[PATCH] of: of_property_read_string return -ENODATA when !length

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>

When the length of the string is zero of_property_read_string should
return -ENODATA according to the description of the function.

However, of_property_read_string doesn't check pp->length. If pp->length
is zero, return -ENODATA.

Without this patch the following command in u-boot:

fdt set /chosen/node property-name

results in of_property_read_string returning -EILSEQ when attempting to
read property-name. With this patch, it returns -ENODATA as expected.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 8e90071de6ed..da0f02c98bb2 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -439,7 +439,7 @@ int of_property_read_string(const struct device_node *np, 
const char *propname,
        const struct property *prop = of_find_property(np, propname, NULL);
        if (!prop)
                return -EINVAL;
-       if (!prop->value)
+       if (!prop->value || !pp->length)
                return -ENODATA;
        if (strnlen(prop->value, prop->length) >= prop->length)
                return -EILSEQ;