[sparse stuff] bug in lp3944_led_set_brightness()

[sparse stuff] bug in lp3944_led_set_brightness()

[Dan Carpenter]

Hi Antonio,

I was going through some Sparse warnings and this one seems pretty
valid.

drivers/leds/leds-lp3944.c +292 23:
	warning: mixing different enum types

   284  static void lp3944_led_set_brightness(struct led_classdev *led_cdev,
   285                                        enum led_brightness brightness)
   286  {
   287          struct lp3944_led_data *led = ldev_to_led(led_cdev);
   288  
   289          dev_dbg(&led->client->dev, "%s: %s, %d\n",
   290                  __func__, led_cdev->name, brightness);
   291  
   292          led->status = brightness;
                ^^^^^^^^^^^^^^^^^^^^^^^^
   293          schedule_work(&led->work);
   294  }

led->status should be values between 0-3.  brightness is 0, 127 and
255.

regards,
dan carpenter

Re: [sparse stuff] bug in lp3944_led_set_brightness()

[Antonio Ospite]

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On Wed, 5 Oct 2011 12:32:48 +0300
Dan Carpenter <dan.carpenter@oracle.com> wrote:

> Hi Antonio,
> 
> I was going through some Sparse warnings and this one seems pretty
> valid.
> 
> drivers/leds/leds-lp3944.c +292 23:
> 	warning: mixing different enum types
> 
>    284  static void lp3944_led_set_brightness(struct led_classdev *led_cdev,
>    285                                        enum led_brightness brightness)
>    286  {
>    287          struct lp3944_led_data *led = ldev_to_led(led_cdev);
>    288  
>    289          dev_dbg(&led->client->dev, "%s: %s, %d\n",
>    290                  __func__, led_cdev->name, brightness);
>    291  
>    292          led->status = brightness;
>                 ^^^^^^^^^^^^^^^^^^^^^^^^
>    293          schedule_work(&led->work);
>    294  }
>
>
> led->status should be values between 0-3.  brightness is 0, 127 and
> 255.
> 

Hi Dan, thanks for reporting that.

AFAICS this is not a problem _in_practice_ as lp3944_led_set_brightness
() is called by the leds framework with brightness values already
limited by max_brightness, so it is always 0 or 1 in our case. The
sparse warning is not pretty tho, so I guess we can safely get rid of it
anyways with:

	led->status = !!brightness;

keeping track of LP3944_LED_STATUS_OFF and LP3944_LED_STATUS_ON only in
lp3944_led_set_brightness() is OK, as the handling of DIM (blinking)
mode[s] is in lp3944_led_set_blink().

I am following up with a patch in that direction tomorrow, after a test
on the actual hardware.

This is the rationale behind the current code if it is of any interest:
in the development phase of the driver I was abusing brightness = {2,3}
to trigger the hardware blinking function, but then I set the
max_brightness to 1 and so this abusing mechanism became inactive and I
must have forgotten about it.

Thanks again.

Regards,
   Antonio

-- 
Antonio Ospite
http://ao2.it

PGP public key ID: 0x4553B001

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?

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[PATCH] leds: leds-lp3944, fix "sparse" warning "mixing different enum types"

[Antonio Ospite]

Fix a warning from "sparse":

drivers/leds/leds-lp3944.c:292:23: warning: mixing different enum types
drivers/leds/leds-lp3944.c:292:23:     int enum led_brightness  versus
drivers/leds/leds-lp3944.c:292:23:     int enum lp3944_status

Keeping track of LP3944_LED_STATUS_OFF and LP3944_LED_STATUS_ON only in
lp3944_led_set_brightness() is OK, as the handling of DIM (blinking)
mode[s] is in lp3944_led_set_blink().

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
---
 drivers/leds/leds-lp3944.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/leds/leds-lp3944.c b/drivers/leds/leds-lp3944.c
index 9010c05..3cc01fb 100644
--- a/drivers/leds/leds-lp3944.c
+++ b/drivers/leds/leds-lp3944.c
@@ -289,7 +289,7 @@ static void lp3944_led_set_brightness(struct led_classdev *led_cdev,
 	dev_dbg(&led->client->dev, "%s: %s, %d\n",
 		__func__, led_cdev->name, brightness);
 
-	led->status = brightness;
+	led->status = !!brightness;
 	schedule_work(&led->work);
 }
 
-- 
1.7.6.3

Re: [PATCH] leds: leds-lp3944, fix "sparse" warning "mixing different enum types"

[Antonio Ospite]

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On Thu,  6 Oct 2011 23:34:44 +0200
Antonio Ospite <ospite@studenti.unina.it> wrote:

> Fix a warning from "sparse":
> 
> drivers/leds/leds-lp3944.c:292:23: warning: mixing different enum types
> drivers/leds/leds-lp3944.c:292:23:     int enum led_brightness  versus
> drivers/leds/leds-lp3944.c:292:23:     int enum lp3944_status
> 
> Keeping track of LP3944_LED_STATUS_OFF and LP3944_LED_STATUS_ON only in
> lp3944_led_set_brightness() is OK, as the handling of DIM (blinking)
> mode[s] is in lp3944_led_set_blink().
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>

Ping.
Dan, did you receive this one? I can't see it in 3.2-rc2.

Regards,
   Antonio.

> ---
>  drivers/leds/leds-lp3944.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/leds/leds-lp3944.c b/drivers/leds/leds-lp3944.c
> index 9010c05..3cc01fb 100644
> --- a/drivers/leds/leds-lp3944.c
> +++ b/drivers/leds/leds-lp3944.c
> @@ -289,7 +289,7 @@ static void lp3944_led_set_brightness(struct led_classdev *led_cdev,
>  	dev_dbg(&led->client->dev, "%s: %s, %d\n",
>  		__func__, led_cdev->name, brightness);
>  
> -	led->status = brightness;
> +	led->status = !!brightness;
>  	schedule_work(&led->work);
>  }
>  
> -- 
> 1.7.6.3
> 
> 


-- 
Antonio Ospite
http://ao2.it

PGP public key ID: 0x4553B001

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?

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Re: [PATCH] leds: leds-lp3944, fix "sparse" warning "mixing different enum types"

[Dan Carpenter]

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On Wed, Nov 16, 2011 at 04:00:07PM +0100, Antonio Ospite wrote:
> On Thu,  6 Oct 2011 23:34:44 +0200
> Antonio Ospite <ospite@studenti.unina.it> wrote:
> 
> > Fix a warning from "sparse":
> > 
> > drivers/leds/leds-lp3944.c:292:23: warning: mixing different enum types
> > drivers/leds/leds-lp3944.c:292:23:     int enum led_brightness  versus
> > drivers/leds/leds-lp3944.c:292:23:     int enum lp3944_status
> > 
> > Keeping track of LP3944_LED_STATUS_OFF and LP3944_LED_STATUS_ON only in
> > lp3944_led_set_brightness() is OK, as the handling of DIM (blinking)
> > mode[s] is in lp3944_led_set_blink().
> > 
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
> 
> Ping.
> Dan, did you receive this one? I can't see it in 3.2-rc2.

Richard is the maintainer, not me.  But he's on the CC list as well
so hopefully he can answer your question.

regards,
dan carpenter


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