drivers/gpio/gpio-ws16c48.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * GPIO driver for the WinSystems WS16C48
   4  * Copyright (C) 2016 William Breathitt Gray
   5  */
   6 #include <linux/bitmap.h>
   7 #include <linux/bitops.h>
   8 #include <linux/device.h>
   9 #include <linux/errno.h>
  10 #include <linux/gpio/driver.h>
  11 #include <linux/io.h>
  12 #include <linux/ioport.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/irqdesc.h>
  15 #include <linux/isa.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/spinlock.h>
  20
  21 #define WS16C48_EXTENT 16
  22 #define MAX_NUM_WS16C48 max_num_isa_dev(WS16C48_EXTENT)
  23
  24 static unsigned int base[MAX_NUM_WS16C48];
  25 static unsigned int num_ws16c48;
  26 module_param_hw_array(base, uint, ioport, &num_ws16c48, 0);
  27 MODULE_PARM_DESC(base, "WinSystems WS16C48 base addresses");
  28
  29 static unsigned int irq[MAX_NUM_WS16C48];
  30 module_param_hw_array(irq, uint, irq, NULL, 0);
  31 MODULE_PARM_DESC(irq, "WinSystems WS16C48 interrupt line numbers");
  32
  33 /**
  34  * struct ws16c48_gpio - GPIO device private data structure
  35  * @chip:       instance of the gpio_chip
  36  * @io_state:   bit I/O state (whether bit is set to input or output)
  37  * @out_state:  output bits state
  38  * @lock:       synchronization lock to prevent I/O race conditions
  39  * @irq_mask:   I/O bits affected by interrupts
  40  * @flow_mask:  IRQ flow type mask for the respective I/O bits
  41  * @base:       base port address of the GPIO device
  42  */
  43 struct ws16c48_gpio {
  44         struct gpio_chip chip;
  45         unsigned char io_state[6];
  46         unsigned char out_state[6];
  47         raw_spinlock_t lock;
  48         unsigned long irq_mask;
  49         unsigned long flow_mask;
  50         unsigned base;
  51 };
  52
  53 static int ws16c48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
  54 {
  55         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
  56         const unsigned port = offset / 8;
  57         const unsigned mask = BIT(offset % 8);
  58
  59         return !!(ws16c48gpio->io_state[port] & mask);
  60 }
  61
  62 static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  63 {
  64         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
  65         const unsigned port = offset / 8;
  66         const unsigned mask = BIT(offset % 8);
  67         unsigned long flags;
  68
  69         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
  70
  71         ws16c48gpio->io_state[port] |= mask;
  72         ws16c48gpio->out_state[port] &= ~mask;
  73         outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
  74
  75         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
  76
  77         return 0;
  78 }
  79
  80 static int ws16c48_gpio_direction_output(struct gpio_chip *chip,
  81         unsigned offset, int value)
  82 {
  83         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
  84         const unsigned port = offset / 8;
  85         const unsigned mask = BIT(offset % 8);
  86         unsigned long flags;
  87
  88         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
  89
  90         ws16c48gpio->io_state[port] &= ~mask;
  91         if (value)
  92                 ws16c48gpio->out_state[port] |= mask;
  93         else
  94                 ws16c48gpio->out_state[port] &= ~mask;
  95         outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
  96
  97         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
  98
  99         return 0;
 100 }
 101
 102 static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
 103 {
 104         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 105         const unsigned port = offset / 8;
 106         const unsigned mask = BIT(offset % 8);
 107         unsigned long flags;
 108         unsigned port_state;
 109
 110         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 111
 112         /* ensure that GPIO is set for input */
 113         if (!(ws16c48gpio->io_state[port] & mask)) {
 114                 raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 115                 return -EINVAL;
 116         }
 117
 118         port_state = inb(ws16c48gpio->base + port);
 119
 120         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 121
 122         return !!(port_state & mask);
 123 }
 124
 125 static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
 126         unsigned long *mask, unsigned long *bits)
 127 {
 128         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 129         const unsigned int gpio_reg_size = 8;
