System I2C (Inter-Integrated Circuit) driver for Allwinner (sunxi) platforms. More...

#include <io.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <types.h>
#include <timer.h>
#include <common.h>
#include <log.h>
#include <sys-clk.h>
#include "reg-ncat.h"
#include "sys-i2c.h"

Include dependency graph for sys-i2c.c:

Macros
#define	I2C_WRITE 0
	I2C write transaction type.

#define	I2C_READ 1
	I2C read transaction type.

#define	I2C_OK 0
	I2C operation successful status.

#define	I2C_NOK 1
	I2C operation failed general status.

#define	I2C_NACK 2
	I2C operation failed with NACK status.

#define	I2C_NOK_LA 3 /* Lost arbitration */
	I2C operation failed with lost arbitration status.

#define	I2C_NOK_TOUT 4 /* time out */
	I2C operation failed with timeout status.

#define	I2C_START_TRANSMIT 0x08
	I2C status code for successful start condition transmission.

#define	I2C_RESTART_TRANSMIT 0x10
	I2C status code for successful repeated start condition transmission.

#define	I2C_ADDRWRITE_ACK 0x18
	I2C status code for successful slave address write with ACK.

#define	I2C_ADDRREAD_ACK 0x40
	I2C status code for successful slave address read with ACK.

#define	I2C_DATAWRITE_ACK 0x28
	I2C status code for successful data write with ACK.

#define	I2C_READY 0xf8
	I2C status code for bus ready state.

#define	I2C_DATAREAD_NACK 0x58
	I2C status code for successful data read with NACK.

#define	I2C_DATAREAD_ACK 0x50
	I2C status code for successful data read with ACK.

Functions
static int32_t	sunxi_i2c_send_byteaddr (sunxi_i2c_t *i2c_dev, uint32_t byteaddr)
	Send a byte address over I2C.

static int32_t	sunxi_i2c_send_start (sunxi_i2c_t *i2c_dev)
	Generate I2C start condition.

static int32_t	sunxi_i2c_send_slave_addr (sunxi_i2c_t *i2c_dev, uint32_t saddr, uint32_t rw)
	Send I2C slave address with read/write bit.

static int32_t	sunxi_i2c_send_restart (sunxi_i2c_t *i2c_dev)
	Generate I2C repeated start condition.

static int32_t	sunxi_i2c_stop (sunxi_i2c_t *i2c_dev)
	Generate I2C stop condition.

static int32_t	sunxi_i2c_get_data (sunxi_i2c_t i2c_dev, uint8_t data_addr, uint32_t data_count)
	Receive data from I2C device.

static int32_t	sunxi_i2c_send_data (sunxi_i2c_t i2c_dev, uint8_t data_addr, uint32_t data_count)
	Sends data to the I2C device.

static int	_sunxi_i2c_read (sunxi_i2c_t i2c_dev, uint8_t chip, uint32_t addr, int alen, uint8_t buffer, int len)
	sunxi_i2c read function

static int	_sunxi_i2c_write (sunxi_i2c_t i2c_dev, uint8_t chip, uint32_t addr, int alen, uint8_t buffer, int len)
	sunxi_i2c write function

int	sunxi_i2c_write (sunxi_i2c_t *i2c_dev, uint8_t addr, uint32_t reg, uint8_t data)
	Write a single byte to I2C device register.

int	sunxi_i2c_read (sunxi_i2c_t i2c_dev, uint8_t addr, uint32_t reg, uint8_t data)
	Read a single byte from I2C device register.

static void	sunxi_i2c_bus_reset (sunxi_i2c_t *i2c_dev)
	Resets the I2C bus for the specified I2C device.

static void	sunxi_i2c_set_clock (sunxi_i2c_t *i2c_dev)
	Configures the clock settings for the specified I2C device.

static void	sunxi_i2c_bus_clk_open (sunxi_i2c_t *i2c_dev)
	Opens the clock for the specified I2C device.

static void	sunxi_i2c_bus_en (sunxi_i2c_t *i2c_dev)
	Enables the I2C bus for the specified I2C device.

void	sunxi_i2c_init (sunxi_i2c_t *i2c_dev)
	Initialize I2C controller and bus.

