[v3,03/10] rtc: max77686: Use usleep_range() instead of msleep()
diff mbox

Message ID 1453836020-29579-4-git-send-email-javier@osg.samsung.com
State New, archived
Headers show

Commit Message

Javier Martinez Canillas Jan. 26, 2016, 7:20 p.m. UTC
Documentation/timers/timers-howto.txt suggest to use usleep_range()
instead of msleep() for small msec (1ms - 20ms) since msleep() will
often sleep for 20ms for any value in that range.

This is fine in this case since 16ms is the _minimum_ delay required
by max77686 for an RTC update but by using usleep_range() instead of
msleep(), the driver can support other RTC IP blocks with a shorter
minimum delay (i.e: in the range of usecs instead of msecs).

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

---

Changes in v3:
- Add Krzysztof Kozlowski's Tested-by tag to patch #3.
- Add Laxman Dewangan's Acked-by tag to patch #3.

Changes in v2:
- Add Krzysztof Kozlowski's Reviewed-by tag to patch #3.
- Fix typo error in changelog. Suggested by Krzysztof Kozlowski.

 drivers/rtc/rtc-max77686.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Andi Shyti Jan. 27, 2016, 1:21 a.m. UTC | #1
On Tue, Jan 26, 2016 at 04:20:13PM -0300, Javier Martinez Canillas wrote:
> Documentation/timers/timers-howto.txt suggest to use usleep_range()
> instead of msleep() for small msec (1ms - 20ms) since msleep() will
> often sleep for 20ms for any value in that range.
> 
> This is fine in this case since 16ms is the _minimum_ delay required
> by max77686 for an RTC update but by using usleep_range() instead of
> msleep(), the driver can support other RTC IP blocks with a shorter
> minimum delay (i.e: in the range of usecs instead of msecs).
> 
> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Reviewed-by: Andi Shyti <andi.shyti@samsung.com>

> ---
> 
> Changes in v3:
> - Add Krzysztof Kozlowski's Tested-by tag to patch #3.
> - Add Laxman Dewangan's Acked-by tag to patch #3.
> 
> Changes in v2:
> - Add Krzysztof Kozlowski's Reviewed-by tag to patch #3.
> - Fix typo error in changelog. Suggested by Krzysztof Kozlowski.
> 
>  drivers/rtc/rtc-max77686.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
> index d84a50c9f7f7..025a17a95da3 100644
> --- a/drivers/rtc/rtc-max77686.c
> +++ b/drivers/rtc/rtc-max77686.c
> @@ -41,7 +41,7 @@
>  #define ALARM_ENABLE_SHIFT		7
>  #define ALARM_ENABLE_MASK		(1 << ALARM_ENABLE_SHIFT)
>  
> -#define MAX77686_RTC_UPDATE_DELAY	16
> +#define MAX77686_RTC_UPDATE_DELAY	16000
>  
>  enum {
>  	RTC_SEC = 0,
> @@ -130,7 +130,8 @@ static int max77686_rtc_update(struct max77686_rtc_info *info,
>  				__func__, ret, data);
>  	else {
>  		/* Minimum 16ms delay required before RTC update. */
> -		msleep(MAX77686_RTC_UPDATE_DELAY);
> +		usleep_range(MAX77686_RTC_UPDATE_DELAY,
> +			     MAX77686_RTC_UPDATE_DELAY * 2);
>  	}
>  
>  	return ret;
> -- 
> 2.5.0
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch
diff mbox

diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
index d84a50c9f7f7..025a17a95da3 100644
--- a/drivers/rtc/rtc-max77686.c
+++ b/drivers/rtc/rtc-max77686.c
@@ -41,7 +41,7 @@ 
 #define ALARM_ENABLE_SHIFT		7
 #define ALARM_ENABLE_MASK		(1 << ALARM_ENABLE_SHIFT)
 
-#define MAX77686_RTC_UPDATE_DELAY	16
+#define MAX77686_RTC_UPDATE_DELAY	16000
 
 enum {
 	RTC_SEC = 0,
@@ -130,7 +130,8 @@  static int max77686_rtc_update(struct max77686_rtc_info *info,
 				__func__, ret, data);
 	else {
 		/* Minimum 16ms delay required before RTC update. */
-		msleep(MAX77686_RTC_UPDATE_DELAY);
+		usleep_range(MAX77686_RTC_UPDATE_DELAY,
+			     MAX77686_RTC_UPDATE_DELAY * 2);
 	}
 
 	return ret;