[U-Boot] [PATCH] video: ipu_disp: squash clang warning

[Troy Kisky <troy.kisky@boundarydevices.com>]

On 6/16/2014 1:37 PM, Jeroen Hofstee wrote:
> On ma, 2014-06-16 at 12:52 -0700, Troy Kisky wrote:
>> On 6/16/2014 12:41 PM, Jeroen Hofstee wrote:
>>> Since &rgb2ycbcr_coeff and friends are declared const, but
>>> assigned to a void pointer, clang will warn that the const
>>> is implicity casted away. Add const to indicate the pointer
>>> points to const data to get rid of these warnings.
>>>
>>> Cc: Stefano Babic <sbabic@denx.de>
>>> Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
>>> ---
>>>  drivers/video/ipu_disp.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/video/ipu_disp.c b/drivers/video/ipu_disp.c
>>> index cefd2dc..31b5a10 100644
>>> --- a/drivers/video/ipu_disp.c
>>> +++ b/drivers/video/ipu_disp.c
>>> @@ -33,7 +33,7 @@ enum csc_type_t {
>>>  
>>>  struct dp_csc_param_t {
>>>  	int mode;
>>> -	void *coeff;
>>> +	void * const coeff;
>>>  };
>>>  
>>>  #define SYNC_WAVE 0
>>>
>>
>> Doesn't this says the pointer is constant, not that it points to constant data?
>> So, commit log needs updated or
>> const void *coeff;
> 
> The reason I wrongly changed it from void const * to void * const was to
> circumvent gcc complaining with:
> 
> drivers/video/ipu_disp.c: In function ?ipu_dp_csc_setup?:
> drivers/video/ipu_disp.c:393:8: warning: assignment discards ?const?
> qualifier from pointer target type [enabled by default]
> 
> This can be solved with:
> 
> @@ -390,7 +390,7 @@ void ipu_dp_csc_setup(int dp, struct dp_csc_param_t
> dp_csc_param,
>                 __raw_writel(reg, DP_COM_CONF());
>         }
> -       coeff = dp_csc_param.coeff;
> +       coeff = (const int (*)[5][3]) dp_csc_param.coeff;
>  
>         if (coeff) {
>                 __raw_writel(mask_a((*coeff)[0][0]) |
> 
> 
> But I am not too happy with that. Happen to know a better way?
> 
> Regards,
> Jeroen
> 


I don't know why it gets that warning. The following doesn't.

diff --git a/drivers/video/ipu_disp.c b/drivers/video/ipu_disp.c
index cefd2dc..209374f 100644
--- a/drivers/video/ipu_disp.c
+++ b/drivers/video/ipu_disp.c
@@ -31,9 +31,11 @@ enum csc_type_t {
        CSC_NUM
 };

+typedef int coeff_t[5][3];
+
 struct dp_csc_param_t {
        int mode;
-       void *coeff;
+       const coeff_t *coeff;
 };

 #define SYNC_WAVE 0
@@ -381,7 +383,7 @@ void ipu_dp_csc_setup(int dp, struct dp_csc_param_t dp_csc_param,
                        unsigned char srm_mode_update)
 {
        u32 reg;
-       const int (*coeff)[5][3];
+       const coeff_t *coeff;

        if (dp_csc_param.mode >= 0) {
                reg = __raw_readl(DP_COM_CONF());