Arm-Linux摄像头驱动程序的移植

Arm开发板上摄像头的移植有两种方法：第一，将驱动程序添加到内核，通过编译内核，烧写到板子上；第二种，通过动态加载摄像头驱动模块的方法进行硬件的驱动。作者首先在PC的linux系统进行摄像驱动程序的移植，保证驱动程序版本正确，然后将驱动程序编译成模块，通过文件系统挂载到板子，然后进行加载，进而创建摄像头设备节点。下面将具体介绍摄像头动态加载的过程。

移植过程所使用的摄像头型号ZC301P，arm板上的内核版本为2.6.9，开发板为pxa270，所采用的驱动程序包为spca5xx-20060501.tar.gz。

第一步，使用命令解压文件： tar zxvf spca5xx-20060501.tar.gz

进入spca5xx-20060501 ： cd spca5xx-20060501

第二步，修改Makefile文件：VERSION = 00.60.00

Makefile的内容如下，注释掉的为蓝色，红色表示修改过的内容：

CC =arm-linux-gcc

LD =arm-linux-ld
CVSVERSION = "$Experimental work Michel Xhaard && Reza Jelveh 03/02/2004"
DEFINES =

###
# The following flags enable experimental features.
# By default, these are enabled for development versions of the driver, and
# disabled for release versions.

# Optional: Enable driver debugging
DEFINES += -DSPCA50X_ENABLE_DEBUG

# Optional: Enable direct register read/write for PAC207 development
#DEFINES += -DSPCA5XX_ENABLE_REGISTERPLAY

###
# The following flags enable features that arent yet implemented, and
# therefore are disabled by default.

# Optional: Enable compression
DEFINES += -DSPCA50X_ENABLE_COMPRESSION

###
# Rest of Makefile follows here. You probably wont need to touch this.

# Setup defines
DEFINES += -DCONFIG_USB_SPCA5XX_MODULE=1 -DMODULE -D__KERNEL__
DEFINES += -DVID_HARDWARE_SPCA5XX=0xFF -DSPCA5XX_VERSION=\"$(VERSION)\"

ifneq ($(shell uname -r | cut -d. -f1,2), 2.4)

ifneq ($(KERNELRELEASE),) # We were called by kbuild
CFLAGS += $(DEFINES)
obj-m += spca5xx.o
spca5xx-objs := drivers/usb/spca5xx.o drivers/usb/spcadecoder.o

else # We were called from command line

#KERNEL_VERSION = `uname -r`

KERNEL_VERSION = 2.6.9

#KERNELDIR := /lib/modules/$(KERNEL_VERSION)/build
KERNELDIR := /up-techpxa270/kernel/linux-2.6.9

PWD := $(shell pwd)
#MODULE_INSTALLDIR = /lib/modules/$(KERNEL_VERSION)/kernel/drivers/usb/media/

MODULE_INSTALLDIR =/root/modules/

# Targets, dont change!
default:
@echo Building SPCA5XX driver for 2.5/2.6 kernel.
@echo Remember: you must have read/write access to your kernel source tree.
$(MAKE) -C $(KERNELDIR) SUBDIRS=$(PWD) CC=$(CC) modules

install:
mkdir -p $(MODULE_INSTALLDIR)
rm -f $(MODULE_INSTALLDIR)spca50x.ko
rm -f $(MODULE_INSTALLDIR)et61x.ko
install -c -m 0644 spca5xx.ko $(MODULE_INSTALLDIR)
/sbin/depmod -ae

uninstall:
rm -f $(MODULE_INSTALLDIR)/spca5xx.ko
/sbin/depmod -aq

endif

else # kernel version test

#############################################################################
# For Linux 2.4 users.
# Change the following lines according to your system configuration.
# It is important to configure your particular source tree ("make dep") before
# compiling this module!
#############################################################################
###
# This makefile will build the spca50x driver module external to the kernel
# source tree. It makes it easier to swap kernels.

#KERNEL_VERSION = `uname -r`

KERNEL_VERSION = 2.4.x

###
# Location of the header files (most importantly the config files)
# for the kernel you want to build the module against.
# This should be correct for the currently installed kernel on your machine.
#KINCLUDE = /lib/modules/$(KERNEL_VERSION)/build/include

KINCLUDE =/up-techpxa270/kernel/linux2.4.x

KERNEL_ACFILE = $(KINCLUDE)/linux/autoconf.h
KERNEL_MODVERSIONSFILE = $(KINCLUDE)/linux/modversions.h
#MODULE_INSTALLDIR = /lib/modules/$(KERNEL_VERSION)/kernel/drivers/usb/

MODULE_INSTALLDIR =/root/modules/

# Detect module versioning support
ifneq ($(strip $(shell grep define CONFIG_MODVERSIONS 1 $(KERNEL_ACFILE))),)
DEFINES += -DMODVERSIONS -include $(KERNEL_MODVERSIONSFILE)
endif