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  * @irq:        Interrupt line number
  50  */
  51 struct ws16c48_gpio {
  52         struct gpio_chip chip;
  53         unsigned char io_state[6];
  54         unsigned char out_state[6];
  55         spinlock_t lock;
  56         unsigned long irq_mask;
  57         unsigned long flow_mask;
  58         unsigned base;
  59         unsigned irq;
  60 };
  61
  62 static int ws16c48_gpio_get_direction(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
  68         return !!(ws16c48gpio->io_state[port] & mask);
  69 }
  70
  71 static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  72 {
  73         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
  74         const unsigned port = offset / 8;
  75         const unsigned mask = BIT(offset % 8);
  76         unsigned long flags;
  77
  78         spin_lock_irqsave(&ws16c48gpio->lock, flags);
  79
  80         ws16c48gpio->io_state[port] |= mask;
  81         ws16c48gpio->out_state[port] &= ~mask;
  82         outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
  83
  84         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
  85
  86         return 0;
  87 }
  88
  89 static int ws16c48_gpio_direction_output(struct gpio_chip *chip,
  90         unsigned offset, int value)
  91 {
  92         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
  93         const unsigned port = offset / 8;
  94         const unsigned mask = BIT(offset % 8);
  95         unsigned long flags;
  96
  97         spin_lock_irqsave(&ws16c48gpio->lock, flags);
  98
  99         ws16c48gpio->io_state[port] &= ~mask;
 100         if (value)
 101                 ws16c48gpio->out_state[port] |= mask;
 102         else
 103                 ws16c48gpio->out_state[port] &= ~mask;
 104         outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
 105
 106         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 107
 108         return 0;
 109 }
 110
 111 static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
 112 {
 113         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 114         const unsigned port = offset / 8;
 115         const unsigned mask = BIT(offset % 8);
 116         unsigned long flags;
 117         unsigned port_state;
 118
 119         spin_lock_irqsave(&ws16c48gpio->lock, flags);
 120
 121         /* ensure that GPIO is set for input */
 122         if (!(ws16c48gpio->io_state[port] & mask)) {
 123                 spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 124                 return -EINVAL;
 125         }
 126
 127         port_state = inb(ws16c48gpio->base + port);
 128
 129         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 130
 131         return !!(port_state & mask);
 132 }
 133
 134 static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 135 {
 136         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 137         const unsigned port = offset / 8;
 138         const unsigned mask = BIT(offset % 8);
 139         unsigned long flags;
 140
 141         spin_lock_irqsave(&ws16c48gpio->lock, flags);
 142
 143         /* ensure that GPIO is set for output */
 144         if (ws16c48gpio->io_state[port] & mask) {
 145                 spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 146                 return;
 147         }
 148
 149         if (value)
 150                 ws16c48gpio->out_state[port] |= mask;
 151         else
 152                 ws16c48gpio->out_state[port] &= ~mask;
 153         outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
 154
 155         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 156 }
 157
 158 static void ws16c48_irq_ack(struct irq_data *data)
 159 {
 160         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 161         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 162         const unsigned long offset = irqd_to_hwirq(data);
 163         const unsigned port = offset / 8;
 164         const unsigned mask = BIT(offset % 8);
 165         unsigned long flags;
 166         unsigned port_state;
 167
 168         /* only the first 3 ports support interrupts */
 169         if (port > 2)
 170                 return;
 171
 172         spin_lock_irqsave(&ws16c48gpio->lock, flags);
 173
 174         port_state = ws16c48gpio->irq_mask >> (8*port);
 175
 176         outb(0x80, ws16c48gpio->base + 7);
 177         outb(port_state & ~mask, ws16c48gpio->base + 8 + port);
 178         outb(port_state | mask, ws16c48gpio->base + 8 + port);
 179         outb(0xC0, ws16c48gpio->base + 7);
 180
 181         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 182 }
 183
 184 static void ws16c48_irq_mask(struct irq_data *data)
 185 {
 186         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 187         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 188         const unsigned long offset = irqd_to_hwirq(data);
 189         const unsigned long mask = BIT(offset);
 190         const unsigned port = offset / 8;
 191         unsigned long flags;
 192
 193         /* only the first 3 ports support interrupts */
 194         if (port > 2)
 195                 return;
 196
 197         spin_lock_irqsave(&ws16c48gpio->lock, flags);
 198
 199         ws16c48gpio->irq_mask &= ~mask;
 200
 201         outb(0x80, ws16c48gpio->base + 7);
 202         outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
 203         outb(0xC0, ws16c48gpio->base + 7);
 204
 205         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 206 }
 207
 208 static void ws16c48_irq_unmask(struct irq_data *data)
 209 {
 210         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 211         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 212         const unsigned long offset = irqd_to_hwirq(data);
 213         const unsigned long mask = BIT(offset);
 214         const unsigned port = offset / 8;
 215         unsigned long flags;
 216
 217         /* only the first 3 ports support interrupts */
 218         if (port > 2)
 219                 return;
 220
 221         spin_lock_irqsave(&ws16c48gpio->lock, flags);
 222
 223         ws16c48gpio->irq_mask |= mask;
 224
 225         outb(0x80, ws16c48gpio->base + 7);
