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

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

[Joonyoung Shim]

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 <jy0922.shim@samsung.com>
Cc: <stable@vger.kernel.org> # 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

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

[Krzysztof Kozlowski]

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 <jy0922.shim@samsung.com>
> Cc: <stable@vger.kernel.org> # 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 <k.kozlowski@samsung.com>

Best regards,
Krzysztof

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

[Alexandre Belloni]

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 <jy0922.shim@samsung.com>
> Cc: <stable@vger.kernel.org> # 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