---
Changes in v3:
- Don't call done_probing() if there are no children; return -ENODEV.
- Split out EXPORT_SYMBOL and kerneldoc fixes to its own patch.
- Used Dmitry's proposed name: of_dp_aux_populate_bus()
Changes in v2:
- Change to assume exactly one device.
- Have a probe callback instead of an extra sub device.
drivers/gpu/drm/display/drm_dp_aux_bus.c | 209 +++++++++++++++--------
include/drm/display/drm_dp_aux_bus.h | 34 +++-
2 files changed, 168 insertions(+), 75 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_aux_bus.c b/drivers/gpu/drm/display/drm_dp_aux_bus.c
index 552f949cff59..f5741b45ca07 100644
--- a/drivers/gpu/drm/display/drm_dp_aux_bus.c
+++ b/drivers/gpu/drm/display/drm_dp_aux_bus.c
@@ -3,10 +3,10 @@
* Copyright 2021 Google Inc.
*
* The DP AUX bus is used for devices that are connected over a DisplayPort
- * AUX bus. The devices on the far side of the bus are referred to as
- * endpoints in this code.
+ * AUX bus. The device on the far side of the bus is referred to as an
+ * endpoint in this code.
*
- * Commonly there is only one device connected to the DP AUX bus: a panel.
+ * There is only one device connected to the DP AUX bus: an eDP panel.
* Though historically panels (even DP panels) have been modeled as simple
* platform devices, putting them under the DP AUX bus allows the panel driver
* to perform transactions on that bus.
@@ -22,6 +22,11 @@
#include <drm/display/drm_dp_aux_bus.h>
#include <drm/display/drm_dp_helper.h>
+struct dp_aux_ep_device_with_data {
+ struct dp_aux_ep_device aux_ep;
+ int (*done_probing)(struct drm_dp_aux *aux);
+};
+
/**
* dp_aux_ep_match() - The match function for the dp_aux_bus.
* @dev: The device to match.
@@ -48,6 +53,8 @@ static int dp_aux_ep_probe(struct device *dev)
{
struct dp_aux_ep_driver *aux_ep_drv = to_dp_aux_ep_drv(dev->driver);
struct dp_aux_ep_device *aux_ep = to_dp_aux_ep_dev(dev);
+ struct dp_aux_ep_device_with_data *aux_ep_with_data =
+ container_of(aux_ep, struct dp_aux_ep_device_with_data, aux_ep);
int ret;
ret = dev_pm_domain_attach(dev, true);
@@ -56,7 +63,32 @@ static int dp_aux_ep_probe(struct device *dev)
ret = aux_ep_drv->probe(aux_ep);
if (ret)
- dev_pm_domain_detach(dev, true);
+ goto err_attached;
+
+ if (aux_ep_with_data->done_probing) {
+ ret = aux_ep_with_data->done_probing(aux_ep->aux);
+ if (ret) {
+ /*
+ * The done_probing() callback should not return
+ * -EPROBE_DEFER to us. If it does, we treat it as an
+ * error. Passing it on as-is would cause the _panel_
+ * to defer.
+ */
+ if (ret == -EPROBE_DEFER) {
+ dev_err(dev,
+ "DP AUX done_probing() can't defer\n");
+ ret = -EINVAL;
+ }
+ goto err_probed;
+ }
+ }
+
+ return 0;
+err_probed:
+ if (aux_ep_drv->remove)
+ aux_ep_drv->remove(aux_ep);
+err_attached:
+ dev_pm_domain_detach(dev, true);
return ret;
}
@@ -122,7 +154,11 @@ ATTRIBUTE_GROUPS(dp_aux_ep_dev);
*/
static void dp_aux_ep_dev_release(struct device *dev)
{
- kfree(to_dp_aux_ep_dev(dev));
+ struct dp_aux_ep_device *aux_ep = to_dp_aux_ep_dev(dev);
+ struct dp_aux_ep_device_with_data *aux_ep_with_data =
+ container_of(aux_ep, struct dp_aux_ep_device_with_data, aux_ep);
+
+ kfree(aux_ep_with_data);
}
static struct device_type dp_aux_device_type_type = {
@@ -136,12 +172,14 @@ static struct device_type dp_aux_device_type_type = {
* @dev: The device to destroy.
