[PATCH v3 03/20] drm/dp: Move i2c init to drm_dp_aux_init, add __must_check and fini

[PATCH v3 03/20] drm/dp: Move i2c init to drm_dp_aux_init, add __must_check and fini

[Lyude Paul]

When moving around drm_dp_aux_register() calls, it turned out we
accidentally managed to cause issues with the Tegra driver due to the fact
the Tegra driver would attempt to retrieve a reference to the AUX channel's
i2c adapter - which wouldn't be initialized until drm_dp_aux_register() is
called.

This doesn't actually make a whole ton of sense, as it's not unexpected for
a driver to need to be able to use an AUX adapter before it's been
registered. Likewise-it's not unexpected for a driver to try using the i2c
adapter for said AUX channel before it's been registered as well. In fact,
the current documentation for drm_dp_aux_init() even seems to imply that
drm_dp_aux_init() is supposed to be handling i2c adapter creation for this
precise reason - not drm_dp_aux_register().

Since the i2c adapter doesn't need to be linked to the DRM device in any
way, we can just fix this problem by moving i2c adapter creation out of
drm_dp_aux_register() and into drm_dp_aux_init(). Additionally, since this
means that drm_dp_aux_init() can fail we go ahead and add a __must_check
attribute to it so that drivers don't ignore its return status on failures.
And finally, we add a drm_dp_aux_fini() and hook it up in all DRM drivers
across the kernel to take care of cleaning up the i2c adapter once it's no
longer needed.

This should also fix the regressions noted in the Tegra driver.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 39c17ae60ea9 ("drm/tegra: Don't register DP AUX channels before connectors")
Cc: Thierry Reding <treding@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_connectors.c    |  7 +-
 drivers/gpu/drm/amd/amdgpu/atombios_dp.c      | 10 ++-
 drivers/gpu/drm/amd/amdgpu/atombios_dp.h      |  2 +-
 .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  6 +-
 .../drm/bridge/analogix/analogix-anx6345.c    |  2 +
 .../drm/bridge/analogix/analogix-anx78xx.c    |  2 +
 .../drm/bridge/analogix/analogix_dp_core.c    |  1 +
 .../drm/bridge/cadence/cdns-mhdp8546-core.c   | 14 ++-
 drivers/gpu/drm/bridge/tc358767.c             |  5 +-
 drivers/gpu/drm/bridge/ti-sn65dsi86.c         | 16 ++--
 drivers/gpu/drm/drm_dp_helper.c               | 88 ++++++++++++++-----
 drivers/gpu/drm/i915/display/intel_dp_aux.c   | 10 ++-
 drivers/gpu/drm/i915/display/intel_dp_aux.h   |  2 +-
 drivers/gpu/drm/msm/dp/dp_aux.c               |  1 +
 drivers/gpu/drm/msm/edp/edp_aux.c             |  1 +
 drivers/gpu/drm/nouveau/nouveau_connector.c   |  1 +
 drivers/gpu/drm/radeon/radeon_connectors.c    |  1 +
 drivers/gpu/drm/tegra/dpaux.c                 | 14 ++-
 drivers/gpu/drm/xlnx/zynqmp_dp.c              |  1 +
 include/drm/drm_dp_helper.h                   |  3 +-
 20 files changed, 140 insertions(+), 47 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
index b9c11c2b2885..23b2134a651b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -1963,8 +1963,11 @@ amdgpu_connector_add(struct amdgpu_device *adev,
 
 	connector->display_info.subpixel_order = subpixel_order;
 
-	if (has_aux)
-		amdgpu_atombios_dp_aux_init(amdgpu_connector);
+	if (has_aux) {
+		int ret = amdgpu_atombios_dp_aux_init(amdgpu_connector);
+		if (ret)
+			goto failed;
+	}
 
 	if (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
 	    connector_type == DRM_MODE_CONNECTOR_eDP) {
diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
index a3ba9ca11e98..54c209ab8c9f 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
@@ -184,12 +184,18 @@ amdgpu_atombios_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *m
 	return ret;
 }
 
-void amdgpu_atombios_dp_aux_init(struct amdgpu_connector *amdgpu_connector)
+int amdgpu_atombios_dp_aux_init(struct amdgpu_connector *amdgpu_connector)
 {
+	int ret;
+
 	amdgpu_connector->ddc_bus->rec.hpd = amdgpu_connector->hpd.hpd;
 	amdgpu_connector->ddc_bus->aux.transfer = amdgpu_atombios_dp_aux_transfer;
-	drm_dp_aux_init(&amdgpu_connector->ddc_bus->aux);
+	ret = drm_dp_aux_init(&amdgpu_connector->ddc_bus->aux);
+	if (ret)
+		return ret;
+
 	amdgpu_connector->ddc_bus->has_aux = true;
+	return ret;
 }
 
 /***** general DP utility functions *****/
diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.h b/drivers/gpu/drm/amd/amdgpu/atombios_dp.h
index f59d85eaddf0..6b65cbf009fd 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.h
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.h
@@ -24,7 +24,7 @@
 #ifndef __ATOMBIOS_DP_H__
 #define __ATOMBIOS_DP_H__
 
-void amdgpu_atombios_dp_aux_init(struct amdgpu_connector *amdgpu_connector);
+int amdgpu_atombios_dp_aux_init(struct amdgpu_connector *amdgpu_connector);
 u8 amdgpu_atombios_dp_get_sinktype(struct amdgpu_connector *amdgpu_connector);
 int amdgpu_atombios_dp_get_dpcd(struct amdgpu_connector *amdgpu_connector);
 int amdgpu_atombios_dp_get_panel_mode(struct drm_encoder *encoder,
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 3dee9cce9c9e..51fbbf3ef59b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -439,7 +439,10 @@ int amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
 	dm_aux->aux.transfer = dm_dp_aux_transfer;
 	dm_aux->ddc_service = aconnector->dc_link->ddc;
 
-	drm_dp_aux_init(&dm_aux->aux);
+	ret = drm_dp_aux_init(&dm_aux->aux);
+	if (ret)
+		goto free_name;
+
 	drm_dp_cec_register_connector(&dm_aux->aux, &aconnector->base);
 
 	if (aconnector->base.connector_type == DRM_MODE_CONNECTOR_eDP)
@@ -456,6 +459,7 @@ int amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
 	return 0;
 unreg_cec:
 	drm_dp_cec_unregister_connector(&dm_aux->aux);
+free_name:
 	kfree(dm_aux->aux.name);
 	return ret;
 }
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
index aa6cda458eb9..c105dcb79c37 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
@@ -794,6 +794,8 @@ static int anx6345_i2c_remove(struct i2c_client *client)
 
 	unregister_i2c_dummy_clients(anx6345);
 
