I Prefer that you write a coustem driver. map the GPIO address (Either make use of mapped area of GPIO that u may find in the source for comercial kernel or else map the physical address in the driver and access it ).
---Misbah Josh Boyer-4 wrote: > > On Tue, 2007-10-16 at 23:21 -0700, Jeff Mock wrote: >> David Hawkins wrote: >> >> I have a PPC440EPx Sequoia Evaluation board that runs on Linux 2.6.21. >> >> What I would want to do is to control (write and read values to) its >> >> GPIO. Perhaps similar to Turbo C's outputb(0x378,0x01) to write and >> >> inportb(0x378) to read. I read the PPC440EPx manual but I find it >> >> difficult to understand. >> >> >> >> Could anyone show me any tutorial or some sample codes? >> > >> > I copied the code below from some test code I wrote for a TS7300 >> > board (uses an ARM EP9302 processor). However, since its user-space >> > code it should work fine. >> > >> >> I might be a little out of date, but I think you must write your own >> driver to wiggle the GPIO pins on a 440 processor. I just finished a >> project using a 440GX with a 2.6.15 kernel (we froze the code about 8 >> months ago). >> >> The 440 powerPC core is a 32-bit processor with 36-bit physical >> addresses. The physical address for the GPIO pins is someplace above >> 4GB. An mmap() of /dev/mem only lets you map the lower 4GB of the >> address space, as a result you can't write a user space program on the >> 440 to wiggle the GPIO pins. (This was true with 2.6.15, I can't speak >> for later kernels). > > This depends on the 440 chip itself. If I recall correctly, the > 440EP(x) chips don't have I/O above 4GB. > > josh > > _______________________________________________ > Linuxppc-embedded mailing list > Linuxppc-embedded@ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-embedded > > -- View this message in context: http://www.nabble.com/PPC440EPx-GPIO-control-help-tf4638058.html#a13252501 Sent from the linuxppc-embedded mailing list archive at Nabble.com. _______________________________________________ Linuxppc-embedded mailing list Linuxppc-embedded@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-embedded