 226         outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
 227         outb(0xC0, ws16c48gpio->base + 7);
 228
 229         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 230 }
 231
 232 static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
 233 {
 234         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 235         struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
 236         const unsigned long offset = irqd_to_hwirq(data);
 237         const unsigned long mask = BIT(offset);
 238         const unsigned port = offset / 8;
 239         unsigned long flags;
 240
 241         /* only the first 3 ports support interrupts */
 242         if (port > 2)
 243                 return -EINVAL;
 244
 245         spin_lock_irqsave(&ws16c48gpio->lock, flags);
 246
 247         switch (flow_type) {
 248         case IRQ_TYPE_NONE:
 249                 break;
 250         case IRQ_TYPE_EDGE_RISING:
 251                 ws16c48gpio->flow_mask |= mask;
 252                 break;
 253         case IRQ_TYPE_EDGE_FALLING:
 254                 ws16c48gpio->flow_mask &= ~mask;
 255                 break;
 256         default:
 257                 spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 258                 return -EINVAL;
 259         }
 260
 261         outb(0x40, ws16c48gpio->base + 7);
 262         outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port);
 263         outb(0xC0, ws16c48gpio->base + 7);
 264
 265         spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
 266
 267         return 0;
 268 }
 269
 270 static struct irq_chip ws16c48_irqchip = {
 271         .name = "ws16c48",
 272         .irq_ack = ws16c48_irq_ack,
 273         .irq_mask = ws16c48_irq_mask,
 274         .irq_unmask = ws16c48_irq_unmask,
 275         .irq_set_type = ws16c48_irq_set_type
 276 };
 277
 278 static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id)
 279 {
 280         struct ws16c48_gpio *const ws16c48gpio = dev_id;
 281         struct gpio_chip *const chip = &ws16c48gpio->chip;
 282         unsigned long int_pending;
 283         unsigned long port;
 284         unsigned long int_id;
 285         unsigned long gpio;
 286
 287         int_pending = inb(ws16c48gpio->base + 6) & 0x7;
 288         if (!int_pending)
 289                 return IRQ_NONE;
 290
 291         /* loop until all pending interrupts are handled */
 292         do {
 293                 for_each_set_bit(port, &int_pending, 3) {
 294                         int_id = inb(ws16c48gpio->base + 8 + port);
 295                         for_each_set_bit(gpio, &int_id, 8)
 296                                 generic_handle_irq(irq_find_mapping(
 297                                         chip->irqdomain, gpio + 8*port));
 298                 }
 299
 300                 int_pending = inb(ws16c48gpio->base + 6) & 0x7;
 301         } while (int_pending);
 302
 303         return IRQ_HANDLED;
 304 }
 305
 306 static int ws16c48_probe(struct device *dev, unsigned int id)
 307 {
 308         struct ws16c48_gpio *ws16c48gpio;
 309         const char *const name = dev_name(dev);
 310         int err;
 311
 312         ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL);
 313         if (!ws16c48gpio)
 314                 return -ENOMEM;
 315
 316         if (!devm_request_region(dev, base[id], WS16C48_EXTENT, name)) {
 317                 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
 318                         base[id], base[id] + WS16C48_EXTENT);
 319                 return -EBUSY;
 320         }
 321
 322         ws16c48gpio->chip.label = name;
 323         ws16c48gpio->chip.parent = dev;
 324         ws16c48gpio->chip.owner = THIS_MODULE;
 325         ws16c48gpio->chip.base = -1;
 326         ws16c48gpio->chip.ngpio = 48;
 327         ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction;
 328         ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
 329         ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
 330         ws16c48gpio->chip.get = ws16c48_gpio_get;
 331         ws16c48gpio->chip.set = ws16c48_gpio_set;
 332         ws16c48gpio->base = base[id];
 333         ws16c48gpio->irq = irq[id];
 334
 335         spin_lock_init(&ws16c48gpio->lock);
 336
 337         dev_set_drvdata(dev, ws16c48gpio);
 338
 339         err = gpiochip_add_data(&ws16c48gpio->chip, ws16c48gpio);
 340         if (err) {
 341                 dev_err(dev, "GPIO registering failed (%d)\n", err);
 342                 return err;
 343         }
 344
 345         /* Disable IRQ by default */
 346         outb(0x80, base[id] + 7);
 347         outb(0, base[id] + 8);
 348         outb(0, base[id] + 9);
 349         outb(0, base[id] + 10);
 350         outb(0xC0, base[id] + 7);
 351
 352         err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_irqchip, 0,
 353                 handle_edge_irq, IRQ_TYPE_NONE);
 354         if (err) {
 355                 dev_err(dev, "Could not add irqchip (%d)\n", err);
 356                 goto err_gpiochip_remove;
 357         }
 358
 359         err = request_irq(irq[id], ws16c48_irq_handler, IRQF_SHARED, name,
 360                 ws16c48gpio);
 361         if (err) {
 362                 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
 363                 goto err_gpiochip_remove;
 364         }
 365
 366         return 0;
 367
 368 err_gpiochip_remove:
 369         gpiochip_remove(&ws16c48gpio->chip);
 370         return err;
 371 }
 372
 373 static int ws16c48_remove(struct device *dev, unsigned int id)
 374 {
 375         struct ws16c48_gpio *const ws16c48gpio = dev_get_drvdata(dev);
 376
 377         free_irq(ws16c48gpio->irq, ws16c48gpio);
 378         gpiochip_remove(&ws16c48gpio->chip);
 379
 380         return 0;
 381 }
 382
 383 static struct isa_driver ws16c48_driver = {
 384         .probe = ws16c48_probe,
 385         .driver = {
 386                 .name = "ws16c48"
 387         },
 388         .remove = ws16c48_remove
 389 };
 390
 391 module_isa_driver(ws16c48_driver, num_ws16c48);
 392
 393 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 394 MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver");
 395 MODULE_LICENSE("GPL v2");