Hey Saravana,
Thanks for taking time to post out this series.

On 6/26/19 3:03 AM, Saravana Kannan wrote:
A Device-A can have a (minimum) performance requirement on another
Device-B to be able to function correctly. This performance requirement
on Device-B can also change based on the current performance level of
Device-A.

The existing required-opps feature fits well to describe this need. So,
instead of limiting required-opps to point to only PM-domain devices,
allow it to point to any device.

Signed-off-by: Saravana Kannan <sarava...@google.com>
---
  drivers/opp/core.c |  2 +-
  drivers/opp/of.c   | 14 --------------
  2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 0e7703fe733f..74c7bdc6f463 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -710,7 +710,7 @@ static int _set_required_opps(struct device *dev,
                return 0;
/* Single genpd case */
-       if (!genpd_virt_devs) {
+       if (!genpd_virt_devs && required_opp_tables[0]->is_genpd) {

https://patchwork.kernel.org/patch/10940671/
This was already removed as a part of ^^ and is in linux-next.

                pstate = opp->required_opps[0]->pstate;
                ret = dev_pm_genpd_set_performance_state(dev, pstate);
                if (ret) {
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index c10c782d15aa..7c8336e94aff 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -195,9 +195,6 @@ static void _opp_table_alloc_required_tables(struct 
opp_table *opp_table,
         */
        count_pd = of_count_phandle_with_args(dev->of_node, "power-domains",
                                              "#power-domain-cells");
-       if (!count_pd)
-               goto put_np;
-
        if (count_pd > 1) {
                genpd_virt_devs = kcalloc(count, sizeof(*genpd_virt_devs),
                                        GFP_KERNEL);
@@ -226,17 +223,6 @@ static void _opp_table_alloc_required_tables(struct 
opp_table *opp_table,
if (IS_ERR(required_opp_tables[i]))
                        goto free_required_tables;
-
-               /*
-                * We only support genpd's OPPs in the "required-opps" for now,
-                * as we don't know how much about other cases. Error out if the
-                * required OPP doesn't belong to a genpd.
-                */
-               if (!required_opp_tables[i]->is_genpd) {
-                       dev_err(dev, "required-opp doesn't belong to genpd: 
%pOF\n",
-                               required_np);
-                       goto free_required_tables;
-               }

I expect the series to not work as is in its current state since I
see a circular dependency here. The required-opp tables of the parent
devfreq won't be populated until we add the opp-table of the child devfreq node while the child devfreq using passive governor would
return -EPROBE_DEFER until the parent devfreq probes.

The same applies to this patch -> https://patchwork.kernel.org/patch
/11046147/ I posted out based on your series. So we would probably have
to address the dependency here.

        }
goto put_np;


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