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altera_ps2.c
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1 /*
2  * Altera University Program PS2 controller driver
3  *
4  * Copyright (C) 2008 Thomas Chou <[email protected]>
5  *
6  * Based on sa1111ps2.c, which is:
7  * Copyright (C) 2002 Russell King
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/input.h>
17 #include <linux/serio.h>
18 #include <linux/interrupt.h>
19 #include <linux/platform_device.h>
20 #include <linux/io.h>
21 #include <linux/slab.h>
22 #include <linux/of.h>
23 
24 #define DRV_NAME "altera_ps2"
25 
26 struct ps2if {
27  struct serio *io;
29  void __iomem *base;
30  unsigned irq;
31 };
32 
33 /*
34  * Read all bytes waiting in the PS2 port. There should be
35  * at the most one, but we loop for safety.
36  */
37 static irqreturn_t altera_ps2_rxint(int irq, void *dev_id)
38 {
39  struct ps2if *ps2if = dev_id;
40  unsigned int status;
41  int handled = IRQ_NONE;
42 
43  while ((status = readl(ps2if->base)) & 0xffff0000) {
44  serio_interrupt(ps2if->io, status & 0xff, 0);
45  handled = IRQ_HANDLED;
46  }
47 
48  return handled;
49 }
50 
51 /*
52  * Write a byte to the PS2 port.
53  */
54 static int altera_ps2_write(struct serio *io, unsigned char val)
55 {
56  struct ps2if *ps2if = io->port_data;
57 
58  writel(val, ps2if->base);
59  return 0;
60 }
61 
62 static int altera_ps2_open(struct serio *io)
63 {
64  struct ps2if *ps2if = io->port_data;
65 
66  /* clear fifo */
67  while (readl(ps2if->base) & 0xffff0000)
68  /* empty */;
69 
70  writel(1, ps2if->base + 4); /* enable rx irq */
71  return 0;
72 }
73 
74 static void altera_ps2_close(struct serio *io)
75 {
76  struct ps2if *ps2if = io->port_data;
77 
78  writel(0, ps2if->base); /* disable rx irq */
79 }
80 
81 /*
82  * Add one device to this driver.
83  */
84 static int __devinit altera_ps2_probe(struct platform_device *pdev)
85 {
86  struct ps2if *ps2if;
87  struct serio *serio;
88  int error, irq;
89 
90  ps2if = kzalloc(sizeof(struct ps2if), GFP_KERNEL);
91  serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
92  if (!ps2if || !serio) {
93  error = -ENOMEM;
94  goto err_free_mem;
95  }
96 
97  serio->id.type = SERIO_8042;
98  serio->write = altera_ps2_write;
99  serio->open = altera_ps2_open;
100  serio->close = altera_ps2_close;
101  strlcpy(serio->name, dev_name(&pdev->dev), sizeof(serio->name));
102  strlcpy(serio->phys, dev_name(&pdev->dev), sizeof(serio->phys));
103  serio->port_data = ps2if;
104  serio->dev.parent = &pdev->dev;
105  ps2if->io = serio;
106 
108  if (ps2if->iomem_res == NULL) {
109  error = -ENOENT;
110  goto err_free_mem;
111  }
112 
113 
114  irq = platform_get_irq(pdev, 0);
115  if (irq < 0) {
116  error = -ENXIO;
117  goto err_free_mem;
118  }
119  ps2if->irq = irq;
120 
121  if (!request_mem_region(ps2if->iomem_res->start,
122  resource_size(ps2if->iomem_res), pdev->name)) {
123  error = -EBUSY;
124  goto err_free_mem;
125  }
126 
127  ps2if->base = ioremap(ps2if->iomem_res->start,
128  resource_size(ps2if->iomem_res));
129  if (!ps2if->base) {
130  error = -ENOMEM;
131  goto err_free_res;
132  }
133 
134  error = request_irq(ps2if->irq, altera_ps2_rxint, 0, pdev->name, ps2if);
135  if (error) {
136  dev_err(&pdev->dev, "could not allocate IRQ %d: %d\n",
137  ps2if->irq, error);
138  goto err_unmap;
139  }
140 
141  dev_info(&pdev->dev, "base %p, irq %d\n", ps2if->base, ps2if->irq);
142 
143  serio_register_port(ps2if->io);
144  platform_set_drvdata(pdev, ps2if);
145 
146  return 0;
147 
148  err_unmap:
149  iounmap(ps2if->base);
150  err_free_res:
151  release_mem_region(ps2if->iomem_res->start,
152  resource_size(ps2if->iomem_res));
153  err_free_mem:
154  kfree(ps2if);
155  kfree(serio);
156  return error;
157 }
158 
159 /*
160  * Remove one device from this driver.
161  */
162 static int __devexit altera_ps2_remove(struct platform_device *pdev)
163 {
164  struct ps2if *ps2if = platform_get_drvdata(pdev);
165 
166  platform_set_drvdata(pdev, NULL);
167  serio_unregister_port(ps2if->io);
168  free_irq(ps2if->irq, ps2if);
169  iounmap(ps2if->base);
170  release_mem_region(ps2if->iomem_res->start,
171  resource_size(ps2if->iomem_res));
172  kfree(ps2if);
173 
174  return 0;
175 }
176 
177 #ifdef CONFIG_OF
178 static const struct of_device_id altera_ps2_match[] = {
179  { .compatible = "ALTR,ps2-1.0", },
180  {},
181 };
182 MODULE_DEVICE_TABLE(of, altera_ps2_match);
183 #endif /* CONFIG_OF */
184 
185 /*
186  * Our device driver structure
187  */
188 static struct platform_driver altera_ps2_driver = {
189  .probe = altera_ps2_probe,
190  .remove = __devexit_p(altera_ps2_remove),
191  .driver = {
192  .name = DRV_NAME,
193  .owner = THIS_MODULE,
194  .of_match_table = of_match_ptr(altera_ps2_match),
195  },
196 };
197 module_platform_driver(altera_ps2_driver);
198 
199 MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
200 MODULE_AUTHOR("Thomas Chou <[email protected]>");
201 MODULE_LICENSE("GPL");
202 MODULE_ALIAS("platform:" DRV_NAME);