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Both gpio-sim and gpio-virtuser share a mechanism to instantiate a platform device, wait for probe completion, and retrieve the probe success or error status synchronously. With gpio-aggregator planned to adopt this approach for its configfs interface, it's time to factor out the common code. Add dev-sync-probe.[ch] to house helper functions used by all such implementations. No functional change. Signed-off-by: Koichiro Den <koichiro.den@canonical.com> Link: https://lore.kernel.org/r/20250221133501.2203897-2-koichiro.den@canonical.com Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
98 lines
2.5 KiB
C
98 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Common code for drivers creating fake platform devices.
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*
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* Provides synchronous device creation: waits for probe completion and
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* returns the probe success or error status to the device creator.
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*
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* Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
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* Copyright (C) 2025 Koichiro Den <koichiro.den@canonical.com>
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*/
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#include <linux/device.h>
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#include <linux/slab.h>
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#include "dev-sync-probe.h"
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static int dev_sync_probe_notifier_call(struct notifier_block *nb,
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unsigned long action, void *data)
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{
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struct dev_sync_probe_data *pdata;
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struct device *dev = data;
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pdata = container_of(nb, struct dev_sync_probe_data, bus_notifier);
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if (!device_match_name(dev, pdata->name))
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return NOTIFY_DONE;
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switch (action) {
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case BUS_NOTIFY_BOUND_DRIVER:
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pdata->driver_bound = true;
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break;
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case BUS_NOTIFY_DRIVER_NOT_BOUND:
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pdata->driver_bound = false;
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break;
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default:
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return NOTIFY_DONE;
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}
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complete(&pdata->probe_completion);
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return NOTIFY_OK;
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}
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void dev_sync_probe_init(struct dev_sync_probe_data *data)
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{
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memset(data, 0, sizeof(*data));
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init_completion(&data->probe_completion);
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data->bus_notifier.notifier_call = dev_sync_probe_notifier_call;
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}
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EXPORT_SYMBOL_GPL(dev_sync_probe_init);
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int dev_sync_probe_register(struct dev_sync_probe_data *data,
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struct platform_device_info *pdevinfo)
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{
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struct platform_device *pdev;
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char *name;
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name = kasprintf(GFP_KERNEL, "%s.%d", pdevinfo->name, pdevinfo->id);
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if (!name)
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return -ENOMEM;
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data->driver_bound = false;
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data->name = name;
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reinit_completion(&data->probe_completion);
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bus_register_notifier(&platform_bus_type, &data->bus_notifier);
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pdev = platform_device_register_full(pdevinfo);
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if (IS_ERR(pdev)) {
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bus_unregister_notifier(&platform_bus_type, &data->bus_notifier);
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kfree(data->name);
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return PTR_ERR(pdev);
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}
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wait_for_completion(&data->probe_completion);
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bus_unregister_notifier(&platform_bus_type, &data->bus_notifier);
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if (!data->driver_bound) {
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platform_device_unregister(pdev);
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kfree(data->name);
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return -ENXIO;
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}
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data->pdev = pdev;
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return 0;
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}
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EXPORT_SYMBOL_GPL(dev_sync_probe_register);
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void dev_sync_probe_unregister(struct dev_sync_probe_data *data)
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{
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platform_device_unregister(data->pdev);
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kfree(data->name);
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data->pdev = NULL;
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}
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EXPORT_SYMBOL_GPL(dev_sync_probe_unregister);
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MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
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MODULE_AUTHOR("Koichiro Den <koichiro.den@canonical.com>");
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MODULE_DESCRIPTION("Utilities for synchronous fake device creation");
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MODULE_LICENSE("GPL");
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