linux-kernel - [PATCH V2] PM / OPP: of_property_count_u32

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Date:	Tue, 22 Sep 2015 09:35:31 -0700
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 V2] 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>
---
V1->V2:
- Dropped 'prop' variable.

 drivers/base/power/opp.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 28cd75c535b0..1194669c2bb5 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -892,10 +892,17 @@ static int opp_get_microvolt(struct dev_pm_opp *opp, struct device *dev)
 	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 */
+	if (!of_find_property(opp->np, "opp-microvolt", NULL))
 		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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