| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* This file is part of the coreboot project. */ |
| |
| #ifndef _DEVICE_I2C_H_ |
| #define _DEVICE_I2C_H_ |
| |
| #include <stdint.h> |
| |
| /** |
| * struct i2c_msg - an I2C transaction segment beginning with START |
| * @addr: Slave address, either seven or ten bits. When this is a ten |
| * bit address, I2C_M_TEN must be set in @flags. |
| * @flags: I2C_M_RD is handled by all adapters. |
| * @len: Number of data bytes in @buf being read from or written to the |
| * I2C slave address. For read transactions where I2C_M_RECV_LEN |
| * is set, the caller guarantees that this buffer can hold up to |
| * 32 bytes in addition to the initial length byte sent by the |
| * slave (plus, if used, the SMBus PEC). |
| * @buf: The buffer into which data is read, or from which it's written. |
| * |
| * An i2c_msg is the low level representation of one segment of an I2C |
| * transaction. It is visible to drivers in the @i2c_transfer() procedure. |
| * |
| * All I2C adapters implement the standard rules for I2C transactions. Each |
| * transaction begins with a START. That is followed by the slave address, |
| * and a bit encoding read versus write. Then follow all the data bytes, |
| * possibly including a byte with SMBus PEC. The transfer terminates with |
| * a NAK, or when all those bytes have been transferred and ACKed. If this |
| * is the last message in a group, it is followed by a STOP. Otherwise it |
| * is followed by the next @i2c_msg transaction segment, beginning with a |
| * (repeated) START. |
| */ |
| struct i2c_msg { |
| uint16_t flags; |
| #define I2C_M_RD 0x0001 /* read data, from slave to master */ |
| #define I2C_M_TEN 0x0010 /* this is a ten bit chip address */ |
| #define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */ |
| #define I2C_M_NOSTART 0x4000 /* don't send a repeated START */ |
| uint16_t slave; /* slave address */ |
| uint16_t len; /* msg length */ |
| uint8_t *buf; /* pointer to msg data */ |
| }; |
| |
| enum i2c_speed { |
| I2C_SPEED_STANDARD = 100000, |
| I2C_SPEED_FAST = 400000, |
| I2C_SPEED_FAST_PLUS = 1000000, |
| I2C_SPEED_HIGH = 3400000, |
| I2C_SPEED_FAST_ULTRA = 5000000, |
| }; |
| |
| enum i2c_address_mode { |
| I2C_MODE_7_BIT, |
| I2C_MODE_10_BIT |
| }; |
| |
| #endif /* _DEVICE_I2C_H_ */ |