2015-08-12 10:21:50

by Joonyoung Shim

[permalink] [raw]
Subject: [PATCH v2] rtc: s3c: fix disabled clocks for alarm

The clock enable/disable codes for alarm have been removed from
commit 24e1455493da ("drivers/rtc/rtc-s3c.c: delete duplicate clock
control") and the clocks are disabled even if alarm is set, so alarm
interrupt can't happen.

The s3c_rtc_setaie function can be called several times with 'enabled'
argument having same value, so it needs to check whether clocks are
enabled or not.

Signed-off-by: Joonyoung Shim <[email protected]>
Cc: <[email protected]> # v4.1
---
This is v2 of prior patch "[PATCH 4/4] rtc: s3c: enable/disable clocks
for alarm".

Changelog for v2:
- commit messages is modified by Krzysztof suggestion
- make to backportable patch
- add Cc-stable

drivers/rtc/rtc-s3c.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index 44b2921..7cc8f73 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -39,6 +39,7 @@ struct s3c_rtc {
void __iomem *base;
struct clk *rtc_clk;
struct clk *rtc_src_clk;
+ bool clk_disabled;

struct s3c_rtc_data *data;

@@ -71,9 +72,12 @@ static void s3c_rtc_enable_clk(struct s3c_rtc *info)
unsigned long irq_flags;

spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
- clk_enable(info->rtc_clk);
- if (info->data->needs_src_clk)
- clk_enable(info->rtc_src_clk);
+ if (info->clk_disabled) {
+ clk_enable(info->rtc_clk);
+ if (info->data->needs_src_clk)
+ clk_enable(info->rtc_src_clk);
+ info->clk_disabled = false;
+ }
spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
}

@@ -82,9 +86,12 @@ static void s3c_rtc_disable_clk(struct s3c_rtc *info)
unsigned long irq_flags;

spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
- if (info->data->needs_src_clk)
- clk_disable(info->rtc_src_clk);
- clk_disable(info->rtc_clk);
+ if (!info->clk_disabled) {
+ if (info->data->needs_src_clk)
+ clk_disable(info->rtc_src_clk);
+ clk_disable(info->rtc_clk);
+ info->clk_disabled = true;
+ }
spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
}

@@ -128,6 +135,11 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)

s3c_rtc_disable_clk(info);

+ if (enabled)
+ s3c_rtc_enable_clk(info);
+ else
+ s3c_rtc_disable_clk(info);
+
return 0;
}

--
1.9.1


2015-08-18 05:44:20

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH v2] rtc: s3c: fix disabled clocks for alarm

On 12.08.2015 19:21, Joonyoung Shim wrote:
> The clock enable/disable codes for alarm have been removed from
> commit 24e1455493da ("drivers/rtc/rtc-s3c.c: delete duplicate clock
> control") and the clocks are disabled even if alarm is set, so alarm
> interrupt can't happen.
>
> The s3c_rtc_setaie function can be called several times with 'enabled'
> argument having same value, so it needs to check whether clocks are
> enabled or not.
>
> Signed-off-by: Joonyoung Shim <[email protected]>
> Cc: <[email protected]> # v4.1
> ---
> This is v2 of prior patch "[PATCH 4/4] rtc: s3c: enable/disable clocks
> for alarm".
>
> Changelog for v2:
> - commit messages is modified by Krzysztof suggestion
> - make to backportable patch
> - add Cc-stable
>
> drivers/rtc/rtc-s3c.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>

Looks good now:
Reviewed-by: Krzysztof Kozlowski <[email protected]>

Best regards,
Krzysztof

2015-08-20 22:59:51

by Alexandre Belloni

[permalink] [raw]
Subject: Re: [PATCH v2] rtc: s3c: fix disabled clocks for alarm

On 12/08/2015 at 19:21:46 +0900, Joonyoung Shim wrote :
> The clock enable/disable codes for alarm have been removed from
> commit 24e1455493da ("drivers/rtc/rtc-s3c.c: delete duplicate clock
> control") and the clocks are disabled even if alarm is set, so alarm
> interrupt can't happen.
>
> The s3c_rtc_setaie function can be called several times with 'enabled'
> argument having same value, so it needs to check whether clocks are
> enabled or not.
>
> Signed-off-by: Joonyoung Shim <[email protected]>
> Cc: <[email protected]> # v4.1
> ---
> This is v2 of prior patch "[PATCH 4/4] rtc: s3c: enable/disable clocks
> for alarm".
>
> Changelog for v2:
> - commit messages is modified by Krzysztof suggestion
> - make to backportable patch
> - add Cc-stable
>
> drivers/rtc/rtc-s3c.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>

Applied, thanks.

However, ...

> @@ -39,6 +39,7 @@ struct s3c_rtc {
> void __iomem *base;
> struct clk *rtc_clk;
> struct clk *rtc_src_clk;
> + bool clk_disabled;
>

This is quite unusual and I would say the principle of least
astonishment would require using clk_enabled and explicitly set it to
true in the probe. I don't expect a lot of changes regarding the clocks
in the probe so this is probably OK but doing so will require extra
carefulness.

--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com