diff options
Diffstat (limited to 'drivers/gpu/drm/bridge/aux-hpd-bridge.c')
| -rw-r--r-- | drivers/gpu/drm/bridge/aux-hpd-bridge.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/gpu/drm/bridge/aux-hpd-bridge.c b/drivers/gpu/drm/bridge/aux-hpd-bridge.c new file mode 100644 index 000000000000..bb55f697a181 --- /dev/null +++ b/drivers/gpu/drm/bridge/aux-hpd-bridge.c @@ -0,0 +1,163 @@ +// 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"); |