| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * Copyright (C) 2023 Linaro Ltd. |
| * |
| * Author: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> |
| */ |
| #include <linux/auxiliary_bus.h> |
| #include <linux/module.h> |
| #include <linux/of.h> |
| |
| #include <drm/drm_bridge.h> |
| #include <drm/bridge/aux-bridge.h> |
| |
| static DEFINE_IDA(drm_aux_hpd_bridge_ida); |
| |
| struct drm_aux_hpd_bridge_data { |
| struct drm_bridge bridge; |
| struct device *dev; |
| }; |
| |
| static void drm_aux_hpd_bridge_release(struct device *dev) |
| { |
| struct auxiliary_device *adev = to_auxiliary_dev(dev); |
| |
| ida_free(&drm_aux_hpd_bridge_ida, adev->id); |
| |
| of_node_put(adev->dev.platform_data); |
| |
| kfree(adev); |
| } |
| |
| static void drm_aux_hpd_bridge_unregister_adev(void *_adev) |
| { |
| struct auxiliary_device *adev = _adev; |
| |
| auxiliary_device_delete(adev); |
| auxiliary_device_uninit(adev); |
| } |
| |
| /** |
| * drm_dp_hpd_bridge_register - Create a simple HPD DisplayPort bridge |
| * @parent: device instance providing this bridge |
| * @np: device node pointer corresponding to this bridge instance |
| * |
| * Creates a simple DRM bridge with the type set to |
| * DRM_MODE_CONNECTOR_DisplayPort, which terminates the bridge chain and is |
| * able to send the HPD events. |
| * |
| * Return: device instance that will handle created bridge or an error code |
| * encoded into the pointer. |
| */ |
| struct device *drm_dp_hpd_bridge_register(struct device *parent, |
| struct device_node *np) |
| { |
| struct auxiliary_device *adev; |
| int ret; |
| |
| adev = kzalloc(sizeof(*adev), GFP_KERNEL); |
| if (!adev) |
| return ERR_PTR(-ENOMEM); |
| |
| ret = ida_alloc(&drm_aux_hpd_bridge_ida, GFP_KERNEL); |
| if (ret < 0) { |
| kfree(adev); |
| return ERR_PTR(ret); |
| } |
| |
| adev->id = ret; |
| adev->name = "dp_hpd_bridge"; |
| adev->dev.parent = parent; |
| adev->dev.of_node = of_node_get(parent->of_node); |
| adev->dev.release = drm_aux_hpd_bridge_release; |
| adev->dev.platform_data = of_node_get(np); |
| |
| ret = auxiliary_device_init(adev); |
| if (ret) { |
| ida_free(&drm_aux_hpd_bridge_ida, adev->id); |
| kfree(adev); |
| return ERR_PTR(ret); |
| } |
| |
| ret = auxiliary_device_add(adev); |
| if (ret) { |
| auxiliary_device_uninit(adev); |
| return ERR_PTR(ret); |
| } |
| |
| ret = devm_add_action_or_reset(parent, drm_aux_hpd_bridge_unregister_adev, adev); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| return &adev->dev; |
| } |
| EXPORT_SYMBOL_GPL(drm_dp_hpd_bridge_register); |
| |
| /** |
| * drm_aux_hpd_bridge_notify - notify hot plug detection events |
| * @dev: device created for the HPD bridge |
| * @status: output connection status |
| * |
| * A wrapper around drm_bridge_hpd_notify() that is used to report hot plug |
| * detection events for bridges created via drm_dp_hpd_bridge_register(). |
| * |
| * This function shall be called in a context that can sleep. |
| */ |
| void drm_aux_hpd_bridge_notify(struct device *dev, enum drm_connector_status status) |
| { |
| struct auxiliary_device *adev = to_auxiliary_dev(dev); |
| struct drm_aux_hpd_bridge_data *data = auxiliary_get_drvdata(adev); |
| |
| if (!data) |
| return; |
| |
| drm_bridge_hpd_notify(&data->bridge, status); |
| } |
| EXPORT_SYMBOL_GPL(drm_aux_hpd_bridge_notify); |
| |
| static int drm_aux_hpd_bridge_attach(struct drm_bridge *bridge, |
| enum drm_bridge_attach_flags flags) |
| { |
| return flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR ? 0 : -EINVAL; |
| } |
| |
| static const struct drm_bridge_funcs drm_aux_hpd_bridge_funcs = { |
| .attach = drm_aux_hpd_bridge_attach, |
| }; |
| |
| static int drm_aux_hpd_bridge_probe(struct auxiliary_device *auxdev, |
| const struct auxiliary_device_id *id) |
| { |
| struct drm_aux_hpd_bridge_data *data; |
| |
| data = devm_kzalloc(&auxdev->dev, sizeof(*data), GFP_KERNEL); |
| if (!data) |
| return -ENOMEM; |
| |
| data->dev = &auxdev->dev; |
| data->bridge.funcs = &drm_aux_hpd_bridge_funcs; |
| data->bridge.of_node = dev_get_platdata(data->dev); |
| data->bridge.ops = DRM_BRIDGE_OP_HPD; |
| data->bridge.type = id->driver_data; |
| |
| auxiliary_set_drvdata(auxdev, data); |
| |
| return devm_drm_bridge_add(data->dev, &data->bridge); |
| } |
| |
| static const struct auxiliary_device_id drm_aux_hpd_bridge_table[] = { |
| { .name = KBUILD_MODNAME ".dp_hpd_bridge", .driver_data = DRM_MODE_CONNECTOR_DisplayPort, }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(auxiliary, drm_aux_hpd_bridge_table); |
| |
| static struct auxiliary_driver drm_aux_hpd_bridge_drv = { |
| .name = "aux_hpd_bridge", |
| .id_table = drm_aux_hpd_bridge_table, |
| .probe = drm_aux_hpd_bridge_probe, |
| }; |
| module_auxiliary_driver(drm_aux_hpd_bridge_drv); |
| |
| MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@linaro.org>"); |
| MODULE_DESCRIPTION("DRM HPD bridge"); |
| MODULE_LICENSE("GPL"); |