Messages in this thread | | | Date | Thu, 23 Oct 2008 02:29:40 +0400 | From | Anton Vorontsov <> | Subject | Re: [PATCH 4/7] gpiolib: implement dev_gpiochip_{add,remove} calls |
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On Wed, Oct 22, 2008 at 02:52:46PM -0700, David Brownell wrote: > On Wednesday 22 October 2008, Anton Vorontsov wrote: > > > > > > > So if we register the board infos after > > > > the controller registered, then nobody will probe the board infos. > > > > > > See above. If you're doing it right, there's no problem. > > > That is, scan the OF tables early. Just like PNP tables > > > get scanned early, for example. > > > > Heh. If we don't want to be able to make the OF-parsing code > > be a module then there is no problem at all. I can use the bus > > notifiers. And it is most straightforward solution then. > > > > But I quite dislike to bloat the kernel image with > > maybe-never-used-on-this-board code. > > So have it live in the __init text section. If you're > building a kernel with support for several boards, you > know it's necessarily going to be larger than it would > be if only one board were supported. But you can shrink > kernel size by judicious use of __init sections..
Won't work, unfortunately. I2C devices are created by the i2c controllers, via drivers/of_i2c.c of_register_i2c_devices().
There is a good reason to do so, the code needs to know controller's OF node to walk down and register the child nodes (devices). See drivers/i2c/busses/i2c-mpc.c -- it calls of_register_i2c_devices() at the end of the probe().
Since we can't call __init stuff from non-__init, the scheme you purpose won't work.
The same is for SPI (drivers/of_spi.c of_register_spi_devices()).
> > My aim was to make the > > OF-parsing part be a module too. Because in the long run we > > need the OF-parsing stuff for _every_ driver that needs > > platform data. It's quite expensive to have it always built-in, > > don't you think? > > If it's discarded early, after translating the data from > OF format into what the drivers need, there will be no > RAM footprint.
There is also kernel image size that matters...
-- Anton Vorontsov email: cbouatmailru@gmail.com irc://irc.freenode.net/bd2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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