drivers/input/serio/altera_ps2.c

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