drivers/input/serio/apbps2.c

   1 /*
   2  * Copyright (C) 2013 Aeroflex Gaisler
   3  *
   4  * This driver supports the APBPS2 PS/2 core available in the GRLIB
   5  * VHDL IP core library.
   6  *
   7  * Full documentation of the APBPS2 core can be found here:
   8  * http://www.gaisler.com/products/grlib/grip.pdf
   9  *
  10  * See "Documentation/devicetree/bindings/input/ps2keyb-mouse-apbps2.txt" for
  11  * information on open firmware properties.
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * Contributors: Daniel Hellstrom <daniel@gaisler.com>
  19  */
  20 #include <linux/platform_device.h>
  21 #include <linux/of_device.h>
  22 #include <linux/module.h>
  23 #include <linux/serio.h>
  24 #include <linux/errno.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/device.h>
  28 #include <linux/delay.h>
  29 #include <linux/err.h>
  30 #include <linux/slab.h>
  31 #include <linux/string.h>
  32 #include <linux/kernel.h>
  33 #include <linux/io.h>
  34
  35 struct apbps2_regs {
  36         u32 __iomem data;       /* 0x00 */
  37         u32 __iomem status;     /* 0x04 */
  38         u32 __iomem ctrl;       /* 0x08 */
  39         u32 __iomem reload;     /* 0x0c */
  40 };
  41
  42 #define APBPS2_STATUS_DR        (1<<0)
  43 #define APBPS2_STATUS_PE        (1<<1)
  44 #define APBPS2_STATUS_FE        (1<<2)
  45 #define APBPS2_STATUS_KI        (1<<3)
  46 #define APBPS2_STATUS_RF        (1<<4)
  47 #define APBPS2_STATUS_TF        (1<<5)
  48 #define APBPS2_STATUS_TCNT      (0x1f<<22)
  49 #define APBPS2_STATUS_RCNT      (0x1f<<27)
  50
  51 #define APBPS2_CTRL_RE          (1<<0)
  52 #define APBPS2_CTRL_TE          (1<<1)
  53 #define APBPS2_CTRL_RI          (1<<2)
  54 #define APBPS2_CTRL_TI          (1<<3)
  55
  56 struct apbps2_priv {
  57         struct serio            *io;
  58         struct apbps2_regs      *regs;
  59 };
  60
  61 static int apbps2_idx;
  62
  63 static irqreturn_t apbps2_isr(int irq, void *dev_id)
  64 {
  65         struct apbps2_priv *priv = dev_id;
  66         unsigned long status, data, rxflags;
  67         irqreturn_t ret = IRQ_NONE;
  68
  69         while ((status = ioread32be(&priv->regs->status)) & APBPS2_STATUS_DR) {
  70                 data = ioread32be(&priv->regs->data);
  71                 rxflags = (status & APBPS2_STATUS_PE) ? SERIO_PARITY : 0;
  72                 rxflags |= (status & APBPS2_STATUS_FE) ? SERIO_FRAME : 0;
  73
  74                 /* clear error bits? */
  75                 if (rxflags)
  76                         iowrite32be(0, &priv->regs->status);
  77
  78                 serio_interrupt(priv->io, data, rxflags);
  79
  80                 ret = IRQ_HANDLED;
  81         }
  82
  83         return ret;
  84 }
  85
  86 static int apbps2_write(struct serio *io, unsigned char val)
  87 {
  88         struct apbps2_priv *priv = io->port_data;
  89         unsigned int tleft = 10000; /* timeout in 100ms */
  90
  91         /* delay until PS/2 controller has room for more chars */
  92         while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) && tleft--)
  93                 udelay(10);
  94
  95         if ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) == 0) {
  96                 iowrite32be(val, &priv->regs->data);
  97
  98                 iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI | APBPS2_CTRL_TE,
  99                                 &priv->regs->ctrl);
 100                 return 0;
 101         }
 102
 103         return -ETIMEDOUT;
 104 }
 105
 106 static int apbps2_open(struct serio *io)
 107 {
 108         struct apbps2_priv *priv = io->port_data;
 109         int limit;
 110         unsigned long tmp;
 111
 112         /* clear error flags */
 113         iowrite32be(0, &priv->regs->status);
 114
 115         /* Clear old data if available (unlikely) */
 116         limit = 1024;
