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