+	drm_dp_aux_fini(&anx6345->aux);
+
 	kfree(anx6345->edid);
 
 	mutex_destroy(&anx6345->lock);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
index f20558618220..0778458e81be 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
@@ -1364,6 +1364,8 @@ static int anx78xx_i2c_remove(struct i2c_client *client)
 
 	unregister_i2c_dummy_clients(anx78xx);
 
+	drm_dp_aux_fini(&anx78xx->aux);
+
 	kfree(anx78xx->edid);
 
 	return 0;
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index f115233b1cb9..f82e193d32ae 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1806,6 +1806,7 @@ EXPORT_SYMBOL_GPL(analogix_dp_unbind);
 void analogix_dp_remove(struct analogix_dp_device *dp)
 {
 	clk_disable_unprepare(dp->clock);
+	drm_dp_aux_fini(&dp->aux);
 }
 EXPORT_SYMBOL_GPL(analogix_dp_remove);
 
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 01e95466502a..c5e2bc75b226 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2436,14 +2436,17 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
 	mutex_init(&mhdp->link_mutex);
 	spin_lock_init(&mhdp->start_lock);
 
-	drm_dp_aux_init(&mhdp->aux);
 	mhdp->aux.dev = dev;
 	mhdp->aux.transfer = cdns_mhdp_transfer;
+	ret = drm_dp_aux_init(&mhdp->aux);
+	if (ret)
+		return ret;
 
 	mhdp->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mhdp->regs)) {
 		dev_err(dev, "Failed to get memory resource\n");
-		return PTR_ERR(mhdp->regs);
+		ret = PTR_ERR(mhdp->regs);
+		goto aux_fini;
 	}
 
 	mhdp->sapb_regs = devm_platform_ioremap_resource_byname(pdev, "mhdptx-sapb");
@@ -2458,7 +2461,8 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
 	mhdp->phy = devm_of_phy_get_by_index(dev, pdev->dev.of_node, 0);
 	if (IS_ERR(mhdp->phy)) {
 		dev_err(dev, "no PHY configured\n");
-		return PTR_ERR(mhdp->phy);
+		ret = PTR_ERR(mhdp->phy);
+		goto aux_fini;
 	}
 
 	platform_set_drvdata(pdev, mhdp);
@@ -2555,6 +2559,8 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
 	pm_runtime_disable(dev);
 clk_disable:
 	clk_disable_unprepare(mhdp->clk);
+aux_fini:
+	drm_dp_aux_fini(&mhdp->aux);
 
 	return ret;
 }
@@ -2597,6 +2603,8 @@ static int cdns_mhdp_remove(struct platform_device *pdev)
 
 	clk_disable_unprepare(mhdp->clk);
 
+	drm_dp_aux_fini(&mhdp->aux);
+
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index da89922721ed..6a56acf36a9a 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1693,7 +1693,9 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	tc->aux.name = "TC358767 AUX i2c adapter";
 	tc->aux.dev = tc->dev;
 	tc->aux.transfer = tc_aux_transfer;
-	drm_dp_aux_init(&tc->aux);
+	ret = drm_dp_aux_init(&tc->aux);
+	if (ret)
+		return ret;
 
 	tc->bridge.funcs = &tc_bridge_funcs;
 	if (tc->hpd_pin >= 0)
@@ -1713,6 +1715,7 @@ static int tc_remove(struct i2c_client *client)
 	struct tc_data *tc = i2c_get_clientdata(client);
 
 	drm_bridge_remove(&tc->bridge);
+	drm_dp_aux_fini(&tc->aux);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 88df4dd0f39d..6190451c9195 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -1291,17 +1291,16 @@ static int ti_sn_bridge_probe(struct i2c_client *client,
 	pm_runtime_enable(pdata->dev);
 
 	ret = ti_sn_setup_gpio_controller(pdata);
-	if (ret) {
-		pm_runtime_disable(pdata->dev);
-		return ret;
-	}
-
+	if (ret)
+		goto fail_pm;
 	i2c_set_clientdata(client, pdata);
 
 	pdata->aux.name = "ti-sn65dsi86-aux";
 	pdata->aux.dev = pdata->dev;
 	pdata->aux.transfer = ti_sn_aux_transfer;
-	drm_dp_aux_init(&pdata->aux);
+	ret = drm_dp_aux_init(&pdata->aux);
+	if (ret)
+		goto fail_pm;
 
 	pdata->bridge.funcs = &ti_sn_bridge_funcs;
 	pdata->bridge.of_node = client->dev.of_node;
@@ -1311,6 +1310,9 @@ static int ti_sn_bridge_probe(struct i2c_client *client,
 	ti_sn_debugfs_init(pdata);
 
 	return 0;
+fail_pm:
+	pm_runtime_disable(pdata->dev);
+	return ret;
 }
 
 static int ti_sn_bridge_remove(struct i2c_client *client)
@@ -1332,6 +1334,8 @@ static int ti_sn_bridge_remove(struct i2c_client *client)
 		mipi_dsi_device_unregister(pdata->dsi);
 	}
 
+	drm_dp_aux_fini(&pdata->aux);
+
 	drm_bridge_remove(&pdata->bridge);
 
 	return 0;
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index cb2f53e56685..6c9e552233fd 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1731,10 +1731,18 @@ EXPORT_SYMBOL(drm_dp_remote_aux_init);
  * If you need to use the drm_dp_aux's i2c adapter prior to registering it
  * with the outside world, call drm_dp_aux_init() first. You must still
  * call drm_dp_aux_register() once the connector has been registered to
- * allow userspace access to the auxiliary DP channel.
+ * allow userspace access to the auxiliary DP channel. Once the AUX channel is
+ * no longer being used and has been unregistered with
+ * drm_dp_aux_unregister(), the driver must clean up any resources it's
+ * allocated with drm_dp_aux_fini().
+ *
+ * Returns:
+ * %0 on success, negative error code on failure
  */
-void drm_dp_aux_init(struct drm_dp_aux *aux)
+int drm_dp_aux_init(struct drm_dp_aux *aux)
 {
+	int ret;
+
 	mutex_init(&aux->hw_mutex);
 	mutex_init(&aux->cec.lock);
 	INIT_WORK(&aux->crc_work, drm_dp_aux_crc_work);
@@ -1744,16 +1752,55 @@ void drm_dp_aux_init(struct drm_dp_aux *aux)
 	aux->ddc.retries = 3;
 
 	aux->ddc.lock_ops = &drm_dp_i2c_lock_ops;
+
+	aux->ddc.class = I2C_CLASS_DDC;
+	aux->ddc.owner = THIS_MODULE;
+	aux->ddc.dev.parent = aux->dev;
+
+	strlcpy(aux->ddc.name, aux->name ?: dev_name(aux->dev), sizeof(aux->ddc.name));
+
+	ret = i2c_add_adapter(&aux->ddc);
+	if (ret) {
+		aux->ddc.algo = NULL;
+		mutex_destroy(&aux->hw_mutex);
+		mutex_destroy(&aux->cec.lock);
+	}
+
+	return ret;
 }
 EXPORT_SYMBOL(drm_dp_aux_init);
 