 117         while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_DR) && --limit)
 118                 tmp = ioread32be(&priv->regs->data);
 119
 120         /* Enable reciever and it's interrupt */
 121         iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI, &priv->regs->ctrl);
 122
 123         return 0;
 124 }
 125
 126 static void apbps2_close(struct serio *io)
 127 {
 128         struct apbps2_priv *priv = io->port_data;
 129
 130         /* stop interrupts at PS/2 HW level */
 131         iowrite32be(0, &priv->regs->ctrl);
 132 }
 133
 134 /* Initialize one APBPS2 PS/2 core */
 135 static int apbps2_of_probe(struct platform_device *ofdev)
 136 {
 137         struct apbps2_priv *priv;
 138         int irq, err;
 139         u32 freq_hz;
 140         struct resource *res;
 141
 142         priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
 143         if (!priv) {
 144                 dev_err(&ofdev->dev, "memory allocation failed\n");
 145                 return -ENOMEM;
 146         }
 147
 148         /* Find Device Address */
 149         res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
 150         priv->regs = devm_ioremap_resource(&ofdev->dev, res);
 151         if (IS_ERR(priv->regs))
 152                 return PTR_ERR(priv->regs);
 153
 154         /* Reset hardware, disable interrupt */
 155         iowrite32be(0, &priv->regs->ctrl);
 156
 157         /* IRQ */
 158         irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
 159         err = devm_request_irq(&ofdev->dev, irq, apbps2_isr,
 160                                 IRQF_SHARED, "apbps2", priv);
 161         if (err) {
 162                 dev_err(&ofdev->dev, "request IRQ%d failed\n", irq);
 163                 return err;
 164         }
 165
 166         /* Get core frequency */
 167         if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) {
 168                 dev_err(&ofdev->dev, "unable to get core frequency\n");
 169                 return -EINVAL;
 170         }
 171
 172         /* Set reload register to core freq in kHz/10 */
 173         iowrite32be(freq_hz / 10000, &priv->regs->reload);
 174
 175         priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
 176         if (!priv->io)
 177                 return -ENOMEM;
 178
 179         priv->io->id.type = SERIO_8042;
 180         priv->io->open = apbps2_open;
 181         priv->io->close = apbps2_close;
 182         priv->io->write = apbps2_write;
 183         priv->io->port_data = priv;
 184         strlcpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name));
 185         snprintf(priv->io->phys, sizeof(priv->io->phys),
 186                  "apbps2_%d", apbps2_idx++);
 187
 188         dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs);
 189
 190         serio_register_port(priv->io);
 191
 192         platform_set_drvdata(ofdev, priv);
 193
 194         return 0;
 195 }
 196
 197 static int apbps2_of_remove(struct platform_device *of_dev)
 198 {
 199         struct apbps2_priv *priv = platform_get_drvdata(of_dev);
 200
 201         serio_unregister_port(priv->io);
 202
 203         return 0;
 204 }
 205
 206 static const struct of_device_id apbps2_of_match[] = {
 207         { .name = "GAISLER_APBPS2", },
 208         { .name = "01_060", },
 209         {}
 210 };
 211
 212 MODULE_DEVICE_TABLE(of, apbps2_of_match);
 213
 214 static struct platform_driver apbps2_of_driver = {
 215         .driver = {
 216                 .name = "grlib-apbps2",
 217                 .of_match_table = apbps2_of_match,
 218         },
 219         .probe = apbps2_of_probe,
 220         .remove = apbps2_of_remove,
 221 };
 222
 223 module_platform_driver(apbps2_of_driver);
 224
 225 MODULE_AUTHOR("Aeroflex Gaisler AB.");
 226 MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
 227 MODULE_LICENSE("GPL");