drivers/gpio/gpio-htc-egpio.c

   1 /*
   2  * Support for the GPIO/IRQ expander chips present on several HTC phones.
   3  * These are implemented in CPLD chips present on the board.
   4  *
   5  * Copyright (c) 2007 Kevin O'Connor <kevin@koconnor.net>
   6  * Copyright (c) 2007 Philipp Zabel <philipp.zabel@gmail.com>
   7  *
   8  * This file may be distributed under the terms of the GNU GPL license.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/irq.h>
  15 #include <linux/io.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/platform_data/gpio-htc-egpio.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20 #include <linux/init.h>
  21 #include <linux/gpio/driver.h>
  22
  23 struct egpio_chip {
  24         int              reg_start;
  25         int              cached_values;
  26         unsigned long    is_out;
  27         struct device    *dev;
  28         struct gpio_chip chip;
  29 };
  30
  31 struct egpio_info {
  32         spinlock_t        lock;
  33
  34         /* iomem info */
  35         void __iomem      *base_addr;
  36         int               bus_shift;    /* byte shift */
  37         int               reg_shift;    /* bit shift */
  38         int               reg_mask;
  39
  40         /* irq info */
  41         int               ack_register;
  42         int               ack_write;
  43         u16               irqs_enabled;
  44         uint              irq_start;
  45         int               nirqs;
  46         uint              chained_irq;
  47
  48         /* egpio info */
  49         struct egpio_chip *chip;
  50         int               nchips;
  51 };
  52
  53 static inline void egpio_writew(u16 value, struct egpio_info *ei, int reg)
  54 {
  55         writew(value, ei->base_addr + (reg << ei->bus_shift));
  56 }
  57
  58 static inline u16 egpio_readw(struct egpio_info *ei, int reg)
  59 {
  60         return readw(ei->base_addr + (reg << ei->bus_shift));
  61 }
  62
  63 /*
  64  * IRQs
  65  */
  66
  67 static inline void ack_irqs(struct egpio_info *ei)
  68 {
  69         egpio_writew(ei->ack_write, ei, ei->ack_register);
  70         pr_debug("EGPIO ack - write %x to base+%x\n",
  71                         ei->ack_write, ei->ack_register << ei->bus_shift);
  72 }
  73
  74 static void egpio_ack(struct irq_data *data)
  75 {
  76 }
  77
  78 /* There does not appear to be a way to proactively mask interrupts
  79  * on the egpio chip itself.  So, we simply ignore interrupts that
  80  * aren't desired. */
  81 static void egpio_mask(struct irq_data *data)
  82 {
  83         struct egpio_info *ei = irq_data_get_irq_chip_data(data);
  84         ei->irqs_enabled &= ~(1 << (data->irq - ei->irq_start));
  85         pr_debug("EGPIO mask %d %04x\n", data->irq, ei->irqs_enabled);
  86 }
  87
  88 static void egpio_unmask(struct irq_data *data)
  89 {
  90         struct egpio_info *ei = irq_data_get_irq_chip_data(data);
  91         ei->irqs_enabled |= 1 << (data->irq - ei->irq_start);
  92         pr_debug("EGPIO unmask %d %04x\n", data->irq, ei->irqs_enabled);
  93 }
  94
  95 static struct irq_chip egpio_muxed_chip = {
  96         .name           = "htc-egpio",
  97         .irq_ack        = egpio_ack,
  98         .irq_mask       = egpio_mask,
  99         .irq_unmask     = egpio_unmask,
 100 };
 101
 102 static void egpio_handler(struct irq_desc *desc)
 103 {
 104         struct egpio_info *ei = irq_desc_get_handler_data(desc);
 105         int irqpin;
 106
 107         /* Read current pins. */
 108         unsigned long readval = egpio_readw(ei, ei->ack_register);
 109         pr_debug("IRQ reg: %x\n", (unsigned int)readval);
 110         /* Ack/unmask interrupts. */
 111         ack_irqs(ei);
 112         /* Process all set pins. */
 113         readval &= ei->irqs_enabled;