 /**
- * drm_dp_aux_register() - initialise and register aux channel
+ * drm_dp_aux_fini() - release resources from an aux channel
  * @aux: DisplayPort AUX channel
  *
- * Automatically calls drm_dp_aux_init() if this hasn't been done yet.
+ * Cleans up any resources associated with a DP AUX channel, along with
+ * removing it's associated i2c adapter. Must always be called once an AUX
+ * channel is being removed. Note that if drm_dp_aux_init() was not called on
+ * @aux, this function is a no-op.
+ */
+void drm_dp_aux_fini(struct drm_dp_aux *aux)
+{
+	if (!aux->ddc.algo)
+		return;
+
+	i2c_del_adapter(&aux->ddc);
+	mutex_destroy(&aux->hw_mutex);
+	mutex_destroy(&aux->cec.lock);
+}
+EXPORT_SYMBOL(drm_dp_aux_fini);
+
+/**
+ * drm_dp_aux_register() - register aux channel
+ * @aux: DisplayPort AUX channel
+ *
+ * Automatically calls drm_dp_aux_init() if this hasn't been done yet. The
+ * driver must make sure to call drm_dp_aux_unregister() to unregister the
+ * device, and drm_dp_aux_fini() to cleanup the device after it's been
+ * unregistered.
+ *
  * This should only be called when the underlying &struct drm_connector is
- * initialiazed already. Therefore the best place to call this is from
+ * initialized already. Therefore the best place to call this is from
  * &drm_connector_funcs.late_register. Not that drivers which don't follow this
  * will Oops when CONFIG_DRM_DP_AUX_CHARDEV is enabled.
  *
@@ -1766,39 +1813,32 @@ EXPORT_SYMBOL(drm_dp_aux_init);
 int drm_dp_aux_register(struct drm_dp_aux *aux)
 {
 	int ret;
+	const bool init_aux = !aux->ddc.algo;
 
-	if (!aux->ddc.algo)
-		drm_dp_aux_init(aux);
-
-	aux->ddc.class = I2C_CLASS_DDC;
-	aux->ddc.owner = THIS_MODULE;
-	aux->ddc.dev.parent = aux->dev;
-
-	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
-		sizeof(aux->ddc.name));
+	if (init_aux) {
+		ret = drm_dp_aux_init(aux);
+		if (ret)
+			return ret;
+	}
 
 	ret = drm_dp_aux_register_devnode(aux);
-	if (ret)
-		return ret;
+	if (ret && init_aux)
+		drm_dp_aux_fini(aux);
 
-	ret = i2c_add_adapter(&aux->ddc);
-	if (ret) {
-		drm_dp_aux_unregister_devnode(aux);
-		return ret;
-	}
-
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(drm_dp_aux_register);
 
 /**
  * drm_dp_aux_unregister() - unregister an AUX adapter
  * @aux: DisplayPort AUX channel
+ *
+ * Note that this function does not take care of calling drm_dp_aux_fini(),
+ * the driver must handle this part itself.
  */
 void drm_dp_aux_unregister(struct drm_dp_aux *aux)
 {
 	drm_dp_aux_unregister_devnode(aux);
-	i2c_del_adapter(&aux->ddc);
 }
 EXPORT_SYMBOL(drm_dp_aux_unregister);
 
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
index 7e83bc2cc34a..a79c6e781638 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
@@ -644,15 +644,17 @@ void intel_dp_aux_fini(struct intel_dp *intel_dp)
 	if (cpu_latency_qos_request_active(&intel_dp->pm_qos))
 		cpu_latency_qos_remove_request(&intel_dp->pm_qos);
 
+	drm_dp_aux_fini(&intel_dp->aux);
 	kfree(intel_dp->aux.name);
 }
 
-void intel_dp_aux_init(struct intel_dp *intel_dp)
+int intel_dp_aux_init(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
 	struct intel_encoder *encoder = &dig_port->base;
 	enum aux_ch aux_ch = dig_port->aux_ch;
+	int ret;
 
 	if (DISPLAY_VER(dev_priv) >= 12) {
 		intel_dp->aux_ch_ctl_reg = tgl_aux_ctl_reg;
@@ -682,7 +684,9 @@ void intel_dp_aux_init(struct intel_dp *intel_dp)
 	else
 		intel_dp->get_aux_send_ctl = g4x_get_aux_send_ctl;
 
-	drm_dp_aux_init(&intel_dp->aux);
+	ret = drm_dp_aux_init(&intel_dp->aux);
+	if (ret)
+		return ret;
 
 	/* Failure to allocate our preferred name is not critical */
 	if (DISPLAY_VER(dev_priv) >= 12 && aux_ch >= AUX_CH_USBC1)
@@ -696,4 +700,6 @@ void intel_dp_aux_init(struct intel_dp *intel_dp)
 
 	intel_dp->aux.transfer = intel_dp_aux_transfer;
 	cpu_latency_qos_add_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
+
+	return ret;
 }
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.h b/drivers/gpu/drm/i915/display/intel_dp_aux.h
index 4afbe76217b9..321bab28eb07 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux.h
@@ -13,6 +13,6 @@ struct intel_dp;
 u32 intel_dp_pack_aux(const u8 *src, int src_bytes);
 
 void intel_dp_aux_fini(struct intel_dp *intel_dp);
-void intel_dp_aux_init(struct intel_dp *intel_dp);
+int intel_dp_aux_init(struct intel_dp *intel_dp);
 
