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/*
  49 * Bit definitions for ISR/IER registers. Both the registers have the same bit
  50 * definitions and are only defined once.
  51 */
  52#define XPS2_IPIXR_WDT_TOUT     0x00000001 /* Watchdog Timeout Interrupt */
  53#define XPS2_IPIXR_TX_NOACK     0x00000002 /* Transmit No ACK Interrupt */
  54#define XPS2_IPIXR_TX_ACK       0x00000004 /* Transmit ACK (Data) Interrupt */
  55#define XPS2_IPIXR_RX_OVF       0x00000008 /* Receive Overflow Interrupt */
  56#define XPS2_IPIXR_RX_ERR       0x00000010 /* Receive Error Interrupt */
  57#define XPS2_IPIXR_RX_FULL      0x00000020 /* Receive Data Interrupt */
  58
  59/* Mask for all the Transmit Interrupts */
  60#define XPS2_IPIXR_TX_ALL       (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
  61
  62/* Mask for all the Receive Interrupts */
  63#define XPS2_IPIXR_RX_ALL       (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
  64                                 XPS2_IPIXR_RX_FULL)
  65
  66/* Mask for all the Interrupts */
  67#define XPS2_IPIXR_ALL          (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
  68                                 XPS2_IPIXR_WDT_TOUT)
  69
  70/* Global Interrupt Enable mask */
  71#define XPS2_GIER_GIE_MASK      0x80000000
  72
  73struct xps2data {
  74        int irq;
  75        spinlock_t lock;
  76        void __iomem *base_address;     /* virt. address of control registers */
  77        unsigned int flags;
  78        struct serio *serio;            /* serio */
  79        struct device *dev;
  80};
  81
  82/************************************/
  83/* XPS PS/2 data transmission calls */
  84/************************************/
  85
  86/**
  87 * xps2_recv() - attempts to receive a byte from the PS/2 port.
  88 * @drvdata:    pointer to ps2 device private data structure
  89 * @byte:       address where the read data will be copied
  90 *
  91 * If there is any data available in the PS/2 receiver, this functions reads
  92 * the data, otherwise it returns error.
  93 */
  94static int xps2_recv(struct xps2data *drvdata, u8 *byte)
  95{
  96        u32 sr;
  97        int status = -1;
  98
  99        /* If there is data available in the PS/2 receiver, read it */
 100        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 101        if (sr & XPS2_STATUS_RX_FULL) {
 102                *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
 103                status = 0;
 104        }
 105
 106        return status;
 107}
 108
 109/*********************/
 110/* Interrupt handler */
 111/*********************/
 112static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 113{
 114        struct xps2data *drvdata = dev_id;
 115        u32 intr_sr;
 116        u8 c;
 117        int status;
 118
 119        /* Get the PS/2 interrupts and clear them */
 120        intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
 121        out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
 122
 123        /* Check which interrupt is active */
 124        if (intr_sr & XPS2_IPIXR_RX_OVF)
 125                dev_warn(drvdata->dev, "receive overrun error\n");
 126
 127        if (intr_sr & XPS2_IPIXR_RX_ERR)
 128                drvdata->flags |= SERIO_PARITY;
 129
 130        if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
 131                drvdata->flags |= SERIO_TIMEOUT;
 132
 133        if (intr_sr & XPS2_IPIXR_RX_FULL) {
 134                status = xps2_recv(drvdata, &c);
 135
 136                /* Error, if a byte is not received */
 137                if (status) {
 138                        dev_err(drvdata->dev,
 139                                "wrong rcvd byte count (%d)\n", status);
 140                } else {
 141                        serio_interrupt(drvdata->serio, c, drvdata->flags);
 142                        drvdata->flags = 0;
 143                }
 144        }
 145
 146        return IRQ_HANDLED;
 147}
 148
 149/*******************/
 150/* serio callbacks */
 151/*******************/
 152
 153/**
 154 * sxps2_write() - sends a byte out through the PS/2 port.
 155 * @pserio:     pointer to the serio structure of the PS/2 port
 156 * @c:          data that needs to be written to the PS/2 port
 157 *
 158 * This function checks if the PS/2 transmitter is empty and sends a byte.
 159 * Otherwise it returns error. Transmission fails only when nothing is connected
 160 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
 161 * failure.
 162 */
 163static int sxps2_write(struct serio *pserio, unsigned char c)
 164{
 165        struct xps2data *drvdata = pserio->port_data;
 166        unsigned long flags;
 167        u32 sr;
 168        int status = -1;
 169
 170        spin_lock_irqsave(&drvdata->lock, flags);
 171
 172        /* If the PS/2 transmitter is empty send a byte of data */
 173        sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 174        if (!(sr & XPS2_STATUS_TX_FULL)) {
 175                out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
 176                status = 0;
 177        }
 178
 179        spin_unlock_irqrestore(&drvdata->lock, flags);
 180
 181        return status;
 182}
 183
 184/**
 185 * sxps2_open() - called when a port is opened by the higher layer.
 186 * @pserio:     pointer to the serio structure of the PS/2 device
 187 *
 188 * This function requests irq and enables interrupts for the PS/2 device.
 189 */
 190static int sxps2_open(struct serio *pserio)
 191{
 192        struct xps2data *drvdata = pserio->port_data;
 193        int error;
 194        u8 c;
 195
 196        error = request_irq(drvdata->irq, &xps2_interrupt, 0,
 197                                DRIVER_NAME, drvdata);
 198        if (error) {
 199                dev_err(drvdata->dev,
 200                        "Couldn't allocate interrupt %d\n", drvdata->irq);
 201                return error;
 202        }
 203
 204        /* start reception by enabling the interrupts */
 205        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 206        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 207        (void)xps2_recv(drvdata, &c);
 208
 209        return 0;               /* success */
 210}
 211
 212/**
 213 * sxps2_close() - frees the interrupt.
