drivers/uio/uio_pdrv.c

/*
 * drivers/uio/uio_pdrv.c
 *
 * Copyright (C) 2008 by Digi International Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */
#include <linux/platform_device.h>
#include <linux/uio_driver.h>
#include <linux/stringify.h>

#define DRIVER_NAME "uio"

struct uio_platdata {
	struct uio_info *uioinfo;
};

static int uio_pdrv_probe(struct platform_device *pdev)
{
	struct uio_info *uioinfo = pdev->dev.platform_data;
	struct uio_platdata *pdata;
	struct uio_mem *uiomem;
	int ret = -ENODEV;
	int i;

	if (!uioinfo || !uioinfo->name || !uioinfo->version) {
		dev_dbg(&pdev->dev, "%s: err_uioinfo\n", __func__);
		goto err_uioinfo;
	}

	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
	if (!pdata) {
		ret = -ENOMEM;
		dev_dbg(&pdev->dev, "%s: err_alloc_pdata\n", __func__);
		goto err_alloc_pdata;
	}

	pdata->uioinfo = uioinfo;

	uiomem = &uioinfo->mem[0];

	for (i = 0; i < pdev->num_resources; ++i) {
		struct resource *r = &pdev->resource[i];

		if (r->flags != IORESOURCE_MEM)
			continue;

		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
			dev_warn(&pdev->dev, "device has more than "
					__stringify(MAX_UIO_MAPS)
					" I/O memory resources.\n");
			break;
		}

		uiomem->memtype = UIO_MEM_PHYS;
		uiomem->addr = r->start;
		uiomem->size = r->end - r->start + 1;
		++uiomem;
	}

	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
		uiomem->size = 0;
		++uiomem;
	}

	pdata->uioinfo->priv = pdata;

	ret = uio_register_device(&pdev->dev, pdata->uioinfo);

	if (ret) {
		kfree(pdata);
err_alloc_pdata:
err_uioinfo:
		return ret;
	}

	platform_set_drvdata(pdev, pdata);

	return 0;
}

static int uio_pdrv_remove(struct platform_device *pdev)
{
	struct uio_platdata *pdata = platform_get_drvdata(pdev);

	uio_unregister_device(pdata->uioinfo);

	kfree(pdata);

	return 0;
}

static struct platform_driver uio_pdrv = {
	.probe = uio_pdrv_probe,
	.remove = uio_pdrv_remove,
	.driver = {
		.name = DRIVER_NAME,
		.owner = THIS_MODULE,
	},
};

static int __init uio_pdrv_init(void)
{
	return platform_driver_register(&uio_pdrv);
}

static void __exit uio_pdrv_exit(void)
{
	platform_driver_unregister(&uio_pdrv);
}
module_init(uio_pdrv_init);
module_exit(uio_pdrv_exit);

MODULE_AUTHOR("Uwe Kleine-Koenig");
MODULE_DESCRIPTION("Userspace I/O platform driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);