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/*
* 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 <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);
/*
* Sends the 16-bit register offset `off` and reads `len` bytes into `buf`.
*
* Returns the number of bytes read on success, negative `enum cb_err`
* value on error.
*/
int i2c_dev_read_at16(struct device *, uint8_t *buf, size_t len, uint16_t off);
#endif /* _DEVICE_I2C_BUS_H_ */