[PATCH] pinctrl: st: constify gpio_chip structure

[PATCH] pinctrl: st: constify gpio_chip structure

[Gustavo A. R. Silva]

This structure is only used to copy into other structure, so declare
it as const.

This issue was detected using Coccinelle and the following semantic patch:

@r disable optional_qualifier@
identifier i;
position p;
@@
static struct gpio_chip i@p = { ... };

@ok@
identifier r.i;
expression e;
position p;
@@
e = i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct gpio_chip e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct gpio_chip i = { ... };

In the following log you can see a significant difference in the code size
and data segment, hence in the dec segment. This log is the output
of the size command, before and after the code change:

before:
   text    data     bss     dec     hex filename
  21671    3632     128   25431    6357 drivers/pinctrl/pinctrl-st.o

after:
   text    data     bss     dec     hex filename
  21366    3576     128   25070    61ee drivers/pinctrl/pinctrl-st.o

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 drivers/pinctrl/pinctrl-st.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
index 3ae8066..5d4789d 100644
--- a/drivers/pinctrl/pinctrl-st.c
+++ b/drivers/pinctrl/pinctrl-st.c
@@ -1442,7 +1442,7 @@ static void st_gpio_irqmux_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-static struct gpio_chip st_gpio_template = {
+static const struct gpio_chip st_gpio_template = {
 	.request		= gpiochip_generic_request,
 	.free			= gpiochip_generic_free,
 	.get			= st_gpio_get,
-- 
2.5.0

Re: [PATCH] pinctrl: st: constify gpio_chip structure

[Patrice CHOTARD]

Hi Gustavo

On 07/11/2017 08:15 PM, Gustavo A. R. Silva wrote:
> This structure is only used to copy into other structure, so declare
> it as const.
> 
> This issue was detected using Coccinelle and the following semantic patch:
> 
> @r disable optional_qualifier@
> identifier i;
> position p;
> @@
> static struct gpio_chip i@p = { ... };
> 
> @ok@
> identifier r.i;
> expression e;
> position p;
> @@
> e = i@p;
> 
> @bad@
> position p != {r.p,ok.p};
> identifier r.i;
> struct gpio_chip e;
> @@
> e@i@p
> 
> @depends on !bad disable optional_qualifier@
> identifier r.i;
> @@
> static
> +const
>   struct gpio_chip i = { ... };
> 
> In the following log you can see a significant difference in the code size
> and data segment, hence in the dec segment. This log is the output
> of the size command, before and after the code change:
> 
> before:
>     text    data     bss     dec     hex filename
>    21671    3632     128   25431    6357 drivers/pinctrl/pinctrl-st.o
> 
> after:
>     text    data     bss     dec     hex filename
>    21366    3576     128   25070    61ee drivers/pinctrl/pinctrl-st.o
> 
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
> ---
>   drivers/pinctrl/pinctrl-st.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
> index 3ae8066..5d4789d 100644
> --- a/drivers/pinctrl/pinctrl-st.c
> +++ b/drivers/pinctrl/pinctrl-st.c
> @@ -1442,7 +1442,7 @@ static void st_gpio_irqmux_handler(struct irq_desc *desc)
>   	chained_irq_exit(chip, desc);
>   }
>   
> -static struct gpio_chip st_gpio_template = {
> +static const struct gpio_chip st_gpio_template = {
>   	.request		= gpiochip_generic_request,
>   	.free			= gpiochip_generic_free,
>   	.get			= st_gpio_get,
> 

Acked-by: Patrice Chotard <patrice.chotard@st.com>

Thanks

Re: [PATCH] pinctrl: st: constify gpio_chip structure

[Gustavo A. R. Silva]

Hi Patrice,

Quoting Patrice CHOTARD <patrice.chotard@st.com>:

> Hi Gustavo
>
> On 07/11/2017 08:15 PM, Gustavo A. R. Silva wrote:
>> This structure is only used to copy into other structure, so declare
>> it as const.
>>
>> This issue was detected using Coccinelle and the following semantic patch:
>>
>> @r disable optional_qualifier@
>> identifier i;
>> position p;
>> @@
>> static struct gpio_chip i@p = { ... };
>>
>> @ok@
>> identifier r.i;
>> expression e;
>> position p;
>> @@
>> e = i@p;
>>
>> @bad@
>> position p != {r.p,ok.p};
>> identifier r.i;
>> struct gpio_chip e;
>> @@
>> e@i@p
>>
>> @depends on !bad disable optional_qualifier@
>> identifier r.i;
>> @@
>> static
>> +const
>>   struct gpio_chip i = { ... };
>>
>> In the following log you can see a significant difference in the code size
>> and data segment, hence in the dec segment. This log is the output
>> of the size command, before and after the code change:
>>
>> before:
>>     text    data     bss     dec     hex filename
>>    21671    3632     128   25431    6357 drivers/pinctrl/pinctrl-st.o
>>
>> after:
>>     text    data     bss     dec     hex filename
>>    21366    3576     128   25070    61ee drivers/pinctrl/pinctrl-st.o
>>
>> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
>> ---
>>   drivers/pinctrl/pinctrl-st.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
>> index 3ae8066..5d4789d 100644
>> --- a/drivers/pinctrl/pinctrl-st.c
>> +++ b/drivers/pinctrl/pinctrl-st.c
>> @@ -1442,7 +1442,7 @@ static void st_gpio_irqmux_handler(struct  
>> irq_desc *desc)
>>   	chained_irq_exit(chip, desc);
>>   }
>>
>> -static struct gpio_chip st_gpio_template = {
>> +static const struct gpio_chip st_gpio_template = {
>>   	.request		= gpiochip_generic_request,
>>   	.free			= gpiochip_generic_free,
>>   	.get			= st_gpio_get,
>>
>
> Acked-by: Patrice Chotard <patrice.chotard@st.com>
>
> Thanks

Glad to help. :)

Thanks
--
Gustavo A. R. Silva

Re: [PATCH] pinctrl: st: constify gpio_chip structure

[Linus Walleij]

On Tue, Jul 11, 2017 at 8:15 PM, Gustavo A. R. Silva
<garsilva@embeddedor.com> wrote:

> This structure is only used to copy into other structure, so declare
> it as const.
>
> This issue was detected using Coccinelle and the following semantic patch:
>
> @r disable optional_qualifier@
> identifier i;
> position p;
> @@
> static struct gpio_chip i@p = { ... };
>
> @ok@
> identifier r.i;
> expression e;
> position p;
> @@
> e = i@p;
>
> @bad@
> position p != {r.p,ok.p};
> identifier r.i;
> struct gpio_chip e;
> @@
> e@i@p
>
> @depends on !bad disable optional_qualifier@
> identifier r.i;
> @@
> static
> +const
>  struct gpio_chip i = { ... };
>
> In the following log you can see a significant difference in the code size
> and data segment, hence in the dec segment. This log is the output
> of the size command, before and after the code change:
>
> before:
>    text    data     bss     dec     hex filename
>   21671    3632     128   25431    6357 drivers/pinctrl/pinctrl-st.o
>
> after:
>    text    data     bss     dec     hex filename
>   21366    3576     128   25070    61ee drivers/pinctrl/pinctrl-st.o
>
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>

Patch applied with Patrice's ACK.

Yours,
Linus Walleij