2024-01-15 23:22:41

by Alexandre Belloni

Subject: [PATCH 1/2] rtc: max31335: remove unecessary locking

From: Alexandre Belloni <[email protected]>

There is no race condition when accessing MAX31335_STATUS1 because it is
always about clearing the alarm interrupt bit.

Signed-off-by: Alexandre Belloni <[email protected]>
---
drivers/rtc/rtc-max31335.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/rtc/rtc-max31335.c b/drivers/rtc/rtc-max31335.c
index 3ddfe71bbb56..2ce23f60a7f3 100644
--- a/drivers/rtc/rtc-max31335.c
+++ b/drivers/rtc/rtc-max31335.c
@@ -348,27 +348,19 @@ static int max31335_alarm_irq_enable(struct device *dev, unsigned int enabled)
static irqreturn_t max31335_handle_irq(int irq, void *dev_id)
{
struct max31335_data *max31335 = dev_id;
- struct mutex *lock = &max31335->rtc->ops_lock;
int ret, status;

- mutex_lock(lock);
-
ret = regmap_read(max31335->regmap, MAX31335_STATUS1, &status);
if (ret)
- goto exit;
+ return IRQ_HANDLED;

if (FIELD_GET(MAX31335_STATUS1_A1F, status)) {
- ret = regmap_update_bits(max31335->regmap, MAX31335_STATUS1,
- MAX31335_STATUS1_A1F, 0);
- if (ret)
- goto exit;
+ regmap_update_bits(max31335->regmap, MAX31335_STATUS1,
+ MAX31335_STATUS1_A1F, 0);

rtc_update_irq(max31335->rtc, 1, RTC_AF | RTC_IRQF);
}

-exit:
- mutex_unlock(lock);
-
return IRQ_HANDLED;
}

--
2.43.0

2024-01-15 23:22:45

by Alexandre Belloni

Subject: [PATCH 2/2] rtc: max31335: use regmap_update_bits_check

From: Alexandre Belloni <[email protected]>

Simplify the IRQ handler by using regmap_update_bits_check.

Signed-off-by: Alexandre Belloni <[email protected]>
---
drivers/rtc/rtc-max31335.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/rtc/rtc-max31335.c b/drivers/rtc/rtc-max31335.c
index 2ce23f60a7f3..a38d303d9df4 100644
--- a/drivers/rtc/rtc-max31335.c
+++ b/drivers/rtc/rtc-max31335.c
@@ -348,18 +348,16 @@ static int max31335_alarm_irq_enable(struct device *dev, unsigned int enabled)
static irqreturn_t max31335_handle_irq(int irq, void *dev_id)
{
struct max31335_data *max31335 = dev_id;
- int ret, status;
+ bool status;
+ int ret;

- ret = regmap_read(max31335->regmap, MAX31335_STATUS1, &status);
+ ret = regmap_update_bits_check(max31335->regmap, MAX31335_STATUS1,
+ MAX31335_STATUS1_A1F, 0, &status);
if (ret)
return IRQ_HANDLED;

- if (FIELD_GET(MAX31335_STATUS1_A1F, status)) {
- regmap_update_bits(max31335->regmap, MAX31335_STATUS1,
- MAX31335_STATUS1_A1F, 0);
-
+ if (status)
rtc_update_irq(max31335->rtc, 1, RTC_AF | RTC_IRQF);
- }

return IRQ_HANDLED;
}
--
2.43.0

2024-01-16 10:47:28

by Antoniu Miclaus

Subject: RE: [PATCH 1/2] rtc: max31335: remove unecessary locking

> From: Alexandre Belloni <[email protected]>
>
> There is no race condition when accessing MAX31335_STATUS1 because it is
> always about clearing the alarm interrupt bit.
>
> Signed-off-by: Alexandre Belloni <[email protected]>
Reviewed-by: Antoniu Miclaus <[email protected]>
> ---
> drivers/rtc/rtc-max31335.c | 14 +++-----------
> 1 file changed, 3 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/rtc/rtc-max31335.c b/drivers/rtc/rtc-max31335.c
> index 3ddfe71bbb56..2ce23f60a7f3 100644
> --- a/drivers/rtc/rtc-max31335.c
> +++ b/drivers/rtc/rtc-max31335.c
> @@ -348,27 +348,19 @@ static int max31335_alarm_irq_enable(struct device
> *dev, unsigned int enabled)
> static irqreturn_t max31335_handle_irq(int irq, void *dev_id)
> {
> struct max31335_data *max31335 = dev_id;
> - struct mutex *lock = &max31335->rtc->ops_lock;
> int ret, status;
>
> - mutex_lock(lock);
> -
> ret = regmap_read(max31335->regmap, MAX31335_STATUS1,
> &status);
> if (ret)
> - goto exit;
> + return IRQ_HANDLED;
>
> if (FIELD_GET(MAX31335_STATUS1_A1F, status)) {
> - ret = regmap_update_bits(max31335->regmap,
> MAX31335_STATUS1,
> - MAX31335_STATUS1_A1F, 0);
> - if (ret)
> - goto exit;
> + regmap_update_bits(max31335->regmap,
> MAX31335_STATUS1,
> + MAX31335_STATUS1_A1F, 0);
>
> rtc_update_irq(max31335->rtc, 1, RTC_AF | RTC_IRQF);
> }
>
> -exit:
> - mutex_unlock(lock);
> -
> return IRQ_HANDLED;
> }
>
> --
> 2.43.0

2024-01-16 10:48:21

by Antoniu Miclaus

Subject: RE: [PATCH 2/2] rtc: max31335: use regmap_update_bits_check

> From: Alexandre Belloni <[email protected]>
>
> Simplify the IRQ handler by using regmap_update_bits_check.
>
> Signed-off-by: Alexandre Belloni <[email protected]>
Reviewed-by: Antoniu Miclaus <[email protected]>
> ---
> drivers/rtc/rtc-max31335.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/rtc/rtc-max31335.c b/drivers/rtc/rtc-max31335.c
> index 2ce23f60a7f3..a38d303d9df4 100644
> --- a/drivers/rtc/rtc-max31335.c
> +++ b/drivers/rtc/rtc-max31335.c
> @@ -348,18 +348,16 @@ static int max31335_alarm_irq_enable(struct device
> *dev, unsigned int enabled)
> static irqreturn_t max31335_handle_irq(int irq, void *dev_id)
> {
> struct max31335_data *max31335 = dev_id;
> - int ret, status;
> + bool status;
> + int ret;
>
> - ret = regmap_read(max31335->regmap, MAX31335_STATUS1,
> &status);
> + ret = regmap_update_bits_check(max31335->regmap,
> MAX31335_STATUS1,
> + MAX31335_STATUS1_A1F, 0, &status);
> if (ret)
> return IRQ_HANDLED;
>
> - if (FIELD_GET(MAX31335_STATUS1_A1F, status)) {
> - regmap_update_bits(max31335->regmap,
> MAX31335_STATUS1,
> - MAX31335_STATUS1_A1F, 0);
> -
> + if (status)
> rtc_update_irq(max31335->rtc, 1, RTC_AF | RTC_IRQF);
> - }
>
> return IRQ_HANDLED;
> }
> --
> 2.43.0