linux-kernel - [PATCH] rtc: max77686: Properly handle regmap_irq_get

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Date:	Thu, 04 Feb 2016 09:26:35 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Chanwoo Choi <cw00.choi@...sung.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	linux-kernel@...r.kernel.org, rtc-linux@...glegroups.com
Cc:	ldewangan@...dia.com, javier@....samsung.com
Subject: [PATCH] rtc: max77686: Properly handle regmap_irq_get_virq() error code

The regmap_irq_get_virq() can return 0 or -EINVAL in error conditions
but driver checked only for value of 0.

This could lead to a cast of -EINVAL to an unsigned int used as a
interrupt number for devm_request_threaded_irq(). Although this is not
yet fatal (devm_request_threaded_irq() will just fail with -EINVAL) but
might be a misleading when diagnosing errors.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
Fixes: 6f1c1e71d933 ("mfd: max77686: Convert to use regmap_irq")

---

Patch rebased on current mainline, not RTC tree, because IMHO it is
a candidate for current RC-cycle.

Not marking cc-stable because behavior is not fatal - unless there is
an interrupt with number 4294967274 (then it would be successfully
requested for RTC driver).
---
 drivers/rtc/rtc-max77686.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
index 7184a0eda793..725dccae24e7 100644
--- a/drivers/rtc/rtc-max77686.c
+++ b/drivers/rtc/rtc-max77686.c
@@ -465,7 +465,7 @@ static int max77686_rtc_probe(struct platform_device *pdev)
 
 	info->virq = regmap_irq_get_virq(max77686->rtc_irq_data,
 					 MAX77686_RTCIRQ_RTCA1);
-	if (!info->virq) {
+	if (info->virq <= 0) {
 		ret = -ENXIO;
 		goto err_rtc;
 	}
-- 
1.9.1