d307c28ca9
Add a return value to the event handler. Some I2C devices will NAK if they have no data, so allow them to do this. This required the following changes: Go through all the event handlers and change them to return int and return 0. Modify i2c_start_transfer to terminate the transaction on a NAK. Modify smbus handing to not assert if a NAK occurs on a second operation, and terminate the transaction and return -1 instead. Add some information on semantics to I2CSlaveClass. Signed-off-by: Corey Minyard <cminyard@mvista.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
96 lines
3.1 KiB
C
96 lines
3.1 KiB
C
#ifndef QEMU_I2C_H
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#define QEMU_I2C_H
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#include "hw/qdev.h"
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/* The QEMU I2C implementation only supports simple transfers that complete
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immediately. It does not support slave devices that need to be able to
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defer their response (eg. CPU slave interfaces where the data is supplied
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by the device driver in response to an interrupt). */
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enum i2c_event {
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I2C_START_RECV,
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I2C_START_SEND,
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I2C_FINISH,
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I2C_NACK /* Masker NACKed a receive byte. */
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};
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typedef struct I2CSlave I2CSlave;
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#define TYPE_I2C_SLAVE "i2c-slave"
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#define I2C_SLAVE(obj) \
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OBJECT_CHECK(I2CSlave, (obj), TYPE_I2C_SLAVE)
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#define I2C_SLAVE_CLASS(klass) \
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OBJECT_CLASS_CHECK(I2CSlaveClass, (klass), TYPE_I2C_SLAVE)
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#define I2C_SLAVE_GET_CLASS(obj) \
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OBJECT_GET_CLASS(I2CSlaveClass, (obj), TYPE_I2C_SLAVE)
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typedef struct I2CSlaveClass
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{
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DeviceClass parent_class;
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/* Callbacks provided by the device. */
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int (*init)(I2CSlave *dev);
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/* Master to slave. Returns non-zero for a NAK, 0 for success. */
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int (*send)(I2CSlave *s, uint8_t data);
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/*
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* Slave to master. This cannot fail, the device should always
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* return something here. Negative values probably result in 0xff
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* and a possible log from the driver, and shouldn't be used.
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*/
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int (*recv)(I2CSlave *s);
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/*
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* Notify the slave of a bus state change. For start event,
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* returns non-zero to NAK an operation. For other events the
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* return code is not used and should be zero.
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*/
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int (*event)(I2CSlave *s, enum i2c_event event);
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} I2CSlaveClass;
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struct I2CSlave
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{
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DeviceState qdev;
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/* Remaining fields for internal use by the I2C code. */
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uint8_t address;
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};
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I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
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void i2c_set_slave_address(I2CSlave *dev, uint8_t address);
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int i2c_bus_busy(I2CBus *bus);
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int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
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void i2c_end_transfer(I2CBus *bus);
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void i2c_nack(I2CBus *bus);
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int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
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int i2c_send(I2CBus *bus, uint8_t data);
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int i2c_recv(I2CBus *bus);
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DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr);
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/* wm8750.c */
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void wm8750_data_req_set(DeviceState *dev,
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void (*data_req)(void *, int, int), void *opaque);
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void wm8750_dac_dat(void *opaque, uint32_t sample);
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uint32_t wm8750_adc_dat(void *opaque);
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void *wm8750_dac_buffer(void *opaque, int samples);
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void wm8750_dac_commit(void *opaque);
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void wm8750_set_bclk_in(void *opaque, int new_hz);
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/* lm832x.c */
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void lm832x_key_event(DeviceState *dev, int key, int state);
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extern const VMStateDescription vmstate_i2c_slave;
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#define VMSTATE_I2C_SLAVE(_field, _state) { \
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.name = (stringify(_field)), \
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.size = sizeof(I2CSlave), \
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.vmsd = &vmstate_i2c_slave, \
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.flags = VMS_STRUCT, \
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.offset = vmstate_offset_value(_state, _field, I2CSlave), \
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}
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#endif
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