i2c.h

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#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_ */