Gustavo A. R. Silva authored Jul 11, 2017 and Linus Walleij committed Aug 14, 2017

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

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>