[PATCH] misc: bmp085: Handle jiffies overflow correctly

[PATCH] misc: bmp085: Handle jiffies overflow correctly

[Bernhard Walle]

By using the time_is_before_jiffies() macro instead of normal
arithmetic, the jiffies overflow is handled correctly.

Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
---
 drivers/misc/bmp085.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c
index b29a2be..7cfc598 100644
--- a/drivers/misc/bmp085.c
+++ b/drivers/misc/bmp085.c
@@ -234,7 +234,8 @@ static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)
 	int status;
 
 	/* alt least every second force an update of the ambient temperature */
-	if (data->last_temp_measurement + 1*HZ < jiffies) {
+	if (data->last_temp_measurement == 0 ||
+			time_is_before_jiffies(data->last_temp_measurement + 1*HZ)) {
 		status = bmp085_get_temperature(data, NULL);
 		if (status != 0)
 			goto exit;
-- 
1.7.9.1

Re: [PATCH] misc: bmp085: Handle jiffies overflow correctly

[Arnd Bergmann]

On Sunday 19 February 2012, Bernhard Walle wrote:
> By using the time_is_before_jiffies() macro instead of normal
> arithmetic, the jiffies overflow is handled correctly.
> 
> Signed-off-by: Bernhard Walle <bernhard@bwalle.de>

Acked-by: Arnd Bergmann <arnd@arndb.de>

BTW, what is the future of this driver? Are there
plans to move it over to the the industrial I/O
framework?

	Arnd

Re: [PATCH] misc: bmp085: Handle jiffies overflow correctly

[Greg KH]

On Sun, Feb 19, 2012 at 06:28:01PM +0100, Bernhard Walle wrote:
> By using the time_is_before_jiffies() macro instead of normal
> arithmetic, the jiffies overflow is handled correctly.
> 
> Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/misc/bmp085.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c
> index b29a2be..7cfc598 100644
> --- a/drivers/misc/bmp085.c
> +++ b/drivers/misc/bmp085.c
> @@ -234,7 +234,8 @@ static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)
>  	int status;
>  
>  	/* alt least every second force an update of the ambient temperature */
> -	if (data->last_temp_measurement + 1*HZ < jiffies) {
> +	if (data->last_temp_measurement == 0 ||
> +			time_is_before_jiffies(data->last_temp_measurement + 1*HZ)) {

This causes a complier warning:
drivers/misc/bmp085.c: In function ‘bmp085_get_pressure’:
drivers/misc/bmp085.c:238:4: warning: comparison of distinct pointer types lacks a cast [enabled by default]

Care to send me a follow-on patch that fixes this?

thanks,

greg k-h

[PATCH] misc: bmp085: Use unsigned long to store jiffies

[Bernhard Walle]

This fixes following compilation warning:

drivers/misc/bmp085.c: In function ‘bmp085_get_pressure’:
drivers/misc/bmp085.c:238:4: warning: comparison of distinct pointer
         types lacks a cast [enabled by default]

Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
---
 drivers/misc/bmp085.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c
index b088abc..76c3064 100644
--- a/drivers/misc/bmp085.c
+++ b/drivers/misc/bmp085.c
@@ -87,7 +87,7 @@ struct bmp085_data {
 	u32 raw_temperature;
 	u32 raw_pressure;
 	unsigned char oversampling_setting;
-	u32 last_temp_measurement;
+	unsigned long last_temp_measurement;
 	s32 b6; /* calculated temperature correction coefficient */
 };
 
-- 
1.7.5.4