[PATCH v2 1/2] drm/bridge: it6505: Adapt runtime power management framework

From: Pin-yen Lin
Date: Mon Oct 03 2022 - 01:04:56 EST


Use pm_runtime_(get|put)_sync to control the bridge power, and add
SET_SYSTEM_SLEEP_PM_OPS with pm_runtime_force_(suspend|resume) to it6505
driver. Without SET_SYSTEM_SLEEP_PM_OPS, the bridge will be powered on
unnecessarily when no external display is connected.

Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx>

---

Changes in v2:
- Handle the error from pm_runtime_get_sync in it6505_extcon_work

drivers/gpu/drm/bridge/ite-it6505.c | 33 +++++++++++++++++++++--------
1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 2bb957cffd94..685d8e750b12 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -421,6 +421,7 @@ struct it6505 {
struct notifier_block event_nb;
struct extcon_dev *extcon;
struct work_struct extcon_wq;
+ int extcon_state;
enum drm_connector_status connector_status;
enum link_train_status link_state;
struct work_struct link_works;
@@ -2685,31 +2686,42 @@ static void it6505_extcon_work(struct work_struct *work)
{
struct it6505 *it6505 = container_of(work, struct it6505, extcon_wq);
struct device *dev = &it6505->client->dev;
- int state = extcon_get_state(it6505->extcon, EXTCON_DISP_DP);
- unsigned int pwroffretry = 0;
+ int state, ret;

if (it6505->enable_drv_hold)
return;

mutex_lock(&it6505->extcon_lock);

+ state = extcon_get_state(it6505->extcon, EXTCON_DISP_DP);
DRM_DEV_DEBUG_DRIVER(dev, "EXTCON_DISP_DP = 0x%02x", state);
+
+ if (state == it6505->extcon_state)
+ goto unlock;
+
if (state > 0) {
DRM_DEV_DEBUG_DRIVER(dev, "start to power on");
msleep(100);
- it6505_poweron(it6505);
+ ret = pm_runtime_get_sync(dev);
+
+ /*
+ * On system resume, extcon_work can be triggered before
+ * pm_runtime_force_resume re-enables runtime power management.
+ * Handling the error here to make sure the bridge is powered on.
+ */
+ if (ret)
+ it6505_poweron(it6505);
} else {
DRM_DEV_DEBUG_DRIVER(dev, "start to power off");
- while (it6505_poweroff(it6505) && pwroffretry++ < 5) {
- DRM_DEV_DEBUG_DRIVER(dev, "power off fail %d times",
- pwroffretry);
- }
+ pm_runtime_put_sync(dev);

drm_helper_hpd_irq_event(it6505->bridge.dev);
memset(it6505->dpcd, 0, sizeof(it6505->dpcd));
DRM_DEV_DEBUG_DRIVER(dev, "power off it6505 success!");
}
+ it6505->extcon_state = state;

+unlock:
mutex_unlock(&it6505->extcon_lock);
}

@@ -3032,8 +3044,10 @@ static __maybe_unused int it6505_bridge_suspend(struct device *dev)
return it6505_poweroff(it6505);
}

-static SIMPLE_DEV_PM_OPS(it6505_bridge_pm_ops, it6505_bridge_suspend,
- it6505_bridge_resume);
+static const struct dev_pm_ops it6505_bridge_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
+ SET_RUNTIME_PM_OPS(it6505_bridge_suspend, it6505_bridge_resume, NULL)
+};

static int it6505_init_pdata(struct it6505 *it6505)
{
@@ -3315,6 +3329,7 @@ static int it6505_i2c_probe(struct i2c_client *client,

DRM_DEV_DEBUG_DRIVER(dev, "it6505 device name: %s", dev_name(dev));
debugfs_init(it6505);
+ pm_runtime_enable(dev);

it6505->bridge.funcs = &it6505_bridge_funcs;
it6505->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
--
2.38.0.rc1.362.ged0d419d3c-goog