Detailed Description

System I2C (Inter-Integrated Circuit) driver for Allwinner (sunxi) platforms.

This file implements I2C communication functionality for Allwinner SoCs, supporting standard I2C master operations including initialization, read/write transactions, clock configuration, and bus reset. The driver handles both 100kHz (standard) and 400kHz (fast) I2C speeds.

Macro Definition Documentation

◆ I2C_ADDRREAD_ACK

#define I2C_ADDRREAD_ACK 0x40

I2C status code for successful slave address read with ACK.

◆ I2C_ADDRWRITE_ACK

#define I2C_ADDRWRITE_ACK 0x18

I2C status code for successful slave address write with ACK.

◆ I2C_DATAREAD_ACK

#define I2C_DATAREAD_ACK 0x50

I2C status code for successful data read with ACK.

◆ I2C_DATAREAD_NACK

#define I2C_DATAREAD_NACK 0x58

I2C status code for successful data read with NACK.

◆ I2C_DATAWRITE_ACK

#define I2C_DATAWRITE_ACK 0x28

I2C status code for successful data write with ACK.

◆ I2C_NACK

#define I2C_NACK 2

I2C operation failed with NACK status.

◆ I2C_NOK

#define I2C_NOK 1

I2C operation failed general status.

◆ I2C_NOK_LA

#define I2C_NOK_LA 3 /* Lost arbitration */

I2C operation failed with lost arbitration status.

◆ I2C_NOK_TOUT

#define I2C_NOK_TOUT 4 /* time out */

I2C operation failed with timeout status.

◆ I2C_OK

#define I2C_OK 0

I2C operation successful status.

◆ I2C_READ

#define I2C_READ 1

I2C read transaction type.

◆ I2C_READY

#define I2C_READY 0xf8

I2C status code for bus ready state.

◆ I2C_RESTART_TRANSMIT

#define I2C_RESTART_TRANSMIT 0x10

I2C status code for successful repeated start condition transmission.

◆ I2C_START_TRANSMIT

#define I2C_START_TRANSMIT 0x08

I2C status code for successful start condition transmission.

◆ I2C_WRITE

#define I2C_WRITE 0

I2C write transaction type.

Function Documentation

◆ _sunxi_i2c_read()

static int _sunxi_i2c_read	(	sunxi_i2c_t *	i2c_dev,
		uint8_t	chip,
		uint32_t	addr,
		int	alen,
		uint8_t *	buffer,
		int	len
	)

static

sunxi_i2c read function

Parameters

i2c_dev	Pointer to the sunxi_i2c controller device structure
chip	Device address
addr	Register to be read from in the device
alen	Length of the register address
buffer	Buffer to store the read data
len	Length of the data to be read

Returns: int Number of status

Internal I2C read function

Performs a complete I2C read transaction, including start, address, register, and data transfer.

Parameters

i2c_dev	Pointer to the I2C device structure
chip	Device address
addr	Register address to read from
alen	Length of the register address (1-3 bytes)
buffer	Buffer to store read data
len	Number of bytes to read

Returns: I2C_OK on success, negative error code on failure

◆ _sunxi_i2c_write()

static int _sunxi_i2c_write	(	sunxi_i2c_t *	i2c_dev,
		uint8_t	chip,
		uint32_t	addr,
		int	alen,
		uint8_t *	buffer,
		int	len
	)

static

sunxi_i2c write function

Parameters

i2c_dev	Pointer to the sunxi_i2c controller device structure
chip	Device address
addr	Register to be read/written in the device
alen	Length of the register address
buffer	Data to be written/read
len	Length of the data

Returns: int Number of status

Internal I2C write function

Performs a complete I2C write transaction, including start, address, register, and data transfer.

Parameters

i2c_dev	Pointer to the I2C device structure
chip	Device address
addr	Register address to write to
alen	Length of the register address (1-3 bytes)
buffer	Buffer containing data to write
len	Number of bytes to write

Returns: I2C_OK on success, negative error code on failure

◆ sunxi_i2c_bus_clk_open()

static void sunxi_i2c_bus_clk_open ( sunxi_i2c_t * i2c_dev )

inlinestatic

Opens the clock for the specified I2C device.

