Polling can also be used for End of conversion completion. Implement logic
to choose either polling or interrupt for End of conversion completion.
Scaling can be done on the voltage to report adc code in physical units.
Add changes to support different scale functions to convert adc code to
physical units.

Signed-off-by: Rama Krishna Phani A <redacted>
---
 .../devicetree/bindings/iio/adc/qcom,spmi-vadc.txt |  14 ++
 drivers/iio/adc/qcom-spmi-vadc.c                   | 263 +++++++++++++++++----
 2 files changed, 236 insertions(+), 41 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
index 0fb4613..39e31c0e 100644
--- a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt

@@ -37,6 +37,12 @@ VADC node:
     Value type: <prop-encoded-array>
     Definition: End of conversion interrupt.
 
+- qcom,vadc-poll-eoc:
+    Usage: optional
+    Value type: <bool>
+    Definition: Use polling instead of interrupts for End of Conversion
+		completion.

+
 Channel node properties:
 
 - reg:

@@ -92,6 +98,14 @@ Channel node properties:
             Valid values are: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512
             If property is not found, 1 sample will be used.
 
+- qcom,scale-function:
+    Usage: optional
+    Value type: <u32>
+    Definition: Scaling function used to convert raw ADC code to
+	units specific to a given channel. Scaled units can be
+	microvolts, millidegC.Valid values are: 0, 1, 2, 3, 4.
+	If property is not found, 0 scaling will be used.