That's a good question---I think the reason is that ARM has much wider choice of peripherals that tend to be simpler than typical peripherals on the x86 architecture. On x86, they are usually connected using the PCI infrastructure, which configures their register and interrupt layout at boot and provides that info to the drivers. ARM peripheral register addresses are defined by the SoC makers and are static, and also tend to be simpler---a typical x86 peripheral might be an ethernet or video card requiring dozens of registers to operate, while a typical ARMs tends to have multiple but simple PWM, timer or serial port devices that have few registers each.
On Sun, Oct 6, 2013 at 12:07 AM, Amalinda J' Gamage <[email protected]> wrote: > I am a new user to beaglebone and I have a couple of basic questions. > I want to know what is meant by DT or Device tree overlay and why it is > required for BB/ ARM335X. Is it not required for other main processors like > Intel because they are " defined" in the Linux kernel? and TI ARM3358 > processor is not " defined" . What support is available for other "popular" > processors and is not available for TI ARM 3358 in Linux Kernal? Or was > there support BEFORE and was it taken BACK? > I mean is this the reason that we make a device tree and pass it to the > system ? I may have mentioned incorrect statements please feel free to > correct me. > > secondly, I know that with no Device tree stuff, it is possible to lighten > up an LED connected to the BB and BBB using the terminal. So if the > definitions are not there in the Linux kernel, how come this method works? I > mean how can one export a GPIO and lighten the LED connected if that is not > found in the kernel? If so, then is a DT necessary at all? > > A confused. > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
