include/hw/i2c/i2c.h

   1 #ifndef QEMU_I2C_H
   2 #define QEMU_I2C_H
   3
   4 #include "hw/qdev-core.h"
   5
   6 /* The QEMU I2C implementation only supports simple transfers that complete
   7    immediately.  It does not support slave devices that need to be able to
   8    defer their response (eg. CPU slave interfaces where the data is supplied
   9    by the device driver in response to an interrupt).  */
  10
  11 enum i2c_event {
  12     I2C_START_RECV,
  13     I2C_START_SEND,
  14     I2C_FINISH,
  15     I2C_NACK /* Masker NACKed a receive byte.  */
  16 };
  17
  18 typedef struct I2CSlave I2CSlave;
  19
  20 #define TYPE_I2C_SLAVE "i2c-slave"
  21 #define I2C_SLAVE(obj) \
  22      OBJECT_CHECK(I2CSlave, (obj), TYPE_I2C_SLAVE)
  23 #define I2C_SLAVE_CLASS(klass) \
  24      OBJECT_CLASS_CHECK(I2CSlaveClass, (klass), TYPE_I2C_SLAVE)
  25 #define I2C_SLAVE_GET_CLASS(obj) \
  26      OBJECT_GET_CLASS(I2CSlaveClass, (obj), TYPE_I2C_SLAVE)
  27
  28 typedef struct I2CSlaveClass {
  29     DeviceClass parent_class;
  30
  31     /* Master to slave. Returns non-zero for a NAK, 0 for success. */
  32     int (*send)(I2CSlave *s, uint8_t data);
  33
  34     /*
  35      * Slave to master.  This cannot fail, the device should always
  36      * return something here.
  37      */
  38     uint8_t (*recv)(I2CSlave *s);
  39
  40     /*
  41      * Notify the slave of a bus state change.  For start event,
  42      * returns non-zero to NAK an operation.  For other events the
  43      * return code is not used and should be zero.
  44      */
  45     int (*event)(I2CSlave *s, enum i2c_event event);
  46 } I2CSlaveClass;
  47
  48 struct I2CSlave {
  49     DeviceState qdev;
  50
  51     /* Remaining fields for internal use by the I2C code.  */
  52     uint8_t address;
  53 };
  54
  55 #define TYPE_I2C_BUS "i2c-bus"
  56 #define I2C_BUS(obj) OBJECT_CHECK(I2CBus, (obj), TYPE_I2C_BUS)
  57
  58 typedef struct I2CNode I2CNode;
  59
  60 struct I2CNode {
  61     I2CSlave *elt;
  62     QLIST_ENTRY(I2CNode) next;
  63 };
  64
  65 struct I2CBus {
  66     BusState qbus;
  67     QLIST_HEAD(, I2CNode) current_devs;
  68     uint8_t saved_address;
  69     bool broadcast;
  70 };
  71
  72 I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
  73 void i2c_set_slave_address(I2CSlave *dev, uint8_t address);
  74 int i2c_bus_busy(I2CBus *bus);
  75 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
  76 void i2c_end_transfer(I2CBus *bus);
  77 void i2c_nack(I2CBus *bus);
  78 int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
  79 int i2c_send(I2CBus *bus, uint8_t data);
  80 uint8_t i2c_recv(I2CBus *bus);
  81
  82 /**
  83  * Create an I2C slave device on the heap.
  84  * @name: a device type name
  85  * @addr: I2C address of the slave when put on a bus
  86  *
  87  * This only initializes the device state structure and allows
  88  * properties to be set. Type @name must exist. The device still
  89  * needs to be realized. See qdev-core.h.
  90  */
  91 I2CSlave *i2c_slave_new(const char *name, uint8_t addr);
  92
  93 /**
  94  * Create and realize an I2C slave device on the heap.
  95  * @bus: I2C bus to put it on
  96  * @name: I2C slave device type name
  97  * @addr: I2C address of the slave when put on a bus
  98  *
  99  * Create the device state structure, initialize it, put it on the
 100  * specified @bus, and drop the reference to it (the device is realized).
 101  */
 102 I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr);
 103
 104 /**
 105  * Realize and drop a reference an I2C slave device
 106  * @dev: I2C slave device to realize
 107  * @bus: I2C bus to put it on
 108  * @addr: I2C address of the slave on the bus
 109  * @errp: pointer to NULL initialized error object
 110  *
 111  * Returns: %true on success, %false on failure.
 112  *
 113  * Call 'realize' on @dev, put it on the specified @bus, and drop the
 114  * reference to it.
 115  *
 116  * This function is useful if you have created @dev via qdev_new(),
 117  * i2c_slave_new() or i2c_slave_try_new() (which take a reference to
 118  * the device it returns to you), so that you can set properties on it
 119  * before realizing it. If you don't need to set properties then
 120  * i2c_slave_create_simple() is probably better (as it does the create,
 121  * init and realize in one step).
 122  *
 123  * If you are embedding the I2C slave into another QOM device and
 124  * initialized it via some variant on object_initialize_child() then
 125  * do not use this function, because that family of functions arrange
 126  * for the only reference to the child device to be held by the parent
 127  * via the child<> property, and so the reference-count-drop done here
 128  * would be incorrect.  (Instead you would want i2c_slave_realize(),
 129  * which doesn't currently exist but would be trivial to create if we
 130  * had any code that wanted it.)
 131  */
 132 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
 133
 134 /* lm832x.c */
 135 void lm832x_key_event(DeviceState *dev, int key, int state);
 136
 137 extern const VMStateDescription vmstate_i2c_slave;
 138
 139 #define VMSTATE_I2C_SLAVE(_field, _state) {                          \
 140     .name       = (stringify(_field)),                               \
 141     .size       = sizeof(I2CSlave),                                  \
 142     .vmsd       = &vmstate_i2c_slave,                                \
 143     .flags      = VMS_STRUCT,                                        \
 144     .offset     = vmstate_offset_value(_state, _field, I2CSlave),    \
 145 }
 146
 147 #endif