LXR linux/drivers/input/serio/xilinx

   1/*
   2 * Xilinx XPS PS/2 device driver
   3 *
   4 * (c) 2005 MontaVista Software, Inc.
   5 * (c) 2008 Xilinx, Inc.
   6 *
   7 * This program is free software; you can redistribute it and/or modify it
   8 * under the terms of the GNU General Public License as published by the
   9 * Free Software Foundation; either version 2 of the License, or (at your
  10 * option) any later version.
  11 *
  12 * You should have received a copy of the GNU General Public License along
  13 * with this program; if not, write to the Free Software Foundation, Inc.,
  14 * 675 Mass Ave, Cambridge, MA 02139, USA.
  15 */
  16
  17
  18#include <linux/module.h>
  19#include <linux/serio.h>
  20#include <linux/interrupt.h>
  21#include <linux/errno.h>
  22#include <linux/slab.h>
  23#include <linux/list.h>
  24#include <linux/io.h>
  25#include <linux/of_address.h>
  26#include <linux/of_device.h>
  27#include <linux/of_irq.h>
  28#include <linux/of_platform.h>
  29
  30#define DRIVER_NAME             "xilinx_ps2"
  31
  32/* Register offsets for the xps2 device */
  33#define XPS2_SRST_OFFSET        0x00000000 /* Software Reset register */
  34#define XPS2_STATUS_OFFSET      0x00000004 /* Status register */
  35#define XPS2_RX_DATA_OFFSET     0x00000008 /* Receive Data register */
  36#define XPS2_TX_DATA_OFFSET     0x0000000C /* Transmit Data register */
  37#define XPS2_GIER_OFFSET        0x0000002C /* Global Interrupt Enable reg */
  38#define XPS2_IPISR_OFFSET       0x00000030 /* Interrupt Status register */
  39#define XPS2_IPIER_OFFSET       0x00000038 /* Interrupt Enable register */
  40
  41/* Reset Register Bit Definitions */
  42#define XPS2_SRST_RESET         0x0000000A /* Software Reset  */
  43
  44/* Status Register Bit Positions */
  45#define XPS2_STATUS_RX_FULL     0x00000001 /* Receive Full  */
  46#define XPS2_STATUS_TX_FULL     0x00000002 /* Transmit Full  */
  47
  48/* Bit definitions for ISR/IER registers. Both the registers have the same bit
  49 * definitions and are only defined once. */
  50#define XPS2_IPIXR_WDT_TOUT     0x00000001 /* Watchdog Timeout Interrupt */
  51#define XPS2_IPIXR_TX_NOACK     0x00000002 /* Transmit No ACK Interrupt */
  52#define XPS2_IPIXR_TX_ACK       0x00000004 /* Transmit ACK (Data) Interrupt */
  53#define XPS2_IPIXR_RX_OVF       0x00000008 /* Receive Overflow Interrupt */
  54#define XPS2_IPIXR_RX_ERR       0x00000010 /* Receive Error Interrupt */
  55#define XPS2_IPIXR_RX_FULL      0x00000020 /* Receive Data Interrupt */
  56
  57/* Mask for all the Transmit Interrupts */
  58#define XPS2_IPIXR_TX_ALL       (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
  59
  60/* Mask for all the Receive Interrupts */
  61#define XPS2_IPIXR_RX_ALL       (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
  62                                 XPS2_IPIXR_RX_FULL)
  63
  64/* Mask for all the Interrupts */
  65#define XPS2_IPIXR_ALL          (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
  66                                 XPS2_IPIXR_WDT_TOUT)
  67
  68/* Global Interrupt Enable mask */
  69#define XPS2_GIER_GIE_MASK      0x80000000
  70
  71struct xps2data {
  72        int irq;
  73        spinlock_t lock;
  74        void __iomem *base_address;     /* virt. address of control registers */
  75        unsigned int flags;
  76        struct serio *serio;            /* serio */
  77        struct device *dev;
  78};
  79
  80/************************************/
  81/* XPS PS/2 data transmission calls */
  82/************************************/
  83
  84/**
  85 * xps2_recv() - attempts to receive a byte from the PS/2 port.
  86 * @drvdata:    pointer to ps2 device private data structure
  87 * @byte:       address where the read data will be copied
  88 *
  89 * If there is any data available in the PS/2 receiver, this functions reads
  90 * the data, otherwise it returns error.
