1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Altera University Program PS2 controller driver
4 *
5 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
6 *
7 * Based on sa1111ps2.c, which is:
8 * Copyright (C) 2002 Russell King
9 */
10
11#include <linux/module.h>
12#include <linux/input.h>
13#include <linux/serio.h>
14#include <linux/interrupt.h>
15#include <linux/platform_device.h>
16#include <linux/io.h>
17#include <linux/slab.h>
18#include <linux/of.h>
19
20#define DRV_NAME "altera_ps2"
21
22struct ps2if {
23	struct serio *io;
24	void __iomem *base;
25};
26
27/*
28 * Read all bytes waiting in the PS2 port.  There should be
29 * at the most one, but we loop for safety.
30 */
31static irqreturn_t altera_ps2_rxint(int irq, void *dev_id)
32{
33	struct ps2if *ps2if = dev_id;
34	unsigned int status;
35	irqreturn_t handled = IRQ_NONE;
36
37	while ((status = readl(ps2if->base)) & 0xffff0000) {
38		serio_interrupt(ps2if->io, status & 0xff, 0);
39		handled = IRQ_HANDLED;
40	}
41
42	return handled;
43}
44
45/*
46 * Write a byte to the PS2 port.
47 */
48static int altera_ps2_write(struct serio *io, unsigned char val)
49{
50	struct ps2if *ps2if = io->port_data;
51
52	writel(val, ps2if->base);
53	return 0;
54}
55
56static int altera_ps2_open(struct serio *io)
57{
58	struct ps2if *ps2if = io->port_data;
59
60	/* clear fifo */
61	while (readl(ps2if->base) & 0xffff0000)
62		/* empty */;
63
64	writel(1, ps2if->base + 4); /* enable rx irq */
65	return 0;
66}
67
68static void altera_ps2_close(struct serio *io)
69{
70	struct ps2if *ps2if = io->port_data;
71
72	writel(0, ps2if->base + 4); /* disable rx irq */
73}
74
75/*
76 * Add one device to this driver.
77 */
78static int altera_ps2_probe(struct platform_device *pdev)
79{
80	struct ps2if *ps2if;
81	struct serio *serio;
82	int error, irq;
83
84	ps2if = devm_kzalloc(&pdev->dev, sizeof(struct ps2if), GFP_KERNEL);
85	if (!ps2if)
86		return -ENOMEM;
87
88	ps2if->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
89	if (IS_ERR(ps2if->base))
90		return PTR_ERR(ps2if->base);
91
92	irq = platform_get_irq(pdev, 0);
93	if (irq < 0)
94		return -ENXIO;
95
96	error = devm_request_irq(&pdev->dev, irq, altera_ps2_rxint, 0,
97				 pdev->name, ps2if);
98	if (error) {
99		dev_err(&pdev->dev, "could not request IRQ %d\n", irq);
100		return error;
101	}
102
103	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
104	if (!serio)
105		return -ENOMEM;
106
107	serio->id.type		= SERIO_8042;
108	serio->write		= altera_ps2_write;
109	serio->open		= altera_ps2_open;
110	serio->close		= altera_ps2_close;
111	strscpy(serio->name, dev_name(&pdev->dev), sizeof(serio->name));
112	strscpy(serio->phys, dev_name(&pdev->dev), sizeof(serio->phys));
113	serio->port_data	= ps2if;
114	serio->dev.parent	= &pdev->dev;
115	ps2if->io		= serio;
116
117	dev_info(&pdev->dev, "base %p, irq %d\n", ps2if->base, irq);
118
119	serio_register_port(ps2if->io);
120	platform_set_drvdata(pdev, ps2if);
121
122	return 0;
123}
124
125/*
126 * Remove one device from this driver.
127 */
128static int altera_ps2_remove(struct platform_device *pdev)
129{
130	struct ps2if *ps2if = platform_get_drvdata(pdev);
131
132	serio_unregister_port(ps2if->io);
133
134	return 0;
135}
136
137#ifdef CONFIG_OF
138static const struct of_device_id altera_ps2_match[] = {
139	{ .compatible = "ALTR,ps2-1.0", },
140	{ .compatible = "altr,ps2-1.0", },
141	{},
142};
143MODULE_DEVICE_TABLE(of, altera_ps2_match);
144#endif /* CONFIG_OF */
145
146/*
147 * Our device driver structure
148 */
149static struct platform_driver altera_ps2_driver = {
150	.probe		= altera_ps2_probe,
151	.remove		= altera_ps2_remove,
152	.driver	= {
153		.name	= DRV_NAME,
154		.of_match_table = of_match_ptr(altera_ps2_match),
155	},
156};
157module_platform_driver(altera_ps2_driver);
158
159MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
160MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
161MODULE_LICENSE("GPL");
162MODULE_ALIAS("platform:" DRV_NAME);
163