drivers/input/serio/apbps2.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2013 Aeroflex Gaisler
   4  *
   5  * This driver supports the APBPS2 PS/2 core available in the GRLIB
   6  * VHDL IP core library.
   7  *
   8  * Full documentation of the APBPS2 core can be found here:
   9  * http://www.gaisler.com/products/grlib/grip.pdf
  10  *
  11  * See "Documentation/devicetree/bindings/input/ps2keyb-mouse-apbps2.txt" for
  12  * information on open firmware properties.
  13  *
  14  * Contributors: Daniel Hellstrom <daniel@gaisler.com>
  15  */
  16 #include <linux/platform_device.h>
  17 #include <linux/of_device.h>
  18 #include <linux/module.h>
  19 #include <linux/serio.h>
  20 #include <linux/errno.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/of_irq.h>
  23 #include <linux/device.h>
  24 #include <linux/delay.h>
  25 #include <linux/err.h>
  26 #include <linux/slab.h>
  27 #include <linux/string.h>
  28 #include <linux/kernel.h>
  29 #include <linux/io.h>
  30
  31 struct apbps2_regs {
  32         u32 __iomem data;       /* 0x00 */
  33         u32 __iomem status;     /* 0x04 */
  34         u32 __iomem ctrl;       /* 0x08 */
  35         u32 __iomem reload;     /* 0x0c */
  36 };
  37
  38 #define APBPS2_STATUS_DR        (1<<0)
  39 #define APBPS2_STATUS_PE        (1<<1)
  40 #define APBPS2_STATUS_FE        (1<<2)
  41 #define APBPS2_STATUS_KI        (1<<3)
  42 #define APBPS2_STATUS_RF        (1<<4)
  43 #define APBPS2_STATUS_TF        (1<<5)
  44 #define APBPS2_STATUS_TCNT      (0x1f<<22)
  45 #define APBPS2_STATUS_RCNT      (0x1f<<27)
  46
  47 #define APBPS2_CTRL_RE          (1<<0)
  48 #define APBPS2_CTRL_TE          (1<<1)
  49 #define APBPS2_CTRL_RI          (1<<2)
  50 #define APBPS2_CTRL_TI          (1<<3)
  51
  52 struct apbps2_priv {
  53         struct serio            *io;
  54         struct apbps2_regs      __iomem *regs;
  55 };
  56
  57 static int apbps2_idx;
  58
  59 static irqreturn_t apbps2_isr(int irq, void *dev_id)
  60 {
  61         struct apbps2_priv *priv = dev_id;
  62         unsigned long status, data, rxflags;
  63         irqreturn_t ret = IRQ_NONE;
  64
  65         while ((status = ioread32be(&priv->regs->status)) & APBPS2_STATUS_DR) {
  66                 data = ioread32be(&priv->regs->data);
  67                 rxflags = (status & APBPS2_STATUS_PE) ? SERIO_PARITY : 0;
  68                 rxflags |= (status & APBPS2_STATUS_FE) ? SERIO_FRAME : 0;
  69
  70                 /* clear error bits? */
  71                 if (rxflags)
  72                         iowrite32be(0, &priv->regs->status);
  73
  74                 serio_interrupt(priv->io, data, rxflags);
  75
  76                 ret = IRQ_HANDLED;
  77         }
  78
  79         return ret;
  80 }
  81
  82 static int apbps2_write(struct serio *io, unsigned char val)
  83 {
  84         struct apbps2_priv *priv = io->port_data;
  85         unsigned int tleft = 10000; /* timeout in 100ms */
  86
  87         /* delay until PS/2 controller has room for more chars */
  88         while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) && tleft--)
  89                 udelay(10);
  90
  91         if ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) == 0) {
  92                 iowrite32be(val, &priv->regs->data);
  93
  94                 iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI | APBPS2_CTRL_TE,
  95                                 &priv->regs->ctrl);
  96                 return 0;
  97         }
  98
  99         return -ETIMEDOUT;
 100 }
 101
 102 static int apbps2_open(struct serio *io)
 103 {
 104         struct apbps2_priv *priv = io->port_data;
 105         int limit;
 106         unsigned long tmp;
 107
 108         /* clear error flags */
 109         iowrite32be(0, &priv->regs->status);
 110
 111         /* Clear old data if available (unlikely) */