 114         for_each_set_bit(irqpin, &readval, ei->nirqs) {
 115                 /* Run irq handler */
 116                 pr_debug("got IRQ %d\n", irqpin);
 117                 generic_handle_irq(ei->irq_start + irqpin);
 118         }
 119 }
 120
 121 int htc_egpio_get_wakeup_irq(struct device *dev)
 122 {
 123         struct egpio_info *ei = dev_get_drvdata(dev);
 124
 125         /* Read current pins. */
 126         u16 readval = egpio_readw(ei, ei->ack_register);
 127         /* Ack/unmask interrupts. */
 128         ack_irqs(ei);
 129         /* Return first set pin. */
 130         readval &= ei->irqs_enabled;
 131         return ei->irq_start + ffs(readval) - 1;
 132 }
 133 EXPORT_SYMBOL(htc_egpio_get_wakeup_irq);
 134
 135 static inline int egpio_pos(struct egpio_info *ei, int bit)
 136 {
 137         return bit >> ei->reg_shift;
 138 }
 139
 140 static inline int egpio_bit(struct egpio_info *ei, int bit)
 141 {
 142         return 1 << (bit & ((1 << ei->reg_shift)-1));
 143 }
 144
 145 /*
 146  * Input pins
 147  */
 148
 149 static int egpio_get(struct gpio_chip *chip, unsigned offset)
 150 {
 151         struct egpio_chip *egpio;
 152         struct egpio_info *ei;
 153         unsigned           bit;
 154         int                reg;
 155         int                value;
 156
 157         pr_debug("egpio_get_value(%d)\n", chip->base + offset);
 158
 159         egpio = gpiochip_get_data(chip);
 160         ei    = dev_get_drvdata(egpio->dev);
 161         bit   = egpio_bit(ei, offset);
 162         reg   = egpio->reg_start + egpio_pos(ei, offset);
 163
 164         if (test_bit(offset, &egpio->is_out)) {
 165                 return !!(egpio->cached_values & (1 << offset));
 166         } else {
 167                 value = egpio_readw(ei, reg);
 168                 pr_debug("readw(%p + %x) = %x\n",
 169                          ei->base_addr, reg << ei->bus_shift, value);
 170                 return !!(value & bit);
 171         }
 172 }
 173
 174 static int egpio_direction_input(struct gpio_chip *chip, unsigned offset)
 175 {
 176         struct egpio_chip *egpio;
 177
 178         egpio = gpiochip_get_data(chip);
 179         return test_bit(offset, &egpio->is_out) ? -EINVAL : 0;
 180 }
 181
 182
 183 /*
 184  * Output pins
 185  */
 186
 187 static void egpio_set(struct gpio_chip *chip, unsigned offset, int value)
 188 {
 189         unsigned long     flag;
 190         struct egpio_chip *egpio;
 191         struct egpio_info *ei;
 192         unsigned          bit;
 193         int               pos;
 194         int               reg;
 195         int               shift;
 196
 197         pr_debug("egpio_set(%s, %d(%d), %d)\n",
 198                         chip->label, offset, offset+chip->base, value);
 199
 200         egpio = gpiochip_get_data(chip);
 201         ei    = dev_get_drvdata(egpio->dev);
 202         bit   = egpio_bit(ei, offset);
 203         pos   = egpio_pos(ei, offset);
 204         reg   = egpio->reg_start + pos;
 205         shift = pos << ei->reg_shift;
 206
 207         pr_debug("egpio %s: reg %d = 0x%04x\n", value ? "set" : "clear",
 208                         reg, (egpio->cached_values >> shift) & ei->reg_mask);
 209
 210         spin_lock_irqsave(&ei->lock, flag);
 211         if (value)
 212                 egpio->cached_values |= (1 << offset);
 213         else
 214                 egpio->cached_values &= ~(1 << offset);
 215         egpio_writew((egpio->cached_values >> shift) & ei->reg_mask, ei, reg);
 216         spin_unlock_irqrestore(&ei->lock, flag);
 217 }
 218
 219 static int egpio_direction_output(struct gpio_chip *chip,
 220                                         unsigned offset, int value)
 221 {
 222         struct egpio_chip *egpio;
 223
 224         egpio = gpiochip_get_data(chip);
