drivers/uio/uio_aec.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * uio_aec.c -- simple driver for Adrienne Electronics Corp time code PCI device
 *
 * Copyright (C) 2008 Brandon Philips <brandon@ifup.org>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/uio_driver.h>
#include <linux/slab.h>

#define PCI_VENDOR_ID_AEC 0xaecb
#define PCI_DEVICE_ID_AEC_VITCLTC 0x6250

#define INT_ENABLE_ADDR		0xFC
#define INT_ENABLE		0x10
#define INT_DISABLE		0x0

#define INT_MASK_ADDR		0x2E
#define INT_MASK_ALL		0x3F

#define INTA_DRVR_ADDR		0xFE
#define INTA_ENABLED_FLAG	0x08
#define INTA_FLAG		0x01

#define MAILBOX			0x0F

static struct pci_device_id ids[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_AEC, PCI_DEVICE_ID_AEC_VITCLTC), },
	{ 0, }
};
MODULE_DEVICE_TABLE(pci, ids);

static irqreturn_t aectc_irq(int irq, struct uio_info *dev_info)
{
	void __iomem *int_flag = dev_info->priv + INTA_DRVR_ADDR;
	unsigned char status = ioread8(int_flag);


	if ((status & INTA_ENABLED_FLAG) && (status & INTA_FLAG)) {
		/* application writes 0x00 to 0x2F to get next interrupt */
		status = ioread8(dev_info->priv + MAILBOX);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static void print_board_data(struct pci_dev *pdev, struct uio_info *i)
{
	dev_info(&pdev->dev, "PCI-TC board vendor: %x%x number: %x%x"
		" revision: %c%c\n",
		ioread8(i->priv + 0x01),
		ioread8(i->priv + 0x00),
		ioread8(i->priv + 0x03),
		ioread8(i->priv + 0x02),
		ioread8(i->priv + 0x06),
		ioread8(i->priv + 0x07));
}

static int probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
	struct uio_info *info;
	int ret;

	info = devm_kzalloc(&pdev->dev, sizeof(struct uio_info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	if (pci_enable_device(pdev))
		return -ENODEV;

	if (pci_request_regions(pdev, "aectc"))
		goto out_disable;

	info->name = "aectc";
	info->port[0].start = pci_resource_start(pdev, 0);
	if (!info->port[0].start)
		goto out_release;
	info->priv = pci_iomap(pdev, 0, 0);
	if (!info->priv)
		goto out_release;
	info->port[0].size = pci_resource_len(pdev, 0);
	info->port[0].porttype = UIO_PORT_GPIO;

	info->version = "0.0.1";
	info->irq = pdev->irq;
	info->irq_flags = IRQF_SHARED;
	info->handler = aectc_irq;

	print_board_data(pdev, info);
	ret = uio_register_device(&pdev->dev, info);
	if (ret)
		goto out_unmap;

	iowrite32(INT_ENABLE, info->priv + INT_ENABLE_ADDR);
	iowrite8(INT_MASK_ALL, info->priv + INT_MASK_ADDR);
	if (!(ioread8(info->priv + INTA_DRVR_ADDR)
			& INTA_ENABLED_FLAG))
		dev_err(&pdev->dev, "aectc: interrupts not enabled\n");

	pci_set_drvdata(pdev, info);

	return 0;

out_unmap:
	pci_iounmap(pdev, info->priv);
out_release:
	pci_release_regions(pdev);
out_disable:
	pci_disable_device(pdev);
	return -ENODEV;
}

static void remove(struct pci_dev *pdev)
{
	struct uio_info *info = pci_get_drvdata(pdev);

	/* disable interrupts */
	iowrite8(INT_DISABLE, info->priv + INT_MASK_ADDR);
	iowrite32(INT_DISABLE, info->priv + INT_ENABLE_ADDR);
	/* read mailbox to ensure board drops irq */
	ioread8(info->priv + MAILBOX);

	uio_unregister_device(info);
	pci_release_regions(pdev);
	pci_disable_device(pdev);
	pci_iounmap(pdev, info->priv);
}

static struct pci_driver pci_driver = {
	.name = "aectc",
	.id_table = ids,
	.probe = probe,
	.remove = remove,
};

module_pci_driver(pci_driver);
MODULE_LICENSE("GPL");