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case 2: |
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return s->rb3;
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} |
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return 0; |
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} |
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/* Interpret a control-byte */
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static void max111x_write(MAX111xState *s, uint32_t value) |
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{ |
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int measure, chan;
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/* Ignore the value if START bit is zero */
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if (!(value & CB_START))
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return;
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s->cycle = 0;
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if (!(value & CB_PD1)) {
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s->tb1 = 0;
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return;
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} |
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s->tb1 = value; |
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if (s->inputs == 8) |
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chan = CHANNEL_NUM(value, 1, 0, 2); |
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else
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chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2); |
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if (value & CB_SGL)
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measure = s->input[chan] - s->com; |
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else
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measure = s->input[chan] - s->input[chan ^ 1];
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if (!(value & CB_UNI))
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measure ^= 0x80;
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s->rb2 = (measure >> 2) & 0x3f; |
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s->rb3 = (measure << 6) & 0xc0; |
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/* FIXME: When should the IRQ be lowered? */
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qemu_irq_raise(s->interrupt); |
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} |
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static uint32_t max111x_transfer(SSISlave *dev, uint32_t value)
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{ |
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MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev); |
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max111x_write(s, value); |
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return max111x_read(s);
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} |
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static const VMStateDescription vmstate_max111x = { |
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.name = "max111x",
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.version_id = 0,
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.minimum_version_id = 0,
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.minimum_version_id_old = 0,
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.fields = (VMStateField[]) { |
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VMSTATE_UINT8(tb1, MAX111xState), |
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VMSTATE_UINT8(rb2, MAX111xState), |
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VMSTATE_UINT8(rb3, MAX111xState), |
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VMSTATE_INT32_EQUAL(inputs, MAX111xState), |
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VMSTATE_INT32(com, MAX111xState), |
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VMSTATE_ARRAY_INT32_UNSAFE(input, MAX111xState, inputs, |
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vmstate_info_uint8, uint8_t), |
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VMSTATE_END_OF_LIST() |
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} |
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}; |
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static int max111x_init(SSISlave *dev, int inputs) |
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{ |
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MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev); |
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qdev_init_gpio_out(&dev->qdev, &s->interrupt, 1);
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s->inputs = inputs; |
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/* TODO: add a user interface for setting these */
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s->input[0] = 0xf0; |
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s->input[1] = 0xe0; |
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s->input[2] = 0xd0; |
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s->input[3] = 0xc0; |
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s->input[4] = 0xb0; |
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s->input[5] = 0xa0; |
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s->input[6] = 0x90; |
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s->input[7] = 0x80; |
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s->com = 0;
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vmstate_register(&dev->qdev, -1, &vmstate_max111x, s);
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return 0; |
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} |
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static int max1110_init(SSISlave *dev) |
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{ |
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return max111x_init(dev, 8); |
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} |
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static int max1111_init(SSISlave *dev) |
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{ |
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return max111x_init(dev, 4); |
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} |
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void max111x_set_input(DeviceState *dev, int line, uint8_t value) |
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{ |
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MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, SSI_SLAVE_FROM_QDEV(dev)); |
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assert(line >= 0 && line < s->inputs);
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s->input[line] = value; |
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} |
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static SSISlaveInfo max1110_info = {
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.qdev.name = "max1110",
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.qdev.size = sizeof(MAX111xState),
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.init = max1110_init, |
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.transfer = max111x_transfer |
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}; |
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static SSISlaveInfo max1111_info = {
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.qdev.name = "max1111",
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.qdev.size = sizeof(MAX111xState),
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.init = max1111_init, |
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.transfer = max111x_transfer |
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}; |
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static void max111x_register_devices(void) |
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{ |
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ssi_register_slave(&max1110_info); |
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ssi_register_slave(&max1111_info); |
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} |
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device_init(max111x_register_devices) |