drivers/gpio/gpio-dln2.c

   1 /*
   2  * Driver for the Diolan DLN-2 USB-GPIO adapter
   3  *
   4  * Copyright (c) 2014 Intel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation, version 2.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/irqdomain.h>
  16 #include <linux/irq.h>
  17 #include <linux/irqchip/chained_irq.h>
  18 #include <linux/gpio.h>
  19 #include <linux/gpio/driver.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mfd/dln2.h>
  22
  23 #define DLN2_GPIO_ID                    0x01
  24
  25 #define DLN2_GPIO_GET_PIN_COUNT         DLN2_CMD(0x01, DLN2_GPIO_ID)
  26 #define DLN2_GPIO_SET_DEBOUNCE          DLN2_CMD(0x04, DLN2_GPIO_ID)
  27 #define DLN2_GPIO_GET_DEBOUNCE          DLN2_CMD(0x05, DLN2_GPIO_ID)
  28 #define DLN2_GPIO_PORT_GET_VAL          DLN2_CMD(0x06, DLN2_GPIO_ID)
  29 #define DLN2_GPIO_PIN_GET_VAL           DLN2_CMD(0x0B, DLN2_GPIO_ID)
  30 #define DLN2_GPIO_PIN_SET_OUT_VAL       DLN2_CMD(0x0C, DLN2_GPIO_ID)
  31 #define DLN2_GPIO_PIN_GET_OUT_VAL       DLN2_CMD(0x0D, DLN2_GPIO_ID)
  32 #define DLN2_GPIO_CONDITION_MET_EV      DLN2_CMD(0x0F, DLN2_GPIO_ID)
  33 #define DLN2_GPIO_PIN_ENABLE            DLN2_CMD(0x10, DLN2_GPIO_ID)
  34 #define DLN2_GPIO_PIN_DISABLE           DLN2_CMD(0x11, DLN2_GPIO_ID)
  35 #define DLN2_GPIO_PIN_SET_DIRECTION     DLN2_CMD(0x13, DLN2_GPIO_ID)
  36 #define DLN2_GPIO_PIN_GET_DIRECTION     DLN2_CMD(0x14, DLN2_GPIO_ID)
  37 #define DLN2_GPIO_PIN_SET_EVENT_CFG     DLN2_CMD(0x1E, DLN2_GPIO_ID)
  38 #define DLN2_GPIO_PIN_GET_EVENT_CFG     DLN2_CMD(0x1F, DLN2_GPIO_ID)
  39
  40 #define DLN2_GPIO_EVENT_NONE            0
  41 #define DLN2_GPIO_EVENT_CHANGE          1
  42 #define DLN2_GPIO_EVENT_LVL_HIGH        2
  43 #define DLN2_GPIO_EVENT_LVL_LOW         3
  44 #define DLN2_GPIO_EVENT_CHANGE_RISING   0x11
  45 #define DLN2_GPIO_EVENT_CHANGE_FALLING  0x21
  46 #define DLN2_GPIO_EVENT_MASK            0x0F
  47
  48 #define DLN2_GPIO_MAX_PINS 32
  49
  50 struct dln2_gpio {
  51         struct platform_device *pdev;
  52         struct gpio_chip gpio;
  53
  54         /*
  55          * Cache pin direction to save us one transfer, since the hardware has
  56          * separate commands to read the in and out values.
  57          */
  58         DECLARE_BITMAP(output_enabled, DLN2_GPIO_MAX_PINS);
  59
  60         /* active IRQs - not synced to hardware */
  61         DECLARE_BITMAP(unmasked_irqs, DLN2_GPIO_MAX_PINS);
  62         /* active IRQS - synced to hardware */
  63         DECLARE_BITMAP(enabled_irqs, DLN2_GPIO_MAX_PINS);
  64         int irq_type[DLN2_GPIO_MAX_PINS];
  65         struct mutex irq_lock;
  66 };
  67
  68 struct dln2_gpio_pin {
  69         __le16 pin;
  70 };
  71
  72 struct dln2_gpio_pin_val {
  73         __le16 pin __packed;
  74         u8 value;
  75 };
  76
  77 static int dln2_gpio_get_pin_count(struct platform_device *pdev)
  78 {
  79         int ret;
  80         __le16 count;
  81         int len = sizeof(count);
  82
  83         ret = dln2_transfer_rx(pdev, DLN2_GPIO_GET_PIN_COUNT, &count, &len);
  84         if (ret < 0)
  85                 return ret;
  86         if (len < sizeof(count))
  87                 return -EPROTO;
  88
  89         return le16_to_cpu(count);
  90 }
  91
  92 static int dln2_gpio_pin_cmd(struct dln2_gpio *dln2, int cmd, unsigned pin)
  93 {
  94         struct dln2_gpio_pin req = {
  95                 .pin = cpu_to_le16(pin),
  96         };
  97
  98         return dln2_transfer_tx(dln2->pdev, cmd, &req, sizeof(req));
  99 }
 100
 101 static int dln2_gpio_pin_val(struct dln2_gpio *dln2, int cmd, unsigned int pin)
 102 {
 103         int ret;
 104         struct dln2_gpio_pin req = {
 105                 .pin = cpu_to_le16(pin),
 106         };
 107         struct dln2_gpio_pin_val rsp;
 108         int len = sizeof(rsp);
 109
 110         ret = dln2_transfer(dln2->pdev, cmd, &req, sizeof(req), &rsp, &len);
 111         if (ret < 0)
 112                 return ret;
 113         if (len < sizeof(rsp) || req.pin != rsp.pin)
 114                 return -EPROTO;
 115
 116         return rsp.value;
 117 }
 118
 119 static int dln2_gpio_pin_get_in_val(struct dln2_gpio *dln2, unsigned int pin)
 120 {
 121         int ret;
 122
 123         ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_VAL, pin);
 124         if (ret < 0)
 125                 return ret;
 126         return !!ret;
 127 }
 128
 129 static int dln2_gpio_pin_get_out_val(struct dln2_gpio *dln2, unsigned int pin)
 130 {
 131         int ret;
 132
 133         ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_OUT_VAL, pin);
 134         if (ret < 0)
 135                 return ret;
 136         return !!ret;
