It is never supposed to fail and cannot return an error, so just have it return the proper type. Have it return 0xff on nothing available, since that's what would happen on a real bus. Signed-off-by: Corey Minyard <cminyard@mvista.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
220 lines
5 KiB
C
220 lines
5 KiB
C
/*
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* MAX7310 8-port GPIO expansion chip.
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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 file is licensed under GNU GPL.
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*/
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#include "qemu/osdep.h"
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#include "hw/i2c/i2c.h"
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#define TYPE_MAX7310 "max7310"
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#define MAX7310(obj) OBJECT_CHECK(MAX7310State, (obj), TYPE_MAX7310)
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typedef struct MAX7310State {
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I2CSlave parent_obj;
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int i2c_command_byte;
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int len;
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uint8_t level;
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uint8_t direction;
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uint8_t polarity;
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uint8_t status;
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uint8_t command;
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qemu_irq handler[8];
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qemu_irq *gpio_in;
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} MAX7310State;
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static void max7310_reset(DeviceState *dev)
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{
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MAX7310State *s = MAX7310(dev);
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s->level &= s->direction;
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s->direction = 0xff;
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s->polarity = 0xf0;
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s->status = 0x01;
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s->command = 0x00;
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}
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static uint8_t max7310_rx(I2CSlave *i2c)
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{
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MAX7310State *s = MAX7310(i2c);
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switch (s->command) {
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case 0x00: /* Input port */
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return s->level ^ s->polarity;
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break;
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case 0x01: /* Output port */
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return s->level & ~s->direction;
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break;
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case 0x02: /* Polarity inversion */
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return s->polarity;
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case 0x03: /* Configuration */
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return s->direction;
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case 0x04: /* Timeout */
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return s->status;
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break;
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case 0xff: /* Reserved */
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return 0xff;
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default:
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#ifdef VERBOSE
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printf("%s: unknown register %02x\n", __func__, s->command);
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#endif
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break;
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}
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return 0xff;
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}
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static int max7310_tx(I2CSlave *i2c, uint8_t data)
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{
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MAX7310State *s = MAX7310(i2c);
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uint8_t diff;
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int line;
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if (s->len ++ > 1) {
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#ifdef VERBOSE
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printf("%s: message too long (%i bytes)\n", __func__, s->len);
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#endif
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return 1;
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}
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if (s->i2c_command_byte) {
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s->command = data;
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s->i2c_command_byte = 0;
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return 0;
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}
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switch (s->command) {
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case 0x01: /* Output port */
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for (diff = (data ^ s->level) & ~s->direction; diff;
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diff &= ~(1 << line)) {
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line = ctz32(diff);
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if (s->handler[line])
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qemu_set_irq(s->handler[line], (data >> line) & 1);
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}
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s->level = (s->level & s->direction) | (data & ~s->direction);
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break;
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case 0x02: /* Polarity inversion */
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s->polarity = data;
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break;
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case 0x03: /* Configuration */
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s->level &= ~(s->direction ^ data);
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s->direction = data;
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break;
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case 0x04: /* Timeout */
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s->status = data;
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break;
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case 0x00: /* Input port - ignore writes */
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break;
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default:
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#ifdef VERBOSE
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printf("%s: unknown register %02x\n", __func__, s->command);
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#endif
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return 1;
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}
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return 0;
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}
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static int max7310_event(I2CSlave *i2c, enum i2c_event event)
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{
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MAX7310State *s = MAX7310(i2c);
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s->len = 0;
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switch (event) {
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case I2C_START_SEND:
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s->i2c_command_byte = 1;
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break;
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case I2C_FINISH:
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#ifdef VERBOSE
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if (s->len == 1)
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printf("%s: message too short (%i bytes)\n", __func__, s->len);
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#endif
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break;
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default:
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break;
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}
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return 0;
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}
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static const VMStateDescription vmstate_max7310 = {
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.name = "max7310",
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.version_id = 0,
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.minimum_version_id = 0,
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.fields = (VMStateField[]) {
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VMSTATE_INT32(i2c_command_byte, MAX7310State),
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VMSTATE_INT32(len, MAX7310State),
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VMSTATE_UINT8(level, MAX7310State),
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VMSTATE_UINT8(direction, MAX7310State),
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VMSTATE_UINT8(polarity, MAX7310State),
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VMSTATE_UINT8(status, MAX7310State),
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VMSTATE_UINT8(command, MAX7310State),
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VMSTATE_I2C_SLAVE(parent_obj, MAX7310State),
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VMSTATE_END_OF_LIST()
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}
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};
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static void max7310_gpio_set(void *opaque, int line, int level)
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{
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MAX7310State *s = (MAX7310State *) opaque;
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if (line >= ARRAY_SIZE(s->handler) || line < 0)
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hw_error("bad GPIO line");
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if (level)
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s->level |= s->direction & (1 << line);
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else
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s->level &= ~(s->direction & (1 << line));
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}
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/* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
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* but also accepts sequences that are not SMBus so return an I2C device. */
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static void max7310_realize(DeviceState *dev, Error **errp)
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{
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I2CSlave *i2c = I2C_SLAVE(dev);
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MAX7310State *s = MAX7310(dev);
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qdev_init_gpio_in(&i2c->qdev, max7310_gpio_set, 8);
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qdev_init_gpio_out(&i2c->qdev, s->handler, 8);
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}
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static void max7310_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
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dc->realize = max7310_realize;
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k->event = max7310_event;
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k->recv = max7310_rx;
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k->send = max7310_tx;
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dc->reset = max7310_reset;
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dc->vmsd = &vmstate_max7310;
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}
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static const TypeInfo max7310_info = {
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.name = TYPE_MAX7310,
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.parent = TYPE_I2C_SLAVE,
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.instance_size = sizeof(MAX7310State),
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.class_init = max7310_class_init,
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};
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static void max7310_register_types(void)
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{
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type_register_static(&max7310_info);
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}
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type_init(max7310_register_types)
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