Re: [PATCH] gpio: gpio-stmpe: make various char arrays static const, shrinks object size

From: walter harms
Date: Wed Nov 29 2017 - 03:19:44 EST




Am 28.11.2017 19:23, schrieb Colin King:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Don't populate the read-only arrays edge_det_values, rise_values and
> fall_values on the stack but instead make them static and constify them.
> Makes the object code smaller by over 240 bytes:
>
> Before:
> text data bss dec hex filename
> 9525 2520 192 12237 2fcd drivers/gpio/gpio-stmpe.o
>
> After:
> text data bss dec hex filename
> 9025 2776 192 11993 2ed9 drivers/gpio/gpio-stmpe.o
>
> (gcc version 7.2.0 x86_64)
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> drivers/gpio/gpio-stmpe.c | 24 +++++++++++++++---------
> 1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
> index e6e5cca624a7..e3d048e65339 100644
> --- a/drivers/gpio/gpio-stmpe.c
> +++ b/drivers/gpio/gpio-stmpe.c
> @@ -273,15 +273,21 @@ static void stmpe_dbg_show_one(struct seq_file *s,
> u8 fall_reg;
> u8 irqen_reg;
>
> - char *edge_det_values[] = {"edge-inactive",
> - "edge-asserted",
> - "not-supported"};
> - char *rise_values[] = {"no-rising-edge-detection",
> - "rising-edge-detection",
> - "not-supported"};
> - char *fall_values[] = {"no-falling-edge-detection",
> - "falling-edge-detection",
> - "not-supported"};
> + static const char * const edge_det_values[] = {
> + "edge-inactive",
> + "edge-asserted",
> + "not-supported"
> + };
> + static const char * const rise_values[] = {
> + "no-rising-edge-detection",
> + "rising-edge-detection",
> + "not-supported"
> + };
> + static const char * const fall_values[] = {
> + "no-falling-edge-detection",
> + "falling-edge-detection",
> + "not-supported"
> + };
> #define NOT_SUPPORTED_IDX 2

@maintainer:
the define here is hard to find, perhaps i should be move to a place
where i can be found more easily. Like the beginning of line.

re,
wh
> u8 edge_det = NOT_SUPPORTED_IDX;
> u8 rise = NOT_SUPPORTED_IDX;