Kurt Van Dijck wrote: > On Tue, Oct 06, 2009 at 01:10:40PM +0200, Oliver Hartkopp wrote: >> Kurt Van Dijck wrote: >>> On Sat, Oct 03, 2009 at 02:33:27PM +0200, Oliver Hartkopp wrote: >>>> Kurt Van Dijck wrote: >>> [...] >>>> So it's not only 'enabling' and 'disabling' the transceiver, there is need >>>> to >>>> control and read the transceiver states and get some properties like >>>> max_phy_bitrate or something like this. >>>> >>>> Does you approach allow these more complex dependencies also? >>>> Or is probably the PHY abstraction layer >>>> >>>> linux/Documentation/networking/phy.txt >>>> >>>> something, we should take a look at? >>>> >>>> As i'm not a 'platform' specialist maybe someone (like you) could give some >>>> feedback to these requirements. >>> I started working on a patch series, that adds a CAN transceiver class >>> that could be a basis for such extended functionality. >>> When ready (few days maybe), I'll resume this. >> Thanks. >> >> If you're interested, i can provide some block schematics that explain how >> fault tolerant transceivers are wired in power-on-CAN setups that are used in >> automotive environments. > I planned to do just a 'proof of concept'. Like, the PCA82c251 has a slope > control resistor, that I don't know the exact formula is, but that resistor > controls the maximum baudrate. I was just making space to implement the > formula. > To extend the concept, I'm working on a tja1041 too, altough I never > used this one before. > What I want to know from this tja1041 or similar is: What pins are usually > connected to the cpu, what pins are usually not, and what pins are > sometimes connected. This allows me to provide a 'minimum required' set > of gpio the transceiver driver needs. > > I _assume_ the wake pin is mostly not connected to the cpu, but direct > into the power circuitry. What can a linux driver do with the wake pin?
it can generate an interrupt that wakes up the whole linux system from suspend to ram. Imagine a fast booting concept in the automotive environment. cheers, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Linux Solutions for Science and Industry | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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