[PATCH 1/4] dt-bindings: display: panel: himax,hx8279: add vddp-supply

[David Lechner]

Add a vddp-supply property and make it required for the Startek
KD070FHFID078 panel.

The Startek KD070FHFID078 panel has a separate VDDP power input, which
feeds its DC-DC converter, in addition to VDD and IOVCC. On the MediaTek
Genio 520 and 720 EVKs, VDDP is switched by its own GPIO-controlled
regulator, and on the Genio 1200 EVK it comes from its own PMIC LDO.
In both cases it is separate from the other two supplies, so it needs to
be described to power the panel.

Making it required means existing device trees with this panel without
it no longer validate. This is ok since the Linux driver will still work
with them because the regulator core uses a dummy regulator for any
missing supply. And anyone who sees the warning about the missing
supply should add it to their device tree.

It stays optional for the Aoly SL101PM1794FOG-V15 panel, as it is not
known whether that panel has a VDDP input.

Signed-off-by: David Lechner <dlechner at baylibre.com>
---
 .../devicetree/bindings/display/panel/himax,hx8279.yaml     | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx8279.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx8279.yaml
index f619aea82bdf..c79056c39037 100644
--- a/Documentation/devicetree/bindings/display/panel/himax,hx8279.yaml
+++ b/Documentation/devicetree/bindings/display/panel/himax,hx8279.yaml
@@ -37,6 +37,9 @@ properties:
   vdd-supply:
     description: Panel power supply
 
+  vddp-supply:
+    description: Panel DC-DC converter power supply (VDDP)
+
 required:
   - compatible
   - reg
@@ -45,6 +48,15 @@ required:
   - iovcc-supply
   - vdd-supply
 
+if:
+  properties:
+    compatible:
+      contains:
+        const: startek,kd070fhfid078
+then:
+  required:
+    - vddp-supply
+
 unevaluatedProperties: false
 
 examples:
@@ -63,6 +75,7 @@ examples:
             reset-gpios = <&pio 45 GPIO_ACTIVE_HIGH>;
             iovcc-supply = <&vreg_lcm_vio>;
             vdd-supply = <&vreg_lcm_vdd>;
+            vddp-supply = <&vreg_lcm_vddp>;
 
             port {
                 panel_in: endpoint {

-- 
2.53.0