diff options
Diffstat (limited to 'drivers/gpu/drm/display/drm_dp_aux_bus.c')
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_aux_bus.c | 211 |
1 files changed, 137 insertions, 74 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_aux_bus.c b/drivers/gpu/drm/display/drm_dp_aux_bus.c index dccf3e2ea323..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; } @@ -66,7 +98,6 @@ static int dp_aux_ep_probe(struct device *dev) * @dev: The device to remove. * * Calls through to the endpoint driver remove. - * */ static void dp_aux_ep_remove(struct device *dev) { @@ -120,12 +151,14 @@ ATTRIBUTE_GROUPS(dp_aux_ep_dev); /** * dp_aux_ep_dev_release() - Free memory for the dp_aux_ep device * @dev: The device to free. - * - * Return: 0 if no error or negative error code. */ 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 = { @@ -139,12 +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. */ @@ -167,122 +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_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) { |