 137 }
 138
 139 static int dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2,
 140                                      unsigned int pin, int value)
 141 {
 142         struct dln2_gpio_pin_val req = {
 143                 .pin = cpu_to_le16(pin),
 144                 .value = value,
 145         };
 146
 147         return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req,
 148                                 sizeof(req));
 149 }
 150
 151 #define DLN2_GPIO_DIRECTION_IN          0
 152 #define DLN2_GPIO_DIRECTION_OUT         1
 153
 154 static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset)
 155 {
 156         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 157         struct dln2_gpio_pin req = {
 158                 .pin = cpu_to_le16(offset),
 159         };
 160         struct dln2_gpio_pin_val rsp;
 161         int len = sizeof(rsp);
 162         int ret;
 163
 164         ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset);
 165         if (ret < 0)
 166                 return ret;
 167
 168         /* cache the pin direction */
 169         ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION,
 170                             &req, sizeof(req), &rsp, &len);
 171         if (ret < 0)
 172                 return ret;
 173         if (len < sizeof(rsp) || req.pin != rsp.pin) {
 174                 ret = -EPROTO;
 175                 goto out_disable;
 176         }
 177
 178         switch (rsp.value) {
 179         case DLN2_GPIO_DIRECTION_IN:
 180                 clear_bit(offset, dln2->output_enabled);
 181                 return 0;
 182         case DLN2_GPIO_DIRECTION_OUT:
 183                 set_bit(offset, dln2->output_enabled);
 184                 return 0;
 185         default:
 186                 ret = -EPROTO;
 187                 goto out_disable;
 188         }
 189
 190 out_disable:
 191         dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
 192         return ret;
 193 }
 194
 195 static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset)
 196 {
 197         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 198
 199         dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
 200 }
 201
 202 static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
 203 {
 204         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 205
 206         if (test_bit(offset, dln2->output_enabled))
 207                 return GPIOF_DIR_OUT;
 208
 209         return GPIOF_DIR_IN;
 210 }
 211
 212 static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
 213 {
 214         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 215         int dir;
 216
 217         dir = dln2_gpio_get_direction(chip, offset);
 218         if (dir < 0)
 219                 return dir;
 220
 221         if (dir == GPIOF_DIR_IN)
 222                 return dln2_gpio_pin_get_in_val(dln2, offset);
 223
 224         return dln2_gpio_pin_get_out_val(dln2, offset);
 225 }
 226
 227 static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 228 {
 229         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 230
 231         dln2_gpio_pin_set_out_val(dln2, offset, value);
 232 }
 233
 234 static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset,
 235                                    unsigned dir)
 236 {
 237         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 238         struct dln2_gpio_pin_val req = {
 239                 .pin = cpu_to_le16(offset),
 240                 .value = dir,
 241         };
 242         int ret;
 243
 244         ret = dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_DIRECTION,
 245                                &req, sizeof(req));
 246         if (ret < 0)
 247                 return ret;
 248
 249         if (dir == DLN2_GPIO_DIRECTION_OUT)
 250                 set_bit(offset, dln2->output_enabled);
 251         else
 252                 clear_bit(offset, dln2->output_enabled);
 253
 254         return ret;
 255 }
 256
 257 static int dln2_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 258 {
 259         return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_IN);
 260 }
 261
 262 static int dln2_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
 263                                       int value)
 264 {
 265         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 266         int ret;
 267
 268         ret = dln2_gpio_pin_set_out_val(dln2, offset, value);
 269         if (ret < 0)
 270                 return ret;
 271
 272         return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_OUT);
 273 }
 274
 275 static int dln2_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
