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/init.h>
  23#include <linux/list.h>
  24#include <linux/io.h>
  25
  26#include <linux/of_device.h>
  27#include <linux/of_platform.h>
  28
  29#define DRIVER_NAME             "xilinx_ps2"
  30
  31/* Register offsets for the xps2 device */
  32#define XPS2_SRST_OFFSET        0x00000000 /* Software Reset register */
  33#define XPS2_STATUS_OFFSET      0x00000004 /* Status register */
  34#define XPS2_RX_DATA_OFFSET     0x00000008 /* Receive Data register */
  35#define XPS2_TX_DATA_OFFSET     0x0000000C /* Transmit Data register */
  36#define XPS2_GIER_OFFSET        0x0000002C /* Global Interrupt Enable reg */
  37#define XPS2_IPISR_OFFSET       0x00000030 /* Interrupt Status register */
  38#define XPS2_IPIER_OFFSET       0x00000038 /* Interrupt Enable register */
  39
  40/* Reset Register Bit Definitions */
  41#define XPS2_SRST_RESET         0x0000000A /* Software Reset  */
  42
  43/* Status Register Bit Positions */
  44#define XPS2_STATUS_RX_FULL     0x00000001 /* Receive Full  */
  45#define XPS2_STATUS_TX_FULL     0x00000002 /* Transmit Full  */
  46
  47/* Bit definitions for ISR/IER registers. Both the registers have the same bit
  48 * definitions and are only defined once. */
  49#define XPS2_IPIXR_WDT_TOUT     0x00000001 /* Watchdog Timeout Interrupt */
  50#define XPS2_IPIXR_TX_NOACK     0x00000002 /* Transmit No ACK Interrupt */
  51#define XPS2_IPIXR_TX_ACK       0x00000004 /* Transmit ACK (Data) Interrupt */
  52#define XPS2_IPIXR_RX_OVF       0x00000008 /* Receive Overflow Interrupt */
  53#define XPS2_IPIXR_RX_ERR       0x00000010 /* Receive Error Interrupt */
  54#define XPS2_IPIXR_RX_FULL      0x00000020 /* Receive Data Interrupt */
  55
  56/* Mask for all the Transmit Interrupts */
  57#define XPS2_IPIXR_TX_ALL       (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
  58
  59/* Mask for all the Receive Interrupts */
  60#define XPS2_IPIXR_RX_ALL       (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
  61                                 XPS2_IPIXR_RX_FULL)
  62
  63/* Mask for all the Interrupts */
  64#define XPS2_IPIXR_ALL          (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
  65                                 XPS2_IPIXR_WDT_TOUT)
  66
  67/* Global Interrupt Enable mask */
  68#define XPS2_GIER_GIE_MASK      0x80000000
  69
  70struct xps2data {
  71        int irq;
  72        spinlock_t lock;
  73        void __iomem *base_address;     /* virt. address of control registers */
  74        unsigned int flags;
  75        struct serio serio;             /* serio */
  76};
  77
  78/************************************/
  79/* XPS PS/2 data transmission calls */
  80/************************************/
  81
  82/**
  83 * xps2_recv() - attempts to receive a byte from the PS/2 port.
  84 * @drvdata:    pointer to ps2 device private data structure
  85 * @byte:       address where the read data will be copied
  86 *
  87 * If there is any data available in the PS/2 receiver, this functions reads
  88 * the data, otherwise it returns error.
  89 */
  90static int xps2_recv(struct xps2data *drvdata, u8 *byte)
  91{
  92        u32 sr;
  93        int status = -1;
  94
  95        /* If there is data available in the PS/2 receiver, read it */
  96        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
  97        if (sr & XPS2_STATUS_RX_FULL) {
  98                *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
  99                status = 0;
 100        }
 101
 102        return status;
 103}
 104
 105/*********************/
 106/* Interrupt handler */
 107/*********************/
 108static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 109{
 110        struct xps2data *drvdata = dev_id;
 111        u32 intr_sr;
 112        u8 c;
 113        int status;
 114
 115        /* Get the PS/2 interrupts and clear them */
 116        intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
 117        out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
 118
 119        /* Check which interrupt is active */
 120        if (intr_sr & XPS2_IPIXR_RX_OVF)
 121                dev_warn(drvdata->serio.dev.parent, "receive overrun error\n");
 122
 123        if (intr_sr & XPS2_IPIXR_RX_ERR)
 124                drvdata->flags |= SERIO_PARITY;
 125
 126        if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
 127                drvdata->flags |= SERIO_TIMEOUT;
 128
 129        if (intr_sr & XPS2_IPIXR_RX_FULL) {
 130                status = xps2_recv(drvdata, &c);
 131
 132                /* Error, if a byte is not received */
 133                if (status) {
 134                        dev_err(drvdata->serio.dev.parent,
 135                                "wrong rcvd byte count (%d)\n", status);
 136                } else {
 137                        serio_interrupt(&drvdata->serio, c, drvdata->flags);
 138                        drvdata->flags = 0;
 139                }
 140        }
 141
 142        return IRQ_HANDLED;
 143}
 144
 145/*******************/
 146/* serio callbacks */
 147/*******************/
 148
 149/**
 150 * sxps2_write() - sends a byte out through the PS/2 port.
