of_property_match_string calls of_find_property to search for the string property. If the device node does not exist, of_find_property returns NULL, and of_property_match_string returns -EINVAL, which is correct. However, if the device node exists, but the property is not found, of_find_property still returns NULL, but it will place -FDT_ERR_NOTFOUND in the *lenp variable. of_property_match_string does not use the lenp parameter, thus this error case is being lost, and treated as if the node is NULL, and returns -EINVAL, which is incorrect.

The callers of of_property_match_string treat the error differently if the return value is -EINVAL or -ENOENT, e.g. in dwc3 driver:

ret = generic_phy_get_by_name(dev, "usb3-phy", &phy); if (!ret) { ret = generic_phy_init(&phy); if (ret) return ret; } else if (ret != -ENOENT && ret != -ENODATA) { debug("could not get phy (err %d)\n", ret); return ret; } else { phy.dev = NULL; }

So the caller drivers will just consider the property missing if -ENOENT is returned, versus the case of -EINVAL, which means something else.

To fix this situation, changed the code to call the of_find_property with the right third argument to catch this error code and treat it accordingly.

Signed-off-by: Eugen Hristev eugen.hristev@collabora.com --- drivers/core/of_access.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/core/of_access.c b/drivers/core/of_access.c index 81a307992c01..57f10445b122 100644 --- a/drivers/core/of_access.c +++ b/drivers/core/of_access.c @@ -593,11 +593,14 @@ int of_read_u64(const struct device_node *np, const char *propname, u64 *outp) int of_property_match_string(const struct device_node *np, const char *propname, const char *string) { - const struct property *prop = of_find_property(np, propname, NULL); + int len = 0; + const struct property *prop = of_find_property(np, propname, &len); size_t l; int i; const char *p, *end;

+ if (!prop && len == -FDT_ERR_NOTFOUND) + return -ENOENT; if (!prop) return -EINVAL; if (!prop->value)