pinctrl: coh901: constify gpio_chip structure

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
12775 3696 64 16535 4097 drivers/pinctrl/pinctrl-coh901.o

after:
bss dec hex filename
12440 3640 64 16144 3f10 drivers/pinctrl/pinctrl-coh901.o

---
 drivers/pinctrl/pinctrl-coh901.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 741b39e..ac155e7 100644
@@ -387,7 +387,7 @@ int u300_gpio_config_set(struct gpio_chip *chip, unsigned offset,
 	return 0;
 }
 
-static struct gpio_chip u300_gpio_chip = {
+static const struct gpio_chip u300_gpio_chip = {
 	.label			= "u300-gpio-chip",
 	.owner			= THIS_MODULE,
 	.request		= gpiochip_generic_request,

2.5.0

Patch applied.

Yours,
Linus Walleij