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 I2CNodeList I2CNodeList; 20 21 #define TYPE_I2C_SLAVE "i2c-slave" 22 OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass, 23 I2C_SLAVE) 24 25 struct I2CSlaveClass { 26 DeviceClass parent_class; 27 28 /* Master to slave. Returns non-zero for a NAK, 0 for success. */ 29 int (*send)(I2CSlave *s, uint8_t data); 30 31 /* 32 * Slave to master. This cannot fail, the device should always 33 * return something here. 34 */ 35 uint8_t (*recv)(I2CSlave *s); 36 37 /* 38 * Notify the slave of a bus state change. For start event, 39 * returns non-zero to NAK an operation. For other events the 40 * return code is not used and should be zero. 41 */ 42 int (*event)(I2CSlave *s, enum i2c_event event); 43 44 /* 45 * Check if this device matches the address provided. Returns bool of 46 * true if it matches (or broadcast), and updates the device list, false 47 * otherwise. 48 * 49 * If broadcast is true, match should add the device and return true. 50 */ 51 bool (*match_and_add)(I2CSlave *candidate, uint8_t address, bool broadcast, 52 I2CNodeList *current_devs); 53 }; 54 55 struct I2CSlave { 56 DeviceState qdev; 57 58 /* Remaining fields for internal use by the I2C code. */ 59 uint8_t address; 60 }; 61 62 #define TYPE_I2C_BUS "i2c-bus" 63 OBJECT_DECLARE_SIMPLE_TYPE(I2CBus, I2C_BUS) 64 65 typedef struct I2CNode I2CNode; 66 67 struct I2CNode { 68 I2CSlave *elt; 69 QLIST_ENTRY(I2CNode) next; 70 }; 71 72 typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList; 73 74 struct I2CBus { 75 BusState qbus; 76 I2CNodeList current_devs; 77 uint8_t saved_address; 78 bool broadcast; 79 }; 80 81 I2CBus *i2c_init_bus(DeviceState *parent, const char *name); 82 int i2c_bus_busy(I2CBus *bus); 83 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv); 84 void i2c_end_transfer(I2CBus *bus); 85 void i2c_nack(I2CBus *bus); 86 int i2c_send(I2CBus *bus, uint8_t data); 87 uint8_t i2c_recv(I2CBus *bus); 88 bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast, 89 I2CNodeList *current_devs); 90 91 /** 92 * Create an I2C slave device on the heap. 93 * @name: a device type name 94 * @addr: I2C address of the slave when put on a bus 95 * 96 * This only initializes the device state structure and allows 97 * properties to be set. Type @name must exist. The device still 98 * needs to be realized. See qdev-core.h. 99 */ 100 I2CSlave *i2c_slave_new(const char *name, uint8_t addr); 101 102 /** 103 * Create and realize an I2C slave device on the heap. 104 * @bus: I2C bus to put it on 105 * @name: I2C slave device type name 106 * @addr: I2C address of the slave when put on a bus 107 * 108 * Create the device state structure, initialize it, put it on the 109 * specified @bus, and drop the reference to it (the device is realized). 110 */ 111 I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr); 112 113 /** 114 * Realize and drop a reference an I2C slave device 115 * @dev: I2C slave device to realize 116 * @bus: I2C bus to put it on 117 * @addr: I2C address of the slave on the bus 118 * @errp: pointer to NULL initialized error object 119 * 120 * Returns: %true on success, %false on failure. 121 * 122 * Call 'realize' on @dev, put it on the specified @bus, and drop the 123 * reference to it. 124 * 125 * This function is useful if you have created @dev via qdev_new(), 126 * i2c_slave_new() or i2c_slave_try_new() (which take a reference to 127 * the device it returns to you), so that you can set properties on it 128 * before realizing it. If you don't need to set properties then 129 * i2c_slave_create_simple() is probably better (as it does the create, 130 * init and realize in one step). 131 * 132 * If you are embedding the I2C slave into another QOM device and 133 * initialized it via some variant on object_initialize_child() then 134 * do not use this function, because that family of functions arrange 135 * for the only reference to the child device to be held by the parent 136 * via the child<> property, and so the reference-count-drop done here 137 * would be incorrect. (Instead you would want i2c_slave_realize(), 138 * which doesn't currently exist but would be trivial to create if we 139 * had any code that wanted it.) 140 */ 141 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp); 142 143 /** 144 * Set the I2C bus address of a slave device 145 * @dev: I2C slave device 146 * @address: I2C address of the slave when put on a bus 147 */ 148 void i2c_slave_set_address(I2CSlave *dev, uint8_t address); 149 150 extern const VMStateDescription vmstate_i2c_slave; 151 152 #define VMSTATE_I2C_SLAVE(_field, _state) { \ 153 .name = (stringify(_field)), \ 154 .size = sizeof(I2CSlave), \ 155 .vmsd = &vmstate_i2c_slave, \ 156 .flags = VMS_STRUCT, \ 157 .offset = vmstate_offset_value(_state, _field, I2CSlave), \ 158 } 159 160 #endif 161