 #endif /* __INTEL_DP_AUX_H__ */
diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index 7c22bfe0fc7d..2ef42ca1fda5 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -494,6 +494,7 @@ int dp_aux_register(struct drm_dp_aux *dp_aux)
 void dp_aux_unregister(struct drm_dp_aux *dp_aux)
 {
 	drm_dp_aux_unregister(dp_aux);
+	drm_dp_aux_fini(dp_aux);
 }
 
 struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog)
diff --git a/drivers/gpu/drm/msm/edp/edp_aux.c b/drivers/gpu/drm/msm/edp/edp_aux.c
index df10a0196d94..ced3a38781ed 100644
--- a/drivers/gpu/drm/msm/edp/edp_aux.c
+++ b/drivers/gpu/drm/msm/edp/edp_aux.c
@@ -218,6 +218,7 @@ void msm_edp_aux_destroy(struct device *dev, struct edp_aux *aux)
 {
 	if (aux) {
 		drm_dp_aux_unregister(&aux->drm_aux);
+		drm_dp_aux_fini(&aux->drm_aux);
 		mutex_destroy(&aux->msg_mutex);
 	}
 }
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 61e6d7412505..e5a93fab856e 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -402,6 +402,7 @@ nouveau_connector_destroy(struct drm_connector *connector)
 	if (nv_connector->aux.transfer) {
 		drm_dp_cec_unregister_connector(&nv_connector->aux);
 		drm_dp_aux_unregister(&nv_connector->aux);
+		drm_dp_aux_fini(&nv_connector->aux);
 		kfree(nv_connector->aux.name);
 	}
 	kfree(connector);
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index 607ad5620bd9..f185d3e96bf8 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -921,6 +921,7 @@ static void radeon_connector_unregister(struct drm_connector *connector)
 
 	if (radeon_connector->ddc_bus && radeon_connector->ddc_bus->has_aux) {
 		drm_dp_aux_unregister(&radeon_connector->ddc_bus->aux);
+		drm_dp_aux_fini(&radeon_connector->ddc_bus->aux);
 		radeon_connector->ddc_bus->has_aux = false;
 	}
 }
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index ea56c6ec25e4..6379f2f32d4d 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -534,7 +534,9 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 	dpaux->aux.transfer = tegra_dpaux_transfer;
 	dpaux->aux.dev = &pdev->dev;
 
-	drm_dp_aux_init(&dpaux->aux);
+	err = drm_dp_aux_init(&dpaux->aux);
+	if (err)
+		return err;
 
 	/*
 	 * Assume that by default the DPAUX/I2C pads will be used for HDMI,
@@ -546,7 +548,7 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 	 */
 	err = tegra_dpaux_pad_config(dpaux, DPAUX_PADCTL_FUNC_I2C);
 	if (err < 0)
-		return err;
+		goto aux_fini;
 
 #ifdef CONFIG_GENERIC_PINCONF
 	dpaux->desc.name = dev_name(&pdev->dev);
@@ -559,7 +561,8 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 	dpaux->pinctrl = devm_pinctrl_register(&pdev->dev, &dpaux->desc, dpaux);
 	if (IS_ERR(dpaux->pinctrl)) {
 		dev_err(&pdev->dev, "failed to register pincontrol\n");
-		return PTR_ERR(dpaux->pinctrl);
+		err = PTR_ERR(dpaux->pinctrl);
+		goto aux_fini;
 	}
 #endif
 	/* enable and clear all interrupts */
@@ -573,6 +576,9 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 	mutex_unlock(&dpaux_lock);
 
 	return 0;
+aux_fini:
+	drm_dp_aux_fini(&dpaux->aux);
+	return err;
 }
 
 static int tegra_dpaux_remove(struct platform_device *pdev)
@@ -584,6 +590,8 @@ static int tegra_dpaux_remove(struct platform_device *pdev)
 	/* make sure pads are powered down when not in use */
 	tegra_dpaux_pad_power_down(dpaux);
 
+	drm_dp_aux_fini(&dpaux->aux);
+
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 59d1fb017da0..5370b99aabdf 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -1083,6 +1083,7 @@ static int zynqmp_dp_aux_init(struct zynqmp_dp *dp)
 static void zynqmp_dp_aux_cleanup(struct zynqmp_dp *dp)
 {
 	drm_dp_aux_unregister(&dp->aux);
+	drm_dp_aux_fini(&dp->aux);
 }
 
 /* -----------------------------------------------------------------------------
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index e44b0ee7b85e..54d13a4d819f 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -2009,7 +2009,8 @@ bool drm_dp_lttpr_voltage_swing_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP
 bool drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
 
 void drm_dp_remote_aux_init(struct drm_dp_aux *aux);
-void drm_dp_aux_init(struct drm_dp_aux *aux);
+__must_check int drm_dp_aux_init(struct drm_dp_aux *aux);
+void drm_dp_aux_fini(struct drm_dp_aux *aux);
 __must_check int drm_dp_aux_register(struct drm_dp_aux *aux);
 void drm_dp_aux_unregister(struct drm_dp_aux *aux);
 
-- 
2.30.2

[PATCH v3 06/20] drm/dp: Add backpointer to drm_device in drm_dp_aux

[Lyude Paul]

This is something that we've wanted for a while now: the ability to
actually look up the respective drm_device for a given drm_dp_aux struct.
This will also allow us to transition over to using the drm_dbg_*() helpers
for debug message printing, as we'll finally have a drm_device to reference
for doing so.

Note that there is one limitation with this - because some DP AUX adapters
exist as platform devices which are initialized independently of their
respective DRM devices, one cannot rely on drm_dp_aux->drm_dev to always be
non-NULL until drm_dp_aux_register() has been called. We make sure to point
this out in the documentation for struct drm_dp_aux.

v3:
* Add WARN_ON_ONCE() to drm_dp_aux_register() if drm_dev isn't filled out

Signed-off-by: Lyude Paul <lyude@redhat.com>
Acked-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/drm/amd/amdgpu/atombios_dp.c                 | 7 ++++---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c  | 1 +
 drivers/gpu/drm/bridge/analogix/analogix-anx6345.c       | 1 +
 drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c       | 1 +
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c       | 1 +
 drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c      | 1 +
 drivers/gpu/drm/bridge/tc358767.c                        | 1 +
 drivers/gpu/drm/bridge/ti-sn65dsi86.c                    | 1 +
 drivers/gpu/drm/drm_dp_aux_dev.c                         | 6 ++++++
 drivers/gpu/drm/drm_dp_helper.c                          | 2 ++
 drivers/gpu/drm/drm_dp_mst_topology.c                    | 1 +
 drivers/gpu/drm/i915/display/intel_dp_aux.c              | 1 +
 drivers/gpu/drm/msm/edp/edp.h                            | 3 +--
 drivers/gpu/drm/msm/edp/edp_aux.c                        | 5 +++--
 drivers/gpu/drm/msm/edp/edp_ctrl.c                       | 2 +-
 drivers/gpu/drm/nouveau/nouveau_connector.c              | 1 +
 drivers/gpu/drm/radeon/atombios_dp.c                     | 1 +
 drivers/gpu/drm/tegra/dpaux.c                            | 1 +
 drivers/gpu/drm/xlnx/zynqmp_dp.c                         | 1 +
 include/drm/drm_dp_helper.h                              | 9 ++++++++-
 20 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
index 54c209ab8c9f..14a097322238 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
@@ -190,11 +190,12 @@ int amdgpu_atombios_dp_aux_init(struct amdgpu_connector *amdgpu_connector)
 
 	amdgpu_connector->ddc_bus->rec.hpd = amdgpu_connector->hpd.hpd;
 	amdgpu_connector->ddc_bus->aux.transfer = amdgpu_atombios_dp_aux_transfer;
+	amdgpu_connector->ddc_bus->aux.drm_dev = amdgpu_connector->base.dev;
+
 	ret = drm_dp_aux_init(&amdgpu_connector->ddc_bus->aux);
-	if (ret)
-		return ret;
+	if (!ret)
+		amdgpu_connector->ddc_bus->has_aux = true;
 