This function de-asserts the reset signal for the I2C clock and enables the clock gating. It first de-asserts the reset, then clears the clock gating bit, waits for a brief period, and finally re-enables the clock.

Parameters

i2c_dev Pointer to the I2C device structure that contains the clock control registers' base address and offsets.

Note: The function uses a delay to ensure that the clock gating changes take effect before proceeding.

◆ sunxi_i2c_bus_en()

static void sunxi_i2c_bus_en ( sunxi_i2c_t * i2c_dev )

inlinestatic

Enables the I2C bus for the specified I2C device.

This function sets the control register to enable the I2C bus and clears any error flags by writing to the error flag register.

Parameters

i2c_dev Pointer to the I2C device structure that contains the base address for the I2C hardware registers.

Note: This function should be called before performing any I2C transactions to ensure that the bus is enabled.

◆ sunxi_i2c_bus_reset()

static void sunxi_i2c_bus_reset ( sunxi_i2c_t * i2c_dev )

static

Resets the I2C bus for the specified I2C device.

This function attempts to reset the I2C control by toggling the SCL and SDA lines until the bus is idle. It first checks the control register to determine if a reset is needed, and then it performs the necessary toggling of the lines.

Parameters

i2c_dev Pointer to the I2C device structure that contains the base address for the I2C hardware registers.

Note: The function uses a timeout mechanism to prevent infinite loops in case the reset process fails.

Warning: Ensure that this function is called when the I2C device is in a known state to avoid unintended behavior.

◆ sunxi_i2c_get_data()

static int32_t sunxi_i2c_get_data	(	sunxi_i2c_t *	i2c_dev,
		uint8_t *	data_addr,
		uint32_t	data_count
	)

static

Receive data from I2C device.

Receives multiple bytes of data from an I2C device, handling ACK/NACK appropriately.

Parameters

i2c_dev	Pointer to the I2C device structure
data_addr	Buffer to store received data
data_count	Number of bytes to receive

Returns: I2C_OK on success, negative error code on failure

◆ sunxi_i2c_init()

void sunxi_i2c_init ( sunxi_i2c_t * i2c_dev )

Initialize I2C controller and bus.

Initializes the I2C controller by configuring GPIO pins, enabling clocks, resetting the bus, setting clock frequency, and enabling the I2C controller.

Parameters

i2c_dev Pointer to the I2C device structure containing configuration parameters

◆ sunxi_i2c_read()

int sunxi_i2c_read	(	sunxi_i2c_t *	i2c_dev,
		uint8_t	addr,
		uint32_t	reg,
		uint8_t *	data
	)

Read a single byte from I2C device register.

sunxi_i2c read function

Reads a single byte from a specified register on an I2C device.

Parameters

i2c_dev	Pointer to the I2C device structure
addr	I2C device address
reg	Register address to read from
data	Pointer to store the read byte

Returns: I2C_OK on success, I2C_NOK if I2C controller is not initialized

◆ sunxi_i2c_send_byteaddr()

static int32_t sunxi_i2c_send_byteaddr	(	sunxi_i2c_t *	i2c_dev,
		uint32_t	byteaddr
	)

static

Send a byte address over I2C.

Sends a single byte address to the I2C device and waits for acknowledgment.

Parameters

i2c_dev	Pointer to the I2C device structure
byteaddr	Byte address to send

Returns: I2C_OK on success, negative error code on failure

◆ sunxi_i2c_send_data()

static int32_t sunxi_i2c_send_data	(	sunxi_i2c_t *	i2c_dev,
		uint8_t *	data_addr,
		uint32_t	data_count
	)

static

Sends data to the I2C device.

This function sends a specified number of bytes of data to the I2C device. It writes data to the data register and waits for the acknowledgment from the device for each byte sent. If a timeout occurs while waiting for acknowledgment, the function will return an error code.

Parameters

i2c_dev	Pointer to the I2C device structure containing the device's configuration and register base address.
data_addr	Pointer to the data buffer that contains the data to be sent.
data_count	The number of bytes to send from the data buffer.

Returns

I2C_OK on success, or a negative error code on failure. Possible error codes include:

I2C_NOK_TOUT: Timeout occurred while waiting for the I2C device to acknowledge data.

