On Wed, Nov 25, 2015 at 11:50:30AM +0200, Adriana Reus wrote: > > > On 25.11.2015 02:01, Rob Herring wrote: > >On Tue, Nov 24, 2015 at 12:59:49PM +0200, Adriana Reus wrote: > >>Add a property to allow changing the default power-saving mode. > >>By default, at read raw the chip will activate and provide > >>one measurent, then it will shut itself down. However, the > >>chip can also work in "continuous" mode which may be more reliable > >>but is also more power consuming. > >> > >>Signed-off-by: Adriana Reus <adriana.reus@xxxxxxxxx> > >>--- > >> Documentation/devicetree/bindings/iio/light/us5182d.txt | 11 +++++++++++ > >> 1 file changed, 11 insertions(+) > >> > >>diff --git a/Documentation/devicetree/bindings/iio/light/us5182d.txt b/Documentation/devicetree/bindings/iio/light/us5182d.txt > >>index 6f0a530..a619799 100644 > >>--- a/Documentation/devicetree/bindings/iio/light/us5182d.txt > >>+++ b/Documentation/devicetree/bindings/iio/light/us5182d.txt > >>@@ -7,13 +7,24 @@ Required properties: > >> Optional properties: > >> - upisemi,glass-coef: glass attenuation factor - compensation factor of > >> resolution 1000 for material transmittance. > >>+ > >> - upisemi,dark-ths: array of 8 elements containing 16-bit thresholds (adc > >> counts) corresponding to every scale. > >>+ > >> - upisemi,upper-dark-gain: 8-bit dark gain compensation factor(4 int and 4 > >> fractional bits - Q4.4) applied when light > threshold > >>+ > >> - upisemi,lower-dark-gain: 8-bit dark gain compensation factor(4 int and 4 > >> fractional bits - Q4.4) applied when light < threshold > >> > >>+- upisemi,continuous: This chip has two power modes: one-shot (chip takes one > >>+ measurement and then shuts itself down) and continuous ( > >>+ chip takes continuous measurements). The one-shot mode is > >>+ more power-friendly but the continuous mode may be more > >>+ reliable. If this property is specified the continuous > >>+ mode will be used instead of the default one-shot one for > >>+ raw reads. > > > >I could imagine an OS may want to decide this on its own or use a > >mixture of the modes. > > > >Rob > > > > There is no possibility of mixing them up (at the same time), so for example > proximity cannot work in one mode and als the other. > > The one-shot mode can only be used for raw reads (for example when > user-space polls in_[proximity|light]_raw). If user-space wants to enable > events (activate interrupts when certain thresholds are met - patch 5 of the > series), then the chip has to switch to continuous nonetheless because it > needs to be active all the time. So one work-flow scenario would be: > > Consumer1 starts polling the raw interface - default_mode > Consumer2 activates events - continuous mode > Consumer2 deactivates events - back to default_mode > > The only choice here is the default mode for raw reads, it currently is > one-shot, this patch allows for continuous to be used if preferred. Okay, then: Acked-by: Rob Herring <robh@xxxxxxxxxx> > -- > 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 -- 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
