From: Thierry Reding treding@nvidia.com
Use existing parsing helpers to probe a DisplayPort link.
Signed-off-by: Thierry Reding treding@nvidia.com --- drivers/gpu/drm/drm_dp_helper.c | 29 ++++++++++++++++++++++------- include/drm/drm_dp_helper.h | 2 ++ 2 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 6fbce4554029..982dd9febb1c 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -299,6 +299,22 @@ ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset, } EXPORT_SYMBOL(drm_dp_dpcd_write);
+/** + * drm_dp_dpcd_read_link_caps() - read DPCD link capabilities + * @aux: DisplayPort AUX channel + * @caps: buffer to store the link capabilities in + * + * Returns: + * The number of bytes transferred on success or a negative error code on + * failure. + */ +int drm_dp_dpcd_read_link_caps(struct drm_dp_aux *aux, + u8 caps[DP_RECEIVER_CAP_SIZE]) +{ + return drm_dp_dpcd_read(aux, DP_DPCD_REV, caps, DP_RECEIVER_CAP_SIZE); +} +EXPORT_SYMBOL(drm_dp_dpcd_read_link_caps); + /** * drm_dp_dpcd_read_link_status() - read DPCD link status (bytes 0x202-0x207) * @aux: DisplayPort AUX channel @@ -355,21 +371,20 @@ static void drm_dp_link_reset(struct drm_dp_link *link) */ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link) { - u8 values[3]; + u8 values[DP_RECEIVER_CAP_SIZE]; int err;
drm_dp_link_reset(link);
- err = drm_dp_dpcd_read(aux, DP_DPCD_REV, values, sizeof(values)); + err = drm_dp_dpcd_read_link_caps(aux, values); if (err < 0) return err;
- link->revision = values[0]; - link->max_rate = drm_dp_bw_code_to_link_rate(values[1]); - link->max_lanes = values[2] & DP_MAX_LANE_COUNT_MASK; + link->revision = values[DP_DPCD_REV]; + link->max_rate = drm_dp_max_link_rate(values); + link->max_lanes = drm_dp_max_lane_count(values);
- if (values[2] & DP_ENHANCED_FRAME_CAP) - link->caps.enhanced_framing = true; + link->caps.enhanced_framing = drm_dp_enhanced_frame_cap(values);
link->rate = link->max_rate; link->lanes = link->max_lanes; diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index e3429abb03f9..85ff67958875 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1091,6 +1091,8 @@ static inline ssize_t drm_dp_dpcd_writeb(struct drm_dp_aux *aux, return drm_dp_dpcd_write(aux, offset, &value, 1); }
+int drm_dp_dpcd_read_link_caps(struct drm_dp_aux *aux, + u8 caps[DP_RECEIVER_CAP_SIZE]); int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux, u8 status[DP_LINK_STATUS_SIZE]);