Re: [PATCH V1] rtc: loongson: Add missing alarm notifications for ACPI RTC events

From: Binbin Zhou
Date: Fri May 09 2025 - 03:13:50 EST


Hi:

On 2025/5/9 09:40, Liu Dalin wrote:
When an application sets and enables an alarm on Loongson RTC devices,
the alarm notification fails to propagate to userspace because the
ACPI event handler omits calling rtc_update_irq().

As a result, processes waiting via select() or poll() on RTC device
files fail to receive alarm notifications.

Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
Signed-off-by: Liu Dalin <liudalin@xxxxxxxxxxxxxxx>
Technically I don't think this is a compliant patch, firstly this patch should be V2 and also you should add "Changlog" for describing the differences from the previous patch.
Anyway, it's good to me.

Reviewed-by: Binbin Zhou <zhoubinbin@xxxxxxxxxxx>

---
drivers/rtc/rtc-loongson.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
index 97e5625c064c..2ca7ffd5d7a9 100644
--- a/drivers/rtc/rtc-loongson.c
+++ b/drivers/rtc/rtc-loongson.c
@@ -129,6 +129,14 @@ static u32 loongson_rtc_handler(void *id)
{
struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
+ rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
+
+ /*
+ * The TOY_MATCH0_REG should be cleared 0 here,
+ * otherwise the interrupt cannot be cleared.
+ */
+ regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
+
spin_lock(&priv->lock);
/* Disable RTC alarm wakeup and interrupt */
writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
Thanks.
Binbin