| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* This file is part of the coreboot project. */ |
| |
| #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_ */ |