LXR qemu/include/hw/i2c/i2c.h

   1#ifndef QEMU_I2C_H
   2#define QEMU_I2C_H
   3
   4#include "hw/qdev-core.h"
   5#include "qom/object.h"
   6
   7/* The QEMU I2C implementation only supports simple transfers that complete
   8   immediately.  It does not support slave devices that need to be able to
   9   defer their response (eg. CPU slave interfaces where the data is supplied
  10   by the device driver in response to an interrupt).  */
  11
  12enum i2c_event {
  13    I2C_START_RECV,
  14    I2C_START_SEND,
  15    I2C_FINISH,
  16    I2C_NACK /* Masker NACKed a receive byte.  */
  17};
  18
  19
  20#define TYPE_I2C_SLAVE "i2c-slave"
  21OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass,
  22                    I2C_SLAVE)
  23
  24struct I2CSlaveClass {
  25    DeviceClass parent_class;
  26
  27    /* Master to slave. Returns non-zero for a NAK, 0 for success. */
  28    int (*send)(I2CSlave *s, uint8_t data);
  29
  30    /*
  31     * Slave to master.  This cannot fail, the device should always
  32     * return something here.
  33     */
  34    uint8_t (*recv)(I2CSlave *s);
  35
  36    /*
  37     * Notify the slave of a bus state change.  For start event,
  38     * returns non-zero to NAK an operation.  For other events the
  39     * return code is not used and should be zero.
  40     */
  41    int (*event)(I2CSlave *s, enum i2c_event event);
  42};
  43
  44struct I2CSlave {
  45    DeviceState qdev;
  46
  47    /* Remaining fields for internal use by the I2C code.  */
  48    uint8_t address;
  49};
  50
  51#define TYPE_I2C_BUS "i2c-bus"
  52OBJECT_DECLARE_SIMPLE_TYPE(I2CBus, I2C_BUS)
  53
  54typedef struct I2CNode I2CNode;
  55
  56struct I2CNode {
  57    I2CSlave *elt;
  58    QLIST_ENTRY(I2CNode) next;
  59};
  60
  61struct I2CBus {
  62    BusState qbus;
  63    QLIST_HEAD(, I2CNode) current_devs;
  64    uint8_t saved_address;
  65    bool broadcast;
  66};
  67
  68I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
  69void i2c_set_slave_address(I2CSlave *dev, uint8_t address);
  70int i2c_bus_busy(I2CBus *bus);
  71int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
  72void i2c_end_transfer(I2CBus *bus);
  73void i2c_nack(I2CBus *bus);
  74int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
  75int i2c_send(I2CBus *bus, uint8_t data);
  76uint8_t i2c_recv(I2CBus *bus);
  77
  78/**
  79 * Create an I2C slave device on the heap.
  80 * @name: a device type name
  81 * @addr: I2C address of the slave when put on a bus
  82 *
  83 * This only initializes the device state structure and allows
  84 * properties to be set. Type @name must exist. The device still
  85 * needs to be realized. See qdev-core.h.
  86 */
  87I2CSlave *i2c_slave_new(const char *name, uint8_t addr);
  88
  89/**
  90 * Create and realize an I2C slave device on the heap.
  91 * @bus: I2C bus to put it on
  92 * @name: I2C slave device type name
  93 * @addr: I2C address of the slave when put on a bus
  94 *
  95 * Create the device state structure, initialize it, put it on the
  96 * specified @bus, and drop the reference to it (the device is realized).
  97 */
  98I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr);
  99
 100/**
 101 * Realize and drop a reference an I2C slave device
 102 * @dev: I2C slave device to realize
 103 * @bus: I2C bus to put it on
 104 * @addr: I2C address of the slave on the bus
 105 * @errp: pointer to NULL initialized error object
 106 *
 107 * Returns: %true on success, %false on failure.
 108 *
 109 * Call 'realize' on @dev, put it on the specified @bus, and drop the
 110 * reference to it.
 111 *
 112 * This function is useful if you have created @dev via qdev_new(),
 113 * i2c_slave_new() or i2c_slave_try_new() (which take a reference to
 114 * the device it returns to you), so that you can set properties on it
 115 * before realizing it. If you don't need to set properties then
 116 * i2c_slave_create_simple() is probably better (as it does the create,
 117 * init and realize in one step).
 118 *
 119 * If you are embedding the I2C slave into another QOM device and
 120 * initialized it via some variant on object_initialize_child() then
 121 * do not use this function, because that family of functions arrange
 122 * for the only reference to the child device to be held by the parent
 123 * via the child<> property, and so the reference-count-drop done here
 124 * would be incorrect.  (Instead you would want i2c_slave_realize(),
 125 * which doesn't currently exist but would be trivial to create if we
 126 * had any code that wanted it.)
 127 */
 128bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
 129
 130/* lm832x.c */
 131void lm832x_key_event(DeviceState *dev, int key, int state);
 132
 133extern const VMStateDescription vmstate_i2c_slave;
 134
 135#define VMSTATE_I2C_SLAVE(_field, _state) {                          \
 136    .name       = (stringify(_field)),                               \
 137    .size       = sizeof(I2CSlave),                                  \
 138    .vmsd       = &vmstate_i2c_slave,                                \
 139    .flags      = VMS_STRUCT,                                        \
 140    .offset     = vmstate_offset_value(_state, _field, I2CSlave),    \
 141}
 142
 143#endif
 144