 130         size_t i;
 131         const size_t num_ports = chip->ngpio / gpio_reg_size;
 132         unsigned int bits_offset;
 133         size_t word_index;
 134         unsigned int word_offset;
 135         unsigned long word_mask;
 136         const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
 137         unsigned long port_state;
 138
 139         /* clear bits array to a clean slate */
 140         bitmap_zero(bits, chip->ngpio);
 141
 142         /* get bits are evaluated a gpio port register at a time */
 143         for (i = 0; i < num_ports; i++) {
 144                 /* gpio offset in bits array */
 145                 bits_offset = i * gpio_reg_size;
 146
 147                 /* word index for bits array */
 148                 word_index = BIT_WORD(bits_offset);
 149
 150                 /* gpio offset within current word of bits array */
 151                 word_offset = bits_offset % BITS_PER_LONG;
 152
 153                 /* mask of get bits for current gpio within current word */
 154                 word_mask = mask[word_index] & (port_mask << word_offset);
 155                 if (!word_mask) {
 156                         /* no get bits in this port so skip to next one */
 157                         continue;
 158                 }
 159
 160                 /* read bits from current gpio port */
 161                 port_state = inb(ws16c48gpio->base + i);
 162
 163                 /* store acquired bits at respective bits array offset */
 164                 bits[word_index] |= (port_state << word_offset) & word_mask;
 165         }
 166
 167         return 0;
 168 }
 169
 170 static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 171 {
 172         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 173         const unsigned port = offset / 8;
 174         const unsigned mask = BIT(offset % 8);
 175         unsigned long flags;
 176
 177         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 178
 179         /* ensure that GPIO is set for output */
 180         if (ws16c48gpio->io_state[port] & mask) {
 181                 raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 182                 return;
 183         }
 184
 185         if (value)
 186                 ws16c48gpio->out_state[port] |= mask;
 187         else
 188                 ws16c48gpio->out_state[port] &= ~mask;
 189         outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
 190
 191         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 192 }
 193
 194 static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
 195         unsigned long *mask, unsigned long *bits)
 196 {
 197         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 198         unsigned int i;
 199         const unsigned int gpio_reg_size = 8;
 200         unsigned int port;
 201         unsigned int iomask;
 202         unsigned int bitmask;
 203         unsigned long flags;
 204
 205         /* set bits are evaluated a gpio register size at a time */
 206         for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
 207                 /* no more set bits in this mask word; skip to the next word */
 208                 if (!mask[BIT_WORD(i)]) {
 209                         i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
 210                         continue;
 211                 }
 212
 213                 port = i / gpio_reg_size;
 214
 215                 /* mask out GPIO configured for input */
 216                 iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
 217                 bitmask = iomask & bits[BIT_WORD(i)];
 218
 219                 raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 220
 221                 /* update output state data and set device gpio register */
 222                 ws16c48gpio->out_state[port] &= ~iomask;
 223                 ws16c48gpio->out_state[port] |= bitmask;
 224                 outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
 225
 226                 raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 227
 228                 /* prepare for next gpio register set */
 229                 mask[BIT_WORD(i)] >>= gpio_reg_size;
 230                 bits[BIT_WORD(i)] >>= gpio_reg_size;
 231         }
 232 }
 233
 234 static void ws16c48_irq_ack(struct irq_data *data)
 235 {
 236         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 237         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 238         const unsigned long offset = irqd_to_hwirq(data);
 239         const unsigned port = offset / 8;
