drivers/input/serio/altera_ps2.c

   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  */
  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  */
  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
  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
  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  */
  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(*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  */
 128 static void 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
 135 #ifdef CONFIG_OF
 136 static const struct of_device_id altera_ps2_match[] = {
 137         { .compatible = "ALTR,ps2-1.0", },
 138         { .compatible = "altr,ps2-1.0", },
 139         {},
 140 };
 141 MODULE_DEVICE_TABLE(of, altera_ps2_match);
 142 #endif /* CONFIG_OF */
 143
 144 /*
 145  * Our device driver structure
 146  */
 147 static struct platform_driver altera_ps2_driver = {
 148         .probe          = altera_ps2_probe,
 149         .remove         = altera_ps2_remove,
 150         .driver = {
 151                 .name   = DRV_NAME,
 152                 .of_match_table = of_match_ptr(altera_ps2_match),
 153         },
 154 };
 155 module_platform_driver(altera_ps2_driver);
 156
 157 MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
 158 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
 159 MODULE_LICENSE("GPL");
 160 MODULE_ALIAS("platform:" DRV_NAME);