/* * This file is part of the coreboot project. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #ifndef _DEVICE_I2C_BUS_H_ #define _DEVICE_I2C_BUS_H_ #include <stdlib.h> #include <stdint.h> #include <device/i2c.h> #include <device/device.h> /* I2C bus operation for ramstage drivers */ struct i2c_bus_operations { int (*transfer)(struct device *, const struct i2c_msg *, size_t count); }; /* * Returns the first upstream facing link whose bus implements either * `i2c_bus_operations` *or* `smbus_bus_operations`. * * If not NULL, guarantees that `->dev`, `->dev->ops` and either * `->dev->ops->ops_i2c_bus` or `->dev->ops->ops_smbus_bus` are * not NULL. */ struct bus *i2c_link(struct device *); /* * Shorthand for `i2c_link(dev)->dev`. * * Returns NULL if i2c_link(dev) returns NULL. */ static inline DEVTREE_CONST struct device *i2c_busdev(struct device *dev) { struct bus *const link = i2c_link(dev); return link ? link->dev : NULL; } /* * Slave driver interface functions. These will look for the next * `i2c_bus_operations` *or* `smbus_bus_operations` and perform the * respective transfers. * * The interface is limited to what current slave drivers demand. * Extend as required. * * All functions return a negative `enum cb_err` value on error. * Either CB_ERR, CB_ERR_ARG or any CB_I2C_* (cf. include/types.h). */ /* * Reads one byte. * Compatible to smbus_recv_byte(). * * Returns the read byte on success, negative `enum cb_err` value on error. */ int i2c_dev_readb(struct device *); /* * Writes the byte `val`. * Compatible to smbus_send_byte(). * * Returns 0 on success, negative `enum cb_err` value on error. */ int i2c_dev_writeb(struct device *, uint8_t val); /* * Sends the register offset `off` and reads one byte. * Compatible to smbus_read_byte(). * * Returns the read byte on success, negative `enum cb_err` value on error. */ int i2c_dev_readb_at(struct device *, uint8_t off); /* * Sends the register offset `off` followed by the byte `val`. * Compatible to smbus_write_byte(). * * Returns 0 on success, negative `enum cb_err` value on error. */ int i2c_dev_writeb_at(struct device *, uint8_t off, uint8_t val); #endif /* _DEVICE_I2C_BUS_H_ */