drivers/gpio/gpio-stmpe.c

   1 /*
   2  * Copyright (C) ST-Ericsson SA 2010
   3  *
   4  * License Terms: GNU General Public License, version 2
   5  * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/slab.h>
  12 #include <linux/gpio.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/of.h>
  15 #include <linux/mfd/stmpe.h>
  16 #include <linux/seq_file.h>
  17
  18 /*
  19  * These registers are modified under the irq bus lock and cached to avoid
  20  * unnecessary writes in bus_sync_unlock.
  21  */
  22 enum { REG_RE, REG_FE, REG_IE };
  23
  24 #define CACHE_NR_REGS   3
  25 /* No variant has more than 24 GPIOs */
  26 #define CACHE_NR_BANKS  (24 / 8)
  27
  28 struct stmpe_gpio {
  29         struct gpio_chip chip;
  30         struct stmpe *stmpe;
  31         struct device *dev;
  32         struct mutex irq_lock;
  33         u32 norequest_mask;
  34         /* Caches of interrupt control registers for bus_lock */
  35         u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
  36         u8 oldregs[CACHE_NR_REGS][CACHE_NR_BANKS];
  37 };
  38
  39 static inline struct stmpe_gpio *to_stmpe_gpio(struct gpio_chip *chip)
  40 {
  41         return container_of(chip, struct stmpe_gpio, chip);
  42 }
  43
  44 static int stmpe_gpio_get(struct gpio_chip *chip, unsigned offset)
  45 {
  46         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
  47         struct stmpe *stmpe = stmpe_gpio->stmpe;
  48         u8 reg = stmpe->regs[STMPE_IDX_GPMR_LSB] - (offset / 8);
  49         u8 mask = 1 << (offset % 8);
  50         int ret;
  51
  52         ret = stmpe_reg_read(stmpe, reg);
  53         if (ret < 0)
  54                 return ret;
  55
  56         return !!(ret & mask);
  57 }
  58
  59 static void stmpe_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
  60 {
  61         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
  62         struct stmpe *stmpe = stmpe_gpio->stmpe;
  63         int which = val ? STMPE_IDX_GPSR_LSB : STMPE_IDX_GPCR_LSB;
  64         u8 reg = stmpe->regs[which] - (offset / 8);
  65         u8 mask = 1 << (offset % 8);
  66
  67         /*
  68          * Some variants have single register for gpio set/clear functionality.
  69          * For them we need to write 0 to clear and 1 to set.
  70          */
  71         if (stmpe->regs[STMPE_IDX_GPSR_LSB] == stmpe->regs[STMPE_IDX_GPCR_LSB])
  72                 stmpe_set_bits(stmpe, reg, mask, val ? mask : 0);
  73         else
  74                 stmpe_reg_write(stmpe, reg, mask);
  75 }
  76
  77 static int stmpe_gpio_direction_output(struct gpio_chip *chip,
  78                                          unsigned offset, int val)
  79 {
  80         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
  81         struct stmpe *stmpe = stmpe_gpio->stmpe;
  82         u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
  83         u8 mask = 1 << (offset % 8);
  84
  85         stmpe_gpio_set(chip, offset, val);
  86
  87         return stmpe_set_bits(stmpe, reg, mask, mask);
  88 }
  89
  90 static int stmpe_gpio_direction_input(struct gpio_chip *chip,
  91                                         unsigned offset)
  92 {
  93         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
  94         struct stmpe *stmpe = stmpe_gpio->stmpe;
  95         u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
  96         u8 mask = 1 << (offset % 8);
  97
  98         return stmpe_set_bits(stmpe, reg, mask, 0);
  99 }
 100
 101 static int stmpe_gpio_request(struct gpio_chip *chip, unsigned offset)
 102 {
 103         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
 104         struct stmpe *stmpe = stmpe_gpio->stmpe;
 105
 106         if (stmpe_gpio->norequest_mask & (1 << offset))
 107                 return -EINVAL;
 108
 109         return stmpe_set_altfunc(stmpe, 1 << offset, STMPE_BLOCK_GPIO);
 110 }
 111
 112 static struct gpio_chip template_chip = {
 113         .label                  = "stmpe",
 114         .owner                  = THIS_MODULE,
