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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Copyright (C) 2023 Linaro Ltd.4 *5 * Author: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>6 */7#include <linux/auxiliary_bus.h>8#include <linux/module.h>9#include <linux/of.h>10 11#include <drm/drm_bridge.h>12#include <drm/bridge/aux-bridge.h>13 14static DEFINE_IDA(drm_aux_hpd_bridge_ida);15 16struct drm_aux_hpd_bridge_data {17 struct drm_bridge bridge;18 struct device *dev;19};20 21static void drm_aux_hpd_bridge_release(struct device *dev)22{23 struct auxiliary_device *adev = to_auxiliary_dev(dev);24 25 ida_free(&drm_aux_hpd_bridge_ida, adev->id);26 27 of_node_put(adev->dev.platform_data);28 of_node_put(adev->dev.of_node);29 30 kfree(adev);31}32 33static void drm_aux_hpd_bridge_free_adev(void *_adev)34{35 auxiliary_device_uninit(_adev);36}37 38/**39 * devm_drm_dp_hpd_bridge_alloc - allocate a HPD DisplayPort bridge40 * @parent: device instance providing this bridge41 * @np: device node pointer corresponding to this bridge instance42 *43 * Creates a simple DRM bridge with the type set to44 * DRM_MODE_CONNECTOR_DisplayPort, which terminates the bridge chain and is45 * able to send the HPD events.46 *47 * Return: bridge auxiliary device pointer or an error pointer48 */49struct auxiliary_device *devm_drm_dp_hpd_bridge_alloc(struct device *parent, struct device_node *np)50{51 struct auxiliary_device *adev;52 int ret;53 54 adev = kzalloc(sizeof(*adev), GFP_KERNEL);55 if (!adev)56 return ERR_PTR(-ENOMEM);57 58 ret = ida_alloc(&drm_aux_hpd_bridge_ida, GFP_KERNEL);59 if (ret < 0) {60 kfree(adev);61 return ERR_PTR(ret);62 }63 64 adev->id = ret;65 adev->name = "dp_hpd_bridge";66 adev->dev.parent = parent;67 adev->dev.of_node = of_node_get(parent->of_node);68 adev->dev.release = drm_aux_hpd_bridge_release;69 adev->dev.platform_data = of_node_get(np);70 71 ret = auxiliary_device_init(adev);72 if (ret) {73 of_node_put(adev->dev.platform_data);74 of_node_put(adev->dev.of_node);75 ida_free(&drm_aux_hpd_bridge_ida, adev->id);76 kfree(adev);77 return ERR_PTR(ret);78 }79 80 ret = devm_add_action_or_reset(parent, drm_aux_hpd_bridge_free_adev, adev);81 if (ret)82 return ERR_PTR(ret);83 84 return adev;85}86EXPORT_SYMBOL_GPL(devm_drm_dp_hpd_bridge_alloc);87 88static void drm_aux_hpd_bridge_del_adev(void *_adev)89{90 auxiliary_device_delete(_adev);91}92 93/**94 * devm_drm_dp_hpd_bridge_add - register a HDP DisplayPort bridge95 * @dev: struct device to tie registration lifetime to96 * @adev: bridge auxiliary device to be registered97 *98 * Returns: zero on success or a negative errno99 */100int devm_drm_dp_hpd_bridge_add(struct device *dev, struct auxiliary_device *adev)101{102 int ret;103 104 ret = auxiliary_device_add(adev);105 if (ret)106 return ret;107 108 return devm_add_action_or_reset(dev, drm_aux_hpd_bridge_del_adev, adev);109}110EXPORT_SYMBOL_GPL(devm_drm_dp_hpd_bridge_add);111 112/**113 * drm_dp_hpd_bridge_register - allocate and register a HDP DisplayPort bridge114 * @parent: device instance providing this bridge115 * @np: device node pointer corresponding to this bridge instance116 *117 * Return: device instance that will handle created bridge or an error pointer118 */119struct device *drm_dp_hpd_bridge_register(struct device *parent, struct device_node *np)120{121 struct auxiliary_device *adev;122 int ret;123 124 adev = devm_drm_dp_hpd_bridge_alloc(parent, np);125 if (IS_ERR(adev))126 return ERR_CAST(adev);127 128 ret = devm_drm_dp_hpd_bridge_add(parent, adev);129 if (ret)130 return ERR_PTR(ret);131 132 return &adev->dev;133}134EXPORT_SYMBOL_GPL(drm_dp_hpd_bridge_register);135 136/**137 * drm_aux_hpd_bridge_notify - notify hot plug detection events138 * @dev: device created for the HPD bridge139 * @status: output connection status140 *141 * A wrapper around drm_bridge_hpd_notify() that is used to report hot plug142 * detection events for bridges created via drm_dp_hpd_bridge_register().143 *144 * This function shall be called in a context that can sleep.145 */146void drm_aux_hpd_bridge_notify(struct device *dev, enum drm_connector_status status)147{148 struct auxiliary_device *adev = to_auxiliary_dev(dev);149 struct drm_aux_hpd_bridge_data *data = auxiliary_get_drvdata(adev);150 151 if (!data)152 return;153 154 drm_bridge_hpd_notify(&data->bridge, status);155}156EXPORT_SYMBOL_GPL(drm_aux_hpd_bridge_notify);157 158static int drm_aux_hpd_bridge_attach(struct drm_bridge *bridge,159 enum drm_bridge_attach_flags flags)160{161 return flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR ? 0 : -EINVAL;162}163 164static const struct drm_bridge_funcs drm_aux_hpd_bridge_funcs = {165 .attach = drm_aux_hpd_bridge_attach,166};167 168static int drm_aux_hpd_bridge_probe(struct auxiliary_device *auxdev,169 const struct auxiliary_device_id *id)170{171 struct drm_aux_hpd_bridge_data *data;172 173 data = devm_kzalloc(&auxdev->dev, sizeof(*data), GFP_KERNEL);174 if (!data)175 return -ENOMEM;176 177 data->dev = &auxdev->dev;178 data->bridge.funcs = &drm_aux_hpd_bridge_funcs;179 data->bridge.of_node = dev_get_platdata(data->dev);180 data->bridge.ops = DRM_BRIDGE_OP_HPD;181 data->bridge.type = id->driver_data;182 183 auxiliary_set_drvdata(auxdev, data);184 185 return devm_drm_bridge_add(data->dev, &data->bridge);186}187 188static const struct auxiliary_device_id drm_aux_hpd_bridge_table[] = {189 { .name = KBUILD_MODNAME ".dp_hpd_bridge", .driver_data = DRM_MODE_CONNECTOR_DisplayPort, },190 {},191};192MODULE_DEVICE_TABLE(auxiliary, drm_aux_hpd_bridge_table);193 194static struct auxiliary_driver drm_aux_hpd_bridge_drv = {195 .name = "aux_hpd_bridge",196 .id_table = drm_aux_hpd_bridge_table,197 .probe = drm_aux_hpd_bridge_probe,198};199module_auxiliary_driver(drm_aux_hpd_bridge_drv);200 201MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@linaro.org>");202MODULE_DESCRIPTION("DRM HPD bridge");203MODULE_LICENSE("GPL");204