# Re: \[PATCH 2/7\] OMAPDSS: DISPC: Move DISPC specific dss\_reg\_fields to dispc\_features

- From: Chandrabhanu Mahapatra \<hidden\>
- Date: 2012-12-03 06:41:26 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2012/12/13464482
- Thread: https://ratatoskr.run/linux-omap/2012/11/13464440/t.md

```text
On Thursday 29 November 2012 05:48 PM, Tomi Valkeinen wrote:
> On 2012-11-28 12:41, Chandrabhanu Mahapatra wrote:
>> The register fields in dss_reg_fields specific to DISPC are moved from struct
>> omap_dss_features to corresponding dispc_reg_fields, initialized in struct
>> dispc_features, thereby enabling local access.
>>
>> Signed-off-by: Chandrabhanu Mahapatra <redacted>
>> ---
>>  drivers/video/omap2/dss/dispc.c        |   87 ++++++++++++++++++++++++++++----
>>  drivers/video/omap2/dss/dss.h          |    4 ++
>>  drivers/video/omap2/dss/dss_features.c |   28 ----------
>>  drivers/video/omap2/dss/dss_features.h |    7 ---
>>  4 files changed, 80 insertions(+), 46 deletions(-)
>>
>> diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
>> index 9f259ba..21fc522 100644
>> --- a/drivers/video/omap2/dss/dispc.c
>> +++ b/drivers/video/omap2/dss/dispc.c
>> @@ -80,6 +80,16 @@ struct dispc_irq_stats {
>>  	unsigned irqs[32];
>>  };
>>  
>> +enum dispc_feat_reg_field {
>> +	FEAT_REG_FIRHINC,
>> +	FEAT_REG_FIRVINC,
>> +	FEAT_REG_FIFOLOWTHRESHOLD,
>> +	FEAT_REG_FIFOHIGHTHRESHOLD,
>> +	FEAT_REG_FIFOSIZE,
>> +	FEAT_REG_HORIZONTALACCU,
>> +	FEAT_REG_VERTICALACCU,
>> +};
>> +
>>  struct dispc_features {
>>  	u8 sw_start;
>>  	u8 fp_start;
>> @@ -107,6 +117,8 @@ struct dispc_features {
>>  
>>  	u32 buffer_size_unit;
>>  	u32 burst_size_unit;
>> +
>> +	struct register_field *reg_fields;
>>  };
> 
> Hmm, would it be simpler to have an explicit struct for the reg fields.
> I mean something like:
> 
> struct dispc_reg_fields {
> 	struct register_field firhinc;
> 	struct register_field firvinc;
> 	struct register_field fifo_low_threshold;
> 	...
> };
> 
> Then accessing it would be
> 
> dispc.feat->reg_fields.firhinc.start;
> 
> instead of
> 
> dispc.feat->reg_fields[FEAT_REG_FIFOSIZE].start;
> 
> Not a big difference, but I don't see any benefit in having an array of
> reg fields here.
> 
>  Tomi
> 
> 

I was thinking to move reg_fields into the dispc_feats structure as

	.burst_size_unit	=	8,
	.reg_fields		=	{
		.firhinc			= { 12,  0 },
		.firvinc			= { 28, 16 },
		.fifo_low_thresh		= { 11,  0 },
		.fifo_high_thresh		= { 27, 16 },
		.fifosize			= { 10,  0 },
		.hori_accu			= {  9,  0 },
		.vert_accu			= { 25, 16 },
	},

This would give us dispc.feat->reg_fields.firhinc.start;
but at the same time would create duplicate information for
omap34xx_rev1_0_dispc_feats and omap34xx_rev3_0_dispc_feats. However,
this duplication never occurs anywhere else in dss.c or dsi.c.

If we still go with the older approach of having dispc_reg_fields
outside dispc_feats the only way  it works is

.reg_fields		=	&omap2_dispc_reg_fields

which changes as dispc.feat->reg_fields->firhinc.start;

but avoids duplicate information. Both approaches seem good enough to me.


-- 
Chandrabhanu Mahapatra
Texas Instruments India Pvt. Ltd.
```