 115         .direction_input        = stmpe_gpio_direction_input,
 116         .get                    = stmpe_gpio_get,
 117         .direction_output       = stmpe_gpio_direction_output,
 118         .set                    = stmpe_gpio_set,
 119         .request                = stmpe_gpio_request,
 120         .can_sleep              = true,
 121 };
 122
 123 static int stmpe_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 124 {
 125         struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 126         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(gc);
 127         int offset = d->hwirq;
 128         int regoffset = offset / 8;
 129         int mask = 1 << (offset % 8);
 130
 131         if (type & IRQ_TYPE_LEVEL_LOW || type & IRQ_TYPE_LEVEL_HIGH)
 132                 return -EINVAL;
 133
 134         /* STMPE801 doesn't have RE and FE registers */
 135         if (stmpe_gpio->stmpe->partnum == STMPE801)
 136                 return 0;
 137
 138         if (type & IRQ_TYPE_EDGE_RISING)
 139                 stmpe_gpio->regs[REG_RE][regoffset] |= mask;
 140         else
 141                 stmpe_gpio->regs[REG_RE][regoffset] &= ~mask;
 142
 143         if (type & IRQ_TYPE_EDGE_FALLING)
 144                 stmpe_gpio->regs[REG_FE][regoffset] |= mask;
 145         else
 146                 stmpe_gpio->regs[REG_FE][regoffset] &= ~mask;
 147
 148         return 0;
 149 }
 150
 151 static void stmpe_gpio_irq_lock(struct irq_data *d)
 152 {
 153         struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 154         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(gc);
 155
 156         mutex_lock(&stmpe_gpio->irq_lock);
 157 }
 158
 159 static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
 160 {
 161         struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 162         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(gc);
 163         struct stmpe *stmpe = stmpe_gpio->stmpe;
 164         int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
 165         static const u8 regmap[] = {
 166                 [REG_RE]        = STMPE_IDX_GPRER_LSB,
 167                 [REG_FE]        = STMPE_IDX_GPFER_LSB,
 168                 [REG_IE]        = STMPE_IDX_IEGPIOR_LSB,
 169         };
 170         int i, j;
 171
 172         for (i = 0; i < CACHE_NR_REGS; i++) {
 173                 /* STMPE801 doesn't have RE and FE registers */
 174                 if ((stmpe->partnum == STMPE801) &&
 175                                 (i != REG_IE))
 176                         continue;
 177
 178                 for (j = 0; j < num_banks; j++) {
 179                         u8 old = stmpe_gpio->oldregs[i][j];
 180                         u8 new = stmpe_gpio->regs[i][j];
 181
 182                         if (new == old)
 183                                 continue;
 184
 185                         stmpe_gpio->oldregs[i][j] = new;
 186                         stmpe_reg_write(stmpe, stmpe->regs[regmap[i]] - j, new);
 187                 }
 188         }
 189
 190         mutex_unlock(&stmpe_gpio->irq_lock);
 191 }
 192
 193 static void stmpe_gpio_irq_mask(struct irq_data *d)
 194 {
 195         struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 196         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(gc);
 197         int offset = d->hwirq;
 198         int regoffset = offset / 8;
 199         int mask = 1 << (offset % 8);
 200
 201         stmpe_gpio->regs[REG_IE][regoffset] &= ~mask;
 202 }
 203
 204 static void stmpe_gpio_irq_unmask(struct irq_data *d)
 205 {
 206         struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 207         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(gc);
 208         int offset = d->hwirq;
 209         int regoffset = offset / 8;
 210         int mask = 1 << (offset % 8);
 211
 212         stmpe_gpio->regs[REG_IE][regoffset] |= mask;
 213 }
 214
 215 static void stmpe_dbg_show_one(struct seq_file *s,
 216                                struct gpio_chip *gc,
