LXR linux/drivers/input/serio/xilinx

   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
  65struct 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 */
  86static 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/*********************/
 104static 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 */
 155static 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 */
 182static 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 */
 210static 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 */
 230static 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
 315failed2:
 316        release_mem_region(phys_addr, remap_size);
 317failed1:
 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 */
 332static 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 */
 352static const struct of_device_id xps2_of_match[] = {
 353        { .compatible = "xlnx,xps-ps2-1.00.a", },
 354        { /* end of list */ },
 355};
 356MODULE_DEVICE_TABLE(of, xps2_of_match);
 357
 358static 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};
 366module_platform_driver(xps2_of_driver);
 367
 368MODULE_AUTHOR("Xilinx, Inc.");
 369MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 370MODULE_LICENSE("GPL");
 371
 372