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/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
  73 struct 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  */
  94 static 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 /*********************/
 112 static 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  */
 163 static 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  */
 190 static 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  */
 218 static 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  */
 238 static 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
 323 failed2:
 324         release_mem_region(phys_addr, remap_size);
 325 failed1:
 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  */
 340 static 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 */
 360 static const struct of_device_id xps2_of_match[] = {
 361         { .compatible = "xlnx,xps-ps2-1.00.a", },
 362         { /* end of list */ },
 363 };
 364 MODULE_DEVICE_TABLE(of, xps2_of_match);
 365
 366 static 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 };
 374 module_platform_driver(xps2_of_driver);
 375
 376 MODULE_AUTHOR("Xilinx, Inc.");
 377 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 378 MODULE_LICENSE("GPL");
 379