[PATCH 10/26] drm/dp: Add helpers to identify downstream facing port types
Ville Syrjala
ville.syrjala at linux.intel.com
Mon Feb 3 15:13:27 UTC 2020
From: Ville Syrjälä <ville.syrjala at linux.intel.com>
Add a few helpers to let us better identify which kind of DFP
we're dealing with.
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
drivers/gpu/drm/drm_dp_helper.c | 60 +++++++++++++++++++++++++++++++++
include/drm/drm_dp_helper.h | 5 +++
2 files changed, 65 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index f8cedbc3da5d..bdb7ae3ce32e 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -362,6 +362,66 @@ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
}
EXPORT_SYMBOL(drm_dp_dpcd_read_link_status);
+static bool is_edid_digital_input_dp(const struct edid *edid)
+{
+ return edid && edid->revision >= 4 &&
+ edid->input & DRM_EDID_INPUT_DIGITAL &&
+ (edid->input & DRM_EDID_DIGITAL_TYPE_MASK) == DRM_EDID_DIGITAL_TYPE_DP;
+}
+
+/**
+ * drm_dp_downstream_is_type() - is the downstream facing port of certain type?
+ * @dpcd: DisplayPort configuration data
+ * @port_cap: port capabilities
+ *
+ * Caveat: Only works with DPCD 1.1+ port caps.
+ *
+ * Returns whether the downstream facing port matches the type.
+ */
+bool drm_dp_downstream_is_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+ const u8 port_cap[4], u8 type)
+{
+ return drm_dp_is_branch(dpcd) &&
+ dpcd[DP_DPCD_REV] >= 0x11 &&
+ (port_cap[0] & DP_DS_PORT_TYPE_MASK) == type;
+}
+EXPORT_SYMBOL(drm_dp_downstream_is_type);
+
+/**
+ * drm_dp_downstream_is_tmds() - is the downstream facing port TMDS?
+ * @dpcd: DisplayPort configuration data
+ * @port_cap: port capabilities
+ * @edid: EDID
+ *
+ * Returns whether the downstream facing port is TMDS (HDMI/DVI).
+ */
+bool drm_dp_downstream_is_tmds(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+ const u8 port_cap[4],
+ const struct edid *edid)
+{
+ if (dpcd[DP_DPCD_REV] < 0x11) {
+ switch (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) {
+ case DP_DWN_STRM_PORT_TYPE_TMDS:
+ return true;
+ default:
+ return false;
+ }
+ }
+
+ switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) {
+ case DP_DS_PORT_TYPE_DP_DUALMODE:
+ if (is_edid_digital_input_dp(edid))
+ return false;
+ /* fall through */
+ case DP_DS_PORT_TYPE_DVI:
+ case DP_DS_PORT_TYPE_HDMI:
+ return true;
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL(drm_dp_downstream_is_tmds);
+
/**
* drm_dp_downstream_max_clock() - extract branch device max
* pixel rate for legacy VGA
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 2ffa47f875fa..958db298adc7 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1475,6 +1475,11 @@ static inline ssize_t drm_dp_dpcd_writeb(struct drm_dp_aux *aux,
int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
u8 status[DP_LINK_STATUS_SIZE]);
+bool drm_dp_downstream_is_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+ const u8 port_cap[4], u8 type);
+bool drm_dp_downstream_is_tmds(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+ const u8 port_cap[4],
+ const struct edid *edid);
int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
const u8 port_cap[4]);
int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
--
2.24.1
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