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 resource *res;
82	struct serio *serio;
83	int error, irq;
84
85	ps2if = devm_kzalloc(&pdev->dev, sizeof(struct ps2if), GFP_KERNEL);
86	if (!ps2if)
87		return -ENOMEM;
88
89	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
90	ps2if->base = devm_ioremap_resource(&pdev->dev, res);
91	if (IS_ERR(ps2if->base))
92		return PTR_ERR(ps2if->base);
93
94	irq = platform_get_irq(pdev, 0);
95	if (irq < 0)
96		return -ENXIO;
97
98	error = devm_request_irq(&pdev->dev, irq, altera_ps2_rxint, 0,
99				 pdev->name, ps2if);
100	if (error) {
101		dev_err(&pdev->dev, "could not request IRQ %d\n", irq);
102		return error;
103	}
104
105	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
106	if (!serio)
107		return -ENOMEM;
108
109	serio->id.type		= SERIO_8042;
110	serio->write		= altera_ps2_write;
111	serio->open		= altera_ps2_open;
112	serio->close		= altera_ps2_close;
113	strlcpy(serio->name, dev_name(&pdev->dev), sizeof(serio->name));
114	strlcpy(serio->phys, dev_name(&pdev->dev), sizeof(serio->phys));
115	serio->port_data	= ps2if;
116	serio->dev.parent	= &pdev->dev;
117	ps2if->io		= serio;
118
119	dev_info(&pdev->dev, "base %p, irq %d\n", ps2if->base, irq);
120
121	serio_register_port(ps2if->io);
122	platform_set_drvdata(pdev, ps2if);
123
124	return 0;
125}
126
127/*
128 * Remove one device from this driver.
129 */
130static int altera_ps2_remove(struct platform_device *pdev)
131{
132	struct ps2if *ps2if = platform_get_drvdata(pdev);
133
134	serio_unregister_port(ps2if->io);
135
136	return 0;
137}
138
139#ifdef CONFIG_OF
140static const struct of_device_id altera_ps2_match[] = {
141	{ .compatible = "ALTR,ps2-1.0", },
142	{ .compatible = "altr,ps2-1.0", },
143	{},
144};
145MODULE_DEVICE_TABLE(of, altera_ps2_match);
146#endif /* CONFIG_OF */
147
148/*
149 * Our device driver structure
150 */
151static struct platform_driver altera_ps2_driver = {
152	.probe		= altera_ps2_probe,
153	.remove		= altera_ps2_remove,
154	.driver	= {
155		.name	= DRV_NAME,
156		.of_match_table = of_match_ptr(altera_ps2_match),
157	},
158};
159module_platform_driver(altera_ps2_driver);
160
161MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
162MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
163MODULE_LICENSE("GPL");
164MODULE_ALIAS("platform:" DRV_NAME);
165