【S32K146 RT-thread】之I2c bus 驱动

andeyqi · 发表于 2024-1-3 11:21:54

本帖最后由 andeyqi 于 2024-1-5 22:49 编辑

概述：

以下链接是官方对I2C设备驱动的介绍，可以从中了解下I2C驱动模型的结构。

RT-Thread I2C 驱动框架提供了一个结构化的方式来支持 I2C 总线通信，方便统一的接口方式访问 I2C 设备。RT-Thread I2C 驱动框架主要包括两个层次的抽象：

I2C 总线核心层 (i2c_core.c): 这一层提供了 I2C 总线的抽象和核心逻辑。它包含 I2C 总线的初始化、数据传输、设备注册和查找等核心功能。
I2C 设备驱动层 (i2c_dev.c): 这一层建立在 I2C 总线核心层之上，提供了对具体 I2C 设备的抽象。它包含 I2C 设备的初始化、打开、关闭、读写等操作，以及设备的控制和关闭。

I2C 驱动的核心文件是i2c_core.c，对应的核心结构体为rt_i2c_bus_device，该结构体是 RT-Thread 中定义的用于表示 I2C 总线设备的结构体。它包含了一些关键的字段，用于描述和管理具体的 I2C 总线。以下是 rt_i2c_bus_device 结构体的主要字段和功能

/*for i2c bus driver*/
struct rt_i2c_bus_device
{
struct rt_device parent;/* 设备基类 device */
const struct rt_i2c_bus_device_ops *ops;/* I2C 下操作方法 */
rt_uint16_t flags;/* I2C 支持的读写标志等 */
struct rt_mutex lock;/* 互斥锁，保证多线程范访问安全 */
rt_uint32_t timeout; /* 超时时间 */
rt_uint32_t retries; /* retry 次数 */
void *priv;/* 私有数据 */
};

复制代码

对于适配I2C总线驱动,我们只需关注struct rt_i2c_bus_device_ops *ops成员即可，ops 成员定义了I2C 总线的访问方法定义如下：

struct rt_i2c_bus_device_ops
{
rt_ssize_t (*master_xfer)(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg msgs[],
rt_uint32_t num);
rt_ssize_t (*slave_xfer)(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg msgs[],
rt_uint32_t num);
rt_err_t (*i2c_bus_control)(struct rt_i2c_bus_device *bus,
int cmd,
void *args);
};

复制代码

本地使用的S32K开发板是master 须实现master_xfer函数，slave_xfer/i2c_bus_control 没有实现不过不影响我们使用I2C总线访问通过RT-thread i2c 驱动框架本地实现代码如下：

/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "drv_i2c.h"
#include "board.h"
struct s32k_i2c
{
struct rt_i2c_bus_device bus;
char *device_name;
rt_uint32_t instance;
rt_uint32_t timeout;
lpi2c_master_state_t state;
};
static rt_ssize_t master_xfer(struct rt_i2c_bus_device *bus, struct rt_i2c_msg msgs[], rt_uint32_t num)
{
rt_ssize_t ret = (0);
rt_uint32_t index = 0;
struct s32k_i2c *i2c = RT_NULL;
struct rt_i2c_msg *msg = RT_NULL;
status_t result = STATUS_SUCCESS;
bool stop = false;
i2c = (struct s32k_i2c *)bus;
LPI2C_DRV_MasterSetSlaveAddr(i2c->instance,msgs[0].addr,false);
for(index = 0; index < num; index++)
{
if(index == (num-1))
stop = true;
msg = &msgs[index];
if(RT_I2C_RD & msg->flags)
{
result = LPI2C_DRV_MasterReceiveDataBlocking(i2c->instance, msg->buf,msg->len, stop , i2c->timeout);
}
else
{
result = LPI2C_DRV_MasterSendDataBlocking(i2c->instance, (const uint8_t * )msg->buf,msg->len, stop , i2c->timeout);
}
if(result != STATUS_SUCCESS)
break;
}
if (result == STATUS_SUCCESS)
{
ret = index;
}
return ret;
}
static rt_ssize_t slave_xfer(struct rt_i2c_bus_device *bus, struct rt_i2c_msg msgs[], rt_uint32_t num)
{
return -RT_ENOSYS;
}
static rt_err_t i2c_bus_control(struct rt_i2c_bus_device *bus, int cmd, void *args)
{
return -RT_EINVAL;
}
static const struct rt_i2c_bus_device_ops ops =
{
master_xfer,
slave_xfer,
i2c_bus_control,
};
extern void LPI2C0_Master_IRQHandler(void);
void S32K14X_LPI2C0_Master_Slave_IRQHandler(void)
{
/* enter interrupt */
rt_interrupt_enter();
LPI2C0_Master_IRQHandler();
/* leave interrupt */
rt_interrupt_leave();
}
static struct s32k_i2c i2c0 = {0};
int rt_hw_i2c_init(void)
{
i2c0.device_name = "i2c0";
i2c0.bus.ops = &ops;
i2c0.instance = INST_LPI2C0;
i2c0.timeout = 500;
INT_SYS_InstallHandler(LPI2C0_Master_IRQn,S32K14X_LPI2C0_Master_Slave_IRQHandler,NULL);
/* init i2c0 bus */
LPI2C_DRV_MasterInit(i2c0.instance, &lpi2c0_MasterConfig0, &i2c0.state);
rt_i2c_bus_device_register(&i2c0.bus, i2c0.device_name);
return RT_EOK;
}
INIT_APP_EXPORT(rt_hw_i2c_init);

