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gpio: altera-a10sr: constify gpio_chip structure

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This structure is only used to copy into another 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
   1954     600       0    2554     9fa drivers/gpio/gpio-altera-a10sr.o

after:
   text    data     bss     dec     hex filename
   1655     512       0    2167     877 drivers/gpio/gpio-altera-a10sr.o

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Gustavo A. R. Silva 2017-07-11 17:15:38 -05:00 committed by Linus Walleij
parent 8340e915ea
commit 1a20c3f8e8
1 changed files with 1 additions and 1 deletions
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2
drivers/gpio/gpio-altera-a10sr.c
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@ -71,7 +71,7 @@ static int altr_a10sr_gpio_direction_output(struct gpio_chip *gc,
return -EINVAL;
}
static struct gpio_chip altr_a10sr_gc = {
static const struct gpio_chip altr_a10sr_gc = {
.label = "altr_a10sr_gpio",
.owner = THIS_MODULE,
.get = altr_a10sr_gpio_get,