 276                                   unsigned debounce)
 277 {
 278         struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
 279         __le32 duration = cpu_to_le32(debounce);
 280
 281         return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_SET_DEBOUNCE,
 282                                 &duration, sizeof(duration));
 283 }
 284
 285 static int dln2_gpio_set_event_cfg(struct dln2_gpio *dln2, unsigned pin,
 286                                    unsigned type, unsigned period)
 287 {
 288         struct {
 289                 __le16 pin;
 290                 u8 type;
 291                 __le16 period;
 292         } __packed req = {
 293                 .pin = cpu_to_le16(pin),
 294                 .type = type,
 295                 .period = cpu_to_le16(period),
 296         };
 297
 298         return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_EVENT_CFG,
 299                                 &req, sizeof(req));
 300 }
 301
 302 static void dln2_irq_unmask(struct irq_data *irqd)
 303 {
 304         struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
 305         struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
 306         int pin = irqd_to_hwirq(irqd);
 307
 308         set_bit(pin, dln2->unmasked_irqs);
 309 }
 310
 311 static void dln2_irq_mask(struct irq_data *irqd)
 312 {
 313         struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
 314         struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
 315         int pin = irqd_to_hwirq(irqd);
 316
 317         clear_bit(pin, dln2->unmasked_irqs);
 318 }
 319
 320 static int dln2_irq_set_type(struct irq_data *irqd, unsigned type)
 321 {
 322         struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
 323         struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
 324         int pin = irqd_to_hwirq(irqd);
 325
 326         switch (type) {
 327         case IRQ_TYPE_LEVEL_HIGH:
 328                 dln2->irq_type[pin] = DLN2_GPIO_EVENT_LVL_HIGH;
 329                 break;
 330         case IRQ_TYPE_LEVEL_LOW:
 331                 dln2->irq_type[pin] = DLN2_GPIO_EVENT_LVL_LOW;
 332                 break;
 333         case IRQ_TYPE_EDGE_BOTH:
 334                 dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE;
 335                 break;
 336         case IRQ_TYPE_EDGE_RISING:
 337                 dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE_RISING;
 338                 break;
 339         case IRQ_TYPE_EDGE_FALLING:
 340                 dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE_FALLING;
 341                 break;
 342         default:
 343                 return -EINVAL;
 344         }
 345
 346         return 0;
 347 }
 348
 349 static void dln2_irq_bus_lock(struct irq_data *irqd)
 350 {
 351         struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
 352         struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
 353
 354         mutex_lock(&dln2->irq_lock);
 355 }
 356
 357 static void dln2_irq_bus_unlock(struct irq_data *irqd)
 358 {
 359         struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
 360         struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
 361         int pin = irqd_to_hwirq(irqd);
 362         int enabled, unmasked;
 363         unsigned type;
 364         int ret;
 365
 366         enabled = test_bit(pin, dln2->enabled_irqs);
 367         unmasked = test_bit(pin, dln2->unmasked_irqs);
 368
 369         if (enabled != unmasked) {
 370                 if (unmasked) {
 371                         type = dln2->irq_type[pin] & DLN2_GPIO_EVENT_MASK;
 372                         set_bit(pin, dln2->enabled_irqs);
 373                 } else {
 374                         type = DLN2_GPIO_EVENT_NONE;
 375                         clear_bit(pin, dln2->enabled_irqs);
 376                 }
 377
 378                 ret = dln2_gpio_set_event_cfg(dln2, pin, type, 0);
 379                 if (ret)
 380                         dev_err(dln2->gpio.dev, "failed to set event\n");
 381         }
 382
 383         mutex_unlock(&dln2->irq_lock);
 384 }
 385
 386 static struct irq_chip dln2_gpio_irqchip = {
 387         .name = "dln2-irq",
 388         .irq_mask = dln2_irq_mask,
 389         .irq_unmask = dln2_irq_unmask,
 390         .irq_set_type = dln2_irq_set_type,
 391         .irq_bus_lock = dln2_irq_bus_lock,
 392         .irq_bus_sync_unlock = dln2_irq_bus_unlock,
 393 };
 394
 395 static void dln2_gpio_event(struct platform_device *pdev, u16 echo,
 396                             const void *data, int len)
 397 {
 398         int pin, irq;
 399
 400         const struct {
 401                 __le16 count;
