147 lines
3.6 KiB
C
147 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2023 Linaro Ltd.
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*
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* Author: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
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*/
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#include <linux/auxiliary_bus.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <drm/drm_bridge.h>
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#include <drm/bridge/aux-bridge.h>
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static DEFINE_IDA(drm_aux_bridge_ida);
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static void drm_aux_bridge_release(struct device *dev)
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{
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struct auxiliary_device *adev = to_auxiliary_dev(dev);
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ida_free(&drm_aux_bridge_ida, adev->id);
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kfree(adev);
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}
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static void drm_aux_bridge_unregister_adev(void *_adev)
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{
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struct auxiliary_device *adev = _adev;
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auxiliary_device_delete(adev);
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auxiliary_device_uninit(adev);
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}
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/**
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* drm_aux_bridge_register - Create a simple bridge device to link the chain
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* @parent: device instance providing this bridge
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*
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* Creates a simple DRM bridge that doesn't implement any drm_bridge
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* operations. Such bridges merely fill a place in the bridge chain linking
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* surrounding DRM bridges.
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*
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* Return: zero on success, negative error code on failure
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*/
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int drm_aux_bridge_register(struct device *parent)
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{
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struct auxiliary_device *adev;
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int ret;
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adev = kzalloc(sizeof(*adev), GFP_KERNEL);
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if (!adev)
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return -ENOMEM;
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ret = ida_alloc(&drm_aux_bridge_ida, GFP_KERNEL);
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if (ret < 0) {
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kfree(adev);
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return ret;
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}
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adev->id = ret;
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adev->name = "aux_bridge";
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adev->dev.parent = parent;
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adev->dev.release = drm_aux_bridge_release;
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device_set_of_node_from_dev(&adev->dev, parent);
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ret = auxiliary_device_init(adev);
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if (ret) {
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ida_free(&drm_aux_bridge_ida, adev->id);
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kfree(adev);
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return ret;
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}
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ret = auxiliary_device_add(adev);
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if (ret) {
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auxiliary_device_uninit(adev);
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return ret;
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}
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return devm_add_action_or_reset(parent, drm_aux_bridge_unregister_adev, adev);
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}
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EXPORT_SYMBOL_GPL(drm_aux_bridge_register);
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struct drm_aux_bridge_data {
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struct drm_bridge bridge;
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struct drm_bridge *next_bridge;
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struct device *dev;
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};
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static int drm_aux_bridge_attach(struct drm_bridge *bridge,
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enum drm_bridge_attach_flags flags)
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{
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struct drm_aux_bridge_data *data;
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if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
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return -EINVAL;
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data = container_of(bridge, struct drm_aux_bridge_data, bridge);
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return drm_bridge_attach(bridge->encoder, data->next_bridge, bridge,
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DRM_BRIDGE_ATTACH_NO_CONNECTOR);
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}
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static const struct drm_bridge_funcs drm_aux_bridge_funcs = {
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.attach = drm_aux_bridge_attach,
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};
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static int drm_aux_bridge_probe(struct auxiliary_device *auxdev,
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const struct auxiliary_device_id *id)
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{
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struct drm_aux_bridge_data *data;
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data = devm_kzalloc(&auxdev->dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->dev = &auxdev->dev;
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data->next_bridge = devm_drm_of_get_bridge(&auxdev->dev, auxdev->dev.of_node, 0, 0);
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if (IS_ERR(data->next_bridge))
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return dev_err_probe(&auxdev->dev, PTR_ERR(data->next_bridge),
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"failed to acquire drm_bridge\n");
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data->bridge.funcs = &drm_aux_bridge_funcs;
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data->bridge.of_node = data->dev->of_node;
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/* passthrough data, allow everything */
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data->bridge.interlace_allowed = true;
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data->bridge.ycbcr_420_allowed = true;
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return devm_drm_bridge_add(data->dev, &data->bridge);
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}
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static const struct auxiliary_device_id drm_aux_bridge_table[] = {
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{ .name = KBUILD_MODNAME ".aux_bridge" },
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{},
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};
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MODULE_DEVICE_TABLE(auxiliary, drm_aux_bridge_table);
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static struct auxiliary_driver drm_aux_bridge_drv = {
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.name = "aux_bridge",
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.id_table = drm_aux_bridge_table,
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.probe = drm_aux_bridge_probe,
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};
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module_auxiliary_driver(drm_aux_bridge_drv);
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MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@linaro.org>");
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MODULE_DESCRIPTION("DRM transparent bridge");
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MODULE_LICENSE("GPL");
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