 214 * @pserio:     pointer to the serio structure of the PS/2 device
 215 *
 216 * This function frees the irq and disables interrupts for the PS/2 device.
 217 */
 218static void sxps2_close(struct serio *pserio)
 219{
 220        struct xps2data *drvdata = pserio->port_data;
 221
 222        /* Disable the PS2 interrupts */
 223        out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
 224        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
 225        free_irq(drvdata->irq, drvdata);
 226}
 227
 228/**
 229 * xps2_of_probe - probe method for the PS/2 device.
 230 * @of_dev:     pointer to OF device structure
 231 * @match:      pointer to the structure used for matching a device
 232 *
 233 * This function probes the PS/2 device in the device tree.
 234 * It initializes the driver data structure and the hardware.
 235 * It returns 0, if the driver is bound to the PS/2 device, or a negative
 236 * value if there is an error.
 237 */
 238static int xps2_of_probe(struct platform_device *ofdev)
 239{
 240        struct resource r_mem; /* IO mem resources */
 241        struct xps2data *drvdata;
 242        struct serio *serio;
 243        struct device *dev = &ofdev->dev;
 244        resource_size_t remap_size, phys_addr;
 245        unsigned int irq;
 246        int error;
 247
 248        dev_info(dev, "Device Tree Probing \'%s\'\n", dev->of_node->name);
 249
 250        /* Get iospace for the device */
 251        error = of_address_to_resource(dev->of_node, 0, &r_mem);
 252        if (error) {
 253                dev_err(dev, "invalid address\n");
 254                return error;
 255        }
 256
 257        /* Get IRQ for the device */
 258        irq = irq_of_parse_and_map(dev->of_node, 0);
 259        if (!irq) {
 260                dev_err(dev, "no IRQ found\n");
 261                return -ENODEV;
 262        }
 263
 264        drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
 265        serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 266        if (!drvdata || !serio) {
 267                error = -ENOMEM;
 268                goto failed1;
 269        }
 270
 271        spin_lock_init(&drvdata->lock);
 272        drvdata->irq = irq;
 273        drvdata->serio = serio;
 274        drvdata->dev = dev;
 275
 276        phys_addr = r_mem.start;
 277        remap_size = resource_size(&r_mem);
 278        if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
 279                dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
 280                        (unsigned long long)phys_addr);
 281                error = -EBUSY;
 282                goto failed1;
 283        }
 284
 285        /* Fill in configuration data and add them to the list */
 286        drvdata->base_address = ioremap(phys_addr, remap_size);
 287        if (drvdata->base_address == NULL) {
 288                dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
 289                        (unsigned long long)phys_addr);
 290                error = -EFAULT;
 291                goto failed2;
 292        }
 293
 294        /* Disable all the interrupts, just in case */
 295        out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
 296
 297        /*
 298         * Reset the PS2 device and abort any current transaction,
 299         * to make sure we have the PS2 in a good state.
 300         */
 301        out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
 302
 303        dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
 304                 (unsigned long long)phys_addr, drvdata->base_address,
 305                 drvdata->irq);
 306
 307        serio->id.type = SERIO_8042;
 308        serio->write = sxps2_write;
 309        serio->open = sxps2_open;
 310        serio->close = sxps2_close;
 311        serio->port_data = drvdata;
 312        serio->dev.parent = dev;
 313        snprintf(serio->name, sizeof(serio->name),
 314                 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
 315        snprintf(serio->phys, sizeof(serio->phys),
 316                 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
 317
 318        serio_register_port(serio);
 319
 320        platform_set_drvdata(ofdev, drvdata);
 321        return 0;               /* success */
 322
 323failed2:
 324        release_mem_region(phys_addr, remap_size);
 325failed1:
 326        kfree(serio);
 327        kfree(drvdata);
 328
 329        return error;
 330}
 331
 332/**
 333 * xps2_of_remove - unbinds the driver from the PS/2 device.
 334 * @of_dev:     pointer to OF device structure
 335 *
 336 * This function is called if a device is physically removed from the system or
 337 * if the driver module is being unloaded. It frees any resources allocated to
 338 * the device.
 339 */
 340static int xps2_of_remove(struct platform_device *of_dev)
 341{
 342        struct xps2data *drvdata = platform_get_drvdata(of_dev);
 343        struct resource r_mem; /* IO mem resources */
 344
 345        serio_unregister_port(drvdata->serio);
 346        iounmap(drvdata->base_address);
 347
 348        /* Get iospace of the device */
 349        if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
 350                dev_err(drvdata->dev, "invalid address\n");
 351        else
 352                release_mem_region(r_mem.start, resource_size(&r_mem));
 353
 354        kfree(drvdata);
 355
 356        return 0;
 357}
 358
 359/* Match table for of_platform binding */
 360static const struct of_device_id xps2_of_match[] = {
 361        { .compatible = "xlnx,xps-ps2-1.00.a", },
 362        { /* end of list */ },
 363};
 364MODULE_DEVICE_TABLE(of, xps2_of_match);
 365
 366static struct platform_driver xps2_of_driver = {
 367        .driver = {
 368                .name = DRIVER_NAME,
 369                .of_match_table = xps2_of_match,
 370        },
 371        .probe          = xps2_of_probe,
 372        .remove         = xps2_of_remove,
 373};
 374module_platform_driver(xps2_of_driver);
 375
 376MODULE_AUTHOR("Xilinx, Inc.");
 377MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 378MODULE_LICENSE("GPL");
 379
 380