* @data: Not used
*
- * This is just used as a callback by of_dp_aux_depopulate_ep_devices() and
+ * This is just used as a callback by of_dp_aux_depopulate_bus() and
* is called for _all_ of the child devices of the device providing the AUX bus.
* We'll only act on those that are of type "dp_aux_bus_type".
*
- * This function is effectively an inverse of what's in the loop
- * in of_dp_aux_populate_ep_devices().
+ * This function is effectively an inverse of what's in
+ * of_dp_aux_populate_bus(). NOTE: since we only populate one child
+ * then it's expected that only one device will match all the "if" tests in
+ * this function and get to the device_unregister().
*
* Return: 0 if no error or negative error code.
*/
@@ -164,123 +202,150 @@ static int of_dp_aux_ep_destroy(struct device *dev, void *data)
}
/**
- * of_dp_aux_depopulate_ep_devices() - Undo of_dp_aux_populate_ep_devices
- * @aux: The AUX channel whose devices we want to depopulate
+ * of_dp_aux_depopulate_bus() - Undo of_dp_aux_populate_bus
+ * @aux: The AUX channel whose device we want to depopulate
*
- * This will destroy all devices that were created
- * by of_dp_aux_populate_ep_devices().
+ * This will destroy the device that was created
+ * by of_dp_aux_populate_bus().
*/
-void of_dp_aux_depopulate_ep_devices(struct drm_dp_aux *aux)
+void of_dp_aux_depopulate_bus(struct drm_dp_aux *aux)
{
device_for_each_child_reverse(aux->dev, NULL, of_dp_aux_ep_destroy);
}
-EXPORT_SYMBOL_GPL(of_dp_aux_depopulate_ep_devices);
+EXPORT_SYMBOL_GPL(of_dp_aux_depopulate_bus);
/**
- * of_dp_aux_populate_ep_devices() - Populate the endpoint devices on the DP AUX
- * @aux: The AUX channel whose devices we want to populate. It is required that
+ * of_dp_aux_populate_bus() - Populate the endpoint device on the DP AUX
+ * @aux: The AUX channel whose device we want to populate. It is required that
* drm_dp_aux_init() has already been called for this AUX channel.
+ * @done_probing: Callback functions to call after EP device finishes probing.
+ * Will not be called if there are no EP devices and this
+ * function will return -ENODEV.
*
- * This will populate all the devices under the "aux-bus" node of the device
- * providing the AUX channel (AKA aux->dev).
+ * This will populate the device (expected to be an eDP panel) under the
+ * "aux-bus" node of the device providing the AUX channel (AKA aux->dev).
*
* When this function finishes, it is _possible_ (but not guaranteed) that
- * our sub-devices will have finished probing. It should be noted that if our
- * sub-devices return -EPROBE_DEFER that we will not return any error codes
- * ourselves but our sub-devices will _not_ have actually probed successfully
- * yet. There may be other cases (maybe added in the future?) where sub-devices
- * won't have been probed yet when this function returns, so it's best not to
- * rely on that.
+ * our sub-device will have finished probing. It should be noted that if our
+ * sub-device returns -EPROBE_DEFER or is probing asynchronously for some
+ * reason that we will not return any error codes ourselves but our
+ * sub-device will _not_ have actually probed successfully yet.
+ *
+ * In many cases it's important for the caller of this function to be notified
+ * when our sub device finishes probing. Our sub device is expected to be an
+ * eDP panel and the caller is expected to be an eDP controller. The eDP
+ * controller needs to be able to get a reference to the panel when it finishes
+ * probing. For this reason the caller can pass in a function pointer that
+ * will be called when our sub-device finishes probing.
