[PATCH 1/2] rtc: renesas-rtca3: Initialize the RTC before requesting interrupts

[Myeonghun Pak]

The alarm handler passes priv->rtc_dev to rtc_update_irq(), but the RTC
allocation is managed after the interrupt requests. Devres can therefore
drop the RTC's allocation reference before freeing and synchronizing the
alarm IRQ. Masking alarm interrupts in remove does not wait for a handler
that has already entered, and a pending alarm flag can still be handled.

Allocate the RTC before requesting the IRQs so that the allocation
reference remains valid until the IRQs have been freed and synchronized
on both removal and probe failure. Initialize its operations and time
range before requesting the IRQs as well, so an early alarm interrupt
cannot queue RTC work before the operations are available.

This issue was found by static analysis.

Fixes: d4488377609e ("rtc: renesas-rtca3: Add driver for RTCA-3 available on Renesas RZ/G3S SoC")
Assisted-by: LLM
Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>
---
Compile-tested with Clang 22.1.2, W=1 (arm64). No runtime testing.

One existing FIELD_GET comparison warning also occurs when compiling
the unmodified driver with the same flags. No new compiler warnings.

 drivers/rtc/rtc-renesas-rtca3.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-renesas-rtca3.c b/drivers/rtc/rtc-renesas-rtca3.c
index b3875d041de5..c304ed60edc6 100644
--- a/drivers/rtc/rtc-renesas-rtca3.c
+++ b/drivers/rtc/rtc-renesas-rtca3.c
@@ -765,12 +765,6 @@ static int rtca3_probe(struct platform_device *pdev)
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to setup the RTC!\n");
 
-	ret = rtca3_request_irqs(pdev, priv);
-	if (ret)
-		return ret;
-
-	device_init_wakeup(&pdev->dev, true);
-
 	priv->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(priv->rtc_dev))
 		return PTR_ERR(priv->rtc_dev);
@@ -779,6 +773,12 @@ static int rtca3_probe(struct platform_device *pdev)
 	priv->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	priv->rtc_dev->range_max = RTC_TIMESTAMP_END_2099;
 
+	ret = rtca3_request_irqs(pdev, priv);
+	if (ret)
+		return ret;
+
+	device_init_wakeup(&pdev->dev, true);
+
 	return devm_rtc_register_device(priv->rtc_dev);
 }