[PATCH 2/2] of: property: fw_devlink: Set 'optional_con_dev' for parse_power_domains

[Ulf Hansson]

The power-domain DT bindings [1] doesn't enforce a compatible string for a
provider node, even if this is common to use. In particular, when
describing a hierarchy with parent/child power-domains, as the psci DT
bindings [2] for example, it's sometimes not applicable to use a compatible
string.

Therefore, let's set the 'optional_con_dev' to true to avoid creating
incorrect fw_devlinks for power-domains.

[1] Documentation/devicetree/bindings/power/power-domain.yaml
[2] Documentation/devicetree/bindings/arm/psci.yaml

Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---

Some more details of what goes on here. I have added a debug print in
of_link_to_phandle() to see the fw_devlinks that gets created.

This is what happens on Dragonboard 410c when 'optional_con_dev' isn't set:
...
[    0.041274] device: 'psci': device_add
[    0.041366] OF: Linking power-domain-cpu0 (consumer) to psci (supplier)
[    0.041395] OF: Linking power-domain-cpu1 (consumer) to psci (supplier)
[    0.041423] OF: Linking power-domain-cpu2 (consumer) to psci (supplier)
[    0.041451] OF: Linking power-domain-cpu3 (consumer) to psci (supplier)
[    0.041494] device: 'platform:psci--platform:psci': device_add
[    0.041556] platform psci: Linked as a sync state only consumer to psci
...

This is what happens on Dragonboard 410c when 'optional_con_dev' is set:
...
[    0.041179] device: 'psci': device_add
[    0.041265] OF: Not linking psci to psci - is descendant
[    0.041293] OF: Not linking psci to psci - is descendant
[    0.041319] OF: Not linking psci to psci - is descendant
[    0.041346] OF: Not linking psci to psci - is descendant
...

The relevant dtsi file:
arch/arm64/boot/dts/qcom/msm8916.dtsi

Kind regards
Ulf Hansson

---
 drivers/of/property.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 2babb1807228..4d607fdbea24 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1356,7 +1356,7 @@ static const struct supplier_bindings of_supplier_bindings[] = {
 	{ .parse_prop = parse_io_channels, },
 	{ .parse_prop = parse_interrupt_parent, },
 	{ .parse_prop = parse_dmas, .optional = true, },
-	{ .parse_prop = parse_power_domains, },
+	{ .parse_prop = parse_power_domains, .optional_con_dev = true, },
 	{ .parse_prop = parse_hwlocks, },
 	{ .parse_prop = parse_extcon, },
 	{ .parse_prop = parse_nvmem_cells, },
-- 
2.25.1