linux-kernel - [PATCH v2 15/48] opp: Support set_opp() customization without requiring to use regulators

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Date:   Thu, 17 Dec 2020 21:06:05 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Peter Geis <pgwipeout@...il.com>,
        Nicolas Chauvet <kwizart@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Kevin Hilman <khilman@...nel.org>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        Viresh Kumar <vireshk@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-media@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-clk@...r.kernel.org
Subject: [PATCH v2 15/48] opp: Support set_opp() customization without requiring to use regulators

Support set_opp() customization without requiring to use regulators. This
is needed by drivers which want to use dev_pm_opp_set_rate() for changing
rates of a multiple clocks and don't need to touch regulator.

One example is NVIDIA Tegra30/114 SoCs which have two sibling 3D hardware
units which should be use to the same clock rate, meanwhile voltage
scaling is done using a power domain. In this case OPP table doesn't have
a regulator, causing a NULL dereference in _set_opp_custom().

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/opp/core.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 3d02fe33630b..625dae7a5ecb 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -828,17 +828,25 @@ static int _set_opp_custom(const struct opp_table *opp_table,
 			   struct dev_pm_opp_supply *old_supply,
 			   struct dev_pm_opp_supply *new_supply)
 {
-	struct dev_pm_set_opp_data *data;
+	struct dev_pm_set_opp_data *data, tmp_data;
+	unsigned int regulator_count;
 	int size;
 
-	data = opp_table->set_opp_data;
+	if (opp_table->set_opp_data) {
+		data = opp_table->set_opp_data;
+		regulator_count = opp_table->regulator_count;
+	} else {
+		data = &tmp_data;
+		regulator_count = 0;
+	}
+
 	data->regulators = opp_table->regulators;
-	data->regulator_count = opp_table->regulator_count;
+	data->regulator_count = regulator_count;
 	data->clk = opp_table->clk;
 	data->dev = dev;
 
 	data->old_opp.rate = old_freq;
-	size = sizeof(*old_supply) * opp_table->regulator_count;
+	size = sizeof(*old_supply) * regulator_count;
 	if (!old_supply)
 		memset(data->old_opp.supplies, 0, size);
 	else
-- 
2.29.2