 112         limit = 1024;
 113         while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_DR) && --limit)
 114                 tmp = ioread32be(&priv->regs->data);
 115
 116         /* Enable reciever and it's interrupt */
 117         iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI, &priv->regs->ctrl);
 118
 119         return 0;
 120 }
 121
 122 static void apbps2_close(struct serio *io)
 123 {
 124         struct apbps2_priv *priv = io->port_data;
 125
 126         /* stop interrupts at PS/2 HW level */
 127         iowrite32be(0, &priv->regs->ctrl);
 128 }
 129
 130 /* Initialize one APBPS2 PS/2 core */
 131 static int apbps2_of_probe(struct platform_device *ofdev)
 132 {
 133         struct apbps2_priv *priv;
 134         int irq, err;
 135         u32 freq_hz;
 136         struct resource *res;
 137
 138         priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
 139         if (!priv) {
 140                 dev_err(&ofdev->dev, "memory allocation failed\n");
 141                 return -ENOMEM;
 142         }
 143
 144         /* Find Device Address */
 145         res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
 146         priv->regs = devm_ioremap_resource(&ofdev->dev, res);
 147         if (IS_ERR(priv->regs))
 148                 return PTR_ERR(priv->regs);
 149
 150         /* Reset hardware, disable interrupt */
 151         iowrite32be(0, &priv->regs->ctrl);
 152
 153         /* IRQ */
 154         irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
 155         err = devm_request_irq(&ofdev->dev, irq, apbps2_isr,
 156                                 IRQF_SHARED, "apbps2", priv);
 157         if (err) {
 158                 dev_err(&ofdev->dev, "request IRQ%d failed\n", irq);
 159                 return err;
 160         }
 161
 162         /* Get core frequency */
 163         if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) {
 164                 dev_err(&ofdev->dev, "unable to get core frequency\n");
 165                 return -EINVAL;
 166         }
 167
 168         /* Set reload register to core freq in kHz/10 */
 169         iowrite32be(freq_hz / 10000, &priv->regs->reload);
 170
 171         priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
 172         if (!priv->io)
 173                 return -ENOMEM;
 174
 175         priv->io->id.type = SERIO_8042;
 176         priv->io->open = apbps2_open;
 177         priv->io->close = apbps2_close;
 178         priv->io->write = apbps2_write;
 179         priv->io->port_data = priv;
 180         strlcpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name));
 181         snprintf(priv->io->phys, sizeof(priv->io->phys),
 182                  "apbps2_%d", apbps2_idx++);
 183
 184         dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs);
 185
 186         serio_register_port(priv->io);
 187
 188         platform_set_drvdata(ofdev, priv);
 189
 190         return 0;
 191 }
 192
 193 static int apbps2_of_remove(struct platform_device *of_dev)
 194 {
 195         struct apbps2_priv *priv = platform_get_drvdata(of_dev);
 196
 197         serio_unregister_port(priv->io);
 198
 199         return 0;
 200 }
 201
 202 static const struct of_device_id apbps2_of_match[] = {
 203         { .name = "GAISLER_APBPS2", },
 204         { .name = "01_060", },
 205         {}
 206 };
 207
 208 MODULE_DEVICE_TABLE(of, apbps2_of_match);
 209
 210 static struct platform_driver apbps2_of_driver = {
 211         .driver = {
 212                 .name = "grlib-apbps2",
 213                 .of_match_table = apbps2_of_match,
 214         },
 215         .probe = apbps2_of_probe,
 216         .remove = apbps2_of_remove,
 217 };
 218
 219 module_platform_driver(apbps2_of_driver);
 220
 221 MODULE_AUTHOR("Aeroflex Gaisler AB.");
 222 MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
 223 MODULE_LICENSE("GPL");