复制代码

上面的代码里我们使用了S32 SDK 的LPI2C_DRV_MasterReceiveDataBlocking/LPI2C_DRV_MasterSendDataBlocking 的API函数，但是S32的SDK 的这些接口时跟OS 相耦合的，在 S32K Software Development Kit (SDK) 中存在一个OSIF层，OSIF (Operating System Interface) 层是一个抽象层，用于提供操作系统相关的接口，使得 S32K SDK 可以在不同的操作系统上运行。OSIF 层包含了对于操作系统的适配接口，互斥锁、信号量等。这种设计使得 S32K SDK 能够灵活地在不同的实时操作系统 (RTOS) 上运行。以下图片可以看出OS 和接口之间夹杂了osif 我们需要实现基于RT-thread 实现osif 相关的接口。

OSIF 依赖OS 相关的接口如下。

按照上面的要是求SDK OS相关的依赖。osif_rtthread.c

/*
*
* NXP Confidential. This software is owned or controlled by NXP and may only be
* used strictly in accordance with the applicable license terms. By expressly
* accepting such terms or by downloading, installing, activating and/or otherwise
* using the software, you are agreeing that you have read, and that you agree to
* comply with and are bound by, such license terms. If you do not agree to be
* bound by the applicable license terms, then you may not retain, install,
* activate or otherwise use the software. The production use license in
* Section 2.3 is expressly granted for this software.
*/
/*!
* @file osif_freertos.c
*
* @page misra_violations MISRA-C:2012 violations
*
* @section [global]
* Violates MISRA 2012 Required Rule 1.3, Taking address of near auto variable
* The code is not dynamically linked. An absolute stack address is obtained when
* taking the address of the near auto variable. A source of error in writing
* dynamic code is that the stack segment may be different from the data segment.
*
* @section [global]
* Violates MISRA 2012 Advisory Directive 4.9, Function-like macro defined.
* The macros are used to validate input parameters to driver functions.
*
* @section [global]
* Violates MISRA 2012 Required Rule 7.2, Unsigned integer literal without a 'U' suffix
* Register address defined by FreeRTOS header files.
*
* @section [global]
* Violates MISRA 2012 Advisory Rule 8.7, External could be made static.
* Function is defined for usage by application code.
*
* @section [global]
* Violates MISRA 2012 Advisory Rule 8.13, Pointer variable could be declared as pointing to const
* Type definition is done in FreeRTOS header files.
*
* @section [global]
* Violates MISRA 2012 Advisory Rule 11.4, Conversion between a pointer and integer type.
* The cast is required to initialize a pointer with an unsigned long define, representing an address.
*
* @section [global]
* Violates MISRA 2012 Required Rule 11.6, Cast from unsigned int to pointer.
* This is required for initializing pointers to the module's memory map, which is located at a
* fixed address.
*
*/
#include <stdbool.h>
#include "device_registers.h"
#include "osif.h"
#include "devassert.h"
#if !defined (USING_OS_RTTHREAD)
#error "Wrong OSIF selected. Please define symbol USING_OS_RTTHREAD in project settings or change the OSIF variant"
#endif
/*******************************************************************************
* Variables
******************************************************************************/
static rt_atomic_t osifid = 0;
/*******************************************************************************
* Private Functions
******************************************************************************/
/*******************************************************************************
* Code
******************************************************************************/
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_TimeDelay
* Description : This function blocks (sleep) the current thread for a number
* of milliseconds.
*
* Implements : OSIF_TimeDelay_freertos_Activity
*END**************************************************************************/
void OSIF_TimeDelay(uint32_t delay)
{
/* One dependency for FreeRTOS config file */
/* INCLUDE_vTaskDelay */
rt_thread_mdelay(delay);
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_GetMilliseconds
* Description : This function returns the number of miliseconds elapsed since
* starting the internal timer (since scheduler was started).
*
* Implements : OSIF_GetMilliseconds_freertos_Activity
*END**************************************************************************/
uint32_t OSIF_GetMilliseconds(void)
{
/*
* Return the tick count in miliseconds
* Note: if configTICK_RATE_HZ is less than 1000, the return value will be truncated
* to 32-bit wide for large values of the tick count.
*/
return (uint32_t)(rt_tick_get_millisecond());
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_MutexLock
* Description : This function obtains the mutex lock or returns error if timeout.
*
* Implements : OSIF_MutexLock_freertos_Activity
*END**************************************************************************/
