linux-kernel - [PATCH] PM / OPP: of_property_count_u32

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Date:	Thu, 17 Sep 2015 22:30:22 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Rafael Wysocki <rjw@...ysocki.net>
Cc:	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	sboyd@...eaurora.org, nm@...com,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Len Brown <len.brown@...el.com>,
	linux-kernel@...r.kernel.org (open list),
	Pavel Machek <pavel@....cz>
Subject: [PATCH] PM / OPP: of_property_count_u32_elems() can return errors

of_property_count_u32_elems() will never return 0, but a -ve error value
of a positive count. And so the current !count check is wrong.

Also, a missing "opp-microvolt" property isn't a problem and so we need
to do of_find_property() separately to confirm that.

Fixes: 274659029c9d ("PM / OPP: Add support to parse "operating-points-v2" bindings")
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
For 4.3.

 drivers/base/power/opp.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 28cd75c535b0..2048164d6c53 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -889,13 +889,22 @@ static int _opp_add_dynamic(struct device *dev, unsigned long freq,
 /* TODO: Support multiple regulators */
 static int opp_get_microvolt(struct dev_pm_opp *opp, struct device *dev)
 {
+	struct property *prop;
 	u32 microvolt[3] = {0};
 	int count, ret;
 
-	count = of_property_count_u32_elems(opp->np, "opp-microvolt");
-	if (!count)
+	/* Missing property isn't a problem, but an invalid entry is */
+	prop = of_find_property(opp->np, "opp-microvolt", NULL);
+	if (!prop)
 		return 0;
 
+	count = of_property_count_u32_elems(opp->np, "opp-microvolt");
+	if (count < 0) {
+		dev_err(dev, "%s: Invalid opp-microvolt property (%d)\n",
+			__func__, count);
+		return count;
+	}
+
 	/* There can be one or three elements here */
 	if (count != 1 && count != 3) {
 		dev_err(dev, "%s: Invalid number of elements in opp-microvolt property (%d)\n",
-- 
2.4.0

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