字符设备驱动第十八课---platform2

概述

从platform中提取设备信息

函数接口

include/linux/platform_device.h

1.提取IO资源

/** 功能：提取资源* 输入参数：struct platform_device：platform设备句柄*          unsigned int：资源类型，是中断还是iomem （IORESOURCE_MEM 或IORESOURCE_IRQ）*          unsigned int：起始索引   * 返回值：成功：资源结构体首地址   失败：NULL*/ struct resource *platform_get_resource(struct platform_device *,                          unsigned int, unsigned int);

2.提取中断资源

/** 功能：提取中断资源* 输入参数：struct platform_device：platform设备句柄*          unsigned int：中断资源序号* 返回值：成功：中断号 失败;负数          */int platform_get_irq(struct platform_device *, unsigned int);

3.提取私有数据：

/** 功能：提取私有数据* 输入参数：struct platform_device：platform设备句柄* 返回值：成功：私有数据首地址 失败;NULL          */void *platform_get_drvdata(const struct platform_device *pdev)

范例

驱动端

#include <linux/init.h>#include <linux/module.h>#include <linux/kernel.h>#include <asm/current.h>#include <linux/sched.h>#include <linux/ioport.h>#include <linux/platform_device.h>#include "../private.h"static int demo_probe(struct platform_device *pdev){    int irq;    struct resource *addr;    struct privatedata *priv;    printk(KERN_INFO "%s : %s : %d - entry.\n", __FILE__, __func__, __LINE__);    priv = dev_get_platdata(&pdev->dev);//从设备树中提取私有数据    if(priv){        printk(KERN_INFO "%x : %s \n", priv->val, priv->str);           }    /*从设备树中提取IO资源*/    addr = platform_get_resource(pdev, IORESOURCE_MEM, 0);    if(addr){        printk(KERN_INFO "0: %x : %d \n", addr->start, resource_size(addr));            }    addr = platform_get_resource(pdev, IORESOURCE_MEM, 1);    if(addr){        printk(KERN_INFO "1: %x : %d \n", addr->start, resource_size(addr));            }    addr = platform_get_resource(pdev, IORESOURCE_MEM, 2);    if(!addr){        printk(KERN_INFO "No 2 resource\n");            }    /*从设备树中提取中断资源*/    irq = platform_get_irq(pdev, 0);    if(0 > irq){        return irq;    }else{        printk(KERN_INFO "irq 0: %d \n", irq);          }    irq = platform_get_irq(pdev, 1);    if(0 > irq){        return irq;    }else{        printk(KERN_INFO "irq 0: %d \n", irq);          }    irq = platform_get_irq(pdev, 2);    if(0 > irq){            printk(KERN_INFO "No 2 irq\n");         }    return 0;}static int demo_remove(struct platform_device *pdev){    printk(KERN_INFO "%s : %s : %d - leave.\n", __FILE__, __func__, __LINE__);    return 0;}static struct platform_device_id tbl[] = {    {"demo0"},    {"demo1"},    {},};MODULE_DEVICE_TABLE(platform, tbl);//1. alloc objstatic struct platform_driver drv = {    .probe  = demo_probe,    .remove = demo_remove,    .driver = {        .name = "demo",    },    .id_table = tbl,};#if 0static int __init drv_init(void){    //get command and pid    printk(KERN_INFO "(%s:pid=%d), %s : %s : %d - entry.\n",        current->comm, current->pid, __FILE__, __func__, __LINE__);    return platform_driver_register(&drv);}static void __exit drv_exit(void){    //get command and pid    printk(KERN_INFO "(%s:pid=%d), %s : %s : %d - leave.\n",        current->comm, current->pid, __FILE__, __func__, __LINE__);    platform_driver_unregister(&drv);}module_init(drv_init);module_exit(drv_exit);#else//3. register objmodule_platform_driver(drv);#endifMODULE_LICENSE("GPL");MODULE_AUTHOR("Farsight");MODULE_DESCRIPTION("Demo for kernel module");

设备端

#include <linux/init.h>#include <linux/module.h>#include <linux/kernel.h>#include <asm/current.h>#include <linux/sched.h>#include <linux/ioport.h>#include <linux/platform_device.h>#include "../private.h"static struct privatedata priv = {    .val = 0x12345678,    .str = "hello world",};struct resource res[] = {    [0] = {        .start  = 0x10000000,        .end    = 0x20000000-1,        .flags  = IORESOURCE_MEM    },    [1] = {        .start  = 10,        .flags  = IORESOURCE_IRQ    },    [2] = DEFINE_RES_MEM(0x20000000, 1024),    [3] = DEFINE_RES_IRQ(11),   };static void dev_release(struct device *dev){    //get command and pid    printk(KERN_INFO "(%s:pid=%d), %s : %s : %d - leave.\n",        current->comm, current->pid, __FILE__, __func__, __LINE__);}//1. alloc objstatic struct platform_device demoobj = {    //2. init obj    .name   = "demo1",    .id = 0,    .dev    = {        .platform_data = &priv, //私有数据        .release = dev_release,    },    .num_resources  = ARRAY_SIZE(res),    .resource   = res,};#if 0static int __init device_init(void){    //get command and pid    printk(KERN_INFO "(%s:pid=%d), %s : %s : %d - leave.\n",        current->comm, current->pid, __FILE__, __func__, __LINE__);    return platform_device_register(&demoobj);}static void __exit device_exit(void){    //get command and pid    printk(KERN_INFO "(%s:pid=%d), %s : %s : %d - leave.\n",        current->comm, current->pid, __FILE__, __func__, __LINE__);    platform_device_unregister(&demoobj);}module_init(device_init);module_exit(device_exit);#else//3. register objmodule_platform_device(demoobj);#endifMODULE_LICENSE("GPL");MODULE_AUTHOR("Farsight");MODULE_DESCRIPTION("Demo for kernel module");