 402                 __u8 type;
 403                 __le16 pin;
 404                 __u8 value;
 405         } __packed *event = data;
 406         struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
 407
 408         if (len < sizeof(*event)) {
 409                 dev_err(dln2->gpio.dev, "short event message\n");
 410                 return;
 411         }
 412
 413         pin = le16_to_cpu(event->pin);
 414         if (pin >= dln2->gpio.ngpio) {
 415                 dev_err(dln2->gpio.dev, "out of bounds pin %d\n", pin);
 416                 return;
 417         }
 418
 419         irq = irq_find_mapping(dln2->gpio.irqdomain, pin);
 420         if (!irq) {
 421                 dev_err(dln2->gpio.dev, "pin %d not mapped to IRQ\n", pin);
 422                 return;
 423         }
 424
 425         switch (dln2->irq_type[pin]) {
 426         case DLN2_GPIO_EVENT_CHANGE_RISING:
 427                 if (event->value)
 428                         generic_handle_irq(irq);
 429                 break;
 430         case DLN2_GPIO_EVENT_CHANGE_FALLING:
 431                 if (!event->value)
 432                         generic_handle_irq(irq);
 433                 break;
 434         default:
 435                 generic_handle_irq(irq);
 436         }
 437 }
 438
 439 static int dln2_gpio_probe(struct platform_device *pdev)
 440 {
 441         struct dln2_gpio *dln2;
 442         struct device *dev = &pdev->dev;
 443         int pins;
 444         int ret;
 445
 446         pins = dln2_gpio_get_pin_count(pdev);
 447         if (pins < 0) {
 448                 dev_err(dev, "failed to get pin count: %d\n", pins);
 449                 return pins;
 450         }
 451         if (pins > DLN2_GPIO_MAX_PINS) {
 452                 pins = DLN2_GPIO_MAX_PINS;
 453                 dev_warn(dev, "clamping pins to %d\n", DLN2_GPIO_MAX_PINS);
 454         }
 455
 456         dln2 = devm_kzalloc(&pdev->dev, sizeof(*dln2), GFP_KERNEL);
 457         if (!dln2)
 458                 return -ENOMEM;
 459
 460         mutex_init(&dln2->irq_lock);
 461
 462         dln2->pdev = pdev;
 463
 464         dln2->gpio.label = "dln2";
 465         dln2->gpio.dev = dev;
 466         dln2->gpio.owner = THIS_MODULE;
 467         dln2->gpio.base = -1;
 468         dln2->gpio.ngpio = pins;
 469         dln2->gpio.exported = true;
 470         dln2->gpio.can_sleep = true;
 471         dln2->gpio.irq_not_threaded = true;
 472         dln2->gpio.set = dln2_gpio_set;
 473         dln2->gpio.get = dln2_gpio_get;
 474         dln2->gpio.request = dln2_gpio_request;
 475         dln2->gpio.free = dln2_gpio_free;
 476         dln2->gpio.get_direction = dln2_gpio_get_direction;
 477         dln2->gpio.direction_input = dln2_gpio_direction_input;
 478         dln2->gpio.direction_output = dln2_gpio_direction_output;
 479         dln2->gpio.set_debounce = dln2_gpio_set_debounce;
 480
 481         platform_set_drvdata(pdev, dln2);
 482
 483         ret = gpiochip_add(&dln2->gpio);
 484         if (ret < 0) {
 485                 dev_err(dev, "failed to add gpio chip: %d\n", ret);
 486                 goto out;
 487         }
 488
 489         ret = gpiochip_irqchip_add(&dln2->gpio, &dln2_gpio_irqchip, 0,
 490                                    handle_simple_irq, IRQ_TYPE_NONE);
 491         if (ret < 0) {
 492                 dev_err(dev, "failed to add irq chip: %d\n", ret);
 493                 goto out_gpiochip_remove;
 494         }
 495
 496         ret = dln2_register_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV,
 497                                      dln2_gpio_event);
 498         if (ret) {
 499                 dev_err(dev, "failed to register event cb: %d\n", ret);
 500                 goto out_gpiochip_remove;
 501         }
 502
 503         return 0;
 504
 505 out_gpiochip_remove:
 506         gpiochip_remove(&dln2->gpio);
 507 out:
 508         return ret;
 509 }
 510
 511 static int dln2_gpio_remove(struct platform_device *pdev)
 512 {
 513         struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
 514
 515         dln2_unregister_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV);
 516         gpiochip_remove(&dln2->gpio);
 517
 518         return 0;
 519 }
 520
 521 static struct platform_driver dln2_gpio_driver = {
 522         .driver.name    = "dln2-gpio",
 523         .probe          = dln2_gpio_probe,
 524         .remove         = dln2_gpio_remove,
 525 };
 526
 527 module_platform_driver(dln2_gpio_driver);
 528
 529 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com");
 530 MODULE_DESCRIPTION("Driver for the Diolan DLN2 GPIO interface");
 531 MODULE_LICENSE("GPL v2");
 532 MODULE_ALIAS("platform:dln2-gpio");