root/drivers/input/serio/xilinx_ps2.c

DEFINITIONS

1. xps2_recv
2. xps2_interrupt
3. sxps2_write
4. sxps2_open
5. sxps2_close
6. xps2_of_probe
7. xps2_of_remove

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Xilinx XPS PS/2 device driver
   4  *
   5  * (c) 2005 MontaVista Software, Inc.
   6  * (c) 2008 Xilinx, Inc.
   7  */
   8 
   9 
  10 #include <linux/module.h>
  11 #include <linux/serio.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/errno.h>
  14 #include <linux/slab.h>
  15 #include <linux/list.h>
  16 #include <linux/io.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_device.h>
  19 #include <linux/of_irq.h>
  20 #include <linux/of_platform.h>
  21 
  22 #define DRIVER_NAME             "xilinx_ps2"
  23 
  24 /* Register offsets for the xps2 device */
  25 #define XPS2_SRST_OFFSET        0x00000000 /* Software Reset register */
  26 #define XPS2_STATUS_OFFSET      0x00000004 /* Status register */
  27 #define XPS2_RX_DATA_OFFSET     0x00000008 /* Receive Data register */
  28 #define XPS2_TX_DATA_OFFSET     0x0000000C /* Transmit Data register */
  29 #define XPS2_GIER_OFFSET        0x0000002C /* Global Interrupt Enable reg */
  30 #define XPS2_IPISR_OFFSET       0x00000030 /* Interrupt Status register */
  31 #define XPS2_IPIER_OFFSET       0x00000038 /* Interrupt Enable register */
  32 
  33 /* Reset Register Bit Definitions */
  34 #define XPS2_SRST_RESET         0x0000000A /* Software Reset  */
  35 
  36 /* Status Register Bit Positions */
  37 #define XPS2_STATUS_RX_FULL     0x00000001 /* Receive Full  */
  38 #define XPS2_STATUS_TX_FULL     0x00000002 /* Transmit Full  */
  39 
  40 /*
  41  * Bit definitions for ISR/IER registers. Both the registers have the same bit
  42  * definitions and are only defined once.
  43  */
  44 #define XPS2_IPIXR_WDT_TOUT     0x00000001 /* Watchdog Timeout Interrupt */
  45 #define XPS2_IPIXR_TX_NOACK     0x00000002 /* Transmit No ACK Interrupt */
  46 #define XPS2_IPIXR_TX_ACK       0x00000004 /* Transmit ACK (Data) Interrupt */
  47 #define XPS2_IPIXR_RX_OVF       0x00000008 /* Receive Overflow Interrupt */
  48 #define XPS2_IPIXR_RX_ERR       0x00000010 /* Receive Error Interrupt */
  49 #define XPS2_IPIXR_RX_FULL      0x00000020 /* Receive Data Interrupt */
  50 
  51 /* Mask for all the Transmit Interrupts */
  52 #define XPS2_IPIXR_TX_ALL       (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
  53 
  54 /* Mask for all the Receive Interrupts */
  55 #define XPS2_IPIXR_RX_ALL       (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
  56                                  XPS2_IPIXR_RX_FULL)
  57 
  58 /* Mask for all the Interrupts */
  59 #define XPS2_IPIXR_ALL          (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
  60                                  XPS2_IPIXR_WDT_TOUT)
  61 
  62 /* Global Interrupt Enable mask */
  63 #define XPS2_GIER_GIE_MASK      0x80000000
  64 
  65 struct xps2data {
  66         int irq;
  67         spinlock_t lock;
  68         void __iomem *base_address;     /* virt. address of control registers */
  69         unsigned int flags;
  70         struct serio *serio;            /* serio */
  71         struct device *dev;
  72 };
  73 
  74 /************************************/
  75 /* XPS PS/2 data transmission calls */
  76 /************************************/
  77 
  78 /**
  79  * xps2_recv() - attempts to receive a byte from the PS/2 port.
  80  * @drvdata:    pointer to ps2 device private data structure
  81  * @byte:       address where the read data will be copied
  82  *
  83  * If there is any data available in the PS/2 receiver, this functions reads
  84  * the data, otherwise it returns error.
