2019-06-04 04:25:11

by Chen-Yu Tsai

Subject: [PATCH 2/3] rtc: pcf8563: Clear event flags and disable interrupts before requesting irq

From: Chen-Yu Tsai <[email protected]>

Besides the alarm, the PCF8563 also has a timer triggered interrupt.
In cases where the previous system left the timer and interrupts on,
or somehow the bits got enabled, the interrupt would keep triggering
as the kernel doesn't know about it.

Clear both the alarm and timer event flags, and disable the interrupts,
before requesting the interrupt line.

Fixes: ede3e9d47cca ("drivers/rtc/rtc-pcf8563.c: add alarm support")
Fixes: a45d528aab8b ("rtc: pcf8563: clear expired alarm at boot time")
Signed-off-by: Chen-Yu Tsai <[email protected]>
---
drivers/rtc/rtc-pcf8563.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index e358313466f1..d8adf69b6697 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -563,7 +563,6 @@ static int pcf8563_probe(struct i2c_client *client,
struct pcf8563 *pcf8563;
int err;
unsigned char buf;
- unsigned char alm_pending;

dev_dbg(&client->dev, "%s\n", __func__);

@@ -587,13 +586,13 @@ static int pcf8563_probe(struct i2c_client *client,
return err;
}

- err = pcf8563_get_alarm_mode(client, NULL, &alm_pending);
- if (err) {
- dev_err(&client->dev, "%s: read error\n", __func__);
+ /* Clear flags and disable interrupts */
+ buf = 0;
+ err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
+ if (err < 0) {
+ dev_err(&client->dev, "%s: write error\n", __func__);
return err;
}
- if (alm_pending)
- pcf8563_set_alarm_mode(client, 0);

pcf8563->rtc = devm_rtc_device_register(&client->dev,
pcf8563_driver.driver.name,
--
2.20.1

2019-06-20 18:38:07

by Alexandre Belloni

Subject: Re: [PATCH 2/3] rtc: pcf8563: Clear event flags and disable interrupts before requesting irq

On 04/06/2019 12:23:36+0800, Chen-Yu Tsai wrote:
> From: Chen-Yu Tsai <[email protected]>
>
> Besides the alarm, the PCF8563 also has a timer triggered interrupt.
> In cases where the previous system left the timer and interrupts on,
> or somehow the bits got enabled, the interrupt would keep triggering
> as the kernel doesn't know about it.
>
> Clear both the alarm and timer event flags, and disable the interrupts,
> before requesting the interrupt line.
>
> Fixes: ede3e9d47cca ("drivers/rtc/rtc-pcf8563.c: add alarm support")
> Fixes: a45d528aab8b ("rtc: pcf8563: clear expired alarm at boot time")
> Signed-off-by: Chen-Yu Tsai <[email protected]>
> ---
> drivers/rtc/rtc-pcf8563.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
Applied, thanks.

--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com