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// 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");
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