Em Wed,  2 Jan 2013 17:23:50 +0530
"Lad, Prabhakar" <prabhakar.cse...@gmail.com> escreveu:

> while the effect is harmless this patch

I disagree that this is a harmless warning. It is here for a reason:
you should not be relying on the enum "magic" value, since the main
reason to use an enum is to fill/compare the enum fields only by their
names, and not by their number.

> fixes following build warning,
> 
> drivers/media/platform/davinci/dm644x_ccdc.c: In function 
> ‘validate_ccdc_param’:
> drivers/media/platform/davinci/dm644x_ccdc.c:233:32: warning: comparison 
> between
> ‘enum ccdc_gama_width’ and ‘enum ccdc_data_size’ [-Wenum-compare]
> 
> Signed-off-by: Lad, Prabhakar <prabhakar....@ti.com>
> ---
>  drivers/media/platform/davinci/dm644x_ccdc.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/media/platform/davinci/dm644x_ccdc.c 
> b/drivers/media/platform/davinci/dm644x_ccdc.c
> index ee7942b..42b473a 100644
> --- a/drivers/media/platform/davinci/dm644x_ccdc.c
> +++ b/drivers/media/platform/davinci/dm644x_ccdc.c
> @@ -228,9 +228,12 @@ static void ccdc_readregs(void)
>  static int validate_ccdc_param(struct ccdc_config_params_raw *ccdcparam)
>  {
>       if (ccdcparam->alaw.enable) {
> +             u32 gama_wd = ccdcparam->alaw.gama_wd;
> +             u32 data_sz = ccdcparam->data_sz;
> +
>               if ((ccdcparam->alaw.gama_wd > CCDC_GAMMA_BITS_09_0) ||
>                   (ccdcparam->alaw.gama_wd < CCDC_GAMMA_BITS_15_6) ||
> -                 (ccdcparam->alaw.gama_wd < ccdcparam->data_sz)) {
> +                 (gama_wd < data_sz)) {

hmm... from include/media/davinci/dm644x_ccdc.h:
enum ccdc_gama_width {
        CCDC_GAMMA_BITS_15_6,   // 0
        CCDC_GAMMA_BITS_14_5,   // 1
        CCDC_GAMMA_BITS_13_4,   // 2
        CCDC_GAMMA_BITS_12_3,   // 3
        CCDC_GAMMA_BITS_11_2,   // 4
        CCDC_GAMMA_BITS_10_1,   // 5
        CCDC_GAMMA_BITS_09_0    // 6
};

enum ccdc_data_size {
        CCDC_DATA_16BITS,       // 0
        CCDC_DATA_15BITS,       // 1
        CCDC_DATA_14BITS,       // 2
        CCDC_DATA_13BITS,       // 3
        CCDC_DATA_12BITS,       // 4
        CCDC_DATA_11BITS,       // 5
        CCDC_DATA_10BITS,       // 6
        CCDC_DATA_8BITS         // 7
};

That doesn't seem right, as comparing the enum integer value won't
warrant that the number of bits of gamma. For example, gamma == 6
means 9 bits, while ccdc == 6 means 10 bits.

In any case, the code is just crappy, as one could anytime add more
values at the enum or reorder.

So, a better fix would be to have an array that would convert from the
enum "magic" number into the number of bits.

Hmm... wait a moment: why are you using an enum here at the first place???

It seems that it would be a way better to just use 2 unsigned integers:
ccdc_data_num_bits and ccdc_gama_num_bits, and just fill it with the
number of bits, instead of declaring an enum for it.

Another alternative would be to merge them into just one enum, like:

enum ccdc_bits {
        CCDC_8_BITS = 8,
        CCDC_9_BITS = 9,
        CCDC_10_BITS = 10,
        CCDC_11_BITS = 11,
        CCDC_12_BITS = 12,
        CCDC_13_BITS = 13,
        CCDC_14_BITS = 14,
        CCDC_15_BITS = 15,
        CCDC_16_BITS = 16,
};

and replace all occurrences of ccdc_data_size and ccdc_gama_width by
the new enum.

This way, you could trust on compare one field with the other.

>                       dev_dbg(ccdc_cfg.dev, "\nInvalid data line select");
>                       return -1;
>               }

Regards,
Mauro
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