drivers/input/serio/xilinx_ps2.c

   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/mod_devicetable.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_irq.h>
  20 #include <linux/platform_device.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         u32 sr;
 159
 160         guard(spinlock_irqsave)(&drvdata->lock);
 161
 162         /* If the PS/2 transmitter is empty send a byte of data */
 163         sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 164         if (sr & XPS2_STATUS_TX_FULL)
 165                 return -EAGAIN;
 166
 167         out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
 168         return 0;
 169 }
 170
 171 /**
 172  * sxps2_open() - called when a port is opened by the higher layer.
 173  * @pserio:     pointer to the serio structure of the PS/2 device
 174  *
 175  * This function requests irq and enables interrupts for the PS/2 device.
 176  */
 177 static int sxps2_open(struct serio *pserio)
 178 {
 179         struct xps2data *drvdata = pserio->port_data;
 180         int error;
 181         u8 c;
 182
 183         error = request_irq(drvdata->irq, &xps2_interrupt, 0,
 184                                 DRIVER_NAME, drvdata);
 185         if (error) {
 186                 dev_err(drvdata->dev,
 187                         "Couldn't allocate interrupt %d\n", drvdata->irq);
 188                 return error;
 189         }
 190
 191         /* start reception by enabling the interrupts */
 192         out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 193         out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 194         (void)xps2_recv(drvdata, &c);
 195
 196         return 0;               /* success */
 197 }
 198
 199 /**
 200  * sxps2_close() - frees the interrupt.
 201  * @pserio:     pointer to the serio structure of the PS/2 device
 202  *
 203  * This function frees the irq and disables interrupts for the PS/2 device.
 204  */
 205 static void sxps2_close(struct serio *pserio)
 206 {
 207         struct xps2data *drvdata = pserio->port_data;
 208
 209         /* Disable the PS2 interrupts */
 210         out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
 211         out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
 212         free_irq(drvdata->irq, drvdata);
 213 }
 214
 215 /**
 216  * xps2_of_probe - probe method for the PS/2 device.
 217  * @ofdev:      pointer to OF device structure
 218  *
 219  * This function probes the PS/2 device in the device tree.
 220  * It initializes the driver data structure and the hardware.
 221  * It returns 0, if the driver is bound to the PS/2 device, or a negative
 222  * value if there is an error.
 223  */
 224 static int xps2_of_probe(struct platform_device *ofdev)
 225 {
 226         struct resource r_mem; /* IO mem resources */
 227         struct xps2data *drvdata;
 228         struct serio *serio;
 229         struct device *dev = &ofdev->dev;
 230         resource_size_t remap_size, phys_addr;
 231         unsigned int irq;
 232         int error;
 233
 234         dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
 235
 236         /* Get iospace for the device */
 237         error = of_address_to_resource(dev->of_node, 0, &r_mem);
 238         if (error) {
 239                 dev_err(dev, "invalid address\n");
 240                 return error;
 241         }
 242
 243         /* Get IRQ for the device */
 244         irq = irq_of_parse_and_map(dev->of_node, 0);
 245         if (!irq) {
 246                 dev_err(dev, "no IRQ found\n");
 247                 return -ENODEV;
 248         }
 249
 250         drvdata = kzalloc(sizeof(*drvdata), GFP_KERNEL);
 251         serio = kzalloc(sizeof(*serio), GFP_KERNEL);
 252         if (!drvdata || !serio) {
 253                 error = -ENOMEM;
 254                 goto failed1;
 255         }
 256
 257         spin_lock_init(&drvdata->lock);
 258         drvdata->irq = irq;
 259         drvdata->serio = serio;
 260         drvdata->dev = dev;
 261
 262         phys_addr = r_mem.start;
 263         remap_size = resource_size(&r_mem);
 264         if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
 265                 dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
 266                         (unsigned long long)phys_addr);
 267                 error = -EBUSY;
 268                 goto failed1;
 269         }
 270
 271         /* Fill in configuration data and add them to the list */
 272         drvdata->base_address = ioremap(phys_addr, remap_size);
 273         if (drvdata->base_address == NULL) {
 274                 dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
 275                         (unsigned long long)phys_addr);
 276                 error = -EFAULT;
 277                 goto failed2;
 278         }
 279
 280         /* Disable all the interrupts, just in case */
 281         out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
 282
 283         /*
 284          * Reset the PS2 device and abort any current transaction,
 285          * to make sure we have the PS2 in a good state.
 286          */
 287         out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
 288
 289         dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
 290                  (unsigned long long)phys_addr, drvdata->base_address,
 291                  drvdata->irq);
 292
 293         serio->id.type = SERIO_8042;
 294         serio->write = sxps2_write;
 295         serio->open = sxps2_open;
 296         serio->close = sxps2_close;
 297         serio->port_data = drvdata;
 298         serio->dev.parent = dev;
 299         snprintf(serio->name, sizeof(serio->name),
 300                  "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
 301         snprintf(serio->phys, sizeof(serio->phys),
 302                  "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
 303
 304         serio_register_port(serio);
 305
 306         platform_set_drvdata(ofdev, drvdata);
 307         return 0;               /* success */
 308
 309 failed2:
 310         release_mem_region(phys_addr, remap_size);
 311 failed1:
 312         kfree(serio);
 313         kfree(drvdata);
 314
 315         return error;
 316 }
 317
 318 /**
 319  * xps2_of_remove - unbinds the driver from the PS/2 device.
 320  * @of_dev:     pointer to OF device structure
 321  *
 322  * This function is called if a device is physically removed from the system or
 323  * if the driver module is being unloaded. It frees any resources allocated to
 324  * the device.
 325  */
 326 static void xps2_of_remove(struct platform_device *of_dev)
 327 {
 328         struct xps2data *drvdata = platform_get_drvdata(of_dev);
 329         struct resource r_mem; /* IO mem resources */
 330
 331         serio_unregister_port(drvdata->serio);
 332         iounmap(drvdata->base_address);
 333
 334         /* Get iospace of the device */
 335         if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
 336                 dev_err(drvdata->dev, "invalid address\n");
 337         else
 338                 release_mem_region(r_mem.start, resource_size(&r_mem));
 339
 340         kfree(drvdata);
 341 }
 342
 343 /* Match table for of_platform binding */
 344 static const struct of_device_id xps2_of_match[] = {
 345         { .compatible = "xlnx,xps-ps2-1.00.a", },
 346         { /* end of list */ },
 347 };
 348 MODULE_DEVICE_TABLE(of, xps2_of_match);
 349
 350 static struct platform_driver xps2_of_driver = {
 351         .driver = {
 352                 .name = DRIVER_NAME,
 353                 .of_match_table = xps2_of_match,
 354         },
 355         .probe          = xps2_of_probe,
 356         .remove         = xps2_of_remove,
 357 };
 358 module_platform_driver(xps2_of_driver);
 359
 360 MODULE_AUTHOR("Xilinx, Inc.");
 361 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 362 MODULE_LICENSE("GPL");
 363