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
  20 #define TYPE_I2C_SLAVE "i2c-slave"
  21 OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass,
  22                     I2C_SLAVE)
  23
  24 struct 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
  44 struct 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"
  52 OBJECT_DECLARE_SIMPLE_TYPE(I2CBus, I2C_BUS)
  53
  54 typedef struct I2CNode I2CNode;
  55
  56 struct I2CNode {
  57     I2CSlave *elt;
  58     QLIST_ENTRY(I2CNode) next;
  59 };
  60
  61 struct I2CBus {
  62     BusState qbus;
  63     QLIST_HEAD(, I2CNode) current_devs;
  64     uint8_t saved_address;
  65     bool broadcast;
  66 };
  67
  68 I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
  69 void i2c_set_slave_address(I2CSlave *dev, uint8_t address);
  70 int i2c_bus_busy(I2CBus *bus);
  71 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
  72 void i2c_end_transfer(I2CBus *bus);
  73 void i2c_nack(I2CBus *bus);
  74 int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
  75 int i2c_send(I2CBus *bus, uint8_t data);
  76 uint8_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  */
  87 I2CSlave *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  */
  98 I2CSlave *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  */
 128 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
 129
 130 /* lm832x.c */
 131 void lm832x_key_event(DeviceState *dev, int key, int state);
 132
 133 extern 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