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/init.h>
  24#include <linux/list.h>
  25#include <linux/io.h>
  26#include <linux/of_address.h>
  27#include <linux/of_device.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};
  78
  79/************************************/
  80/* XPS PS/2 data transmission calls */
  81/************************************/
  82
  83/**
  84 * xps2_recv() - attempts to receive a byte from the PS/2 port.
  85 * @drvdata:    pointer to ps2 device private data structure
  86 * @byte:       address where the read data will be copied
  87 *
  88 * If there is any data available in the PS/2 receiver, this functions reads
  89 * the data, otherwise it returns error.
  90 */
  91static int xps2_recv(struct xps2data *drvdata, u8 *byte)
  92{
  93        u32 sr;
  94        int status = -1;
  95
  96        /* If there is data available in the PS/2 receiver, read it */
  97        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
  98        if (sr & XPS2_STATUS_RX_FULL) {
  99                *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
 100                status = 0;
 101        }
 102
 103        return status;
 104}
 105
 106/*********************/
 107/* Interrupt handler */
 108/*********************/
 109static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 110{
 111        struct xps2data *drvdata = dev_id;
 112        u32 intr_sr;
 113        u8 c;
 114        int status;
 115
 116        /* Get the PS/2 interrupts and clear them */
 117        intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
 118        out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
 119
 120        /* Check which interrupt is active */
 121        if (intr_sr & XPS2_IPIXR_RX_OVF)
 122                dev_warn(drvdata->serio.dev.parent, "receive overrun error\n");
 123
 124        if (intr_sr & XPS2_IPIXR_RX_ERR)
 125                drvdata->flags |= SERIO_PARITY;
 126
 127        if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
 128                drvdata->flags |= SERIO_TIMEOUT;
 129
 130        if (intr_sr & XPS2_IPIXR_RX_FULL) {
 131                status = xps2_recv(drvdata, &c);
 132
 133                /* Error, if a byte is not received */
 134                if (status) {
 135                        dev_err(drvdata->serio.dev.parent,
 136                                "wrong rcvd byte count (%d)\n", status);
 137                } else {
 138                        serio_interrupt(&drvdata->serio, c, drvdata->flags);
 139                        drvdata->flags = 0;
 140                }
 141        }
 142
 143        return IRQ_HANDLED;
 144}
 145
 146/*******************/
 147/* serio callbacks */
 148/*******************/
 149
 150/**
 151 * sxps2_write() - sends a byte out through the PS/2 port.
 152 * @pserio:     pointer to the serio structure of the PS/2 port
 153 * @c:          data that needs to be written to the PS/2 port
 154 *
 155 * This function checks if the PS/2 transmitter is empty and sends a byte.
 156 * Otherwise it returns error. Transmission fails only when nothing is connected
 157 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
 158 * failure.
 159 */
 160static int sxps2_write(struct serio *pserio, unsigned char c)
 161{
 162        struct xps2data *drvdata = pserio->port_data;
 163        unsigned long flags;
 164        u32 sr;
 165        int status = -1;
 166
 167        spin_lock_irqsave(&drvdata->lock, flags);
 168
 169        /* If the PS/2 transmitter is empty send a byte of data */
 170        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 171        if (!(sr & XPS2_STATUS_TX_FULL)) {
 172                out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
 173                status = 0;
 174        }
 175
 176        spin_unlock_irqrestore(&drvdata->lock, flags);
 177
 178        return status;
 179}
 180
 181/**
 182 * sxps2_open() - called when a port is opened by the higher layer.
 183 * @pserio:     pointer to the serio structure of the PS/2 device
 184 *
 185 * This function requests irq and enables interrupts for the PS/2 device.
 186 */
 187static int sxps2_open(struct serio *pserio)
 188{
 189        struct xps2data *drvdata = pserio->port_data;
 190        int error;
 191        u8 c;
 192
 193        error = request_irq(drvdata->irq, &xps2_interrupt, 0,
 194                                DRIVER_NAME, drvdata);
 195        if (error) {
 196                dev_err(drvdata->serio.dev.parent,
 197                        "Couldn't allocate interrupt %d\n", drvdata->irq);
 198                return error;
 199        }
 200
 201        /* start reception by enabling the interrupts */
 202        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 203        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 204        (void)xps2_recv(drvdata, &c);
 205
 206        return 0;               /* success */
 207}
 208
 209/**
 210 * sxps2_close() - frees the interrupt.
 211 * @pserio:     pointer to the serio structure of the PS/2 device
 212 *
 213 * This function frees the irq and disables interrupts for the PS/2 device.
 214 */
 215static void sxps2_close(struct serio *pserio)
 216{
 217        struct xps2data *drvdata = pserio->port_data;
 218
 219        /* Disable the PS2 interrupts */
 220        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
 221        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
 222        free_irq(drvdata->irq, drvdata);
 223}
 224
 225/**
 226 * xps2_of_probe - probe method for the PS/2 device.
 227 * @of_dev:     pointer to OF device structure
 228 * @match:      pointer to the structure used for matching a device
 229 *
 230 * This function probes the PS/2 device in the device tree.
 231 * It initializes the driver data structure and the hardware.
 232 * It returns 0, if the driver is bound to the PS/2 device, or a negative
 233 * value if there is an error.
 234 */
 235static int __devinit xps2_of_probe(struct platform_device *ofdev)
 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->dev.of_node->name);
 247
 248        /* Get iospace for the device */
 249        error = of_address_to_resource(ofdev->dev.of_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->dev.of_node, 0, &r_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 = resource_size(&r_mem);
 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 platform_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->dev.of_node, 0, &r_mem))
 345                dev_err(dev, "invalid address\n");
 346        else
 347                release_mem_region(r_mem.start, resource_size(&r_mem));
 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 const struct of_device_id xps2_of_match[] __devinitconst = {
 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                .owner = THIS_MODULE,
 367                .of_match_table = xps2_of_match,
 368        },
 369        .probe          = xps2_of_probe,
 370        .remove         = __devexit_p(xps2_of_remove),
 371};
 372module_platform_driver(xps2_of_driver);
 373
 374MODULE_AUTHOR("Xilinx, Inc.");
 375MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 376MODULE_LICENSE("GPL");
 377
 378