xref: /openbmc/linux/drivers/input/serio/altera_ps2.c (revision 6cb86b0a)
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 
22 struct 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  */
altera_ps2_rxint(int irq,void * dev_id)31 static 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  */
altera_ps2_write(struct serio * io,unsigned char val)48 static 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 
altera_ps2_open(struct serio * io)56 static 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 
altera_ps2_close(struct serio * io)68 static 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  */
altera_ps2_probe(struct platform_device * pdev)78 static 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  */
altera_ps2_remove(struct platform_device * pdev)128 static 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
138 static const struct of_device_id altera_ps2_match[] = {
139 	{ .compatible = "ALTR,ps2-1.0", },
140 	{ .compatible = "altr,ps2-1.0", },
141 	{},
142 };
143 MODULE_DEVICE_TABLE(of, altera_ps2_match);
144 #endif /* CONFIG_OF */
145 
146 /*
147  * Our device driver structure
148  */
149 static 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 };
157 module_platform_driver(altera_ps2_driver);
158 
159 MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
160 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
161 MODULE_LICENSE("GPL");
162 MODULE_ALIAS("platform:" DRV_NAME);
163