linux-kernel - [PATCH 04/11] rtc: at91rm9200: remove race condition

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Date:   Thu,  6 Jul 2017 11:42:01 +0200
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     linux-rtc@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Subject: [PATCH 04/11] rtc: at91rm9200: remove race condition

While highly unlikely, it is possible to get an interrupt as soon as it is
requested. In that case, at91_rtc_interrupt() will be called with rtc ==
NULL.

Solve that by using devm_rtc_allocate_device/rtc_register_device.

Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
---
 drivers/rtc/rtc-at91rm9200.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index b60fd477778f..e221b78b6f10 100644
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -409,6 +409,11 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
+	rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+	platform_set_drvdata(pdev, rtc);
+
 	sclk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(sclk))
 		return PTR_ERR(sclk);
@@ -441,13 +446,10 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
 	if (!device_can_wakeup(&pdev->dev))
 		device_init_wakeup(&pdev->dev, 1);
 
-	rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
-				&at91_rtc_ops, THIS_MODULE);
-	if (IS_ERR(rtc)) {
-		ret = PTR_ERR(rtc);
+	rtc->ops = &at91_rtc_ops;
+	ret = rtc_register_device(rtc);
+	if (ret)
 		goto err_clk;
-	}
-	platform_set_drvdata(pdev, rtc);
 
 	/* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
 	 * completion.
-- 
2.11.0