[PATCH V2 1/4] opp: Enable resources again if they were disabled earlier

[Viresh Kumar]

From: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>

dev_pm_opp_set_rate() can now be called with freq = 0 in order
to either drop performance or bandwidth votes or to disable
regulators on platforms which support them.

In such cases, a subsequent call to dev_pm_opp_set_rate() with
the same frequency ends up returning early because 'old_freq == freq'

Instead make it fall through and put back the dropped performance
and bandwidth votes and/or enable back the regulators.

Cc: v5.3+ <stable@xxxxxxxxxxxxxxx> # v5.3+
Fixes: cd7ea582 ("opp: Make dev_pm_opp_set_rate() handle freq = 0 to drop performance votes")
Reported-by: Sajida Bhanu <sbhanu@xxxxxxxxxxxxxx>
Reviewed-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
Reported-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Tested-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Signed-off-by: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>
[ Viresh: Don't skip clk_set_rate() and massaged changelog ]
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
Hi Rajendra,

I wasn't able to test this stuff, please give it a try. I have
simplified your patch and cleaned up a bunch of stuff as well.

 drivers/opp/core.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index bdb028c7793d..9668ea04cc80 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -934,10 +934,13 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 
 	/* Return early if nothing to do */
 	if (old_freq == freq) {
-		dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
-			__func__, freq);
-		ret = 0;
-		goto put_opp_table;
+		if (!opp_table->required_opp_tables && !opp_table->regulators &&
+		    !opp_table->paths) {
+			dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
+				__func__, freq);
+			ret = 0;
+			goto put_opp_table;
+		}
 	}
 
 	/*
-- 
2.14.1