◆ sunxi_i2c_send_restart()

static int32_t sunxi_i2c_send_restart ( sunxi_i2c_t * i2c_dev )

static

Generate I2C repeated start condition.

Generates a repeated start condition on the I2C bus to change operation mode.

Parameters

i2c_dev Pointer to the I2C device structure

Returns: I2C_OK on success, negative error code on failure

◆ sunxi_i2c_send_slave_addr()

static int32_t sunxi_i2c_send_slave_addr	(	sunxi_i2c_t *	i2c_dev,
		uint32_t	saddr,
		uint32_t	rw
	)

static

Send I2C slave address with read/write bit.

Transmits the slave address along with read/write bit and waits for acknowledgment.

Parameters

i2c_dev	Pointer to the I2C device structure
saddr	Slave device address
rw	Read (1) or Write (0) operation

Returns: I2C_OK on success, negative error code on failure

◆ sunxi_i2c_send_start()

static int32_t sunxi_i2c_send_start ( sunxi_i2c_t * i2c_dev )

static

Generate I2C start condition.

Generates a start condition on the I2C bus to initiate communication.

Parameters

i2c_dev Pointer to the I2C device structure

Returns: I2C_OK on success, negative error code on failure

◆ sunxi_i2c_set_clock()

static void sunxi_i2c_set_clock ( sunxi_i2c_t * i2c_dev )

static

Configures the clock settings for the specified I2C device.

This function calculates and sets the appropriate clock divider values based on the desired I2C speed and the source clock frequency. It finds suitable values for clk_m and clk_n, and adjusts the clock control register accordingly.

Parameters

i2c_dev Pointer to the I2C device structure that contains the base address for the I2C hardware registers and clock configuration parameters.

Note: The function adjusts the clock settings to ensure the I2C speed is achievable with the given source clock. It handles both 100kHz and 400kHz configurations.

Warning: Ensure that the parent clock frequency is set correctly before calling this function to avoid incorrect clock settings.

◆ sunxi_i2c_stop()

static int32_t sunxi_i2c_stop ( sunxi_i2c_t * i2c_dev )

static

Generate I2C stop condition.

Generates a stop condition on the I2C bus to terminate communication.

Parameters

i2c_dev Pointer to the I2C device structure

Returns: I2C_OK on success, negative error code on failure

◆ sunxi_i2c_write()

int sunxi_i2c_write	(	sunxi_i2c_t *	i2c_dev,
		uint8_t	addr,
		uint32_t	reg,
		uint8_t	data
	)

Write a single byte to I2C device register.

sunxi_i2c write function

Writes a single byte to a specified register on an I2C device.

Parameters

i2c_dev	Pointer to the I2C device structure
addr	I2C device address
reg	Register address to write to
data	Byte value to write

Returns: I2C_OK on success, I2C_NOK if I2C controller is not initialized

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ I2C_ADDRREAD_ACK

◆ I2C_ADDRWRITE_ACK

◆ I2C_DATAREAD_ACK

◆ I2C_DATAREAD_NACK

◆ I2C_DATAWRITE_ACK

◆ I2C_NACK

◆ I2C_NOK

◆ I2C_NOK_LA

◆ I2C_NOK_TOUT

◆ I2C_OK

◆ I2C_READ

◆ I2C_READY

◆ I2C_RESTART_TRANSMIT

◆ I2C_START_TRANSMIT

◆ I2C_WRITE

Function Documentation

◆ _sunxi_i2c_read()

◆ _sunxi_i2c_write()

◆ sunxi_i2c_bus_clk_open()

◆ sunxi_i2c_bus_en()

◆ sunxi_i2c_bus_reset()

◆ sunxi_i2c_get_data()

◆ sunxi_i2c_init()

◆ sunxi_i2c_read()

◆ sunxi_i2c_send_byteaddr()

◆ sunxi_i2c_send_data()

◆ sunxi_i2c_send_restart()

◆ sunxi_i2c_send_slave_addr()

◆ sunxi_i2c_send_start()

◆ sunxi_i2c_set_clock()

◆ sunxi_i2c_stop()

◆ sunxi_i2c_write()