On Wednesday 29 April 2015 16:33:18 Marek Vasut wrote: > On Wednesday, April 29, 2015 at 01:51:21 PM, Gabriele Mazzotta wrote: > > On Wednesday 29 April 2015 13:27:25 Gabriele Mazzotta wrote: > > > Add basic implementation of the ACPI0008 Ambient Light Sensor driver. > > > This driver currently supports only the ALI property, yet is ready to > > > be easily extended to handle ALC, ALT, ALP ones as well. > > > > > > Signed-off-by: Martin Liska <marxin.liska@xxxxxxxxx> > > > Signed-off-by: Marek Vasut <marex@xxxxxxx> > > > Signed-off-by: Gabriele Mazzotta <gabriele.mzt@xxxxxxxxx> > > > Cc: Zhang Rui <rui.zhang@xxxxxxxxx> > > > --- > > > This continues http://marc.info/?t=140163463200002 > > > > > > I've made few adjustments over the original patch: > > > - Code aligned with 4.1-rc1 and cleaned up > > > - Use signed integers to store values: sensors report 32bit signed > > > > > > values. In particular, -1 is reported when the current reading > > > is above the supported range of sensitivity. > > > > > > Most of the changes are just a consequence of the changes in the > > > iio subsystem. > > > > > > Gabriele > > > > I'm sorry, I've just noticed that I haven't changed the value of > > realbits in acpi_als_channels. This makes me wonder what would be the > > proper value, given that this is a generic driver and all the > > information I have are those in the ACPI specification (which states > > what I reported here above). > > > > Should I just set realbits to 32? > > I believe the ALS reports only 16bit signel value, no ? > My observation with a strong coherent light source is that > the saturated sensor reported 0xffff . Probably it's the same for me. I couldn't get to the point where ALI reports 0xffff, just really close, I will have to try with some stronger lights. However, looking at my ACPI table, I can see that the value returned by _ALI is just the composition of two 8 bits variables put side by side, so yes, I can say that even on my system it's a 16bit value. The problem here is that I'm not sure we can assume this as true in general since the ACPI specification doesn't say anything. Gabriele > Best regards, > Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