-	amdgpu_connector->ddc_bus->has_aux = true;
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 51fbbf3ef59b..a98bd3b521b2 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -438,6 +438,7 @@ int amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
 
 	dm_aux->aux.transfer = dm_dp_aux_transfer;
 	dm_aux->ddc_service = aconnector->dc_link->ddc;
+	dm_aux->aux.drm_dev = dm->ddev;
 
 	ret = drm_dp_aux_init(&dm_aux->aux);
 	if (ret)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
index c105dcb79c37..f4e6a53f3821 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
@@ -537,6 +537,7 @@ static int anx6345_bridge_attach(struct drm_bridge *bridge,
 	/* Register aux channel */
 	anx6345->aux.name = "DP-AUX";
 	anx6345->aux.dev = &anx6345->client->dev;
+	anx6345->aux.drm_dev = bridge->dev;
 	anx6345->aux.transfer = anx6345_aux_transfer;
 
 	err = drm_dp_aux_register(&anx6345->aux);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
index 0778458e81be..7bd28c077181 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
@@ -905,6 +905,7 @@ static int anx78xx_bridge_attach(struct drm_bridge *bridge,
 	/* Register aux channel */
 	anx78xx->aux.name = "DP-AUX";
 	anx78xx->aux.dev = &anx78xx->client->dev;
+	anx78xx->aux.drm_dev = bridge->dev;
 	anx78xx->aux.transfer = anx78xx_aux_transfer;
 
 	err = drm_dp_aux_register(&anx78xx->aux);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index f82e193d32ae..17359bb7a82d 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1765,6 +1765,7 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
 	dp->aux.name = "DP-AUX";
 	dp->aux.transfer = analogix_dpaux_transfer;
 	dp->aux.dev = dp->dev;
+	dp->aux.drm_dev = drm_dev;
 
 	ret = drm_dp_aux_register(&dp->aux);
 	if (ret)
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 518e9a441c21..72ace172e0e9 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -1719,6 +1719,7 @@ static int cdns_mhdp_attach(struct drm_bridge *bridge,
 
 	dev_dbg(mhdp->dev, "%s\n", __func__);
 
+	mhdp->aux.drm_dev = bridge->dev;
 	ret = drm_dp_aux_register(&mhdp->aux);
 	if (ret < 0)
 		return ret;
diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 6a56acf36a9a..9c8e8be2a088 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1414,6 +1414,7 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
 	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
 		return 0;
 
+	tc->aux.drm_dev = drm;
 	ret = drm_dp_aux_register(&tc->aux);
 	if (ret < 0)
 		return ret;
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 6190451c9195..6245dfaf6fd7 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -362,6 +362,7 @@ static int ti_sn_bridge_attach(struct drm_bridge *bridge,
 		return -EINVAL;
 	}
 
+	pdata->aux.drm_dev = bridge->dev;
 	ret = drm_dp_aux_register(&pdata->aux);
 	if (ret < 0) {
 		drm_err(bridge->dev, "Failed to register DP AUX channel: %d\n", ret);
diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c b/drivers/gpu/drm/drm_dp_aux_dev.c
index e25181bf2c48..06b374cae956 100644
--- a/drivers/gpu/drm/drm_dp_aux_dev.c
+++ b/drivers/gpu/drm/drm_dp_aux_dev.c
@@ -278,6 +278,12 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux)
 	if (!aux_dev) /* attach must have failed */
 		return;
 
+	/*
+	 * As some AUX adapters may exist as platform devices which outlive their respective DRM
+	 * devices, we clear drm_dev to ensure that we never accidentally reference a stale pointer
+	 */
+	aux->drm_dev = NULL;
+
 	mutex_lock(&aux_idr_mutex);
 	idr_remove(&aux_idr, aux_dev->index);
 	mutex_unlock(&aux_idr_mutex);
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 6c9e552233fd..b34105c41867 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1815,6 +1815,8 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
 	int ret;
 	const bool init_aux = !aux->ddc.algo;
 
+	WARN_ON_ONCE(!aux->drm_dev);
+
 	if (init_aux) {
 		ret = drm_dp_aux_init(aux);
 		if (ret)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 159014455fab..276f7f054d62 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2350,6 +2350,7 @@ drm_dp_mst_add_port(struct drm_device *dev,
 	port->aux.is_remote = true;
 
 	/* initialize the MST downstream port's AUX crc work queue */
+	port->aux.drm_dev = dev;
 	drm_dp_remote_aux_init(&port->aux);
 
 	/*
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
index a79c6e781638..ac6f697c1862 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
@@ -684,6 +684,7 @@ int intel_dp_aux_init(struct intel_dp *intel_dp)
 	else
 		intel_dp->get_aux_send_ctl = g4x_get_aux_send_ctl;
 
+	intel_dp->aux.drm_dev = &dev_priv->drm;
 	ret = drm_dp_aux_init(&intel_dp->aux);
 	if (ret)
 		return ret;
diff --git a/drivers/gpu/drm/msm/edp/edp.h b/drivers/gpu/drm/msm/edp/edp.h
index eb34243dad53..8590f2ce274d 100644
--- a/drivers/gpu/drm/msm/edp/edp.h
+++ b/drivers/gpu/drm/msm/edp/edp.h
@@ -46,8 +46,7 @@ void edp_bridge_destroy(struct drm_bridge *bridge);
 struct drm_connector *msm_edp_connector_init(struct msm_edp *edp);
 