 225         if (test_bit(offset, &egpio->is_out)) {
 226                 egpio_set(chip, offset, value);
 227                 return 0;
 228         } else {
 229                 return -EINVAL;
 230         }
 231 }
 232
 233 static int egpio_get_direction(struct gpio_chip *chip, unsigned offset)
 234 {
 235         struct egpio_chip *egpio;
 236
 237         egpio = gpiochip_get_data(chip);
 238
 239         return !test_bit(offset, &egpio->is_out);
 240 }
 241
 242 static void egpio_write_cache(struct egpio_info *ei)
 243 {
 244         int               i;
 245         struct egpio_chip *egpio;
 246         int               shift;
 247
 248         for (i = 0; i < ei->nchips; i++) {
 249                 egpio = &(ei->chip[i]);
 250                 if (!egpio->is_out)
 251                         continue;
 252
 253                 for (shift = 0; shift < egpio->chip.ngpio;
 254                                 shift += (1<<ei->reg_shift)) {
 255
 256                         int reg = egpio->reg_start + egpio_pos(ei, shift);
 257
 258                         if (!((egpio->is_out >> shift) & ei->reg_mask))
 259                                 continue;
 260
 261                         pr_debug("EGPIO: setting %x to %x, was %x\n", reg,
 262                                 (egpio->cached_values >> shift) & ei->reg_mask,
 263                                 egpio_readw(ei, reg));
 264
 265                         egpio_writew((egpio->cached_values >> shift)
 266                                         & ei->reg_mask, ei, reg);
 267                 }
 268         }
 269 }
 270
 271
 272 /*
 273  * Setup
 274  */
 275
 276 static int __init egpio_probe(struct platform_device *pdev)
 277 {
 278         struct htc_egpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
 279         struct resource   *res;
 280         struct egpio_info *ei;
 281         struct gpio_chip  *chip;
 282         unsigned int      irq, irq_end;
 283         int               i;
 284         int               ret;
 285
 286         /* Initialize ei data structure. */
 287         ei = devm_kzalloc(&pdev->dev, sizeof(*ei), GFP_KERNEL);
 288         if (!ei)
 289                 return -ENOMEM;
 290
 291         spin_lock_init(&ei->lock);
 292
 293         /* Find chained irq */
 294         ret = -EINVAL;
 295         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 296         if (res)
 297                 ei->chained_irq = res->start;
 298
 299         /* Map egpio chip into virtual address space. */
 300         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 301         if (!res)
 302                 goto fail;
 303         ei->base_addr = devm_ioremap_nocache(&pdev->dev, res->start,
 304                                              resource_size(res));
 305         if (!ei->base_addr)
 306                 goto fail;
 307         pr_debug("EGPIO phys=%08x virt=%p\n", (u32)res->start, ei->base_addr);
 308
 309         if ((pdata->bus_width != 16) && (pdata->bus_width != 32))
 310                 goto fail;
 311         ei->bus_shift = fls(pdata->bus_width - 1) - 3;
 312         pr_debug("bus_shift = %d\n", ei->bus_shift);
 313
 314         if ((pdata->reg_width != 8) && (pdata->reg_width != 16))
 315                 goto fail;
 316         ei->reg_shift = fls(pdata->reg_width - 1);
 317         pr_debug("reg_shift = %d\n", ei->reg_shift);
 318
 319         ei->reg_mask = (1 << pdata->reg_width) - 1;
 320
 321         platform_set_drvdata(pdev, ei);
 322
 323         ei->nchips = pdata->num_chips;
 324         ei->chip = devm_kcalloc(&pdev->dev,
 325                                 ei->nchips, sizeof(struct egpio_chip),
 326                                 GFP_KERNEL);
 327         if (!ei->chip) {
 328                 ret = -ENOMEM;
 329                 goto fail;
