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
  12 enum i2c_event {
  13     I2C_START_RECV,
  14     I2C_START_SEND,
  15     I2C_FINISH,
  16     I2C_NACK /* Masker NACKed a receive byte.  */
  17 };
  18
  19 typedef struct I2CSlave I2CSlave;
  20
  21 #define TYPE_I2C_SLAVE "i2c-slave"
  22 typedef struct I2CSlaveClass I2CSlaveClass;
  23 #define I2C_SLAVE(obj) \
  24      OBJECT_CHECK(I2CSlave, (obj), TYPE_I2C_SLAVE)
  25 #define I2C_SLAVE_CLASS(klass) \
  26      OBJECT_CLASS_CHECK(I2CSlaveClass, (klass), TYPE_I2C_SLAVE)
  27 #define I2C_SLAVE_GET_CLASS(obj) \
  28      OBJECT_GET_CLASS(I2CSlaveClass, (obj), TYPE_I2C_SLAVE)
  29
  30 struct I2CSlaveClass {
  31     DeviceClass parent_class;
  32
  33     /* Master to slave. Returns non-zero for a NAK, 0 for success. */
  34     int (*send)(I2CSlave *s, uint8_t data);
  35
  36     /*
  37      * Slave to master.  This cannot fail, the device should always
  38      * return something here.
  39      */
  40     uint8_t (*recv)(I2CSlave *s);
  41
  42     /*
  43      * Notify the slave of a bus state change.  For start event,
  44      * returns non-zero to NAK an operation.  For other events the
  45      * return code is not used and should be zero.
  46      */
  47     int (*event)(I2CSlave *s, enum i2c_event event);
  48 };
  49
  50 struct I2CSlave {
  51     DeviceState qdev;
  52
  53     /* Remaining fields for internal use by the I2C code.  */
  54     uint8_t address;
  55 };
  56
  57 #define TYPE_I2C_BUS "i2c-bus"
  58 #define I2C_BUS(obj) OBJECT_CHECK(I2CBus, (obj), TYPE_I2C_BUS)
  59
  60 typedef struct I2CNode I2CNode;
  61
  62 struct I2CNode {
  63     I2CSlave *elt;
  64     QLIST_ENTRY(I2CNode) next;
  65 };
  66
  67 struct I2CBus {
  68     BusState qbus;
  69     QLIST_HEAD(, I2CNode) current_devs;
  70     uint8_t saved_address;
  71     bool broadcast;
  72 };
  73
  74 I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
  75 void i2c_set_slave_address(I2CSlave *dev, uint8_t address);
  76 int i2c_bus_busy(I2CBus *bus);
  77 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
  78 void i2c_end_transfer(I2CBus *bus);
  79 void i2c_nack(I2CBus *bus);
  80 int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
  81 int i2c_send(I2CBus *bus, uint8_t data);
  82 uint8_t i2c_recv(I2CBus *bus);
  83
  84 /**
  85  * Create an I2C slave device on the heap.
  86  * @name: a device type name
  87  * @addr: I2C address of the slave when put on a bus
  88  *
  89  * This only initializes the device state structure and allows
  90  * properties to be set. Type @name must exist. The device still
  91  * needs to be realized. See qdev-core.h.
  92  */
  93 I2CSlave *i2c_slave_new(const char *name, uint8_t addr);
  94
  95 /**
  96  * Create and realize an I2C slave device on the heap.
  97  * @bus: I2C bus to put it on
  98  * @name: I2C slave device type name
  99  * @addr: I2C address of the slave when put on a bus
 100  *
 101  * Create the device state structure, initialize it, put it on the
 102  * specified @bus, and drop the reference to it (the device is realized).
 103  */
 104 I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr);
 105
 106 /**
 107  * Realize and drop a reference an I2C slave device
 108  * @dev: I2C slave device to realize
 109  * @bus: I2C bus to put it on
 110  * @addr: I2C address of the slave on the bus
 111  * @errp: pointer to NULL initialized error object
 112  *
 113  * Returns: %true on success, %false on failure.
 114  *
 115  * Call 'realize' on @dev, put it on the specified @bus, and drop the
 116  * reference to it.
 117  *
 118  * This function is useful if you have created @dev via qdev_new(),
 119  * i2c_slave_new() or i2c_slave_try_new() (which take a reference to
 120  * the device it returns to you), so that you can set properties on it
 121  * before realizing it. If you don't need to set properties then
 122  * i2c_slave_create_simple() is probably better (as it does the create,
 123  * init and realize in one step).
 124  *
 125  * If you are embedding the I2C slave into another QOM device and
 126  * initialized it via some variant on object_initialize_child() then
 127  * do not use this function, because that family of functions arrange
 128  * for the only reference to the child device to be held by the parent
 129  * via the child<> property, and so the reference-count-drop done here
 130  * would be incorrect.  (Instead you would want i2c_slave_realize(),
 131  * which doesn't currently exist but would be trivial to create if we
 132  * had any code that wanted it.)
 133  */
 134 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
 135
 136 /* lm832x.c */
 137 void lm832x_key_event(DeviceState *dev, int key, int state);
 138
 139 extern const VMStateDescription vmstate_i2c_slave;
 140
 141 #define VMSTATE_I2C_SLAVE(_field, _state) {                          \
 142     .name       = (stringify(_field)),                               \
 143     .size       = sizeof(I2CSlave),                                  \
 144     .vmsd       = &vmstate_i2c_slave,                                \
 145     .flags      = VMS_STRUCT,                                        \
 146     .offset     = vmstate_offset_value(_state, _field, I2CSlave),    \
 147 }
 148
 149 #endif