status_t OSIF_MutexLock(const mutex_t * const pMutex,
const uint32_t timeout)
{
/* The (pMutex == NULL) case is a valid option, signaling that the mutex does
* not need to be locked - do not use DEV_ASSERT in this case */
status_t osif_ret_code = STATUS_SUCCESS;
if (pMutex != NULL)
{
rt_err_t ret = rt_mutex_take(pMutex->handle,timeout);
osif_ret_code = (ret == RT_EOK) ? STATUS_SUCCESS : STATUS_ERROR;
}
return osif_ret_code;
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_MutexUnlock
* Description : This function unlocks the mutex, fails if the current thread
* is not the mutex holder.
*
* Implements : OSIF_MutexUnlock_freertos_Activity
*END**************************************************************************/
status_t OSIF_MutexUnlock(const mutex_t * const pMutex)
{
/* The (pMutex == NULL) case is a valid option, signaling that the mutex does
* not need to be unlocked - do not use DEV_ASSERT in this case */
status_t osif_ret_code = STATUS_SUCCESS;
if (pMutex != NULL)
{
rt_err_t ret = rt_mutex_release(pMutex->handle);
osif_ret_code = (ret == RT_EOK) ? STATUS_SUCCESS : STATUS_ERROR;
}
return osif_ret_code;
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_MutexCreate
* Description : This function creates (registers) a mutex object to the OS.
*
* Implements : OSIF_MutexCreate_freertos_Activity
*END**************************************************************************/
status_t OSIF_MutexCreate(mutex_t * const pMutex)
{
/* The (pMutex == NULL) case is a valid option, signaling that the mutex does
* not need to be created - do not use DEV_ASSERT in this case */
char name[RT_NAME_MAX] = {'\0'};
rt_atomic_add(&(osifid), 1);
rt_sprintf(name,"oi%d",osifid);
pMutex->handle = rt_mutex_create(name, RT_IPC_FLAG_PRIO);
return pMutex->handle ? STATUS_SUCCESS: STATUS_ERROR;
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_MutexDestroy
* Description : This function removes the mutex from the OS (and frees memory).
*
* Implements : OSIF_MutexDestroy_freertos_Activity
*END**************************************************************************/
status_t OSIF_MutexDestroy(const mutex_t * const pMutex)
{
/* The (pMutex == NULL) case is a valid option, signaling that the mutex does
* not need to be destroyed - do not use DEV_ASSERT in this case */
rt_mutex_delete(pMutex->handle);
return STATUS_SUCCESS;
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_SemaWait
* Description : This function performs the 'wait' (decrement) operation on a semaphore,
* returns error if operation times out.
*
* Implements : OSIF_SemaWait_freertos_Activity
*END**************************************************************************/
status_t OSIF_SemaWait(semaphore_t * const pSem,
const uint32_t timeout)
{
DEV_ASSERT(pSem);
rt_err_t ret;
if(OSIF_WAIT_FOREVER == timeout)
{
ret = rt_sem_take(pSem->handle,RT_WAITING_FOREVER);
}
else
{
ret = rt_sem_take(pSem->handle,timeout);
}
return ret == RT_EOK ? STATUS_SUCCESS : STATUS_ERROR;
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_SemaPost
* Description : This function performs the 'post' (increment) operation on a semaphore.
*
* Implements : OSIF_SemaPost_freertos_Activity
*END**************************************************************************/
status_t OSIF_SemaPost(semaphore_t * const pSem)
{
DEV_ASSERT(pSem);
//status_t osif_ret_code;
rt_sem_release(pSem->handle);
return STATUS_SUCCESS;
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_SemaCreate
* Description : This function creates (registers) a semaphore object to the OS.
*
* Implements : OSIF_SemaCreate_freertos_Activity
*END**************************************************************************/
status_t OSIF_SemaCreate(semaphore_t * const pSem,
const uint8_t initValue)
{
DEV_ASSERT(pSem);
char name[RT_NAME_MAX] = {'\0'};
rt_atomic_add(&(osifid), 1);
rt_sprintf(name,"oi%d",osifid);
pSem->handle = rt_sem_create((const char *)name, initValue, RT_IPC_FLAG_PRIO);
return pSem->handle ? STATUS_SUCCESS: STATUS_ERROR;
}
/*FUNCTION**********************************************************************
*
* Function Name : OSIF_SemaDestroy
* Description : This function removes a semaphore object from the OS (frees memory).
*
* Implements : OSIF_SemaDestroy_freertos_Activity
*END**************************************************************************/
status_t OSIF_SemaDestroy(const semaphore_t * const pSem)
{
DEV_ASSERT(pSem);
rt_sem_delete(pSem->handle);
return STATUS_SUCCESS;
}
/*******************************************************************************
* EOF
******************************************************************************/

