Re: [PATCH 2/7] OMAPDSS: DISPC: Move DISPC specific dss_reg_fields to dispc_features

On Thursday 29 November 2012 05:48 PM, Tomi Valkeinen wrote:

On 2012-11-28 12:41, Chandrabhanu Mahapatra wrote:

quoted

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.