*
* If this function succeeds you should later make sure you call
- * of_dp_aux_depopulate_ep_devices() to undo it, or just use the devm version
+ * of_dp_aux_depopulate_bus() to undo it, or just use the devm version
* of this function.
*
- * Return: 0 if no error or negative error code.
+ * Return: 0 if no error or negative error code; returns -ENODEV if there are
+ * no children. The done_probing() function won't be called in that
+ * case.
*/
-int of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux)
+int of_dp_aux_populate_bus(struct drm_dp_aux *aux,
+ int (*done_probing)(struct drm_dp_aux *aux))
{
- struct device_node *bus, *np;
+ struct device_node *bus = NULL, *np = NULL;
struct dp_aux_ep_device *aux_ep;
+ struct dp_aux_ep_device_with_data *aux_ep_with_data;
int ret;
/* drm_dp_aux_init() should have been called already; warn if not */
WARN_ON_ONCE(!aux->ddc.algo);
if (!aux->dev->of_node)
- return 0;
-
+ return -ENODEV;
bus = of_get_child_by_name(aux->dev->of_node, "aux-bus");
if (!bus)
- return 0;
+ return -ENODEV;
- for_each_available_child_of_node(bus, np) {
- if (of_node_test_and_set_flag(np, OF_POPULATED))
- continue;
+ np = of_get_next_available_child(bus, NULL);
+ of_node_put(bus);
+ if (!np)
+ return -ENODEV;
- aux_ep = kzalloc(sizeof(*aux_ep), GFP_KERNEL);
- if (!aux_ep)
- continue;
- aux_ep->aux = aux;
+ if (of_node_test_and_set_flag(np, OF_POPULATED)) {
+ dev_err(aux->dev, "DP AUX EP device already populated\n");
+ ret = -EINVAL;
+ goto err_did_get_np;
+ }
- aux_ep->dev.parent = aux->dev;
- aux_ep->dev.bus = &dp_aux_bus_type;
- aux_ep->dev.type = &dp_aux_device_type_type;
- aux_ep->dev.of_node = of_node_get(np);
- dev_set_name(&aux_ep->dev, "aux-%s", dev_name(aux->dev));
+ aux_ep_with_data = kzalloc(sizeof(*aux_ep_with_data), GFP_KERNEL);
+ if (!aux_ep_with_data) {
+ ret = -ENOMEM;
+ goto err_did_set_populated;
+ }
- ret = device_register(&aux_ep->dev);
- if (ret) {
- dev_err(aux->dev, "Failed to create AUX EP for %pOF: %d\n", np, ret);
- of_node_clear_flag(np, OF_POPULATED);
- of_node_put(np);
+ aux_ep_with_data->done_probing = done_probing;
- /*
- * As per docs of device_register(), call this instead
- * of kfree() directly for error cases.
- */
- put_device(&aux_ep->dev);
+ aux_ep = &aux_ep_with_data->aux_ep;
+ aux_ep->aux = aux;
+ aux_ep->dev.parent = aux->dev;
+ aux_ep->dev.bus = &dp_aux_bus_type;
+ aux_ep->dev.type = &dp_aux_device_type_type;
+ aux_ep->dev.of_node = of_node_get(np);
+ dev_set_name(&aux_ep->dev, "aux-%s", dev_name(aux->dev));
- /*
- * Following in the footsteps of of_i2c_register_devices(),
- * we won't fail the whole function here--we'll just
- * continue registering any other devices we find.
- */
- }
- }
+ ret = device_register(&aux_ep->dev);
+ if (ret) {
+ dev_err(aux->dev, "Failed to create AUX EP for %pOF: %d\n", np, ret);
- of_node_put(bus);
+ /*
+ * As per docs of device_register(), call this instead
+ * of kfree() directly for error cases.