复制代码

osif.h更新

/*
*
* NXP Confidential. This software is owned or controlled by NXP and may only be
* used strictly in accordance with the applicable license terms. By expressly
* accepting such terms or by downloading, installing, activating and/or otherwise
* using the software, you are agreeing that you have read, and that you agree to
* comply with and are bound by, such license terms. If you do not agree to be
* bound by the applicable license terms, then you may not retain, install,
* activate or otherwise use the software. The production use license in
* Section 2.3 is expressly granted for this software.
*/
#ifndef OSIF_H
#define OSIF_H
#include <stdint.h>
/**
* @page misra_violations MISRA-C:2012 violations
*
* @section [global]
* Violates MISRA 2012 Advisory Rule 2.5, Global macro not referenced.
* The macro defines a value that will be interpreted as an infinite timeout.
*
*/
/*! @file */
/*!
* @addtogroup osif
* @{
*/
/*******************************************************************************
* Definitions
******************************************************************************/
/*! @cond DRIVER_INTERNAL_USE_ONLY */
#ifdef USING_OS_FREERTOS
/* FreeRTOS implementation */
#include "FreeRTOS.h"
#include "semphr.h"
#if configSUPPORT_STATIC_ALLOCATION == 1
typedef struct {
SemaphoreHandle_t handle;
StaticSemaphore_t buffer;
} semaphore_t;
typedef semaphore_t mutex_t;
#else /* configSUPPORT_STATIC_ALLOCATION == 0, it's dynamic allocation */
/*! @brief Type for a mutex. */
typedef SemaphoreHandle_t mutex_t;
/*! @brief Type for a semaphore. */
typedef SemaphoreHandle_t semaphore_t;
#endif /* configSUPPORT_STATIC_ALLOCATION == 1 */
#elif defined(USING_OS_RTTHREAD)
#include <rtthread.h>
typedef struct {
rt_sem_t handle;
} semaphore_t;
typedef struct{
rt_mutex_t handle;
}mutex_t;
#else
/* Bare-metal implementation */
/*! @brief Type for a mutex. */
typedef uint8_t mutex_t;
/*! @brief Type for a semaphore. */
typedef volatile uint8_t semaphore_t;
#endif /* ifdef USING_OS_FREERTOS */
/*! @endcond */
#define OSIF_WAIT_FOREVER 0xFFFFFFFFu
#include "status.h"
/*******************************************************************************
* API
******************************************************************************/
#if defined (__cplusplus)
extern "C" {
#endif
/*!
* @brief Delays execution for a number of milliseconds.
*
* @param[in] delay Time delay in milliseconds.
*/
void OSIF_TimeDelay(const uint32_t delay);
/*!
* @brief Returns the number of miliseconds elapsed since starting the internal timer
* or starting the scheduler.
*
* @return the number of miliseconds elapsed
*/
uint32_t OSIF_GetMilliseconds(void);
/*!
* @brief Waits for a mutex and locks it.
*
* @param[in] pMutex reference to the mutex object
* @param[in] timeout time-out value in milliseconds
