Several ADC channels are supported in PMIC which can be used to
measure voltage, temperature, current etc. Different scaling can be
applied on the obtained voltage to report in physical units. Scaling
functionality can be different per channel. Add scaling support per
channel. Every channel present in adc has an unique conversion formula
for obtained voltage. Add support to report in Raw as well as in
processed format. Scaling is applied when processed read is requested
and is not applied when a Raw read is requested.
Signed-off-by: NRama Krishna Phani A <rphani@codeaurora.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Several channels are supported in ADC of PMIC which can be used to
measure voltage, temperature, current etc., Hardware provides
readings for all channels in adc code. That adc code needs to be
converted to voltage. Logic for conversion of adc code to voltage
is common for all ADC channels(voltage, temperature, current
.,etc). Implement separate function for generic conversion logic.
Signed-off-by: NRama Krishna Phani A <rphani@codeaurora.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

for_each_available_child_of_node performs an of_node_get on each iteration,
so a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
@@

 for_each_available_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
(
   return child;
|
+  of_node_put(child);
?  return ...;
)
   ...
 }
// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Cc: <Stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

With 'dx' equal to 0.625V and 15 bit ADC, calculations overflow
when difference against GND is ~20% of the ADC range. Fix this.
Signed-off-by: NIvan T. Ivanov <ivan.ivanov@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has
15bits resolution and register space inside PMIC accessible across
SPMI bus.

The vadc driver registers itself through IIO interface.
Signed-off-by: NStanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: NIvan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>