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_START_SEND_ASYNC,
  16     I2C_FINISH,
  17     I2C_NACK /* Masker NACKed a receive byte.  */
  18 };
  19
  20 typedef struct I2CNodeList I2CNodeList;
  21
  22 #define TYPE_I2C_SLAVE "i2c-slave"
  23 OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass,
  24                     I2C_SLAVE)
  25
  26 struct I2CSlaveClass {
  27     DeviceClass parent_class;
  28
  29     /* Master to slave. Returns non-zero for a NAK, 0 for success. */
  30     int (*send)(I2CSlave *s, uint8_t data);
  31
  32     /* Master to slave (asynchronous). Receiving slave must call i2c_ack(). */
  33     void (*send_async)(I2CSlave *s, uint8_t data);
  34
  35     /*
  36      * Slave to master.  This cannot fail, the device should always
  37      * return something here.
  38      */
  39     uint8_t (*recv)(I2CSlave *s);
  40
  41     /*
  42      * Notify the slave of a bus state change.  For start event,
  43      * returns non-zero to NAK an operation.  For other events the
  44      * return code is not used and should be zero.
  45      */
  46     int (*event)(I2CSlave *s, enum i2c_event event);
  47
  48     /*
  49      * Check if this device matches the address provided.  Returns bool of
  50      * true if it matches (or broadcast), and updates the device list, false
  51      * otherwise.
  52      *
  53      * If broadcast is true, match should add the device and return true.
  54      */
  55     bool (*match_and_add)(I2CSlave *candidate, uint8_t address, bool broadcast,
  56                           I2CNodeList *current_devs);
  57 };
  58
  59 struct I2CSlave {
  60     DeviceState qdev;
  61
  62     /* Remaining fields for internal use by the I2C code.  */
  63     uint8_t address;
  64 };
  65
  66 #define TYPE_I2C_BUS "i2c-bus"
  67 OBJECT_DECLARE_SIMPLE_TYPE(I2CBus, I2C_BUS)
  68
  69 typedef struct I2CNode I2CNode;
  70
  71 struct I2CNode {
  72     I2CSlave *elt;
  73     QLIST_ENTRY(I2CNode) next;
  74 };
  75
  76 typedef struct I2CPendingMaster I2CPendingMaster;
  77
  78 struct I2CPendingMaster {
  79     QEMUBH *bh;
  80     QSIMPLEQ_ENTRY(I2CPendingMaster) entry;
  81 };
  82
  83 typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList;
  84 typedef QSIMPLEQ_HEAD(I2CPendingMasters, I2CPendingMaster) I2CPendingMasters;
  85
  86 struct I2CBus {
  87     BusState qbus;
  88     I2CNodeList current_devs;
  89     I2CPendingMasters pending_masters;
  90     uint8_t saved_address;
  91     bool broadcast;
  92
  93     /* Set from slave currently mastering the bus. */
  94     QEMUBH *bh;
  95 };
  96
  97 I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
  98 int i2c_bus_busy(I2CBus *bus);
  99
 100 /**
 101  * i2c_start_transfer: start a transfer on an I2C bus.
 102  *
 103  * @bus: #I2CBus to be used
 104  * @address: address of the slave
 105  * @is_recv: indicates the transfer direction
 106  *
 107  * When @is_recv is a known boolean constant, use the
 108  * i2c_start_recv() or i2c_start_send() helper instead.
 109  *
 110  * Returns: 0 on success, -1 on error
 111  */
 112 int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv);
 113
 114 /**
 115  * i2c_start_recv: start a 'receive' transfer on an I2C bus.
 116  *
 117  * @bus: #I2CBus to be used
 118  * @address: address of the slave
 119  *
 120  * Returns: 0 on success, -1 on error
 121  */
 122 int i2c_start_recv(I2CBus *bus, uint8_t address);
 123
 124 /**
 125  * i2c_start_send: start a 'send' transfer on an I2C bus.