* @return One of the possible status codes:
* - STATUS_SUCCESS: mutex lock operation success
* - STATUS_ERROR: mutex already owned by current thread
* - STATUS_TIMEOUT: mutex lock operation timed out
*
*/
status_t OSIF_MutexLock(const mutex_t * const pMutex,
const uint32_t timeout);
/*!
* @brief Unlocks a previously locked mutex.
*
* @param[in] pMutex reference to the mutex object
* @return One of the possible status codes:
* - STATUS_SUCCESS: mutex unlock operation success
* - STATUS_ERROR: mutex unlock failed
*/
status_t OSIF_MutexUnlock(const mutex_t * const pMutex);
/*!
* @brief Create an unlocked mutex.
*
* @param[in] pMutex reference to the mutex object
* @return One of the possible status codes:
* - STATUS_SUCCESS: mutex created
* - STATUS_ERROR: mutex could not be created
*/
status_t OSIF_MutexCreate(mutex_t * const pMutex);
/*!
* @brief Destroys a previously created mutex.
*
* @param[in] pMutex reference to the mutex object
* @return One of the possible status codes:
* - STATUS_SUCCESS: mutex destroyed
*/
status_t OSIF_MutexDestroy(const mutex_t * const pMutex);
/*!
* @brief Decrement a semaphore with timeout.
*
* @param[in] pSem reference to the semaphore object
* @param[in] timeout time-out value in milliseconds
* @return One of the possible status codes:
* - STATUS_SUCCESS: semaphore wait operation success
* - STATUS_TIMEOUT: semaphore wait timed out
*/
status_t OSIF_SemaWait(semaphore_t * const pSem,
const uint32_t timeout);
/*!
* @brief Increment a semaphore
*
* @param[in] pSem reference to the semaphore object
* @return One of the possible status codes:
* - STATUS_SUCCESS: semaphore post operation success
* - STATUS_ERROR: semaphore could not be incremented
*/
status_t OSIF_SemaPost(semaphore_t * const pSem);
/*!
* @brief Creates a semaphore with a given value.
*
* @param[in] pSem reference to the semaphore object
* @param[in] initValue initial value of the semaphore
* @return One of the possible status codes:
* - STATUS_SUCCESS: semaphore created
* - STATUS_ERROR: semaphore could not be created
*/
status_t OSIF_SemaCreate(semaphore_t * const pSem,
const uint8_t initValue);
/*!
* @brief Destroys a previously created semaphore.
*
* @param[in] pSem reference to the semaphore object
* @return One of the possible status codes:
* - STATUS_SUCCESS: semaphore destroyed
*/
status_t OSIF_SemaDestroy(const semaphore_t * const pSem);
/*! @}*/
#if defined (__cplusplus)
}
#endif
/*! @}*/
#endif /* OSIF_H */
/*******************************************************************************
* EOF
******************************************************************************/

复制代码

至此I2C 驱动程序已经适配完成，后续使用RT-thread 的I2C-tool 软件包来验证I2C总线通信状况详见（https://www.nxpic.org.cn/module/forum/thread-802558-1-1.html）

阅读全文

stm1024 · 发表于 2024-1-5 08:50:02

感谢大佬分享~

[原创] 【S32K146 RT-thread】之I2c bus 驱动

浏览过的版块

站长推荐 /3