 217                                unsigned offset, unsigned gpio)
 218 {
 219         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(gc);
 220         struct stmpe *stmpe = stmpe_gpio->stmpe;
 221         const char *label = gpiochip_is_requested(gc, offset);
 222         int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
 223         bool val = !!stmpe_gpio_get(gc, offset);
 224         u8 dir_reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
 225         u8 mask = 1 << (offset % 8);
 226         int ret;
 227         u8 dir;
 228
 229         ret = stmpe_reg_read(stmpe, dir_reg);
 230         if (ret < 0)
 231                 return;
 232         dir = !!(ret & mask);
 233
 234         if (dir) {
 235                 seq_printf(s, " gpio-%-3d (%-20.20s) out %s",
 236                            gpio, label ?: "(none)",
 237                            val ? "hi" : "lo");
 238         } else {
 239                 u8 edge_det_reg = stmpe->regs[STMPE_IDX_GPEDR_MSB] + num_banks - 1 - (offset / 8);
 240                 u8 rise_reg = stmpe->regs[STMPE_IDX_GPRER_LSB] - (offset / 8);
 241                 u8 fall_reg = stmpe->regs[STMPE_IDX_GPFER_LSB] - (offset / 8);
 242                 u8 irqen_reg = stmpe->regs[STMPE_IDX_IEGPIOR_LSB] - (offset / 8);
 243                 bool edge_det;
 244                 bool rise;
 245                 bool fall;
 246                 bool irqen;
 247
 248                 ret = stmpe_reg_read(stmpe, edge_det_reg);
 249                 if (ret < 0)
 250                         return;
 251                 edge_det = !!(ret & mask);
 252                 ret = stmpe_reg_read(stmpe, rise_reg);
 253                 if (ret < 0)
 254                         return;
 255                 rise = !!(ret & mask);
 256                 ret = stmpe_reg_read(stmpe, fall_reg);
 257                 if (ret < 0)
 258                         return;
 259                 fall = !!(ret & mask);
 260                 ret = stmpe_reg_read(stmpe, irqen_reg);
 261                 if (ret < 0)
 262                         return;
 263                 irqen = !!(ret & mask);
 264
 265                 seq_printf(s, " gpio-%-3d (%-20.20s) in  %s %s %s%s%s",
 266                            gpio, label ?: "(none)",
 267                            val ? "hi" : "lo",
 268                            edge_det ? "edge-asserted" : "edge-inactive",
 269                            irqen ? "IRQ-enabled" : "",
 270                            rise ? " rising-edge-detection" : "",
 271                            fall ? " falling-edge-detection" : "");
 272         }
 273 }
 274
 275 static void stmpe_dbg_show(struct seq_file *s, struct gpio_chip *gc)
 276 {
 277         unsigned i;
 278         unsigned gpio = gc->base;
 279
 280         for (i = 0; i < gc->ngpio; i++, gpio++) {
 281                 stmpe_dbg_show_one(s, gc, i, gpio);
 282                 seq_printf(s, "\n");
 283         }
 284 }
 285
 286 static struct irq_chip stmpe_gpio_irq_chip = {
 287         .name                   = "stmpe-gpio",
 288         .irq_bus_lock           = stmpe_gpio_irq_lock,
 289         .irq_bus_sync_unlock    = stmpe_gpio_irq_sync_unlock,
 290         .irq_mask               = stmpe_gpio_irq_mask,
 291         .irq_unmask             = stmpe_gpio_irq_unmask,
 292         .irq_set_type           = stmpe_gpio_irq_set_type,
 293 };
 294
 295 static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
 296 {
 297         struct stmpe_gpio *stmpe_gpio = dev;
 298         struct stmpe *stmpe = stmpe_gpio->stmpe;
 299         u8 statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_MSB];
 300         int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
 301         u8 status[num_banks];
 302         int ret;
 303         int i;
 304
 305         ret = stmpe_block_read(stmpe, statmsbreg, num_banks, status);
 306         if (ret < 0)
 307                 return IRQ_NONE;
 308
 309         for (i = 0; i < num_banks; i++) {
 310                 int bank = num_banks - i - 1;
