Re: [PATCH v2 1/4] OPP: Allow required-opps even if the device doesn't have power-domains

From: Sibi Sankar
Date: Tue Jul 16 2019 - 13:18:01 EST

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

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 <saravanak@xxxxxxxxxx>
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) {
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",
- if (!count_pd)
- goto put_np;
if (count_pd > 1) {
genpd_virt_devs = kcalloc(count, sizeof(*genpd_virt_devs),
@@ -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 ->
/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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