 240         const unsigned mask = BIT(offset % 8);
 241         unsigned long flags;
 242         unsigned port_state;
 243
 244         /* only the first 3 ports support interrupts */
 245         if (port > 2)
 246                 return;
 247
 248         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 249
 250         port_state = ws16c48gpio->irq_mask >> (8*port);
 251
 252         outb(0x80, ws16c48gpio->base + 7);
 253         outb(port_state & ~mask, ws16c48gpio->base + 8 + port);
 254         outb(port_state | mask, ws16c48gpio->base + 8 + port);
 255         outb(0xC0, ws16c48gpio->base + 7);
 256
 257         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 258 }
 259
 260 static void ws16c48_irq_mask(struct irq_data *data)
 261 {
 262         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 263         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 264         const unsigned long offset = irqd_to_hwirq(data);
 265         const unsigned long mask = BIT(offset);
 266         const unsigned port = offset / 8;
 267         unsigned long flags;
 268
 269         /* only the first 3 ports support interrupts */
 270         if (port > 2)
 271                 return;
 272
 273         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 274
 275         ws16c48gpio->irq_mask &= ~mask;
 276
 277         outb(0x80, ws16c48gpio->base + 7);
 278         outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
 279         outb(0xC0, ws16c48gpio->base + 7);
 280
 281         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 282 }
 283
 284 static void ws16c48_irq_unmask(struct irq_data *data)
 285 {
 286         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 287         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 288         const unsigned long offset = irqd_to_hwirq(data);
 289         const unsigned long mask = BIT(offset);
 290         const unsigned port = offset / 8;
 291         unsigned long flags;
 292
 293         /* only the first 3 ports support interrupts */
 294         if (port > 2)
 295                 return;
 296
 297         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 298
 299         ws16c48gpio->irq_mask |= mask;
 300
 301         outb(0x80, ws16c48gpio->base + 7);
 302         outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
 303         outb(0xC0, ws16c48gpio->base + 7);
 304
 305         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 306 }
 307
 308 static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
 309 {
 310         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 311         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 312         const unsigned long offset = irqd_to_hwirq(data);
 313         const unsigned long mask = BIT(offset);
 314         const unsigned port = offset / 8;
 315         unsigned long flags;
 316
 317         /* only the first 3 ports support interrupts */
 318         if (port > 2)
 319                 return -EINVAL;
 320
 321         raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 322
 323         switch (flow_type) {
 324         case IRQ_TYPE_NONE:
 325                 break;
 326         case IRQ_TYPE_EDGE_RISING:
 327                 ws16c48gpio->flow_mask |= mask;
 328                 break;
 329         case IRQ_TYPE_EDGE_FALLING:
 330                 ws16c48gpio->flow_mask &= ~mask;
 331                 break;
 332         default:
 333                 raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 334                 return -EINVAL;
 335         }
 336
 337         outb(0x40, ws16c48gpio->base + 7);
 338         outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port);
 339         outb(0xC0, ws16c48gpio->base + 7);
 340
 341         raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 342
 343         return 0;
 344 }
 345
 346 static struct irq_chip ws16c48_irqchip = {
 347         .name = "ws16c48",
 348         .irq_ack = ws16c48_irq_ack,
 349         .irq_mask = ws16c48_irq_mask,
 350         .irq_unmask = ws16c48_irq_unmask,
 351         .irq_set_type = ws16c48_irq_set_type
 352 };
 353
 354 static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id)
 355 {
 356         struct ws16c48_gpio *const ws16c48gpio = dev_id;
 357         struct gpio_chip *const chip = &ws16c48gpio->chip;
 358         unsigned long int_pending;
 359         unsigned long port;
 360         unsigned long int_id;
 361         unsigned long gpio;
 362
 363         int_pending = inb(ws16c48gpio->base + 6) & 0x7;
 364         if (!int_pending)
