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