  85  */
  86 static int xps2_recv(struct xps2data *drvdata, u8 *byte)
  87 {
  88         u32 sr;
  89         int status = -1;
  90 
  91         /* If there is data available in the PS/2 receiver, read it */
  92         sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
  93         if (sr & XPS2_STATUS_RX_FULL) {
  94                 *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
  95                 status = 0;
  96         }
  97 
  98         return status;
  99 }
 100 
 101 /*********************/
 102 /* Interrupt handler */
 103 /*********************/
 104 static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 105 {
 106         struct xps2data *drvdata = dev_id;
 107         u32 intr_sr;
 108         u8 c;
 109         int status;
 110 
 111         /* Get the PS/2 interrupts and clear them */
 112         intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
 113         out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
 114 
 115         /* Check which interrupt is active */
 116         if (intr_sr & XPS2_IPIXR_RX_OVF)
 117                 dev_warn(drvdata->dev, "receive overrun error\n");
 118 
 119         if (intr_sr & XPS2_IPIXR_RX_ERR)
 120                 drvdata->flags |= SERIO_PARITY;
 121 
 122         if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
 123                 drvdata->flags |= SERIO_TIMEOUT;
 124 
 125         if (intr_sr & XPS2_IPIXR_RX_FULL) {
 126                 status = xps2_recv(drvdata, &c);
 127 
 128                 /* Error, if a byte is not received */
 129                 if (status) {
 130                         dev_err(drvdata->dev,
 131                                 "wrong rcvd byte count (%d)\n", status);
 132                 } else {
 133                         serio_interrupt(drvdata->serio, c, drvdata->flags);
 134                         drvdata->flags = 0;
 135                 }
 136         }
 137 
 138         return IRQ_HANDLED;
 139 }
 140 
 141 /*******************/
 142 /* serio callbacks */
 143 /*******************/
 144 
 145 /**
 146  * sxps2_write() - sends a byte out through the PS/2 port.
 147  * @pserio:     pointer to the serio structure of the PS/2 port
 148  * @c:          data that needs to be written to the PS/2 port
 149  *
 150  * This function checks if the PS/2 transmitter is empty and sends a byte.
 151  * Otherwise it returns error. Transmission fails only when nothing is connected
 152  * to the PS/2 port. Thats why, we do not try to resend the data in case of a
 153  * failure.
 154  */
 155 static int sxps2_write(struct serio *pserio, unsigned char c)
 156 {
 157         struct xps2data *drvdata = pserio->port_data;
 158         unsigned long flags;
 159         u32 sr;
 160         int status = -1;
 161 
 162         spin_lock_irqsave(&drvdata->lock, flags);
 163 
 164         /* If the PS/2 transmitter is empty send a byte of data */
 165         sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 166         if (!(sr & XPS2_STATUS_TX_FULL)) {
 167                 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
 168                 status = 0;
 169         }
 170 
 171         spin_unlock_irqrestore(&drvdata->lock, flags);
 172 
 173         return status;
 174 }
 175 
 176 /**
 177  * sxps2_open() - called when a port is opened by the higher layer.
 178  * @pserio:     pointer to the serio structure of the PS/2 device
 179  *
 180  * This function requests irq and enables interrupts for the PS/2 device.
 181  */
 182 static int sxps2_open(struct serio *pserio)
 183 {
 184         struct xps2data *drvdata = pserio->port_data;
 185         int error;
 186         u8 c;
 187 
 188         error = request_irq(drvdata->irq, &xps2_interrupt, 0,
 189                                 DRIVER_NAME, drvdata);
 190         if (error) {
 191                 dev_err(drvdata->dev,
 192                         "Couldn't allocate interrupt %d\n", drvdata->irq);
 193                 return error;
 194         }
 195 
 196         /* start reception by enabling the interrupts */
 197         out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 198         out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 199         (void)xps2_recv(drvdata, &c);
 200 
 201         return 0;               /* success */
 202 }
 203 
 204 /**
 205  * sxps2_close() - frees the interrupt.
 206  * @pserio:     pointer to the serio structure of the PS/2 device
 207  *
 208  * This function frees the irq and disables interrupts for the PS/2 device.
 209  */
 210 static void sxps2_close(struct serio *pserio)
 211 {
 212         struct xps2data *drvdata = pserio->port_data;
 213 
 214         /* Disable the PS2 interrupts */
 215         out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
 216         out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
 217         free_irq(drvdata->irq, drvdata);
 218 }
 219 
 220 /**
 221  * xps2_of_probe - probe method for the PS/2 device.
 222  * @of_dev:     pointer to OF device structure
 223  * @match:      pointer to the structure used for matching a device
 224  *
 225  * This function probes the PS/2 device in the device tree.
 226  * It initializes the driver data structure and the hardware.
 227  * It returns 0, if the driver is bound to the PS/2 device, or a negative
 228  * value if there is an error.