 365                 return IRQ_NONE;
 366
 367         /* loop until all pending interrupts are handled */
 368         do {
 369                 for_each_set_bit(port, &int_pending, 3) {
 370                         int_id = inb(ws16c48gpio->base + 8 + port);
 371                         for_each_set_bit(gpio, &int_id, 8)
 372                                 generic_handle_irq(irq_find_mapping(
 373                                         chip->irq.domain, gpio + 8*port));
 374                 }
 375
 376                 int_pending = inb(ws16c48gpio->base + 6) & 0x7;
 377         } while (int_pending);
 378
 379         return IRQ_HANDLED;
 380 }
 381
 382 #define WS16C48_NGPIO 48
 383 static const char *ws16c48_names[WS16C48_NGPIO] = {
 384         "Port 0 Bit 0", "Port 0 Bit 1", "Port 0 Bit 2", "Port 0 Bit 3",
 385         "Port 0 Bit 4", "Port 0 Bit 5", "Port 0 Bit 6", "Port 0 Bit 7",
 386         "Port 1 Bit 0", "Port 1 Bit 1", "Port 1 Bit 2", "Port 1 Bit 3",
 387         "Port 1 Bit 4", "Port 1 Bit 5", "Port 1 Bit 6", "Port 1 Bit 7",
 388         "Port 2 Bit 0", "Port 2 Bit 1", "Port 2 Bit 2", "Port 2 Bit 3",
 389         "Port 2 Bit 4", "Port 2 Bit 5", "Port 2 Bit 6", "Port 2 Bit 7",
 390         "Port 3 Bit 0", "Port 3 Bit 1", "Port 3 Bit 2", "Port 3 Bit 3",
 391         "Port 3 Bit 4", "Port 3 Bit 5", "Port 3 Bit 6", "Port 3 Bit 7",
 392         "Port 4 Bit 0", "Port 4 Bit 1", "Port 4 Bit 2", "Port 4 Bit 3",
 393         "Port 4 Bit 4", "Port 4 Bit 5", "Port 4 Bit 6", "Port 4 Bit 7",
 394         "Port 5 Bit 0", "Port 5 Bit 1", "Port 5 Bit 2", "Port 5 Bit 3",
 395         "Port 5 Bit 4", "Port 5 Bit 5", "Port 5 Bit 6", "Port 5 Bit 7"
 396 };
 397
 398 static int ws16c48_probe(struct device *dev, unsigned int id)
 399 {
 400         struct ws16c48_gpio *ws16c48gpio;
 401         const char *const name = dev_name(dev);
 402         int err;
 403
 404         ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL);
 405         if (!ws16c48gpio)
 406                 return -ENOMEM;
 407
 408         if (!devm_request_region(dev, base[id], WS16C48_EXTENT, name)) {
 409                 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
 410                         base[id], base[id] + WS16C48_EXTENT);
 411                 return -EBUSY;
 412         }
 413
 414         ws16c48gpio->chip.label = name;
 415         ws16c48gpio->chip.parent = dev;
 416         ws16c48gpio->chip.owner = THIS_MODULE;
 417         ws16c48gpio->chip.base = -1;
 418         ws16c48gpio->chip.ngpio = WS16C48_NGPIO;
 419         ws16c48gpio->chip.names = ws16c48_names;
 420         ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction;
 421         ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
 422         ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
 423         ws16c48gpio->chip.get = ws16c48_gpio_get;
 424         ws16c48gpio->chip.get_multiple = ws16c48_gpio_get_multiple;
 425         ws16c48gpio->chip.set = ws16c48_gpio_set;
 426         ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
 427         ws16c48gpio->base = base[id];
 428
 429         raw_spin_lock_init(&ws16c48gpio->lock);
 430
 431         err = devm_gpiochip_add_data(dev, &ws16c48gpio->chip, ws16c48gpio);
 432         if (err) {
 433                 dev_err(dev, "GPIO registering failed (%d)\n", err);
 434                 return err;
 435         }
 436
 437         /* Disable IRQ by default */
 438         outb(0x80, base[id] + 7);
 439         outb(0, base[id] + 8);
 440         outb(0, base[id] + 9);
 441         outb(0, base[id] + 10);
 442         outb(0xC0, base[id] + 7);
 443
 444         err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_irqchip, 0,
 445                 handle_edge_irq, IRQ_TYPE_NONE);
 446         if (err) {
 447                 dev_err(dev, "Could not add irqchip (%d)\n", err);
 448                 return err;
 449         }
 450
 451         err = devm_request_irq(dev, irq[id], ws16c48_irq_handler, IRQF_SHARED,
 452                 name, ws16c48gpio);
 453         if (err) {
 454                 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
 455                 return err;
 456         }
 457
 458         return 0;
 459 }
 460
 461 static struct isa_driver ws16c48_driver = {
 462         .probe = ws16c48_probe,
 463         .driver = {
 464                 .name = "ws16c48"
 465         },
 466 };
 467
 468 module_isa_driver(ws16c48_driver, num_ws16c48);
 469
 470 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 471 MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver");
 472 MODULE_LICENSE("GPL v2");