[ Android ] Add device driver to kernel

take a note!

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To cross compile your own driver in the arm architecture you have to follow some steps as mentioned below.

1. Create a directory like my_drvr inside drivers(which is in the Linux source code) for your driver and put your driver (my_driver.c) file inside this directory. It will looks like /linux_source_code/drivers/my_drvr/my_driver.c
2. Create one Makefile inside your driver directory (using vi any editor) and inside this put obj-$((CONFIG_MY_DRIVER) += my_driver.o and save this file. This will appears like /linux_source_code/drivers/my_drvr/Makefile
3. Create one Kconfig file inside your driver directory (using vi any editor) and inside this put
   

   config MY_DRIVER
   tristate "my driver" //gives your driver description like vendor name etc.
   depends on ARM
   default y if ARM
   help
     my driver module.

4. Save this file, this will appears like /linux_source_code/drivers/my_drvr/Kconfig
5. Add both Makefile and Kconfig file in the Linux source drivers Makefile and Kconfig file which are at /linux_source_code/drivers/Makefile and /linux_source_code/drivers/Kconfig
6. In the Makefile add below in last line
   

    obj-y    += my_drvr/ 

   or
   

    obj-$((CONFIG_MY_DRIVER)  += my_drvr/

7. In Kconfig file add below in last line
   

   source "drivers/my_drvr/Kconfig"

8. Finally have to add Kconfig file into architecture specific config file which will be at kernel_source/arch/arm/configs/--defconfig in this add below line in the last
   

   CONFIG_MY_DRIVER=y

Note:- Last step will differ according to your architecture, so that you have take care. Now you can compile your driver by using make command.

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