 330         }
 331         for (i = 0; i < ei->nchips; i++) {
 332                 ei->chip[i].reg_start = pdata->chip[i].reg_start;
 333                 ei->chip[i].cached_values = pdata->chip[i].initial_values;
 334                 ei->chip[i].is_out = pdata->chip[i].direction;
 335                 ei->chip[i].dev = &(pdev->dev);
 336                 chip = &(ei->chip[i].chip);
 337                 chip->label           = "htc-egpio";
 338                 chip->parent          = &pdev->dev;
 339                 chip->owner           = THIS_MODULE;
 340                 chip->get             = egpio_get;
 341                 chip->set             = egpio_set;
 342                 chip->direction_input = egpio_direction_input;
 343                 chip->direction_output = egpio_direction_output;
 344                 chip->get_direction   = egpio_get_direction;
 345                 chip->base            = pdata->chip[i].gpio_base;
 346                 chip->ngpio           = pdata->chip[i].num_gpios;
 347
 348                 gpiochip_add_data(chip, &ei->chip[i]);
 349         }
 350
 351         /* Set initial pin values */
 352         egpio_write_cache(ei);
 353
 354         ei->irq_start = pdata->irq_base;
 355         ei->nirqs = pdata->num_irqs;
 356         ei->ack_register = pdata->ack_register;
 357
 358         if (ei->chained_irq) {
 359                 /* Setup irq handlers */
 360                 ei->ack_write = 0xFFFF;
 361                 if (pdata->invert_acks)
 362                         ei->ack_write = 0;
 363                 irq_end = ei->irq_start + ei->nirqs;
 364                 for (irq = ei->irq_start; irq < irq_end; irq++) {
 365                         irq_set_chip_and_handler(irq, &egpio_muxed_chip,
 366                                                  handle_simple_irq);
 367                         irq_set_chip_data(irq, ei);
 368                         irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
 369                 }
 370                 irq_set_irq_type(ei->chained_irq, IRQ_TYPE_EDGE_RISING);
 371                 irq_set_chained_handler_and_data(ei->chained_irq,
 372                                                  egpio_handler, ei);
 373                 ack_irqs(ei);
 374
 375                 device_init_wakeup(&pdev->dev, 1);
 376         }
 377
 378         return 0;
 379
 380 fail:
 381         printk(KERN_ERR "EGPIO failed to setup\n");
 382         return ret;
 383 }
 384
 385 #ifdef CONFIG_PM
 386 static int egpio_suspend(struct platform_device *pdev, pm_message_t state)
 387 {
 388         struct egpio_info *ei = platform_get_drvdata(pdev);
 389
 390         if (ei->chained_irq && device_may_wakeup(&pdev->dev))
 391                 enable_irq_wake(ei->chained_irq);
 392         return 0;
 393 }
 394
 395 static int egpio_resume(struct platform_device *pdev)
 396 {
 397         struct egpio_info *ei = platform_get_drvdata(pdev);
 398
 399         if (ei->chained_irq && device_may_wakeup(&pdev->dev))
 400                 disable_irq_wake(ei->chained_irq);
 401
 402         /* Update registers from the cache, in case
 403            the CPLD was powered off during suspend */
 404         egpio_write_cache(ei);
 405         return 0;
 406 }
 407 #else
 408 #define egpio_suspend NULL
 409 #define egpio_resume NULL
 410 #endif
 411
 412
 413 static struct platform_driver egpio_driver = {
 414         .driver = {
 415                 .name = "htc-egpio",
 416                 .suppress_bind_attrs = true,
 417         },
 418         .suspend      = egpio_suspend,
 419         .resume       = egpio_resume,
 420 };
 421
 422 static int __init egpio_init(void)
 423 {
 424         return platform_driver_probe(&egpio_driver, egpio_probe);
 425 }
 426 /* start early for dependencies */
 427 subsys_initcall(egpio_init);