[PATCH] powermac: Use of_property_match_string() in pmac_has_backlight_type()

Markus Elfring posted 1 patch 1 month, 2 weeks ago
arch/powerpc/platforms/powermac/backlight.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)
[PATCH] powermac: Use of_property_match_string() in pmac_has_backlight_type()
Posted by Markus Elfring 1 month, 2 weeks ago
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Fri, 11 Oct 2024 18:10:06 +0200

Replace an of_get_property() call by of_property_match_string()
so that this function implementation can be simplified.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/linuxppc-dev/d9bdc1b6-ea7e-47aa-80aa-02ae649abf72@csgroup.eu/
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/linuxppc-dev/87cyk97ufp.fsf@mail.lhotse/
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 arch/powerpc/platforms/powermac/backlight.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/powermac/backlight.c b/arch/powerpc/platforms/powermac/backlight.c
index 12bc01353bd3..79741370c40c 100644
--- a/arch/powerpc/platforms/powermac/backlight.c
+++ b/arch/powerpc/platforms/powermac/backlight.c
@@ -57,18 +57,10 @@ struct backlight_device *pmac_backlight;
 int pmac_has_backlight_type(const char *type)
 {
 	struct device_node* bk_node = of_find_node_by_name(NULL, "backlight");
+	int i = of_property_match_string(bk_node, "backlight-control", type);

-	if (bk_node) {
-		const char *prop = of_get_property(bk_node,
-				"backlight-control", NULL);
-		if (prop && strncmp(prop, type, strlen(type)) == 0) {
-			of_node_put(bk_node);
-			return 1;
-		}
-		of_node_put(bk_node);
-	}
-
-	return 0;
+	of_node_put(bk_node);
+	return i >= 0;
 }

 static void pmac_backlight_key_worker(struct work_struct *work)
--
2.46.1
Re: [PATCH] powermac: Use of_property_match_string() in pmac_has_backlight_type()
Posted by Michael Ellerman 1 week, 2 days ago
On Fri, 11 Oct 2024 18:18:42 +0200, Markus Elfring wrote:
> Replace an of_get_property() call by of_property_match_string()
> so that this function implementation can be simplified.
> 
> 

Applied to powerpc/next.

[1/1] powermac: Use of_property_match_string() in pmac_has_backlight_type()
      https://git.kernel.org/powerpc/c/2e716f5cdebed2fb98cafffaf626645c2e922dbb

cheers
Re: [PATCH] powermac: Use of_property_match_string() in pmac_has_backlight_type()
Posted by Christophe Leroy 1 month, 2 weeks ago

Le 11/10/2024 à 18:18, Markus Elfring a écrit :
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Fri, 11 Oct 2024 18:10:06 +0200
> 
> Replace an of_get_property() call by of_property_match_string()
> so that this function implementation can be simplified.
> 
> Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Link: https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flinuxppc-dev%2Fd9bdc1b6-ea7e-47aa-80aa-02ae649abf72%40csgroup.eu%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cf278e44683c04b931b9c08dcea106447%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C638642603333398766%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=6byvgvuGiBSVu8F6kLA2OozUuHZunJRH%2BU%2Bq9q7osmM%3D&reserved=0
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Link: https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flinuxppc-dev%2F87cyk97ufp.fsf%40mail.lhotse%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cf278e44683c04b931b9c08dcea106447%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C638642603333422636%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=IDuYfe3UoaIEmedJ07H67zvzrPnzbQ2g8EeTtbJ%2BbZ8%3D&reserved=0
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>   arch/powerpc/platforms/powermac/backlight.c | 14 +++-----------
>   1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powermac/backlight.c b/arch/powerpc/platforms/powermac/backlight.c
> index 12bc01353bd3..79741370c40c 100644
> --- a/arch/powerpc/platforms/powermac/backlight.c
> +++ b/arch/powerpc/platforms/powermac/backlight.c
> @@ -57,18 +57,10 @@ struct backlight_device *pmac_backlight;
>   int pmac_has_backlight_type(const char *type)
>   {
>   	struct device_node* bk_node = of_find_node_by_name(NULL, "backlight");
> +	int i = of_property_match_string(bk_node, "backlight-control", type);
> 
> -	if (bk_node) {
> -		const char *prop = of_get_property(bk_node,
> -				"backlight-control", NULL);
> -		if (prop && strncmp(prop, type, strlen(type)) == 0) {
> -			of_node_put(bk_node);
> -			return 1;
> -		}
> -		of_node_put(bk_node);
> -	}
> -
> -	return 0;
> +	of_node_put(bk_node);
> +	return i >= 0;

Could have been:

	return !IS_ERR_VALUE(i);


Never mind,

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

>   }
> 
>   static void pmac_backlight_key_worker(struct work_struct *work)
> --
> 2.46.1
> 
Re: [PATCH] powermac: Use of_property_match_string() in pmac_has_backlight_type()
Posted by Dan Carpenter 1 month, 2 weeks ago
On Fri, Oct 11, 2024 at 06:25:45PM +0200, Christophe Leroy wrote:
> > diff --git a/arch/powerpc/platforms/powermac/backlight.c b/arch/powerpc/platforms/powermac/backlight.c
> > index 12bc01353bd3..79741370c40c 100644
> > --- a/arch/powerpc/platforms/powermac/backlight.c
> > +++ b/arch/powerpc/platforms/powermac/backlight.c
> > @@ -57,18 +57,10 @@ struct backlight_device *pmac_backlight;
> >   int pmac_has_backlight_type(const char *type)
> >   {
> >   	struct device_node* bk_node = of_find_node_by_name(NULL, "backlight");
> > +	int i = of_property_match_string(bk_node, "backlight-control", type);
> > 
> > -	if (bk_node) {
> > -		const char *prop = of_get_property(bk_node,
> > -				"backlight-control", NULL);
> > -		if (prop && strncmp(prop, type, strlen(type)) == 0) {
> > -			of_node_put(bk_node);
> > -			return 1;
> > -		}
> > -		of_node_put(bk_node);
> > -	}
> > -
> > -	return 0;
> > +	of_node_put(bk_node);
> > +	return i >= 0;
> 
> Could have been:
> 
> 	return !IS_ERR_VALUE(i);
> 

IS_ERR_VALUE() macro should only be used when you're dealing with memory
addresses.  What I mean is there places in mm/ where we pass addresses as
unsigned long values instead of pointers.  For example, get_unmapped_area()
returns unsigned long.  The IS_ERR_VALUE() macro is necessary for that.

For regular error codes, we can just check for negatives.  we don't have do
anything fancy.

Of course, you can find counter examples, like msm_iommu_attach_dev() or
st_fdma_of_xlate().  <small joke>But in those cases, it's done to deliberately
to ensure that the code will never accidentally get built on 64bit systems.
</small joke>

regards,
dan carpenter