 151 * @pserio:     pointer to the serio structure of the PS/2 port
 152 * @c:          data that needs to be written to the PS/2 port
 153 *
 154 * This function checks if the PS/2 transmitter is empty and sends a byte.
 155 * Otherwise it returns error. Transmission fails only when nothing is connected
 156 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
 157 * failure.
 158 */
 159static int sxps2_write(struct serio *pserio, unsigned char c)
 160{
 161        struct xps2data *drvdata = pserio->port_data;
 162        unsigned long flags;
 163        u32 sr;
 164        int status = -1;
 165
 166        spin_lock_irqsave(&drvdata->lock, flags);
 167
 168        /* If the PS/2 transmitter is empty send a byte of data */
 169        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 170        if (!(sr & XPS2_STATUS_TX_FULL)) {
 171                out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
 172                status = 0;
 173        }
 174
 175        spin_unlock_irqrestore(&drvdata->lock, flags);
 176
 177        return status;
 178}
 179
 180/**
 181 * sxps2_open() - called when a port is opened by the higher layer.
 182 * @pserio:     pointer to the serio structure of the PS/2 device
 183 *
 184 * This function requests irq and enables interrupts for the PS/2 device.
 185 */
 186static int sxps2_open(struct serio *pserio)
 187{
 188        struct xps2data *drvdata = pserio->port_data;
 189        int error;
 190        u8 c;
 191
 192        error = request_irq(drvdata->irq, &xps2_interrupt, 0,
 193                                DRIVER_NAME, drvdata);
 194        if (error) {
 195                dev_err(drvdata->serio.dev.parent,
 196                        "Couldn't allocate interrupt %d\n", drvdata->irq);
 197                return error;
 198        }
 199
 200        /* start reception by enabling the interrupts */
 201        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 202        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 203        (void)xps2_recv(drvdata, &c);
 204
 205        return 0;               /* success */
 206}
 207
 208/**
 209 * sxps2_close() - frees the interrupt.
 210 * @pserio:     pointer to the serio structure of the PS/2 device
 211 *
 212 * This function frees the irq and disables interrupts for the PS/2 device.
 213 */
 214static void sxps2_close(struct serio *pserio)
 215{
 216        struct xps2data *drvdata = pserio->port_data;
 217
 218        /* Disable the PS2 interrupts */
 219        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
 220        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
 221        free_irq(drvdata->irq, drvdata);
 222}
 223
 224/**
 225 * xps2_of_probe - probe method for the PS/2 device.
 226 * @of_dev:     pointer to OF device structure
 227 * @match:      pointer to the stucture used for matching a device
 228 *
 229 * This function probes the PS/2 device in the device tree.
 230 * It initializes the driver data structure and the hardware.
 231 * It returns 0, if the driver is bound to the PS/2 device, or a negative
 232 * value if there is an error.
