xref: /openbmc/linux/drivers/uio/uio_aec.c (revision dccdb2fc)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * uio_aec.c -- simple driver for Adrienne Electronics Corp time code PCI device
4  *
5  * Copyright (C) 2008 Brandon Philips <brandon@ifup.org>
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/pci.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/cdev.h>
14 #include <linux/fs.h>
15 #include <linux/io.h>
16 #include <linux/uaccess.h>
17 #include <linux/uio_driver.h>
18 #include <linux/slab.h>
19 
20 #define PCI_VENDOR_ID_AEC 0xaecb
21 #define PCI_DEVICE_ID_AEC_VITCLTC 0x6250
22 
23 #define INT_ENABLE_ADDR		0xFC
24 #define INT_ENABLE		0x10
25 #define INT_DISABLE		0x0
26 
27 #define INT_MASK_ADDR		0x2E
28 #define INT_MASK_ALL		0x3F
29 
30 #define INTA_DRVR_ADDR		0xFE
31 #define INTA_ENABLED_FLAG	0x08
32 #define INTA_FLAG		0x01
33 
34 #define MAILBOX			0x0F
35 
36 static struct pci_device_id ids[] = {
37 	{ PCI_DEVICE(PCI_VENDOR_ID_AEC, PCI_DEVICE_ID_AEC_VITCLTC), },
38 	{ 0, }
39 };
40 MODULE_DEVICE_TABLE(pci, ids);
41 
aectc_irq(int irq,struct uio_info * dev_info)42 static irqreturn_t aectc_irq(int irq, struct uio_info *dev_info)
43 {
44 	void __iomem *int_flag = dev_info->priv + INTA_DRVR_ADDR;
45 	unsigned char status = ioread8(int_flag);
46 
47 
48 	if ((status & INTA_ENABLED_FLAG) && (status & INTA_FLAG)) {
49 		/* application writes 0x00 to 0x2F to get next interrupt */
50 		status = ioread8(dev_info->priv + MAILBOX);
51 		return IRQ_HANDLED;
52 	}
53 
54 	return IRQ_NONE;
55 }
56 
print_board_data(struct pci_dev * pdev,struct uio_info * i)57 static void print_board_data(struct pci_dev *pdev, struct uio_info *i)
58 {
59 	dev_info(&pdev->dev, "PCI-TC board vendor: %x%x number: %x%x"
60 		" revision: %c%c\n",
61 		ioread8(i->priv + 0x01),
62 		ioread8(i->priv + 0x00),
63 		ioread8(i->priv + 0x03),
64 		ioread8(i->priv + 0x02),
65 		ioread8(i->priv + 0x06),
66 		ioread8(i->priv + 0x07));
67 }
68 
probe(struct pci_dev * pdev,const struct pci_device_id * id)69 static int probe(struct pci_dev *pdev, const struct pci_device_id *id)
70 {
71 	struct uio_info *info;
72 	int ret;
73 
74 	info = devm_kzalloc(&pdev->dev, sizeof(struct uio_info), GFP_KERNEL);
75 	if (!info)
76 		return -ENOMEM;
77 
78 	if (pci_enable_device(pdev))
79 		return -ENODEV;
80 
81 	if (pci_request_regions(pdev, "aectc"))
82 		goto out_disable;
83 
84 	info->name = "aectc";
85 	info->port[0].start = pci_resource_start(pdev, 0);
86 	if (!info->port[0].start)
87 		goto out_release;
88 	info->priv = pci_iomap(pdev, 0, 0);
89 	if (!info->priv)
90 		goto out_release;
91 	info->port[0].size = pci_resource_len(pdev, 0);
92 	info->port[0].porttype = UIO_PORT_GPIO;
93 
94 	info->version = "0.0.1";
95 	info->irq = pdev->irq;
96 	info->irq_flags = IRQF_SHARED;
97 	info->handler = aectc_irq;
98 
99 	print_board_data(pdev, info);
100 	ret = uio_register_device(&pdev->dev, info);
101 	if (ret)
102 		goto out_unmap;
103 
104 	iowrite32(INT_ENABLE, info->priv + INT_ENABLE_ADDR);
105 	iowrite8(INT_MASK_ALL, info->priv + INT_MASK_ADDR);
106 	if (!(ioread8(info->priv + INTA_DRVR_ADDR)
107 			& INTA_ENABLED_FLAG))
108 		dev_err(&pdev->dev, "aectc: interrupts not enabled\n");
109 
110 	pci_set_drvdata(pdev, info);
111 
112 	return 0;
113 
114 out_unmap:
115 	pci_iounmap(pdev, info->priv);
116 out_release:
117 	pci_release_regions(pdev);
118 out_disable:
119 	pci_disable_device(pdev);
120 	return -ENODEV;
121 }
122 
remove(struct pci_dev * pdev)123 static void remove(struct pci_dev *pdev)
124 {
125 	struct uio_info *info = pci_get_drvdata(pdev);
126 
127 	/* disable interrupts */
128 	iowrite8(INT_DISABLE, info->priv + INT_MASK_ADDR);
129 	iowrite32(INT_DISABLE, info->priv + INT_ENABLE_ADDR);
130 	/* read mailbox to ensure board drops irq */
131 	ioread8(info->priv + MAILBOX);
132 
133 	uio_unregister_device(info);
134 	pci_release_regions(pdev);
135 	pci_disable_device(pdev);
136 	pci_iounmap(pdev, info->priv);
137 }
138 
139 static struct pci_driver pci_driver = {
140 	.name = "aectc",
141 	.id_table = ids,
142 	.probe = probe,
143 	.remove = remove,
144 };
145 
146 module_pci_driver(pci_driver);
147 MODULE_LICENSE("GPL");
148