On Mon, May 30, 2011 at 02:29:58PM +0000, Tabi Timur-B04825 wrote: > On Mon, May 30, 2011 at 3:24 AM, Wolfram Sang <w.s...@pengutronix.de> wrote: > > > The first place where this should be mentioned is the datasheet of the > > pt-chip, so you might ask the producer to add this information (don't > > expect much to happen, though). > > It's true that the data sheet does not mention that it's identical to > the DS1307, but that's still no excuse for not noticing it and writing > a whole driver for it. :-( > > > IIRC I asked you explicitly for the differences between the chips. If > > there are none, you can use the driver directly, right? :) > > Yes. The device tree node for the PT7C4338 device should just say > > /* The board has a PT7C4338, which is compatible with the DS1307 */ > compatible = "dallas,ds1307";
While it seems to be 100% compatible, there could be chip-specific bugs or some interesting features that are hidden behind "reserved" bits and registers. So I think device tree should not lie about the chip model. Doing 'compatible = "pericom,pt7c4338", "dallas,ds1307"' is perfectly fine. Note that today the several compatible entries approach gives you almost nothing, as you will need to add pt7c4338 entry into the driver anyway. I tried to improve this, i.e. make linux do OF-matching on the most generic compatible entry (the last one): http://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg21196.html It was received coldly though: http://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg22041.html http://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg21273.html -- Anton Vorontsov Email: cbouatmai...@gmail.com _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
