drivers/gpio/gpio-ws16c48.c

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