[PATCH 2/3] drm/bridge: it6505: Setup links in it6505_irq_hpd

From: Pin-yen Lin
Date: Wed Oct 12 2022 - 12:29:42 EST


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@xxxxxxxxxxxx>
---

drivers/gpu/drm/bridge/ite-it6505.c | 74 +++++++++++------------------
1 file changed, 29 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index f7f6c3e20fae..cf94e44ec73a 100644
--- 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);

@@ -2328,14 +2314,21 @@ static void it6505_irq_hpd(struct it6505 *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;
+
+ DRM_DEV_DEBUG_DRIVER(dev, "it6505->sink_count: %d",
+ it6505->sink_count);
+
it6505_lane_termination_on(it6505);
it6505_lane_power_on(it6505);

@@ -2363,6 +2356,9 @@ 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 +2621,14 @@ 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",
--
2.38.0.rc1.362.ged0d419d3c-goog