[PATCH 08/10] drm: bridge: it66121: Set DDC preamble only once before reading EDID

From: Paul Cercueil
Date: Wed Dec 14 2022 - 07:59:41 EST


The DDC preamble and target address only need to be set once before
reading the EDID, even if multiple segments have to be read.

Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/bridge/ite-it66121.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
index 5335d4abd7c5..7972003d4776 100644
--- a/drivers/gpu/drm/bridge/ite-it66121.c
+++ b/drivers/gpu/drm/bridge/ite-it66121.c
@@ -506,9 +506,6 @@ static int it66121_get_edid_block(void *context, u8 *buf,
while (remain > 0) {
cnt = (remain > IT66121_EDID_FIFO_SIZE) ?
IT66121_EDID_FIFO_SIZE : remain;
- ret = it66121_preamble_ddc(ctx);
- if (ret)
- return ret;

ret = regmap_write(ctx->regmap, IT66121_DDC_COMMAND_REG,
IT66121_DDC_COMMAND_FIFO_CLR);
@@ -519,15 +516,6 @@ static int it66121_get_edid_block(void *context, u8 *buf,
if (ret)
return ret;

- ret = it66121_preamble_ddc(ctx);
- if (ret)
- return ret;
-
- ret = regmap_write(ctx->regmap, IT66121_DDC_HEADER_REG,
- IT66121_DDC_HEADER_EDID);
- if (ret)
- return ret;
-
ret = regmap_write(ctx->regmap, IT66121_DDC_OFFSET_REG, offset);
if (ret)
return ret;
@@ -842,9 +830,25 @@ static struct edid *it66121_bridge_get_edid(struct drm_bridge *bridge,
{
struct it66121_ctx *ctx = container_of(bridge, struct it66121_ctx, bridge);
struct edid *edid;
+ int ret;

mutex_lock(&ctx->lock);
+ ret = it66121_preamble_ddc(ctx);
+ if (ret) {
+ edid = ERR_PTR(ret);
+ goto out_unlock;
+ }
+
+ ret = regmap_write(ctx->regmap, IT66121_DDC_HEADER_REG,
+ IT66121_DDC_HEADER_EDID);
+ if (ret) {
+ edid = ERR_PTR(ret);
+ goto out_unlock;
+ }
+
edid = drm_do_get_edid(connector, it66121_get_edid_block, ctx);
+
+out_unlock:
mutex_unlock(&ctx->lock);

return edid;
--
2.35.1