  91 */
  92static int xps2_recv(struct xps2data *drvdata, u8 *byte)
  93{
  94        u32 sr;
  95        int status = -1;
  96
  97        /* If there is data available in the PS/2 receiver, read it */
  98        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
  99        if (sr & XPS2_STATUS_RX_FULL) {
 100                *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
 101                status = 0;
 102        }
 103
 104        return status;
 105}
 106
 107/*********************/
 108/* Interrupt handler */
 109/*********************/
 110static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 111{
 112        struct xps2data *drvdata = dev_id;
 113        u32 intr_sr;
 114        u8 c;
 115        int status;
 116
 117        /* Get the PS/2 interrupts and clear them */
 118        intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
 119        out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
 120
 121        /* Check which interrupt is active */
 122        if (intr_sr & XPS2_IPIXR_RX_OVF)
 123                dev_warn(drvdata->dev, "receive overrun error\n");
 124
 125        if (intr_sr & XPS2_IPIXR_RX_ERR)
 126                drvdata->flags |= SERIO_PARITY;
 127
 128        if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
 129                drvdata->flags |= SERIO_TIMEOUT;
 130
 131        if (intr_sr & XPS2_IPIXR_RX_FULL) {
 132                status = xps2_recv(drvdata, &c);
 133
 134                /* Error, if a byte is not received */
 135                if (status) {
 136                        dev_err(drvdata->dev,
 137                                "wrong rcvd byte count (%d)\n", status);
 138                } else {
 139                        serio_interrupt(drvdata->serio, c, drvdata->flags);
 140                        drvdata->flags = 0;
 141                }
 142        }
 143
 144        return IRQ_HANDLED;
 145}
 146
 147/*******************/
 148/* serio callbacks */
 149/*******************/
 150
 151/**
 152 * sxps2_write() - sends a byte out through the PS/2 port.
 153 * @pserio:     pointer to the serio structure of the PS/2 port
 154 * @c:          data that needs to be written to the PS/2 port
 155 *
 156 * This function checks if the PS/2 transmitter is empty and sends a byte.
 157 * Otherwise it returns error. Transmission fails only when nothing is connected
 158 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
 159 * failure.
 160 */
 161static int sxps2_write(struct serio *pserio, unsigned char c)
 162{
 163        struct xps2data *drvdata = pserio->port_data;
 164        unsigned long flags;
 165        u32 sr;
 166        int status = -1;
 167
 168        spin_lock_irqsave(&drvdata->lock, flags);
 169
 170        /* If the PS/2 transmitter is empty send a byte of data */
 171        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 172        if (!(sr & XPS2_STATUS_TX_FULL)) {
 173                out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
 174                status = 0;
 175        }
 176
 177        spin_unlock_irqrestore(&drvdata->lock, flags);
 178
 179        return status;
 180}
 181
 182/**
 183 * sxps2_open() - called when a port is opened by the higher layer.
 184 * @pserio:     pointer to the serio structure of the PS/2 device
 185 *
 186 * This function requests irq and enables interrupts for the PS/2 device.
 187 */
 188static int sxps2_open(struct serio *pserio)
 189{
 190        struct xps2data *drvdata = pserio->port_data;
 191        int error;
 192        u8 c;
 193
 194        error = request_irq(drvdata->irq, &xps2_interrupt, 0,
 195                                DRIVER_NAME, drvdata);
 196        if (error) {
 197                dev_err(drvdata->dev,
 198                        "Couldn't allocate interrupt %d\n", drvdata->irq);
 199                return error;
 200        }
 201
 202        /* start reception by enabling the interrupts */
 203        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 204        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 205        (void)xps2_recv(drvdata, &c);
 206
 207        return 0;               /* success */
 208}
 209
 210/**
 211 * sxps2_close() - frees the interrupt.
 212 * @pserio:     pointer to the serio structure of the PS/2 device
 213 *
 214 * This function frees the irq and disables interrupts for the PS/2 device.
 215 */
 216static void sxps2_close(struct serio *pserio)
 217{
 218        struct xps2data *drvdata = pserio->port_data;
 219
 220        /* Disable the PS2 interrupts */
 221        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
 222        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
 223        free_irq(drvdata->irq, drvdata);
 224}
 225
 226/**
 227 * xps2_of_probe - probe method for the PS/2 device.
 228 * @of_dev:     pointer to OF device structure
 229 * @match:      pointer to the structure used for matching a device
 230 *
 231 * This function probes the PS/2 device in the device tree.
 232 * It initializes the driver data structure and the hardware.
 233 * It returns 0, if the driver is bound to the PS/2 device, or a negative
 234 * value if there is an error.