 /* AUX */
-void *msm_edp_aux_init(struct device *dev, void __iomem *regbase,
-			struct drm_dp_aux **drm_aux);
+void *msm_edp_aux_init(struct msm_edp *edp, void __iomem *regbase, struct drm_dp_aux **drm_aux);
 void msm_edp_aux_destroy(struct device *dev, struct edp_aux *aux);
 irqreturn_t msm_edp_aux_irq(struct edp_aux *aux, u32 isr);
 void msm_edp_aux_ctrl(struct edp_aux *aux, int enable);
diff --git a/drivers/gpu/drm/msm/edp/edp_aux.c b/drivers/gpu/drm/msm/edp/edp_aux.c
index ced3a38781ed..1a48084c9bdc 100644
--- a/drivers/gpu/drm/msm/edp/edp_aux.c
+++ b/drivers/gpu/drm/msm/edp/edp_aux.c
@@ -184,9 +184,9 @@ static ssize_t edp_aux_transfer(struct drm_dp_aux *drm_aux,
 	return ret;
 }
 
-void *msm_edp_aux_init(struct device *dev, void __iomem *regbase,
-	struct drm_dp_aux **drm_aux)
+void *msm_edp_aux_init(struct msm_edp *edp, void __iomem *regbase, struct drm_dp_aux **drm_aux)
 {
+	struct device *dev = &edp->pdev->dev;
 	struct edp_aux *aux = NULL;
 	int ret;
 
@@ -201,6 +201,7 @@ void *msm_edp_aux_init(struct device *dev, void __iomem *regbase,
 
 	aux->drm_aux.name = "msm_edp_aux";
 	aux->drm_aux.dev = dev;
+	aux->drm_aux.drm_dev = edp->dev;
 	aux->drm_aux.transfer = edp_aux_transfer;
 	ret = drm_dp_aux_register(&aux->drm_aux);
 	if (ret) {
diff --git a/drivers/gpu/drm/msm/edp/edp_ctrl.c b/drivers/gpu/drm/msm/edp/edp_ctrl.c
index 0d9657cc70db..57af3d8b6699 100644
--- a/drivers/gpu/drm/msm/edp/edp_ctrl.c
+++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c
@@ -1153,7 +1153,7 @@ int msm_edp_ctrl_init(struct msm_edp *edp)
 	}
 
 	/* Init aux and phy */
-	ctrl->aux = msm_edp_aux_init(dev, ctrl->base, &ctrl->drm_aux);
+	ctrl->aux = msm_edp_aux_init(edp, ctrl->base, &ctrl->drm_aux);
 	if (!ctrl->aux || !ctrl->drm_aux) {
 		pr_err("%s:failed to init aux\n", __func__);
 		return -ENOMEM;
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 56eaa29b34d6..b4cefb0a34d0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -1355,6 +1355,7 @@ nouveau_connector_create(struct drm_device *dev,
 	case DRM_MODE_CONNECTOR_DisplayPort:
 	case DRM_MODE_CONNECTOR_eDP:
 		nv_connector->aux.dev = connector->kdev;
+		nv_connector->aux.drm_dev = dev;
 		nv_connector->aux.transfer = nouveau_connector_aux_xfer;
 		snprintf(aux_name, sizeof(aux_name), "sor-%04x-%04x",
 			 dcbe->hasht, dcbe->hashm);
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 15b00a347560..c50c504bad50 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -232,6 +232,7 @@ void radeon_dp_aux_init(struct radeon_connector *radeon_connector)
 
 	radeon_connector->ddc_bus->rec.hpd = radeon_connector->hpd.hpd;
 	radeon_connector->ddc_bus->aux.dev = radeon_connector->base.kdev;
+	radeon_connector->ddc_bus->aux.drm_dev = radeon_connector->base.dev;
 	if (ASIC_IS_DCE5(rdev)) {
 		if (radeon_auxch)
 			radeon_connector->ddc_bus->aux.transfer = radeon_dp_aux_transfer_native;
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index 6379f2f32d4d..84a4c46c201d 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -727,6 +727,7 @@ int drm_dp_aux_attach(struct drm_dp_aux *aux, struct tegra_output *output)
 	unsigned long timeout;
 	int err;
 
+	aux->drm_dev = output->connector.dev;
 	err = drm_dp_aux_register(aux);
 	if (err < 0)
 		return err;
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 5370b99aabdf..e8efbab5ae69 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -1069,6 +1069,7 @@ static int zynqmp_dp_aux_init(struct zynqmp_dp *dp)
 
 	dp->aux.name = "ZynqMP DP AUX";
 	dp->aux.dev = dp->dev;
+	dp->aux.drm_dev = dp->drm;
 	dp->aux.transfer = zynqmp_dp_aux_transfer;
 
 	return drm_dp_aux_register(&dp->aux);
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 54d13a4d819f..417b2c101a1e 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1840,6 +1840,8 @@ struct drm_dp_aux_cec {
  * @name: user-visible name of this AUX channel and the I2C-over-AUX adapter
  * @ddc: I2C adapter that can be used for I2C-over-AUX communication
  * @dev: pointer to struct device that is the parent for this AUX channel
+ * @drm_dev: pointer to the &drm_device that owns this AUX channel. Beware, this may be %NULL
+ * before drm_dp_aux_register() has been called.
  * @crtc: backpointer to the crtc that is currently using this AUX channel
  * @hw_mutex: internal mutex used for locking transfers
  * @crc_work: worker that captures CRCs for each frame
@@ -1847,7 +1849,11 @@ struct drm_dp_aux_cec {
  * @transfer: transfers a message representing a single AUX transaction
  *
  * The @dev field should be set to a pointer to the device that implements the
- * AUX channel.
+ * AUX channel. As well, the @drm_dev field should be set to the &drm_device
+ * that will be using this AUX channel as early as possible. For many graphics
+ * drivers this should happen before drm_dp_aux_init(), however it's perfectly
+ * fine to set this field later so long as it's assigned before calling
+ * drm_dp_aux_register().
  *
  * The @name field may be used to specify the name of the I2C adapter. If set to
  * %NULL, dev_name() of @dev will be used.
@@ -1879,6 +1885,7 @@ struct drm_dp_aux {
 	const char *name;
 	struct i2c_adapter ddc;
 	struct device *dev;
+	struct drm_device *drm_dev;
 	struct drm_crtc *crtc;
 	struct mutex hw_mutex;
 	struct work_struct crc_work;
-- 
2.30.2

[PATCH v3 08/20] drm/dp: Pass drm_dp_aux to drm_dp_link_train_clock_recovery_delay()

[Lyude Paul]

So that we can start using drm_dbg_*() in
drm_dp_link_train_clock_recovery_delay().

