lkml.org 
[lkml]   [2022]   [Dec]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v15 4/5] Add capability to parser and retrieve max DP link supported rate from link-frequencies property of dp_out endpoint.
Date
Changes in v6:
-- second patch after split parser patch into two patches

Changes in v7:
-- without checking cnt against DP_MAX_NUM_DP_LANES to retrieve link rate

Changes in v9:
-- separate parser link-frequencies out of data-lanes

Changes in v10:
-- add dp_parser_link_frequencies()

Changes in v11:
-- return 0 if(!endpoint)

Changes in v12:
-- replace khz with kbytes at dp_parser.h

Changes in v14:
-- replace "parser" with "parse" at commit subject
-- use do_div() for 64 bits division

Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
drivers/gpu/drm/msm/dp/dp_parser.c | 28 ++++++++++++++++++++++++++++
drivers/gpu/drm/msm/dp/dp_parser.h | 2 ++
2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c b/drivers/gpu/drm/msm/dp/dp_parser.c
index e3ba322..42c0793 100644
--- a/drivers/gpu/drm/msm/dp/dp_parser.c
+++ b/drivers/gpu/drm/msm/dp/dp_parser.c
@@ -91,6 +91,30 @@ static int dp_parser_ctrl_res(struct dp_parser *parser)
return 0;
}

+static u32 dp_parser_link_frequencies(struct device_node *of_node)
+{
+ struct device_node *endpoint;
+ u64 frequency = 0;
+ int cnt;
+
+ endpoint = of_graph_get_endpoint_by_regs(of_node, 1, 0); /* port@1 */
+ if (!endpoint)
+ return 0;
+
+ cnt = of_property_count_u64_elems(endpoint, "link-frequencies");
+
+ if (cnt > 0)
+ of_property_read_u64_index(endpoint, "link-frequencies",
+ cnt - 1, &frequency);
+ of_node_put(endpoint);
+
+ do_div(frequency,
+ 10 * /* from symbol rate to link rate */
+ 1000); /* kbytes */
+
+ return frequency;
+}
+
static int dp_parser_misc(struct dp_parser *parser)
{
struct device_node *of_node = parser->pdev->dev.of_node;
@@ -110,6 +134,10 @@ static int dp_parser_misc(struct dp_parser *parser)
else
parser->max_dp_lanes = DP_MAX_NUM_DP_LANES; /* 4 lanes */

+ parser->max_dp_link_rate = dp_parser_link_frequencies(of_node);
+ if (!parser->max_dp_link_rate)
+ parser->max_dp_link_rate = DP_LINK_RATE_HBR2;
+
return 0;
}

diff --git a/drivers/gpu/drm/msm/dp/dp_parser.h b/drivers/gpu/drm/msm/dp/dp_parser.h
index 866c1a8..526131ee 100644
--- a/drivers/gpu/drm/msm/dp/dp_parser.h
+++ b/drivers/gpu/drm/msm/dp/dp_parser.h
@@ -15,6 +15,7 @@
#define DP_LABEL "MDSS DP DISPLAY"
#define DP_MAX_PIXEL_CLK_KHZ 675000
#define DP_MAX_NUM_DP_LANES 4
+#define DP_LINK_RATE_HBR2 540000 /* kbytes */

enum dp_pm_type {
DP_CORE_PM,
@@ -119,6 +120,7 @@ struct dp_parser {
struct dp_io io;
struct dp_display_data disp_data;
u32 max_dp_lanes;
+ u32 max_dp_link_rate;
struct drm_bridge *next_bridge;

int (*parse)(struct dp_parser *parser);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
\
 
 \ /
  Last update: 2022-12-16 22:46    [W:0.090 / U:0.176 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site