 235 */
 236static int xps2_of_probe(struct platform_device *ofdev)
 237{
 238        struct resource r_mem; /* IO mem resources */
 239        struct xps2data *drvdata;
 240        struct serio *serio;
 241        struct device *dev = &ofdev->dev;
 242        resource_size_t remap_size, phys_addr;
 243        unsigned int irq;
 244        int error;
 245
 246        dev_info(dev, "Device Tree Probing \'%s\'\n",
 247                        ofdev->dev.of_node->name);
 248
 249        /* Get iospace for the device */
 250        error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
 251        if (error) {
 252                dev_err(dev, "invalid address\n");
 253                return error;
 254        }
 255
 256        /* Get IRQ for the device */
 257        irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
 258        if (!irq) {
 259                dev_err(dev, "no IRQ found\n");
 260                return -ENODEV;
 261        }
 262
 263        drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
 264        serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 265        if (!drvdata || !serio) {
 266                error = -ENOMEM;
 267                goto failed1;
 268        }
 269
 270        spin_lock_init(&drvdata->lock);
 271        drvdata->irq = irq;
 272        drvdata->serio = serio;
 273        drvdata->dev = dev;
 274
 275        phys_addr = r_mem.start;
 276        remap_size = resource_size(&r_mem);
 277        if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
 278                dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
 279                        (unsigned long long)phys_addr);
 280                error = -EBUSY;
 281                goto failed1;
 282        }
 283
 284        /* Fill in configuration data and add them to the list */
 285        drvdata->base_address = ioremap(phys_addr, remap_size);
 286        if (drvdata->base_address == NULL) {
 287                dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
 288                        (unsigned long long)phys_addr);
 289                error = -EFAULT;
 290                goto failed2;
 291        }
 292
 293        /* Disable all the interrupts, just in case */
 294        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
 295
 296        /* Reset the PS2 device and abort any current transaction, to make sure
 297         * we have the PS2 in a good state */
 298        out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
 299
 300        dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
 301                 (unsigned long long)phys_addr, drvdata->base_address,
 302                 drvdata->irq);
 303
 304        serio->id.type = SERIO_8042;
 305        serio->write = sxps2_write;
 306        serio->open = sxps2_open;
 307        serio->close = sxps2_close;
 308        serio->port_data = drvdata;
 309        serio->dev.parent = dev;
 310        snprintf(serio->name, sizeof(serio->name),
 311                 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
 312        snprintf(serio->phys, sizeof(serio->phys),
 313                 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
 314
 315        serio_register_port(serio);
 316
 317        platform_set_drvdata(ofdev, drvdata);
 318        return 0;               /* success */
 319
 320failed2:
 321        release_mem_region(phys_addr, remap_size);
 322failed1:
 323        kfree(serio);
 324        kfree(drvdata);
 325
 326        return error;
 327}
 328
 329/**
 330 * xps2_of_remove - unbinds the driver from the PS/2 device.
 331 * @of_dev:     pointer to OF device structure
 332 *
 333 * This function is called if a device is physically removed from the system or
 334 * if the driver module is being unloaded. It frees any resources allocated to
 335 * the device.
 336 */
 337static int xps2_of_remove(struct platform_device *of_dev)
 338{
 339        struct xps2data *drvdata = platform_get_drvdata(of_dev);
 340        struct resource r_mem; /* IO mem resources */
 341
 342        serio_unregister_port(drvdata->serio);
 343        iounmap(drvdata->base_address);
 344
 345        /* Get iospace of the device */
 346        if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
 347                dev_err(drvdata->dev, "invalid address\n");
 348        else
 349                release_mem_region(r_mem.start, resource_size(&r_mem));
 350
 351        kfree(drvdata);
 352
 353        return 0;
 354}
 355
 356/* Match table for of_platform binding */
 357static const struct of_device_id xps2_of_match[] = {
 358        { .compatible = "xlnx,xps-ps2-1.00.a", },
 359        { /* end of list */ },
 360};
 361MODULE_DEVICE_TABLE(of, xps2_of_match);
 362
 363static struct platform_driver xps2_of_driver = {
 364        .driver = {
 365                .name = DRIVER_NAME,
 366                .of_match_table = xps2_of_match,
 367        },
 368        .probe          = xps2_of_probe,
 369        .remove         = xps2_of_remove,
 370};
 371module_platform_driver(xps2_of_driver);
 372
 373MODULE_AUTHOR("Xilinx, Inc.");
 374MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 375MODULE_LICENSE("GPL");
 376
 377