The opp binding now allows to have an empty opp table and shared-opp to
merely describe a hw connection among devices (f/v lines).

When initialising an opp table, allow such case by:
- treating some errors as warnings
- do not mark empty tables as shared
- don't fail on empty table

Signed-off-by: Nicola Mazzucato <nicola.mazzuc...@arm.com>
---
 drivers/opp/of.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 874b58756220..b0230490bb31 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -157,6 +157,11 @@ static void _opp_table_free_required_tables(struct 
opp_table *opp_table)
 /*
  * Populate all devices and opp tables which are part of "required-opps" list.
  * Checking only the first OPP node should be enough.
+ *
+ * Corner case: empty opp table and opp-shared found. In this case we set
+ * unconditionally the opp table access to exclusive, as the opp-shared 
property
+ * is used purely to describe hw connections. Such information will be 
retrieved
+ * via dev_pm_opp_of_get_sharing_cpus().
  */
 static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
                                             struct device *dev,
@@ -169,7 +174,9 @@ static void _opp_table_alloc_required_tables(struct 
opp_table *opp_table,
        /* Traversing the first OPP node is all we need */
        np = of_get_next_available_child(opp_np, NULL);
        if (!np) {
-               dev_err(dev, "Empty OPP table\n");
+               dev_warn(dev, "Empty OPP table\n");
+
+               opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;
                return;
        }
 
@@ -377,7 +384,9 @@ int dev_pm_opp_of_find_icc_paths(struct device *dev,
        struct icc_path **paths;
 
        ret = _bandwidth_supported(dev, opp_table);
-       if (ret <= 0)
+       if (ret == -EINVAL)
+               return 0; /* Empty OPP table is a valid corner-case, let's not 
fail */
+       else if (ret <= 0)
                return ret;
 
        ret = 0;
-- 
2.27.0

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