drivers/input/serio/xilinx_ps2.c

   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
  70 struct 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  */
  90 static 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 /*********************/
 108 static 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  */
 159 static 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  */
 186 static 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  */
 214 static 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  */
 234 static 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
 317 failed2:
 318         release_mem_region(phys_addr, remap_size);
 319 failed1:
 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  */
 334 static 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 */
 357 static struct of_device_id xps2_of_match[] __devinitdata = {
 358         { .compatible = "xlnx,xps-ps2-1.00.a", },
 359         { /* end of list */ },
 360 };
 361 MODULE_DEVICE_TABLE(of, xps2_of_match);
 362
 363 static 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
 370 static int __init xps2_init(void)
 371 {
 372         return of_register_platform_driver(&xps2_of_driver);
 373 }
 374
 375 static void __exit xps2_cleanup(void)
 376 {
 377         of_unregister_platform_driver(&xps2_of_driver);
 378 }
 379
 380 module_init(xps2_init);
 381 module_exit(xps2_cleanup);
 382
 383 MODULE_AUTHOR("Xilinx, Inc.");
 384 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 385 MODULE_LICENSE("GPL");
 386