Hi Sylwester, On Monday 09 March 2015 13:22:12 Sylwester Nawrocki wrote: > On 09/03/15 12:29, Laurent Pinchart wrote: > > On Monday 09 March 2015 11:35:52 Sylwester Nawrocki wrote: > >> On 08/03/15 14:45, Laurent Pinchart wrote: > >>> +++ b/Documentation/devicetree/bindings/media/i2c/mt9v032.txt > >>> @@ -0,0 +1,41 @@ > >>> +* Aptina 1/3-Inch WVGA CMOS Digital Image Sensor > >>> + > >>> +The Aptina MT9V032 is a 1/3-inch CMOS active pixel digital image sensor > >>> with > >>> +an active array size of 752H x 480V. It is programmable through a > >>> simple > >>> +two-wire serial interface. > >>> + > >>> +Required Properties: > >>> + > >>> +- compatible: value should be either one among the following > >>> + (a) "aptina,mt9v032" for MT9V032 color sensor > >>> + (b) "aptina,mt9v032m" for MT9V032 monochrome sensor > >>> + (c) "aptina,mt9v034" for MT9V034 color sensor > >>> + (d) "aptina,mt9v034m" for MT9V034 monochrome sensor > >> > >> It can't be determined at runtime whether the sensor is just > >> monochromatic ? > > > > Unfortunately not. As far as I'm aware the only difference between the > > monochromatic and color sensors is the colour filter array. The register > > set is identical. > > > >> Al in all the color filter array is a physical property of the sensor, > >> still the driver seems to be ignoring the "m" suffix. > > > > No, the driver relies on the I2C core filling returning the I2C device id > > instance corresponding to the DT compatible string, and gets sensor model > > information from id->driver_data. > > Sorry, I missed the I2C id part. > > >> Hence I suspect the > >> register interfaces for both color and monochromatic versions are > >> compatible. I'm wondering whether using a boolean property to indicate > >> the > >> color filter array type would do as well. > > > > That's an option as well, yes. I don't have a strong preference at the > > moment, but it should be noted that the "m" suffix is contained in the > > chip's part number. > > > > MT9V032C12STM > > MT9V032C12STC > > MT9V032C12STMD > > MT9V032C12STMH > > MT9V032C12STCD > > MT9V032C12STCH > > > > Granted, they use "c" for colour sensors, which the DT bindings don't use, > > and a "C12ST" that we completely ignore. > > OK, deriving the compatible strings from current I2C device ids seems less > trouble from the driver's writer POV. However, my feeling is that using same > compatible and additional property to indicate colour/monochrome is cleaner > as far as device tree binding is concerned. > Anyway, I'm not going to object against your current approach, I suppose > it's acceptable as well. It wouldn't take much to convince me about that, I'm really undecided. I'll send v2 to fix other issues, we can continue discussing this point then. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
