drm/bridge: it6505: Setup links in it6505_irq_hpd

Move the DPCD read and link setup steps to HPD IRQ handler to remove
an unnecessary dependency between .detect callback and the HPD IRQ
handler before registering it6505 as a DRM bridge. This is safe because
there is always a .detect call after each HPD IRQ handler triggered by
the drm_helper_hpd_irq_event call.

Signed-off-by: Pin-yen Lin <treapking@chromium.org>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221013110411.1674359-3-treapking@chromium.org

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 24460beb59054d50def6534d0856ba9cd422975c..6feeb3e49b0a13f10baa5d08945db02f91d5236e 100644 (file)
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -725,28 +725,6 @@ static void it6505_calc_video_info(struct it6505 *it6505)
                             DRM_MODE_ARG(&it6505->video_info));
 }
 
-static int it6505_drm_dp_link_probe(struct drm_dp_aux *aux,
-                                   struct it6505_drm_dp_link *link)
-{
-       u8 values[3];
-       int err;
-
-       memset(link, 0, sizeof(*link));
-
-       err = drm_dp_dpcd_read(aux, DP_DPCD_REV, values, sizeof(values));
-       if (err < 0)
-               return err;
-
-       link->revision = values[0];
-       link->rate = drm_dp_bw_code_to_link_rate(values[1]);
-       link->num_lanes = values[2] & DP_MAX_LANE_COUNT_MASK;
-
-       if (values[2] & DP_ENHANCED_FRAME_CAP)
-               link->capabilities = DP_ENHANCED_FRAME_CAP;
-
-       return 0;
-}
-
 static int it6505_drm_dp_link_set_power(struct drm_dp_aux *aux,
                                        struct it6505_drm_dp_link *link,
                                        u8 mode)
@@ -1456,11 +1434,19 @@ static void it6505_parse_link_capabilities(struct it6505 *it6505)
        int bcaps;
 
        if (it6505->dpcd[0] == 0) {
-               it6505_aux_on(it6505);
-               it6505_get_dpcd(it6505, DP_DPCD_REV, it6505->dpcd,
-                               ARRAY_SIZE(it6505->dpcd));
+               dev_err(dev, "DPCD is not initialized");
+               return;
        }
 
+       memset(link, 0, sizeof(*link));
+
+       link->revision = it6505->dpcd[0];
+       link->rate = drm_dp_bw_code_to_link_rate(it6505->dpcd[1]);
+       link->num_lanes = it6505->dpcd[2] & DP_MAX_LANE_COUNT_MASK;
+
+       if (it6505->dpcd[2] & DP_ENHANCED_FRAME_CAP)
+               link->capabilities = DP_ENHANCED_FRAME_CAP;
+
        DRM_DEV_DEBUG_DRIVER(dev, "DPCD Rev.: %d.%d",
                             link->revision >> 4, link->revision & 0x0F);
 
@@ -2323,19 +2309,32 @@ static int it6505_process_hpd_irq(struct it6505 *it6505)
 static void it6505_irq_hpd(struct it6505 *it6505)
 {
        struct device *dev = &it6505->client->dev;
+       int dp_sink_count;
 
        it6505->hpd_state = it6505_get_sink_hpd_status(it6505);
        DRM_DEV_DEBUG_DRIVER(dev, "hpd change interrupt, change to %s",
                             it6505->hpd_state ? "high" : "low");
 
-       if (it6505->bridge.dev)
-               drm_helper_hpd_irq_event(it6505->bridge.dev);
-       DRM_DEV_DEBUG_DRIVER(dev, "it6505->sink_count: %d",
-                            it6505->sink_count);
-
        if (it6505->hpd_state) {
                wait_for_completion_timeout(&it6505->wait_edid_complete,
                                            msecs_to_jiffies(6000));
+               it6505_aux_on(it6505);
+               if (it6505->dpcd[0] == 0) {
+                       it6505_get_dpcd(it6505, DP_DPCD_REV, it6505->dpcd,
+                                       ARRAY_SIZE(it6505->dpcd));
+                       it6505_variable_config(it6505);
+                       it6505_parse_link_capabilities(it6505);
+               }
+               it6505->auto_train_retry = AUTO_TRAIN_RETRY;
+
+               it6505_drm_dp_link_set_power(&it6505->aux, &it6505->link,
+                                            DP_SET_POWER_D0);
+               dp_sink_count = it6505_dpcd_read(it6505, DP_SINK_COUNT);
+               it6505->sink_count = DP_GET_SINK_COUNT(dp_sink_count);
+
+               DRM_DEV_DEBUG_DRIVER(dev, "it6505->sink_count: %d",
+                                    it6505->sink_count);
+
                it6505_lane_termination_on(it6505);
                it6505_lane_power_on(it6505);
 
@@ -2363,6 +2362,9 @@ static void it6505_irq_hpd(struct it6505 *it6505)
                it6505_lane_off(it6505);
                it6505_link_reset_step_train(it6505);
        }
+
+       if (it6505->bridge.dev)
+               drm_helper_hpd_irq_event(it6505->bridge.dev);
 }
 
 static void it6505_irq_hpd_irq(struct it6505 *it6505)
@@ -2625,26 +2627,14 @@ static enum drm_connector_status it6505_detect(struct it6505 *it6505)
                goto unlock;
 
        if (it6505->enable_drv_hold) {
-               status = it6505_get_sink_hpd_status(it6505) ?
-                                       connector_status_connected :
-                                       connector_status_disconnected;
+               status = it6505->hpd_state ? connector_status_connected :
+                                            connector_status_disconnected;
                goto unlock;
        }
 
-       if (it6505_get_sink_hpd_status(it6505)) {
-               it6505_aux_on(it6505);
-               it6505_drm_dp_link_probe(&it6505->aux, &it6505->link);
+       if (it6505->hpd_state) {
                it6505_drm_dp_link_set_power(&it6505->aux, &it6505->link,
                                             DP_SET_POWER_D0);
-               it6505->auto_train_retry = AUTO_TRAIN_RETRY;
-
-               if (it6505->dpcd[0] == 0) {
-                       it6505_get_dpcd(it6505, DP_DPCD_REV, it6505->dpcd,
-                                       ARRAY_SIZE(it6505->dpcd));
-                       it6505_variable_config(it6505);
-                       it6505_parse_link_capabilities(it6505);
-               }
-
                dp_sink_count = it6505_dpcd_read(it6505, DP_SINK_COUNT);
                it6505->sink_count = DP_GET_SINK_COUNT(dp_sink_count);
                DRM_DEV_DEBUG_DRIVER(dev, "it6505->sink_count:%d branch:%d",