[PATCH] davinci: dm355: Fix uninitialized variable compiler warnings

[PATCH] davinci: dm355: Fix uninitialized variable compiler warnings

[Lad, Prabhakar]

drivers/media/platform/davinci/dm355_ccdc.c:593:9: warning: ‘val1’ may be
used uninitialized in this function [-Wuninitialized]
drivers/media/platform/davinci/dm355_ccdc.c:560:6: note: ‘val1’ was declared here

This is a false positive but the compiler has no way to know about it,
so initialize the variable to 0.

Signed-off-by: Lad, Prabhakar <prabhakar.lad@ti.com>
---
 drivers/media/platform/davinci/dm355_ccdc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/media/platform/davinci/dm355_ccdc.c b/drivers/media/platform/davinci/dm355_ccdc.c
index ce0e413..3c28aaa 100644
--- a/drivers/media/platform/davinci/dm355_ccdc.c
+++ b/drivers/media/platform/davinci/dm355_ccdc.c
@@ -557,7 +557,7 @@ static int ccdc_config_vdfc(struct ccdc_vertical_dft *dfc)
  */
 static void ccdc_config_csc(struct ccdc_csc *csc)
 {
-	u32 val1, val2;
+	u32 val1 = 0, val2;
 	int i;
 
 	if (!csc->enable)
-- 
1.7.4.1

[PATCH] davinci: dm644x: fix enum ccdc_gama_width and enum ccdc_data_size comparision warning

[Lad, Prabhakar]

while the effect is harmless this patch 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.lad@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)) {
 			dev_dbg(ccdc_cfg.dev, "\nInvalid data line select");
 			return -1;
 		}
-- 
1.7.4.1

Re: [PATCH] davinci: dm644x: fix enum ccdc_gama_width and enum ccdc_data_size comparision warning

[Mauro Carvalho Chehab]

Em Wed,  2 Jan 2013 17:23:50 +0530
"Lad, Prabhakar" <prabhakar.csengg@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.lad@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

Re: [PATCH] davinci: dm644x: fix enum ccdc_gama_width and enum ccdc_data_size comparision warning

[Prabhakar Lad]

Hi Mauro,

On Tue, Feb 5, 2013 at 9:54 PM, Mauro Carvalho Chehab
<mchehab@infradead.org> wrote:
> Em Wed,  2 Jan 2013 17:23:50 +0530
> "Lad, Prabhakar" <prabhakar.csengg@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.
>
OK

>> 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.lad@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.
>
yes

> 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.
>
I will pick this option :)


Regards,
--Prabhakar

> 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