[PATCH v2 4/7] of: property: fw_devlink: Follow PWM nexus maps

[Ernest Van Hoecke <ernestvanhoecke@gmail.com>]

From: Ernest Van Hoecke <ernest.vanhoecke@toradex.com>

PWM consumers use of_parse_phandle_with_args_map() to resolve specifiers
through pwm-map properties. fw_devlink instead parses the pwms property
as a direct phandle reference, so it records the nexus node as the
supplier rather than the mapped PWM provider.

A nexus is a translation node, not the PWM provider, and need not be
populated as a device. The resulting fwnode link can therefore remain
unresolved and indefinitely defer the consumer while
device_links_check_suppliers() waits for the nexus.

Use the map-aware parser for pwms so fw_devlink resolves the same
provider as the PWM consumer API. Direct PWM references continue to work
because the map-aware parser returns the original provider when no
pwm-map property is present.

Fixes: e71e46a6f19c ("pwm: Add support for pwm nexus dt bindings")
Reported-by: Leonardo Costa <leonardo.costa@toradex.com>
Link: https://lore.kernel.org/all/juuc4af7ndbajcl7gzf4tg5qz2q2j5tt3rvql4jbauradujrre@gc5nbdhhixaf/
Tested-by: Leonardo Costa <leonardo.costa@toradex.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@toradex.com>
---
 drivers/of/property.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index eba7e9fe6c38..a9c51d639a2b 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1331,6 +1331,15 @@ static struct device_node *parse_##fname(struct device_node *np,	  \
 	return parse_prop_cells(np, prop_name, index, name, cells);	  \
 }
 
+#define DEFINE_SIMPLE_NEXUS_PROP(fname, name, stem)			  \
+static struct device_node *parse_##fname(struct device_node *np,	  \
+					const char *prop_name, int index) \
+{									  \
+	if (strcmp(prop_name, name))					  \
+		return NULL;						  \
+	return parse_nexus_prop(np, prop_name, index, stem);		  \
+}
+
 /**
  * parse_suffix_prop_cells - Suffix property parsing function for suppliers
  *
@@ -1426,7 +1435,7 @@ DEFINE_SIMPLE_PROP(extcon, "extcon", NULL)
 DEFINE_SIMPLE_PROP(nvmem_cells, "nvmem-cells", "#nvmem-cell-cells")
 DEFINE_SIMPLE_PROP(phys, "phys", "#phy-cells")
 DEFINE_SIMPLE_PROP(wakeup_parent, "wakeup-parent", NULL)
-DEFINE_SIMPLE_PROP(pwms, "pwms", "#pwm-cells")
+DEFINE_SIMPLE_NEXUS_PROP(pwms, "pwms", "pwm")
 DEFINE_SIMPLE_PROP(resets, "resets", "#reset-cells")
 DEFINE_SIMPLE_PROP(leds, "leds", NULL)
 DEFINE_SIMPLE_PROP(backlight, "backlight", NULL)

-- 
2.43.0