I am struggling to find out, what steps are necessary to access a gpio-pin from a linux kernel module. Maybe someone can explain it to me by a simple example. I like to use pin 4(input) and 33(output). My steps so far:
1.) Device Tree(dts): I leave the dts file untouched - Do I need to setup the pin 4 and 33 via pin control?
2.) kernel module: some pseudo code
gpio_is_valid(4)
gpio_request_one(4, GPIOF_DIR_IN | GPIOF_EXPORT_DIR_FIXED , "myPin4")
gpio_export(4, false)
gpio_get_value(4)
gpio_is_valid(33)
gpio_request_one(33, GPIOF_DIR_OUT | GPIOF_INIT_LOW | GPIOF_OPEN_SOURCE | GPIOF_EXPORT_DIR_FIXED , "myPin33")
gpio_export(33, false)
gpio_set_value(33, 1)
How to do it in a proper way?