On Thu, Jan 2, 2014 at 10:11 AM, Robert Ianovich <rianovic...@gmail.com> wrote: > The question is why can't be accessed regularly from user space by reading > /dev/i2c-0 bus? > The I2C buses and devices can't be owned exclusively even by kernel due to > I2C architecture, so as far as the bus is free, anyone should read/write to > any address. > > I have worked on many industrial boards considerably bigger than BBB > (WindRiver kernel) and all devices with I2C for maintenance (RapidIO, DSP, > MAC/PHY, etc) are accessible. > > Why on BeagleBone the addresses of HDMI framer, PMIC and onboard EE are > intentionally blocked by driver ? > Or why the DRM driver is written that way?
Well the hdmi/edid is the easly one.. As the beaglebone dose not have direct access to that bus, take look at page 10: https://github.com/CircuitCo/BeagleBone-Black/blob/master/BBB_SCH.pdf Thus we need to query the TDA19988 device thru drm for the edid... As far as PMIC/EE are registered by the dts in i2c0: tps: tps@24 { reg = <0x24>; }; baseboard_eeprom: baseboard_eeprom@50 { compatible = "at,24c256"; reg = <0x50>; }; Thus if that blocks access thru /dev/i2c-0, i guess it blocks it... Regards, -- Robert Nelson http://www.rcn-ee.com/ -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