 233 */
 234static int __devinit xps2_of_probe(struct of_device *ofdev,
 235                                   const struct of_device_id *match)
 236{
 237        struct resource r_irq; /* Interrupt resources */
 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        int error;
 244
 245        dev_info(dev, "Device Tree Probing \'%s\'\n",
 246                        ofdev->node->name);
 247
 248        /* Get iospace for the device */
 249        error = of_address_to_resource(ofdev->node, 0, &r_mem);
 250        if (error) {
 251                dev_err(dev, "invalid address\n");
 252                return error;
 253        }
 254
 255        /* Get IRQ for the device */
 256        if (of_irq_to_resource(ofdev->node, 0, &r_irq) == NO_IRQ) {
 257                dev_err(dev, "no IRQ found\n");
 258                return -ENODEV;
 259        }
 260
 261        drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
 262        if (!drvdata) {
 263                dev_err(dev, "Couldn't allocate device private record\n");
 264                return -ENOMEM;
 265        }
 266
 267        dev_set_drvdata(dev, drvdata);
 268
 269        spin_lock_init(&drvdata->lock);
 270        drvdata->irq = r_irq.start;
 271
 272        phys_addr = r_mem.start;
 273        remap_size = r_mem.end - r_mem.start + 1;
 274        if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
 275                dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
 276                        (unsigned long long)phys_addr);
 277                error = -EBUSY;
 278                goto failed1;
 279        }
 280
 281        /* Fill in configuration data and add them to the list */
 282        drvdata->base_address = ioremap(phys_addr, remap_size);
 283        if (drvdata->base_address == NULL) {
 284                dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
 285                        (unsigned long long)phys_addr);
 286                error = -EFAULT;
 287                goto failed2;
 288        }
 289
 290        /* Disable all the interrupts, just in case */
 291        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
 292
 293        /* Reset the PS2 device and abort any current transaction, to make sure
 294         * we have the PS2 in a good state */
 295        out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
 296
 297        dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
 298                 (unsigned long long)phys_addr, drvdata->base_address,
 299                 drvdata->irq);
 300
 301        serio = &drvdata->serio;
 302        serio->id.type = SERIO_8042;
 303        serio->write = sxps2_write;
 304        serio->open = sxps2_open;
 305        serio->close = sxps2_close;
 306        serio->port_data = drvdata;
 307        serio->dev.parent = dev;
 308        snprintf(serio->name, sizeof(serio->name),
 309                 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
 310        snprintf(serio->phys, sizeof(serio->phys),
 311                 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
 312
 313        serio_register_port(serio);
 314
 315        return 0;               /* success */
 316
 317failed2:
 318        release_mem_region(phys_addr, remap_size);
 319failed1:
 320        kfree(drvdata);
 321        dev_set_drvdata(dev, NULL);
 322
 323        return error;
 324}
 325
 326/**
 327 * xps2_of_remove - unbinds the driver from the PS/2 device.
 328 * @of_dev:     pointer to OF device structure
 329 *
 330 * This function is called if a device is physically removed from the system or
 331 * if the driver module is being unloaded. It frees any resources allocated to
 332 * the device.
 333 */
 334static int __devexit xps2_of_remove(struct of_device *of_dev)
 335{
 336        struct device *dev = &of_dev->dev;
 337        struct xps2data *drvdata = dev_get_drvdata(dev);
 338        struct resource r_mem; /* IO mem resources */
 339
 340        serio_unregister_port(&drvdata->serio);
 341        iounmap(drvdata->base_address);
 342
 343        /* Get iospace of the device */
 344        if (of_address_to_resource(of_dev->node, 0, &r_mem))
 345                dev_err(dev, "invalid address\n");
 346        else
 347                release_mem_region(r_mem.start, r_mem.end - r_mem.start + 1);
 348
 349        kfree(drvdata);
 350
 351        dev_set_drvdata(dev, NULL);
 352
 353        return 0;
 354}
 355
 356/* Match table for of_platform binding */
 357static struct of_device_id xps2_of_match[] __devinitdata = {
 358        { .compatible = "xlnx,xps-ps2-1.00.a", },
 359        { /* end of list */ },
 360};
 361MODULE_DEVICE_TABLE(of, xps2_of_match);
 362
 363static struct of_platform_driver xps2_of_driver = {
 364        .name           = DRIVER_NAME,
 365        .match_table    = xps2_of_match,
 366        .probe          = xps2_of_probe,
 367        .remove         = __devexit_p(xps2_of_remove),
 368};
 369
 370static int __init xps2_init(void)
 371{
 372        return of_register_platform_driver(&xps2_of_driver);
 373}
 374
 375static void __exit xps2_cleanup(void)
 376{
 377        of_unregister_platform_driver(&xps2_of_driver);
 378}
 379
 380module_init(xps2_init);
 381module_exit(xps2_cleanup);
 382
 383MODULE_AUTHOR("Xilinx, Inc.");
 384MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 385MODULE_LICENSE("GPL");
 386
 387