【Rico Board试用体验】第十篇☞关于设备驱动模型platform设备驱动示例

2016-11-22 16:12:44 3160

0 前些天，把案件驱动改成了input子系统，今天学习下platform子系统。在linux2.6以后的设备驱动模型中，需关心总线、设备和驱动这3个实体。 1.总线：总线将设备和驱动绑定。在系统通过某一总线每注册一个设备的时候，会寻找与之匹配的驱动。同样，在系统每注册一个驱动的时候，会寻找与之匹配的设备，而匹配由总线完成。总线中重要的结构体是：这个一般不需要我们来操作，系统会把需要的总线初始化好。 struct bus_type { . . const char name; . . } 复制代码* 2.设备：就是要操作的硬件的描述。重要的结构体： struct device { . . struct bus_type bus; / type of bus device is on / struct device_driver driver; /* which driver has allocated this device / void platform_data; /* Platform specific data, device core doesn't touch it / . . } 复制代码* 对应的注册和卸载函数: device_register(struct device * dev) device_unregister(struct device * dev) 复制代码 3.设备驱动：具体操作硬件的操作函数。 struct device_driver { . . const char name; struct bus_type bus; int (probe) (struct device dev); int (remove) (struct device dev); . . } 复制代码对应的注册和卸载函数： driver_register(struct device_driver * drv) driver_unregister(struct device_driver * drv) 复制代码 ------------------------------------------------------------------------------------------------- 本次设计到的platform总线，类似于继承了上述的设备和设备驱动。在设备层对应的重要的数据结构为（我直接实例化了这个数据结构的重要成员变量）： struct platform_device pt_platform_dev = { .name = "pt2262", .resource = pt2262_resource, .num_resources = ARRAY_SIZE(pt2262_resource), .dev = { .platform_data = pt2262_devs, .release = pt2262_release, } }; 复制代码对应的注册和注销函数 platform_driver_unregister(&pt_platform_drv); platform_device_unregister(&pt_platform_dev); 复制代码在设备驱动层对应的重要的数据结构为（我也直接实例化了这个数据结构的重要成员变量）： struct platform_driver pt_platform_drv = { .driver = { .name = "pt2262", .owner = THIS_MODULE, }, .probe = pt_probe, .remove = pt_remove, }; 复制代码对应的注册和注销函数 ret = platform_driver_register(&pt_platform_drv); platform_driver_unregister(&pt_platform_drv); 复制代码以上关于platform部分，我都是从我的代码中直接复制下来的。完整的代码如下： #include #include #include #include #include #include #include #include "pt2262.h" const int gpio_num[4]={49,60,51,50}; MODULE_LICENSE("GPL"); struct resource pt2262_resource[]= { { .flags = IORESOURCE_IRQ, }, { .flags = IORESOURCE_IRQ, }, { .flags = IORESOURCE_IRQ, }, { // .start = gpio_to_irq(gpio_num[3]), // .end = gpio_to_irq(gpio_num[3]), .flags = IORESOURCE_IRQ, } }; struct pt2262_dev pt2262_devs[] = { { .desc = "A", .gpio = 49, .code = KEY_A, }, { .desc = "B", .gpio = 60, .code = KEY_B, }, { .desc = "C", .gpio = 51, .code = KEY_C, }, { .desc = "D", .gpio = 50, .code = KEY_D, } }; void pt2262_release(struct device dev) { printk(KERN_INFO "pt2262 release func.n"); } struct platform_device pt_platform_dev = { .name = "pt2262", .resource = pt2262_resource, .num_resources = ARRAY_SIZE(pt2262_resource), .dev = { .platform_data = pt2262_devs, .release = pt2262_release, } }; irqreturn_t pt_irq_handler(int irq, void pdev) { struct pt2262_dev * pt2262_devp = (struct pt2262_dev)pdev; int i; for(i=0; i { if(0 == strcmp(pt2262_devp->desc ,pt2262_devs[i].desc)) { printk(KERN_INFO "pt2262's code is %dtdesc is %sti is %d.n", pt2262_devp->code, pt2262_devp->desc, i); break; } continue; } return IRQ_HANDLED; } int pt_probe(struct platform_device plat_pdev) { int i,j,ret; char buf[16]; struct pt2262_dev* pt2262_pdev_tmp = plat_pdev->dev.platform_data; for(i=0; inum_resources; i++) { //j = plat_pdev->dev.platform_data j = pt2262_pdev_tmp[i].gpio; sprintf(buf, "pt_gpio_%d", j); ret = gpio_request(j, buf); if(ret < 0) goto fail; gpio_direction_input(j); ((plat_pdev->resource)+i)->start = gpio_to_irq(j); ((plat_pdev->resource)+i)->end = gpio_to_irq(j); ret = request_irq(((plat_pdev->resource)+i)->start,pt_irq_handler,IRQF_TRIGGER_RISING\|IRQF_TRIGGER_FALLING,"pt_irq_handler", pt2262_pdev_tmp+i); if(ret < 0) goto fail2; } printk(KERN_INFO "num_resources is %d.n", plat_pdev->num_resources); return ret; fail: printk(KERN_ERR "failed to request %sn",buf); return ret; fail2: printk(KERN_ERR "failed to request irq %sn",buf); return ret; } int pt_remove(struct platform_device plat_pdev) { int i; struct pt2262_dev pt2262_pdev_tmp = plat_pdev->dev.platform_data; printk("pt_remove goodbye.n"); for(i=0; inum_resources; i++) { free_irq(plat_pdev->resource[i].start, pt2262_pdev_tmp+i); gpio_free((pt2262_pdev_tmp+i)->gpio); } return 0; } struct platform_driver pt_platform_drv = { .driver = { .name = "pt2262", .owner = THIS_MODULE, }, .probe = pt_probe, .remove = pt_remove, }; int __init pt_init(void) { int ret; ret = platform_device_register(&pt_platform_dev); ret = platform_driver_register(&pt_platform_drv); return ret; } module_init(pt_init); void __exit pt_exit(void) { platform_driver_unregister(&pt_platform_drv); platform_device_unregister(&pt_platform_dev); } module_exit(pt_exit); 复制代码还有一个头文件pt2262.h： #ifndef __PT2262_H__ #define __PT2262_H__ struct pt2262_dev { char desc[8]; int gpio; int code; }; #endif 复制代码安装之后的效果如下图：在/sys/bus/platform/drivers目录下多出来pt2262这一项。 0 0001.PNG (43.39 KB, 下载次数: 17)
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