 229  */
 230 static int xps2_of_probe(struct platform_device *ofdev)
 231 {
 232         struct resource r_mem; /* IO mem resources */
 233         struct xps2data *drvdata;
 234         struct serio *serio;
 235         struct device *dev = &ofdev->dev;
 236         resource_size_t remap_size, phys_addr;
 237         unsigned int irq;
 238         int error;
 239 
 240         dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
 241 
 242         /* Get iospace for the device */
 243         error = of_address_to_resource(dev->of_node, 0, &r_mem);
 244         if (error) {
 245                 dev_err(dev, "invalid address\n");
 246                 return error;
 247         }
 248 
 249         /* Get IRQ for the device */
 250         irq = irq_of_parse_and_map(dev->of_node, 0);
 251         if (!irq) {
 252                 dev_err(dev, "no IRQ found\n");
 253                 return -ENODEV;
 254         }
 255 
 256         drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
 257         serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 258         if (!drvdata || !serio) {
 259                 error = -ENOMEM;
 260                 goto failed1;
 261         }
 262 
 263         spin_lock_init(&drvdata->lock);
 264         drvdata->irq = irq;
 265         drvdata->serio = serio;
 266         drvdata->dev = dev;
 267 
 268         phys_addr = r_mem.start;
 269         remap_size = resource_size(&r_mem);
 270         if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
 271                 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
 272                         (unsigned long long)phys_addr);
 273                 error = -EBUSY;
 274                 goto failed1;
 275         }
 276 
 277         /* Fill in configuration data and add them to the list */
 278         drvdata->base_address = ioremap(phys_addr, remap_size);
 279         if (drvdata->base_address == NULL) {
 280                 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
 281                         (unsigned long long)phys_addr);
 282                 error = -EFAULT;
 283                 goto failed2;
 284         }
 285 
 286         /* Disable all the interrupts, just in case */
 287         out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
 288 
 289         /*
 290          * Reset the PS2 device and abort any current transaction,
 291          * to make sure we have the PS2 in a good state.
 292          */
 293         out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
 294 
 295         dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
 296                  (unsigned long long)phys_addr, drvdata->base_address,
 297                  drvdata->irq);
 298 
 299         serio->id.type = SERIO_8042;
 300         serio->write = sxps2_write;
 301         serio->open = sxps2_open;
 302         serio->close = sxps2_close;
 303         serio->port_data = drvdata;
 304         serio->dev.parent = dev;
 305         snprintf(serio->name, sizeof(serio->name),
 306                  "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
 307         snprintf(serio->phys, sizeof(serio->phys),
 308                  "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
 309 
 310         serio_register_port(serio);
 311 
 312         platform_set_drvdata(ofdev, drvdata);
 313         return 0;               /* success */
 314 
 315 failed2:
 316         release_mem_region(phys_addr, remap_size);
 317 failed1:
 318         kfree(serio);
 319         kfree(drvdata);
 320 
 321         return error;
 322 }
 323 
 324 /**
 325  * xps2_of_remove - unbinds the driver from the PS/2 device.
 326  * @of_dev:     pointer to OF device structure
 327  *
 328  * This function is called if a device is physically removed from the system or
 329  * if the driver module is being unloaded. It frees any resources allocated to
 330  * the device.
 331  */
 332 static int xps2_of_remove(struct platform_device *of_dev)
 333 {
 334         struct xps2data *drvdata = platform_get_drvdata(of_dev);
 335         struct resource r_mem; /* IO mem resources */
 336 
 337         serio_unregister_port(drvdata->serio);
 338         iounmap(drvdata->base_address);
 339 
 340         /* Get iospace of the device */
 341         if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
 342                 dev_err(drvdata->dev, "invalid address\n");
 343         else
 344                 release_mem_region(r_mem.start, resource_size(&r_mem));
 345 
 346         kfree(drvdata);
 347 
 348         return 0;
 349 }
 350 
 351 /* Match table for of_platform binding */
 352 static const struct of_device_id xps2_of_match[] = {
 353         { .compatible = "xlnx,xps-ps2-1.00.a", },
 354         { /* end of list */ },
 355 };
 356 MODULE_DEVICE_TABLE(of, xps2_of_match);
 357 
 358 static struct platform_driver xps2_of_driver = {
 359         .driver = {
 360                 .name = DRIVER_NAME,
 361                 .of_match_table = xps2_of_match,
 362         },
 363         .probe          = xps2_of_probe,
 364         .remove         = xps2_of_remove,
 365 };
 366 module_platform_driver(xps2_of_driver);
 367 
 368 MODULE_AUTHOR("Xilinx, Inc.");
 369 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 370 MODULE_LICENSE("GPL");
 371