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drm/dp: Add helpers to identify downstream facing port types

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Add a few helpers to let us better identify which kind of DFP
we're dealing with.

v2: Use Returns: for kdoc (Lyude)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200904115354.25336-7-ville.syrjala@linux.intel.com
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2020-09-04 14:53:42 +03:00
parent 530df3c031
commit 38784f6f88
2 changed files with 65 additions and 0 deletions
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60
drivers/gpu/drm/drm_dp_helper.c
View File

@ -363,6 +363,66 @@ 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;
fallthrough;
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_send_real_edid_checksum() - send back real edid checksum value
* @aux: DisplayPort AUX channel

5
include/drm/drm_dp_helper.h
View File

@ -1638,6 +1638,11 @@ bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
int drm_dp_read_downstream_info(struct drm_dp_aux *aux,
const u8 dpcd[DP_RECEIVER_CAP_SIZE],
u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS]);
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],