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
 drivers/gpu/drm/amd/amdgpu/atombios_dp.c              | 2 +-
 drivers/gpu/drm/drm_dp_helper.c                       | 3 ++-
 drivers/gpu/drm/i915/display/intel_dp_link_training.c | 2 +-
 drivers/gpu/drm/msm/dp/dp_ctrl.c                      | 2 +-
 drivers/gpu/drm/msm/edp/edp_ctrl.c                    | 2 +-
 drivers/gpu/drm/radeon/atombios_dp.c                  | 2 +-
 drivers/gpu/drm/xlnx/zynqmp_dp.c                      | 2 +-
 include/drm/drm_dp_helper.h                           | 4 +++-
 8 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
index 14a097322238..b0eaeb6afd29 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
@@ -617,7 +617,7 @@ amdgpu_atombios_dp_link_train_cr(struct amdgpu_atombios_dp_link_train_info *dp_i
 	dp_info->tries = 0;
 	voltage = 0xff;
 	while (1) {
-		drm_dp_link_train_clock_recovery_delay(dp_info->dpcd);
+		drm_dp_link_train_clock_recovery_delay(dp_info->aux, dp_info->dpcd);
 
 		if (drm_dp_dpcd_read_link_status(dp_info->aux,
 						 dp_info->link_status) <= 0) {
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index b197fdac2334..3a3c4cfb9ac6 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -132,7 +132,8 @@ u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZ
 }
 EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor);
 
-void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux,
+					    const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 {
 	unsigned long rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] &
 					 DP_TRAINING_AUX_RD_MASK;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 591ddc4b876c..198ddb3c173a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -513,7 +513,7 @@ static void intel_dp_link_training_clock_recovery_delay(struct intel_dp *intel_d
 							enum drm_dp_phy dp_phy)
 {
 	if (dp_phy == DP_PHY_DPRX)
-		drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
+		drm_dp_link_train_clock_recovery_delay(&intel_dp->aux, intel_dp->dpcd);
 	else
 		drm_dp_lttpr_link_train_clock_recovery_delay();
 }
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 1390f3547fde..264a9eae87d3 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1103,7 +1103,7 @@ static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
 	tries = 0;
 	old_v_level = ctrl->link->phy_params.v_level;
 	for (tries = 0; tries < maximum_retries; tries++) {
-		drm_dp_link_train_clock_recovery_delay(ctrl->panel->dpcd);
+		drm_dp_link_train_clock_recovery_delay(ctrl->aux, ctrl->panel->dpcd);
 
 		ret = dp_ctrl_read_link_status(ctrl, link_status);
 		if (ret)
diff --git a/drivers/gpu/drm/msm/edp/edp_ctrl.c b/drivers/gpu/drm/msm/edp/edp_ctrl.c
index 57af3d8b6699..6501598448b4 100644
--- a/drivers/gpu/drm/msm/edp/edp_ctrl.c
+++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c
@@ -608,7 +608,7 @@ static int edp_start_link_train_1(struct edp_ctrl *ctrl)
 	tries = 0;
 	old_v_level = ctrl->v_level;
 	while (1) {
-		drm_dp_link_train_clock_recovery_delay(ctrl->dpcd);
+		drm_dp_link_train_clock_recovery_delay(ctrl->drm_aux, ctrl->dpcd);
 
 		rlen = drm_dp_dpcd_read_link_status(ctrl->drm_aux, link_status);
 		if (rlen < DP_LINK_STATUS_SIZE) {
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index c50c504bad50..299b9d8da376 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -680,7 +680,7 @@ static int radeon_dp_link_train_cr(struct radeon_dp_link_train_info *dp_info)
 	dp_info->tries = 0;
 	voltage = 0xff;
 	while (1) {
-		drm_dp_link_train_clock_recovery_delay(dp_info->dpcd);
+		drm_dp_link_train_clock_recovery_delay(dp_info->aux, dp_info->dpcd);
 
 		if (drm_dp_dpcd_read_link_status(dp_info->aux,
 						 dp_info->link_status) <= 0) {
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index e8efbab5ae69..6ef2d9b3884c 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -713,7 +713,7 @@ static int zynqmp_dp_link_train_cr(struct zynqmp_dp *dp)
 		if (ret)
 			return ret;
 
-		drm_dp_link_train_clock_recovery_delay(dp->dpcd);
+		drm_dp_link_train_clock_recovery_delay(&dp->aux, dp->dpcd);
 		ret = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
 		if (ret < 0)
 			return ret;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 417b2c101a1e..9900c93e4f2c 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -29,6 +29,7 @@
 #include <drm/drm_connector.h>
 
 struct drm_device;
+struct drm_dp_aux;
 
 /*
  * Unless otherwise noted, all values are from the DP 1.1a spec.  Note that
@@ -1482,7 +1483,8 @@ u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZ
 #define DP_LTTPR_COMMON_CAP_SIZE	8
 #define DP_LTTPR_PHY_CAP_SIZE		3
 
-void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
+void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux,
+					    const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
 void drm_dp_lttpr_link_train_clock_recovery_delay(void);
 void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
 void drm_dp_lttpr_link_train_channel_eq_delay(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
-- 
2.30.2

[PATCH v3 09/20] drm/dp: Pass drm_dp_aux to drm_dp*_link_train_channel_eq_delay()

[Lyude Paul]

So that we can start using drm_dbg_*() for
drm_dp_link_train_channel_eq_delay() and
drm_dp_lttpr_link_train_channel_eq_delay().

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/gpu/drm/amd/amdgpu/atombios_dp.c           |  2 +-
 drivers/gpu/drm/drm_dp_helper.c                    | 14 +++++++++-----
 .../gpu/drm/i915/display/intel_dp_link_training.c  |  4 ++--
 drivers/gpu/drm/msm/dp/dp_ctrl.c                   |  4 ++--
 drivers/gpu/drm/msm/edp/edp_ctrl.c                 |  4 ++--
 drivers/gpu/drm/radeon/atombios_dp.c               |  2 +-
 drivers/gpu/drm/xlnx/zynqmp_dp.c                   |  2 +-
 include/drm/drm_dp_helper.h                        |  6 ++++--
 8 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
index b0eaeb6afd29..9f0acee0a271 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
@@ -682,7 +682,7 @@ amdgpu_atombios_dp_link_train_ce(struct amdgpu_atombios_dp_link_train_info *dp_i
 	dp_info->tries = 0;
 	channel_eq = false;
 	while (1) {
-		drm_dp_link_train_channel_eq_delay(dp_info->dpcd);
+		drm_dp_link_train_channel_eq_delay(dp_info->aux, dp_info->dpcd);
 
 		if (drm_dp_dpcd_read_link_status(dp_info->aux,
 						 dp_info->link_status) <= 0) {
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 3a3c4cfb9ac6..eaafc676aa0c 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -151,7 +151,8 @@ void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux,
 }
 EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay);
 
