Hardware Reference
In-Depth Information
There are usually two ways to enable an option:
Compiled-in
If you opt to compile in a feature or driver, it will appear in the TUI with an asterisk.
You can select to compile in an item by hitting the spacebar when it is highlighted.
The upside to compiling things into the Linux kernel is that the feature/driver will
always be active. The downside is that the kernel becomes bigger and will use
more memory.
Modular
To enable a feature or driver as a module, just hit the
M
key when the item is
highlighted. Not everything can be built as a module, but most things can.
PinMux
One advantage to modularizing drivers is that it simplifies PinMux control on the
Raspberry Pi. PinMux is short for Pin-Multiplexing. The Broadcom BCM2835
system-on-chip used in the Raspberry Pi uses PinMux to select which signals will
be present on the pins of the chip. The multiplexing is necessary because the
number of available signals exceeds the number of available pins. Or, to put it
simply, some of the GPIO pins can be connected to different things within the
BCM2835 at different times. If your drivers which affect the GPIO pins or devices
are built as modules, you can switch the PinMux by simply loading/unloading the
module.
You should also be aware that some items, when enabled in the TUI, will expose ad-
ditional items (or even new submenus).
Quite a few of the hacks in our topic connect to the Raspberry Pi across the I2C bus,
so you will definitely want to enable “I2C Support” (
CONFIG_I2C
). This option is under
the Device Drivers menu, and you will want to compile it into your kernel.
