[PATCH v5 2/3] drm/msm/dp: parser data-lanes and link-frequencies from endpoint node

From: Kuogee Hsieh
Date: Tue Nov 29 2022 - 19:13:09 EST


Both data-lanes and link-frequencies are property of endpoint. This
patch parser endpoint to retrieve max data lanes and max link rate
supported specified at dp_out endpoint. In the case where no endpoint
specified, then 4 data lanes with HBR2 link rate (5.4G) will be the
default link configuration.

Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_parser.c | 34 ++++++++++++++++++++++++++--------
drivers/gpu/drm/msm/dp/dp_parser.h | 2 ++
2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c b/drivers/gpu/drm/msm/dp/dp_parser.c
index dd73221..9367f8c 100644
--- a/drivers/gpu/drm/msm/dp/dp_parser.c
+++ b/drivers/gpu/drm/msm/dp/dp_parser.c
@@ -94,16 +94,34 @@ static int dp_parser_ctrl_res(struct dp_parser *parser)
static int dp_parser_misc(struct dp_parser *parser)
{
struct device_node *of_node = parser->pdev->dev.of_node;
- int len;
-
- len = drm_of_get_data_lanes_count(of_node, 1, DP_MAX_NUM_DP_LANES);
- if (len < 0) {
- DRM_WARN("Invalid property \"data-lanes\", default max DP lanes = %d\n",
- DP_MAX_NUM_DP_LANES);
- len = DP_MAX_NUM_DP_LANES;
+ struct device_node *endpoint;
+ int cnt;
+ u64 frequence[4];
+
+ endpoint = of_graph_get_endpoint_by_regs(of_node, 1, 0); /* port@1 */
+ if (endpoint) {
+ cnt = of_property_count_u32_elems(endpoint, "data-lanes");
+ if (cnt < 0)
+ parser->max_dp_lanes = DP_MAX_NUM_DP_LANES; /* 4 lanes */
+ else
+ parser->max_dp_lanes = cnt;
+
+ cnt = of_property_count_u64_elems(endpoint, "link-frequencies");
+ if (cnt < 0) {
+ parser->max_dp_link_rate = DP_LINK_FREQUENCY_HBR2; /* 54000 khz */
+ } else {
+ if (cnt > 4) /* 4 frequency at most */
+ cnt = 4;
+ of_property_read_u64_array(endpoint, "link-frequencies", frequence, cnt);
+ parser->max_dp_link_rate = (u32)frequence[cnt -1];
+ parser->max_dp_link_rate /= 1000; /* khz */
+ }
+ } else {
+ /* default */
+ parser->max_dp_lanes = DP_MAX_NUM_DP_LANES; /* 4 lanes */
+ parser->max_dp_link_rate = DP_LINK_FREQUENCY_HBR2; /* 54000 khz */
}

- parser->max_dp_lanes = len;
return 0;
}

diff --git a/drivers/gpu/drm/msm/dp/dp_parser.h b/drivers/gpu/drm/msm/dp/dp_parser.h
index 866c1a8..76ddb751 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_FREQUENCY_HBR2 540000

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);
--
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