-static void __drm_dp_link_train_channel_eq_delay(unsigned long rd_interval)
+static void __drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
+						 unsigned long rd_interval)
 {
 	if (rd_interval > 4)
 		DRM_DEBUG_KMS("AUX interval %lu, out of range (max 4)\n",
@@ -165,9 +166,11 @@ static void __drm_dp_link_train_channel_eq_delay(unsigned long rd_interval)
 	usleep_range(rd_interval, rd_interval * 2);
 }
 
-void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+void drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
+					const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 {
-	__drm_dp_link_train_channel_eq_delay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] &
+	__drm_dp_link_train_channel_eq_delay(aux,
+					     dpcd[DP_TRAINING_AUX_RD_INTERVAL] &
 					     DP_TRAINING_AUX_RD_MASK);
 }
 EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay);
@@ -183,13 +186,14 @@ static u8 dp_lttpr_phy_cap(const u8 phy_cap[DP_LTTPR_PHY_CAP_SIZE], int r)
 	return phy_cap[r - DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1];
 }
 
-void drm_dp_lttpr_link_train_channel_eq_delay(const u8 phy_cap[DP_LTTPR_PHY_CAP_SIZE])
+void drm_dp_lttpr_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
+					      const u8 phy_cap[DP_LTTPR_PHY_CAP_SIZE])
 {
 	u8 interval = dp_lttpr_phy_cap(phy_cap,
 				       DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1) &
 		      DP_TRAINING_AUX_RD_MASK;
 
-	__drm_dp_link_train_channel_eq_delay(interval);
+	__drm_dp_link_train_channel_eq_delay(aux, interval);
 }
 EXPORT_SYMBOL(drm_dp_lttpr_link_train_channel_eq_delay);
 
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 198ddb3c173a..6bf6f1ec13ed 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -665,11 +665,11 @@ intel_dp_link_training_channel_equalization_delay(struct intel_dp *intel_dp,
 						  enum drm_dp_phy dp_phy)
 {
 	if (dp_phy == DP_PHY_DPRX) {
-		drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
+		drm_dp_link_train_channel_eq_delay(&intel_dp->aux, intel_dp->dpcd);
 	} else {
 		const u8 *phy_caps = intel_dp_lttpr_phy_caps(intel_dp, dp_phy);
 
-		drm_dp_lttpr_link_train_channel_eq_delay(phy_caps);
+		drm_dp_lttpr_link_train_channel_eq_delay(&intel_dp->aux, phy_caps);
 	}
 }
 
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 264a9eae87d3..2cebd17a7289 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1184,7 +1184,7 @@ static int dp_ctrl_link_lane_down_shift(struct dp_ctrl_private *ctrl)
 static void dp_ctrl_clear_training_pattern(struct dp_ctrl_private *ctrl)
 {
 	dp_ctrl_train_pattern_set(ctrl, DP_TRAINING_PATTERN_DISABLE);
-	drm_dp_link_train_channel_eq_delay(ctrl->panel->dpcd);
+	drm_dp_link_train_channel_eq_delay(ctrl->aux, ctrl->panel->dpcd);
 }
 
 static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl,
@@ -1215,7 +1215,7 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl,
 	dp_ctrl_train_pattern_set(ctrl, pattern | DP_RECOVERED_CLOCK_OUT_EN);
 
 	for (tries = 0; tries <= maximum_retries; tries++) {
-		drm_dp_link_train_channel_eq_delay(ctrl->panel->dpcd);
+		drm_dp_link_train_channel_eq_delay(ctrl->aux, ctrl->panel->dpcd);
 
 		ret = dp_ctrl_read_link_status(ctrl, link_status);
 		if (ret)
diff --git a/drivers/gpu/drm/msm/edp/edp_ctrl.c b/drivers/gpu/drm/msm/edp/edp_ctrl.c
index 6501598448b4..4fb397ee7c84 100644
--- a/drivers/gpu/drm/msm/edp/edp_ctrl.c
+++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c
@@ -665,7 +665,7 @@ static int edp_start_link_train_2(struct edp_ctrl *ctrl)
 		return ret;
 
 	while (1) {
-		drm_dp_link_train_channel_eq_delay(ctrl->dpcd);
+		drm_dp_link_train_channel_eq_delay(ctrl->drm_aux, ctrl->dpcd);
 
 		rlen = drm_dp_dpcd_read_link_status(ctrl->drm_aux, link_status);
 		if (rlen < DP_LINK_STATUS_SIZE) {
@@ -743,7 +743,7 @@ static int edp_clear_training_pattern(struct edp_ctrl *ctrl)
 
 	ret = edp_train_pattern_set_write(ctrl, 0);
 
-	drm_dp_link_train_channel_eq_delay(ctrl->dpcd);
+	drm_dp_link_train_channel_eq_delay(ctrl->drm_aux, ctrl->dpcd);
 
 	return ret;
 }
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 299b9d8da376..4c1e551d9714 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -743,7 +743,7 @@ static int radeon_dp_link_train_ce(struct radeon_dp_link_train_info *dp_info)
 	dp_info->tries = 0;
 	channel_eq = false;
 	while (1) {
-		drm_dp_link_train_channel_eq_delay(dp_info->dpcd);
+		drm_dp_link_train_channel_eq_delay(dp_info->aux, dp_info->dpcd);
 
 		if (drm_dp_dpcd_read_link_status(dp_info->aux,
 						 dp_info->link_status) <= 0) {
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 6ef2d9b3884c..cc98ac009ecd 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -778,7 +778,7 @@ static int zynqmp_dp_link_train_ce(struct zynqmp_dp *dp)
 		if (ret)
 			return ret;
 
-		drm_dp_link_train_channel_eq_delay(dp->dpcd);
+		drm_dp_link_train_channel_eq_delay(&dp->aux, dp->dpcd);
 		ret = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
 		if (ret < 0)
 			return ret;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 9900c93e4f2c..b162aed6f1c8 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1486,8 +1486,10 @@ u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZ
 void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux,
 					    const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
 void drm_dp_lttpr_link_train_clock_recovery_delay(void);
-void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
-void drm_dp_lttpr_link_train_channel_eq_delay(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
+void drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
+					const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
+void drm_dp_lttpr_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
+					      const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
 
 u8 drm_dp_link_rate_to_bw_code(int link_rate);
 int drm_dp_bw_code_to_link_rate(u8 link_bw);
-- 
2.30.2