-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Awesome! I'm looking forward to playing with this!
...now where did I put all that free time?!? :) On 5/7/2013 2:52 PM, Ian McMahon wrote: > There's a mostly functionally complete bb_gpio driver in the > bb-hal-gpio branch: > > http://git.mah.priv.at/gitweb?p=emc2-dev.git;a=shortlog;h=refs/heads/bb-hal-gpio > > It doesn't solve all pin-conflict issues yet, but the good news is > it seems to fail in pinmuxing if a pin isn't available. The crash > is not very pretty or helpful, but it seems safe enough :) > > Here's a simple little hal test: > > ############ loadrt threads name1=test-thread period1=1000000 > loadrt hal_bb_gpio user_leds=0,1,2,3 input_pins=212 > output_pins=214 loadrt siggen num_chan=1 > > addf bb_gpio.write test-thread addf bb_gpio.read test-thread addf > siggen.0.update test-thread > > setp siggen.0.frequency 1 > > net pulse0 bb_gpio.p9.out-14 <= siggen.0.clock > > net led0 bb_gpio.p9.in-12 => bb_gpio.userled0 ############ > > This links a 1hz siggen to an output pin, and links an input pin to > a userled. If you connect a wire between the output pin and the > input pin, the userled will flash with the siggen. > > Ian > > On May 5, 2013, at 9:47 PM, Charles Steinkuehler > <[email protected]> wrote: > > On 5/5/2013 8:30 PM, Ian McMahon wrote: >>>> What Michael and I had discussed was using the sysfs >>>> mechanism to request the pins at driver load, and only >>>> "claim" the pins that succeed, or fail if a user has asked >>>> for pins that we can't claim, or something along those lines. >>>> It's not going to stop code from going behind our back and >>>> manipulating registers directly, but we just have to assume >>>> that we're all playing in the same sandbox. > > This seems like a good approach. > >>>> What I'm as-yet unsure of is whether we will have a reliable >>>> way to find out whether the onboard peripherals (emmc, hdmi) >>>> are driving the pins they're attached to. > > - From what I have read, if a "proper" kernel driver is accessing > specific SoC pins for something (ie: eMMC or HDMI), attempting to > map those ports properly via the kernel (via sysfs or > gpio_request() ) will fail, which is the desired behavior. For > instance, there is some detail in the BBB manual on disabling the > HDMI and MMC drivers if you need access to those I/O pins. > > Of course, this assumes everyone is "playing by the rules". When > I modified the pinmux registers (as root writing directly to the > pinmux physical memory locations) to output all PRU I/O to the > physical pins, my BB instantly hung, as I broke the SD-card > interface. But we should do what we can to "play nice" to avoid > such problems, and as a bonus accessing GPIO via the kernel is > essentially identical across most ARM SoCs, so the allocation and > (slow) access routines can be shared among the BB, Pi, and > hopefully whatever else comes along next. > > > > ------------------------------------------------------------------------------ > > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases > and their applications. This 200-page book is written by three > acclaimed leaders in the field. The early access version is > available now. Download your free book today! > http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ Emc-developers > mailing list [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > - -- Charles Steinkuehler [email protected] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlGJbF4ACgkQLywbqEHdNFwbTACfQ5NeF6d3TEBTDQqvb0evzbnT AOAAoI+uoKGmFIWywymM9WF1pSnEmxhs =K3bJ -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. This 200-page book is written by three acclaimed leaders in the field. The early access version is available now. Download your free book today! http://p.sf.net/sfu/neotech_d2d_may _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
