I have spent some time reading the document. I still have some things, not present in the document, I want to figure out first, like the new cape manager for 3.14, but the document had clarified some ideas.
Thank you :) On Friday, May 29, 2015 at 3:53:11 PM UTC+2, Nic Cyn wrote: > > Hi Inigo > > >I have been surfing around this board and I have some ideas about how it > works, but I haven't figured out it yet. > > It is quite a complex topic. I too spent a quite some time trying to > figure out the Device Tree and once I thought I had an understanding I > wrote up my notes afterwards. Perhaps you will find the document below > provides some useful background. Basically its contents are the information > I wish I had when I was first trying to figure out the Device Tree. > > http://ofitselfso.com/BeagleNotes/AboutTheDeviceTree.pdf > > Cheers > Nic > > On Friday, 29 May 2015 12:28:27 UTC+1, Iñigo Martínez wrote: >> >> >> Hi, >> >> I have been reading/testing information regarding Device Tree, GPIOs >> since I updated to 3.14, where bone_capemgr.* has dissapaeared, trying to >> understand how everything works. I have been surfing around this board and >> I have some ideas about how it works, but I haven't figured out it yet. >> >> I have attached a proto board and I created the device tree and loaded it >> using the dtb option in uEnv.txt. I think that it's loaded correctly >> because I disabled the can ports and they aren't loaded anymore. >> >> I have the following two paths: >> >> /sys/devices/44e10000.control_module >> /sys/devices/44e10800.pinmux >> >> And these paths too: >> >> /sys/devices/ocp/*.gpio|.i2c etc... (* = 40300000 ... 56000000) >> /sys/devices/ocp/cape-universal >> /sys/devices/ocp/ocp:*.pinmux (* = P8_07 ... P9_91) >> >> And finally regarding GPIOs: >> >> /sys/class/gpio/export >> /sys/class/gpio/gpiochip* (* = 0, 32, 64, 96) >> /sys/class/gpio/unexport >> >> I can use the GPIOs after exporting them, and the behaviour is correct, >> so as I said, everything looks that works fine. >> >> Questions: >> >> - Is everything correct this way ? >> - How can I export gpio pins at boot so I have them available ? Is >> there any option in u-boot/kernel for this ? Should I create systemd >> service ? >> - I have been reading about beaglebone-black-pinmux and >> beaglebone-universal-io too, how they fit in this setup ? Is config-pin >> related with exporting gpios on boot ? >> >> >> Thank you, >> >> Best regards, >> > -- 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/d/optout.
