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Diffstat (limited to 'include/hw/i2c/i2c.h')
| -rw-r--r-- | include/hw/i2c/i2c.h | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h new file mode 100644 index 000000000..5ca3b708c --- /dev/null +++ b/include/hw/i2c/i2c.h @@ -0,0 +1,194 @@ +#ifndef QEMU_I2C_H +#define QEMU_I2C_H + +#include "hw/qdev-core.h" +#include "qom/object.h" + +/* The QEMU I2C implementation only supports simple transfers that complete + immediately. It does not support slave devices that need to be able to + defer their response (eg. CPU slave interfaces where the data is supplied + by the device driver in response to an interrupt). */ + +enum i2c_event { + I2C_START_RECV, + I2C_START_SEND, + I2C_FINISH, + I2C_NACK /* Masker NACKed a receive byte. */ +}; + +typedef struct I2CNodeList I2CNodeList; + +#define TYPE_I2C_SLAVE "i2c-slave" +OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass, + I2C_SLAVE) + +struct I2CSlaveClass { + DeviceClass parent_class; + + /* Master to slave. Returns non-zero for a NAK, 0 for success. */ + int (*send)(I2CSlave *s, uint8_t data); + + /* + * Slave to master. This cannot fail, the device should always + * return something here. + */ + uint8_t (*recv)(I2CSlave *s); + + /* + * Notify the slave of a bus state change. For start event, + * returns non-zero to NAK an operation. For other events the + * return code is not used and should be zero. + */ + int (*event)(I2CSlave *s, enum i2c_event event); + + /* + * Check if this device matches the address provided. Returns bool of + * true if it matches (or broadcast), and updates the device list, false + * otherwise. + * + * If broadcast is true, match should add the device and return true. + */ + bool (*match_and_add)(I2CSlave *candidate, uint8_t address, bool broadcast, + I2CNodeList *current_devs); +}; + +struct I2CSlave { + DeviceState qdev; + + /* Remaining fields for internal use by the I2C code. */ + uint8_t address; +}; + +#define TYPE_I2C_BUS "i2c-bus" +OBJECT_DECLARE_SIMPLE_TYPE(I2CBus, I2C_BUS) + +typedef struct I2CNode I2CNode; + +struct I2CNode { + I2CSlave *elt; + QLIST_ENTRY(I2CNode) next; +}; + +typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList; + +struct I2CBus { + BusState qbus; + I2CNodeList current_devs; + uint8_t saved_address; + bool broadcast; +}; + +I2CBus *i2c_init_bus(DeviceState *parent, const char *name); +int i2c_bus_busy(I2CBus *bus); + +/** + * i2c_start_transfer: start a transfer on an I2C bus. + * + * @bus: #I2CBus to be used + * @address: address of the slave + * @is_recv: indicates the transfer direction + * + * When @is_recv is a known boolean constant, use the + * i2c_start_recv() or i2c_start_send() helper instead. + * + * Returns: 0 on success, -1 on error + */ +int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv); + +/** + * i2c_start_recv: start a 'receive' transfer on an I2C bus. + * + * @bus: #I2CBus to be used + * @address: address of the slave + * + * Returns: 0 on success, -1 on error + */ +int i2c_start_recv(I2CBus *bus, uint8_t address); + +/** + * i2c_start_send: start a 'send' transfer on an I2C bus. + * + * @bus: #I2CBus to be used + * @address: address of the slave + * + * Returns: 0 on success, -1 on error + */ +int i2c_start_send(I2CBus *bus, uint8_t address); + +void i2c_end_transfer(I2CBus *bus); +void i2c_nack(I2CBus *bus); +int i2c_send(I2CBus *bus, uint8_t data); +uint8_t i2c_recv(I2CBus *bus); +bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast, + I2CNodeList *current_devs); + +/** + * Create an I2C slave device on the heap. + * @name: a device type name + * @addr: I2C address of the slave when put on a bus + * + * This only initializes the device state structure and allows + * properties to be set. Type @name must exist. The device still + * needs to be realized. See qdev-core.h. + */ +I2CSlave *i2c_slave_new(const char *name, uint8_t addr); + +/** + * Create and realize an I2C slave device on the heap. + * @bus: I2C bus to put it on + * @name: I2C slave device type name + * @addr: I2C address of the slave when put on a bus + * + * Create the device state structure, initialize it, put it on the + * specified @bus, and drop the reference to it (the device is realized). + */ +I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr); + +/** + * Realize and drop a reference an I2C slave device + * @dev: I2C slave device to realize + * @bus: I2C bus to put it on + * @addr: I2C address of the slave on the bus + * @errp: pointer to NULL initialized error object + * + * Returns: %true on success, %false on failure. + * + * Call 'realize' on @dev, put it on the specified @bus, and drop the + * reference to it. + * + * This function is useful if you have created @dev via qdev_new(), + * i2c_slave_new() or i2c_slave_try_new() (which take a reference to + * the device it returns to you), so that you can set properties on it + * before realizing it. If you don't need to set properties then + * i2c_slave_create_simple() is probably better (as it does the create, + * init and realize in one step). + * + * If you are embedding the I2C slave into another QOM device and + * initialized it via some variant on object_initialize_child() then + * do not use this function, because that family of functions arrange + * for the only reference to the child device to be held by the parent + * via the child<> property, and so the reference-count-drop done here + * would be incorrect. (Instead you would want i2c_slave_realize(), + * which doesn't currently exist but would be trivial to create if we + * had any code that wanted it.) + */ +bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp); + +/** + * Set the I2C bus address of a slave device + * @dev: I2C slave device + * @address: I2C address of the slave when put on a bus + */ +void i2c_slave_set_address(I2CSlave *dev, uint8_t address); + +extern const VMStateDescription vmstate_i2c_slave; + +#define VMSTATE_I2C_SLAVE(_field, _state) { \ + .name = (stringify(_field)), \ + .size = sizeof(I2CSlave), \ + .vmsd = &vmstate_i2c_slave, \ + .flags = VMS_STRUCT, \ + .offset = vmstate_offset_value(_state, _field, I2CSlave), \ +} + +#endif |