Hi Rob,

On Wed, Jul 25, 2018 at 10:07 PM Rob Herring [off-list ref] wrote:

On Sat, Jul 21, 2018 at 09:28:44PM +0200, Martin Blumenstingl wrote:

quoted

The clock controller on Meson8/Meson8m2 and Meson8b is part of a
register region called "HHI". This register area contains more
functionality than just a clock controller:
- the clock controller
- some reset controller bits
- temperature sensor calibration data (on Meson8b and Meson8m2 only)
- HDMI controller

The HHI register area may be accessed concurrently. Allow this by using
a "system controller" as parent node.

Why? A single node can be a provider of multiple things. Maybe the HDMI
should be a child since it will involve graph nodes, but the rest can be
one node. There should be numerous examples of blocks that are clock and
reset controllers.

I understand that a node can provide multiple "things" - currently
it's a clock controller and a reset controller
the HDMI controller could also be integrated in a similar way

however, I do not know how to access the temperature sensor calibration data
there is an ADC - one of it's channel has access to a temperature sensor
this ADC is located at CBUS offset 0x8680 and we already have a driver
for it (meson-saradc)
my problem is that the temperature sensor has to be calibrated - this
is done by:
- read data from efuse
- write 4 bits of calibration data to some register in the ADC's register space
- write a 5th bit of calibration data to a (seemingly random) register
in the HHI register space
(if one of the 5 bits is not written to it's correct location then the
temperature sensor reads bogus values)

I am not sure how to handle this without passing the HHI region to the
meson-saradc driver and letting that initialize all the temperature
calibration data bits (in it's own register space as well as the HHI
register space)
do you have any suggestion here?

quoted

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 .../bindings/clock/amlogic,meson8b-clkc.txt         | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt b/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt
index b455c5aa9139..38fb979210d3 100644
--- a/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt
+++ b/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt

@@ -9,15 +9,13 @@ Required Properties:
      - "amlogic,meson8-clkc" for Meson8 (S802) SoCs
      - "amlogic,meson8b-clkc" for Meson8 (S805) SoCs
      - "amlogic,meson8m2-clkc" for Meson8m2 (S812) SoCs
-- reg: it must be composed by two tuples:
-     0) physical base address of the xtal register and length of memory
-        mapped region.
-     1) physical base address of the clock controller and length of memory
-        mapped region.
-
 - #clock-cells: should be 1.
 - #reset-cells: should be 1.

+Parent node should have the following properties :
+- compatible: "syscon", "simple-mfd"

These 2 compatibles alone are not valid.

so I should add (for example) "amlogic,meson8b-hhi-sysctrl" as first compatible?
so the result would be: compatible = "amlogic,meson8b-hhi-sysctrl",
"syscon", "simple-mfd";


Regards
Martin