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SubjectRe: [PATCH 08/10] drm: bridge: it66121: Set DDC preamble only once before reading EDID
On Wed, 14 Dec 2022 at 13:59, Paul Cercueil <paul@crapouillou.net> wrote:
>
> 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@crapouillou.net>
> ---
> 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
>

Reviewed-by: Robert Foss <robert.foss@linaro.org>

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