[PATCH v10 2/6] dt-bindings: mmc: Add reset-card-at-resume property

[Ulf Hansson <ulf.hansson@oss.qualcomm.com>]

From: Kamal Dasu <kamal.dasu@broadcom.com>

On some platforms, firmware or other hardware accesses the card
during suspend/resume, before the kernel's own resume path has run,
leaving the card in a state the kernel can no longer assume it knows.
Add a flag property so such boards can tell the mmc core the card
needs to be reset before it can be used again.

This is expected to be paired with keep-power-in-suspend on boards
whose firmware needs the card to stay powered and live throughout
suspend: since the card is never power-cycled, nothing else would
force it back to a known state on resume.

Signed-off-by: Kamal Dasu <kamal.dasu@broadcom.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
 .../devicetree/bindings/mmc/mmc-controller-common.yaml    | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
index 2fc8e06d5ec9..c824b95f2ae2 100644
--- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
+++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
@@ -303,6 +303,13 @@ properties:
     description:
       Preserves card power during a suspend/resume cycle.
 
+  reset-card-at-resume:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The HW/FW may have accessed the card during suspend/resume,
+      leaving it in an unknown state. Hence, before the card can be
+      used, it must be reset.
+
   wakeup-source:
     $ref: /schemas/types.yaml#/definitions/flag
     description:
@@ -371,5 +378,6 @@ patternProperties:
 dependencies:
   cd-debounce-delay-ms: [ cd-gpios ]
   fixed-emmc-driver-type: [ non-removable ]
+  reset-card-at-resume: [ keep-power-in-suspend ]
 
 additionalProperties: true
-- 
2.43.0