 126  *
 127  * @bus: #I2CBus to be used
 128  * @address: address of the slave
 129  *
 130  * Returns: 0 on success, -1 on error
 131  */
 132 int i2c_start_send(I2CBus *bus, uint8_t address);
 133
 134 /**
 135  * i2c_start_send_async: start an asynchronous 'send' transfer on an I2C bus.
 136  *
 137  * @bus: #I2CBus to be used
 138  * @address: address of the slave
 139  *
 140  * Return: 0 on success, -1 on error
 141  */
 142 int i2c_start_send_async(I2CBus *bus, uint8_t address);
 143
 144 void i2c_schedule_pending_master(I2CBus *bus);
 145
 146 void i2c_end_transfer(I2CBus *bus);
 147 void i2c_nack(I2CBus *bus);
 148 void i2c_ack(I2CBus *bus);
 149 void i2c_bus_master(I2CBus *bus, QEMUBH *bh);
 150 void i2c_bus_release(I2CBus *bus);
 151 int i2c_send(I2CBus *bus, uint8_t data);
 152 int i2c_send_async(I2CBus *bus, uint8_t data);
 153 uint8_t i2c_recv(I2CBus *bus);
 154 bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
 155                   I2CNodeList *current_devs);
 156
 157 /**
 158  * Create an I2C slave device on the heap.
 159  * @name: a device type name
 160  * @addr: I2C address of the slave when put on a bus
 161  *
 162  * This only initializes the device state structure and allows
 163  * properties to be set. Type @name must exist. The device still
 164  * needs to be realized. See qdev-core.h.
 165  */
 166 I2CSlave *i2c_slave_new(const char *name, uint8_t addr);
 167
 168 /**
 169  * Create and realize an I2C slave device on the heap.
 170  * @bus: I2C bus to put it on
 171  * @name: I2C slave device type name
 172  * @addr: I2C address of the slave when put on a bus
 173  *
 174  * Create the device state structure, initialize it, put it on the
 175  * specified @bus, and drop the reference to it (the device is realized).
 176  */
 177 I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr);
 178
 179 /**
 180  * Realize and drop a reference an I2C slave device
 181  * @dev: I2C slave device to realize
 182  * @bus: I2C bus to put it on
 183  * @addr: I2C address of the slave on the bus
 184  * @errp: pointer to NULL initialized error object
 185  *
 186  * Returns: %true on success, %false on failure.
 187  *
 188  * Call 'realize' on @dev, put it on the specified @bus, and drop the
 189  * reference to it.
 190  *
 191  * This function is useful if you have created @dev via qdev_new(),
 192  * i2c_slave_new() or i2c_slave_try_new() (which take a reference to
 193  * the device it returns to you), so that you can set properties on it
 194  * before realizing it. If you don't need to set properties then
 195  * i2c_slave_create_simple() is probably better (as it does the create,
 196  * init and realize in one step).
 197  *
 198  * If you are embedding the I2C slave into another QOM device and
 199  * initialized it via some variant on object_initialize_child() then
 200  * do not use this function, because that family of functions arrange
 201  * for the only reference to the child device to be held by the parent
 202  * via the child<> property, and so the reference-count-drop done here
 203  * would be incorrect.  (Instead you would want i2c_slave_realize(),
 204  * which doesn't currently exist but would be trivial to create if we
 205  * had any code that wanted it.)
 206  */
 207 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
 208
 209 /**
 210  * Set the I2C bus address of a slave device
 211  * @dev: I2C slave device
 212  * @address: I2C address of the slave when put on a bus
 213  */
 214 void i2c_slave_set_address(I2CSlave *dev, uint8_t address);
 215
 216 extern const VMStateDescription vmstate_i2c_slave;
 217
 218 #define VMSTATE_I2C_SLAVE(_field, _state) {                          \
 219     .name       = (stringify(_field)),                               \
 220     .size       = sizeof(I2CSlave),                                  \
 221     .vmsd       = &vmstate_i2c_slave,                                \
 222     .flags      = VMS_STRUCT,                                        \
 223     .offset     = vmstate_offset_value(_state, _field, I2CSlave),    \
 224 }
 225
 226 #endif