Hi Asha, On Fri, Jul 8, 2011 at 2:25 AM, Asha R <rd.asha22@gmail.com> wrote:

Hi,

I would like to know how to add new function to a driver in Linux Framework?

For eg: In GPIO driver, there is gpio_chip structure defined.

static struct gpio_chip mygpio_chip = {         .label                         = "mygpio",         .owner                        = THIS_MODULE,         .direction_input           = mygpio_direction_input,         .get                            = mygpio_get,         .direction_output         = mygpio_direction_output,         .set                            = mygpio_set,         .to_irq                        = mygpio_to_irq, }; If i want to add mygpio_pulldown or mygpio_altfunc to support few more gpio functionalities, how and where can i add these functions in the structure?

It depends on whether you're trying to do it by modifying the gpio_chip structure, or want to "make an extension". If you want to modify the structure itself, you would do so here: http://lxr.linux.no/linux+v2.6.39/include/asm-generic/gpio.h#L90 If you want to make an extension, then you'd make your own structure which includes the gpio_chip structure as its first member. I often use this technique to add say an I/O address for the gpio bank, when there are multiple banks of gpio registers on a chip. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com