mctp_i2c_gpio_target.h File Reference

#include <stdint.h>
#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/pmci/mctp/mctp_i2c_gpio_common.h>
#include <libmctp.h>

Go to the source code of this file.

Data Structures
struct	mctp_binding_i2c_gpio_target
	An MCTP binding for Zephyr's I2C target interface using GPIO. More...

Macros
#define	MCTP_I2C_GPIO_TARGET_DT_DEFINE(_name, _node_id)
	INTERNAL_HIDDEN.

Macro Definition Documentation

MCTP_I2C_GPIO_TARGET_DT_DEFINE

#define MCTP_I2C_GPIO_TARGET_DT_DEFINE	(		_name,
			_node_id )

Value:

        K_SEM_DEFINE(_name ##_tx_lock, 1, 1);                                                      \
        K_SEM_DEFINE(_name ##_tx_complete, 0, 1);                                                  \
        struct mctp_binding_i2c_gpio_target _name = {                                              \
                .binding = {                                                                       \
                        .name = STRINGIFY(_name), .version = 1,                                    \
                        .start = mctp_i2c_gpio_target_start,                                       \
                        .tx = mctp_i2c_gpio_target_tx,                                             \
                        .pkt_size = MCTP_I2C_GPIO_MAX_PKT_SIZE,                                    \
                },                                                                                 \
                .i2c = DEVICE_DT_GET(DT_PHANDLE(_node_id, i2c)),                                   \
                .i2c_target_cfg = {                                                                \
                        .address = DT_PROP(_node_id, i2c_addr),                                    \
                        .callbacks = &mctp_i2c_gpio_target_callbacks,                              \
                },                                                                                 \
                .endpoint_id = DT_PROP(_node_id, endpoint_id),                                     \
                .endpoint_gpio = GPIO_DT_SPEC_GET(_node_id, endpoint_gpios),                       \
                .tx_lock = &_name##_tx_lock,                                                       \
                .tx_complete = &_name##_tx_complete,                                               \
        };

INTERNAL_HIDDEN.

Define a MCTP bus binding for I2C target with GPIO

Rather than mode switching as the MCTP standard wishes, this is a custom binding. On the target side a gpio pin is set active (could be active low or active high) when writes are pending. It's expected the controller then reads from the I2C target device at some point in the future. Reads are accepted at any time and are expected to contain full mctp packets.

In effect each device has a pair of pseudo registers for reading or writing as a packet FIFO.

Thus the sequence for a I2C target to send a message would be...

1. Setup a length and message value (pseudo registers).
2. Signal the controller with a GPIO level set
3. The controller then is expected to read the length (write of addr 0 + read 1 byte)
4. The controller then is expected to read the message (write of addr 1 + read N bytes)
5. The target clears the pin set
6. The controller reports a message receive to MCTP

Parameters

_name	Symbolic name of the bus binding variable
_node_id	DeviceTree Node containing the configuration of this MCTP binding