作者：华清远见嵌入式学院。《Linux设备驱动开发详解》（08&09年度畅销榜TOP50）第12章、Linux字符设备驱动综合实例。本章将分析5个典型的字符设备驱动，在这些驱动中，将灵活地运用到前面各章所讲解的内容。12.1节讲解按键的设备驱动，加深读者对字符设备驱动架构、阻塞与非阻塞、中断、定时器等相关知识的理解。12.2节讲解触摸屏的设备驱动，触摸屏的设备驱动比按键的设备驱动稍微复杂一些，但是很类似。12.3节讲解TI的DSP提供给通用CPU的HPI（主机并行接口）的设备驱动，硬件结构为ARM+DSP，ARM的总线连接DSP的HPI接口。12.4节讲解通用NVRAM的设备驱动，并会引入一个新的概念，即miscdevice（混杂设备）。12.5节讲解看门狗的设备驱动，它也被归入miscdevice，这一节还会引入两个新的概念，即platform_device（平台设备）和platform_driver（平台驱动）。NVRAM和看门狗的设备驱动与普通字符设备驱动有细微的差别。-Author: HuaQing vision embedded institute. The Linux device driver development "(08 and 09 sep TOP50) annual list of best-selling chapter 12, Linux character device driver comprehensive examples. This chapter will five typical character analysis device drivers, in these drivers will be flexible, apply in the front of the book, the explanation content. Section 12.1 explain the device driver, deepen buttons to readers character device driven architecture, obstruction and the obstruction, and interrupt, timer and other related knowledge of understanding. Section 12.2 interpretation of the touch screen device drivers, touch screen device driver than buttons device driver a little more complex, but some s similar. Section 12.3 explain the DSP provide general TI CPU HPI (parallel interface) host device drivers, hardware structure for ARM and DSP, ARM bus connection DSP HPI interface. Section 12.4 of the general NVRAM explain device drivers