On 02/07/2013 14:58, Lars-Peter Clausen wrote: > On 07/02/2013 12:49 PM, Hector Palacios wrote: >> Greetings, >> >> The mxs-lradc has some hardware specific features like the DIVIDE_BY_TWO (an >> analog divide by two circuit that can be activated per channel). >> This is not currently implemented in the driver and I was wondering what would >> be the way to expose and control such setting. A specific sysfs entry? Somehow >> through the device tree? >> >> Is there any example of how to control a hw-specific feature in other similar >> iio drivers? >> > > This sounds as if the channel scale is programmable. There are quite a few > drivers for devices which have similar features, just make the scale property > writable and provide a scale_available. > I was looking at that yesterday as I had to had a scale for the temperature sensors. You'll have to be careful because the maximum measured voltage when DIVIDE_BY_TWO is not set is 1.85V and when it is set, it becomes VDDIO - 50mv. Also, scaling for quite a lot of channels is fixed. You'll also get channels with a fixed divider that can take DIVIDE_BY_TWO. That is quite a mess ;) -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- 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
