To ease reviewing code using the I2C bus API, introduce the i2c_start_recv() and i2c_start_send() helpers which don't take the confusing 'is_recv' boolean argument. Use these new helpers in the SMBus / AUX bus models. Suggested-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Corey Minyard <cminyard@mvista.com>
195 lines
6 KiB
C
195 lines
6 KiB
C
#ifndef QEMU_I2C_H
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#define QEMU_I2C_H
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#include "hw/qdev-core.h"
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#include "qom/object.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 I2CNodeList I2CNodeList;
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#define TYPE_I2C_SLAVE "i2c-slave"
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OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass,
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I2C_SLAVE)
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struct I2CSlaveClass {
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DeviceClass parent_class;
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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.
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*/
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uint8_t (*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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/*
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* Check if this device matches the address provided. Returns bool of
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* true if it matches (or broadcast), and updates the device list, false
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* otherwise.
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*
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* If broadcast is true, match should add the device and return true.
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*/
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bool (*match_and_add)(I2CSlave *candidate, uint8_t address, bool broadcast,
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I2CNodeList *current_devs);
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};
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struct I2CSlave {
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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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#define TYPE_I2C_BUS "i2c-bus"
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OBJECT_DECLARE_SIMPLE_TYPE(I2CBus, I2C_BUS)
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typedef struct I2CNode I2CNode;
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struct I2CNode {
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I2CSlave *elt;
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QLIST_ENTRY(I2CNode) next;
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};
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typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList;
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struct I2CBus {
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BusState qbus;
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I2CNodeList current_devs;
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uint8_t saved_address;
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bool broadcast;
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};
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I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
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int i2c_bus_busy(I2CBus *bus);
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/**
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* i2c_start_transfer: start a transfer on an I2C bus.
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*
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* @bus: #I2CBus to be used
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* @address: address of the slave
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* @is_recv: indicates the transfer direction
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*
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* When @is_recv is a known boolean constant, use the
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* i2c_start_recv() or i2c_start_send() helper instead.
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*
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* Returns: 0 on success, -1 on error
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*/
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int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv);
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/**
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* i2c_start_recv: start a 'receive' transfer on an I2C bus.
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*
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* @bus: #I2CBus to be used
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* @address: address of the slave
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*
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* Returns: 0 on success, -1 on error
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*/
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int i2c_start_recv(I2CBus *bus, uint8_t address);
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/**
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* i2c_start_send: start a 'send' transfer on an I2C bus.
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*
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* @bus: #I2CBus to be used
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* @address: address of the slave
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*
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* Returns: 0 on success, -1 on error
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*/
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int i2c_start_send(I2CBus *bus, uint8_t address);
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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(I2CBus *bus, uint8_t data);
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uint8_t i2c_recv(I2CBus *bus);
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bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
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I2CNodeList *current_devs);
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/**
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* Create an I2C slave device on the heap.
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* @name: a device type name
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* @addr: I2C address of the slave when put on a bus
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*
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* This only initializes the device state structure and allows
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* properties to be set. Type @name must exist. The device still
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* needs to be realized. See qdev-core.h.
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*/
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I2CSlave *i2c_slave_new(const char *name, uint8_t addr);
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/**
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* Create and realize an I2C slave device on the heap.
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* @bus: I2C bus to put it on
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* @name: I2C slave device type name
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* @addr: I2C address of the slave when put on a bus
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*
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* Create the device state structure, initialize it, put it on the
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* specified @bus, and drop the reference to it (the device is realized).
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*/
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I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr);
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/**
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* Realize and drop a reference an I2C slave device
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* @dev: I2C slave device to realize
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* @bus: I2C bus to put it on
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* @addr: I2C address of the slave on the bus
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* @errp: pointer to NULL initialized error object
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*
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* Returns: %true on success, %false on failure.
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*
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* Call 'realize' on @dev, put it on the specified @bus, and drop the
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* reference to it.
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*
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* This function is useful if you have created @dev via qdev_new(),
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* i2c_slave_new() or i2c_slave_try_new() (which take a reference to
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* the device it returns to you), so that you can set properties on it
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* before realizing it. If you don't need to set properties then
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* i2c_slave_create_simple() is probably better (as it does the create,
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* init and realize in one step).
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*
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* If you are embedding the I2C slave into another QOM device and
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* initialized it via some variant on object_initialize_child() then
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* do not use this function, because that family of functions arrange
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* for the only reference to the child device to be held by the parent
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* via the child<> property, and so the reference-count-drop done here
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* would be incorrect. (Instead you would want i2c_slave_realize(),
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* which doesn't currently exist but would be trivial to create if we
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* had any code that wanted it.)
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*/
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bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
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/**
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* Set the I2C bus address of a slave device
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* @dev: I2C slave device
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* @address: I2C address of the slave when put on a bus
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*/
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void i2c_slave_set_address(I2CSlave *dev, uint8_t address);
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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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