+ */
+ put_device(&aux_ep->dev);
+
+ goto err_did_set_populated;
+ }
return 0;
+
+err_did_set_populated:
+ of_node_clear_flag(np, OF_POPULATED);
+
+err_did_get_np:
+ of_node_put(np);
+
+ return ret;
}
-EXPORT_SYMBOL_GPL(of_dp_aux_populate_ep_devices);
+EXPORT_SYMBOL_GPL(of_dp_aux_populate_bus);
-static void of_dp_aux_depopulate_ep_devices_void(void *data)
+static void of_dp_aux_depopulate_bus_void(void *data)
{
- of_dp_aux_depopulate_ep_devices(data);
+ of_dp_aux_depopulate_bus(data);
}
/**
- * devm_of_dp_aux_populate_ep_devices() - devm wrapper for of_dp_aux_populate_ep_devices()
- * @aux: The AUX channel whose devices we want to populate
+ * devm_of_dp_aux_populate_bus() - devm wrapper for of_dp_aux_populate_bus()
+ * @aux: The AUX channel whose device we want to populate
+ * @done_probing: Callback functions to call after EP device finishes probing.
+ * Will not be called if there are no EP devices and this
+ * function will return -ENODEV.
*
* Handles freeing w/ devm on the device "aux->dev".
*
- * Return: 0 if no error or negative error code.
+ * Return: 0 if no error or negative error code; returns -ENODEV if there are
+ * no children. The done_probing() function won't be called in that
+ * case.
*/
-int devm_of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux)
+int devm_of_dp_aux_populate_bus(struct drm_dp_aux *aux,
+ int (*done_probing)(struct drm_dp_aux *aux))
{
int ret;
- ret = of_dp_aux_populate_ep_devices(aux);
+ ret = of_dp_aux_populate_bus(aux, done_probing);
if (ret)
return ret;
return devm_add_action_or_reset(aux->dev,
- of_dp_aux_depopulate_ep_devices_void,
- aux);
+ of_dp_aux_depopulate_bus_void, aux);
}
-EXPORT_SYMBOL_GPL(devm_of_dp_aux_populate_ep_devices);
+EXPORT_SYMBOL_GPL(devm_of_dp_aux_populate_bus);
int __dp_aux_dp_driver_register(struct dp_aux_ep_driver *drv, struct module *owner)
{
diff --git a/include/drm/display/drm_dp_aux_bus.h b/include/drm/display/drm_dp_aux_bus.h
index 4f19b20b1dd6..8a0a486383c5 100644
--- a/include/drm/display/drm_dp_aux_bus.h
+++ b/include/drm/display/drm_dp_aux_bus.h
@@ -44,9 +44,37 @@ static inline struct dp_aux_ep_driver *to_dp_aux_ep_drv(struct device_driver *dr
return container_of(drv, struct dp_aux_ep_driver, driver);
}
-int of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux);
-void of_dp_aux_depopulate_ep_devices(struct drm_dp_aux *aux);
-int devm_of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux);
+int of_dp_aux_populate_bus(struct drm_dp_aux *aux,
+ int (*done_probing)(struct drm_dp_aux *aux));
+void of_dp_aux_depopulate_bus(struct drm_dp_aux *aux);
+int devm_of_dp_aux_populate_bus(struct drm_dp_aux *aux,
+ int (*done_probing)(struct drm_dp_aux *aux));
+
+/* Deprecated versions of the above functions. To be removed when no callers. */
+static inline int of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux)
+{
+ int ret;
+
+ ret = of_dp_aux_populate_bus(aux, NULL);
+
+ /* New API returns -ENODEV for no child case; adapt to old assumption */
+ return (ret != -ENODEV) ? ret : 0;
+}
+
+static inline int devm_of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux)
+{
+ int ret;
+
+ ret = devm_of_dp_aux_populate_bus(aux, NULL);
+
+ /* New API returns -ENODEV for no child case; adapt to old assumption */
+ return (ret != -ENODEV) ? ret : 0;
+}
+
+static inline void of_dp_aux_depopulate_ep_devices(struct drm_dp_aux *aux)
+{
+ of_dp_aux_depopulate_bus(aux);
+}
#define dp_aux_dp_driver_register(aux_ep_drv) \
__dp_aux_dp_driver_register(aux_ep_drv, THIS_MODULE)