 311                 unsigned int enabled = stmpe_gpio->regs[REG_IE][bank];
 312                 unsigned int stat = status[i];
 313
 314                 stat &= enabled;
 315                 if (!stat)
 316                         continue;
 317
 318                 while (stat) {
 319                         int bit = __ffs(stat);
 320                         int line = bank * 8 + bit;
 321                         int child_irq = irq_find_mapping(stmpe_gpio->chip.irqdomain,
 322                                                          line);
 323
 324                         handle_nested_irq(child_irq);
 325                         stat &= ~(1 << bit);
 326                 }
 327
 328                 stmpe_reg_write(stmpe, statmsbreg + i, status[i]);
 329
 330                 /* Edge detect register is not present on 801 */
 331                 if (stmpe->partnum != STMPE801)
 332                         stmpe_reg_write(stmpe, stmpe->regs[STMPE_IDX_GPEDR_MSB]
 333                                         + i, status[i]);
 334         }
 335
 336         return IRQ_HANDLED;
 337 }
 338
 339 static int stmpe_gpio_probe(struct platform_device *pdev)
 340 {
 341         struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
 342         struct device_node *np = pdev->dev.of_node;
 343         struct stmpe_gpio *stmpe_gpio;
 344         int ret;
 345         int irq = 0;
 346
 347         irq = platform_get_irq(pdev, 0);
 348
 349         stmpe_gpio = kzalloc(sizeof(struct stmpe_gpio), GFP_KERNEL);
 350         if (!stmpe_gpio)
 351                 return -ENOMEM;
 352
 353         mutex_init(&stmpe_gpio->irq_lock);
 354
 355         stmpe_gpio->dev = &pdev->dev;
 356         stmpe_gpio->stmpe = stmpe;
 357         stmpe_gpio->chip = template_chip;
 358         stmpe_gpio->chip.ngpio = stmpe->num_gpios;
 359         stmpe_gpio->chip.dev = &pdev->dev;
 360         stmpe_gpio->chip.of_node = np;
 361         stmpe_gpio->chip.base = -1;
 362
 363         if (IS_ENABLED(CONFIG_DEBUG_FS))
 364                 stmpe_gpio->chip.dbg_show = stmpe_dbg_show;
 365
 366         of_property_read_u32(np, "st,norequest-mask",
 367                         &stmpe_gpio->norequest_mask);
 368
 369         if (irq < 0)
 370                 dev_info(&pdev->dev,
 371                         "device configured in no-irq mode: "
 372                         "irqs are not available\n");
 373
 374         ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
 375         if (ret)
 376                 goto out_free;
 377
 378         ret = gpiochip_add(&stmpe_gpio->chip);
 379         if (ret) {
 380                 dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
 381                 goto out_disable;
 382         }
 383
 384         if (irq > 0) {
 385                 ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 386                                 stmpe_gpio_irq, IRQF_ONESHOT,
 387                                 "stmpe-gpio", stmpe_gpio);
 388                 if (ret) {
 389                         dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
 390                         goto out_disable;
 391                 }
 392                 ret =  gpiochip_irqchip_add(&stmpe_gpio->chip,
 393                                             &stmpe_gpio_irq_chip,
 394                                             0,
 395                                             handle_simple_irq,
 396                                             IRQ_TYPE_NONE);
 397                 if (ret) {
 398                         dev_err(&pdev->dev,
 399                                 "could not connect irqchip to gpiochip\n");
 400                         goto out_disable;
 401                 }
 402
 403                 gpiochip_set_chained_irqchip(&stmpe_gpio->chip,
 404                                              &stmpe_gpio_irq_chip,
 405                                              irq,
 406                                              NULL);
 407         }
 408
 409         platform_set_drvdata(pdev, stmpe_gpio);
 410
 411         return 0;
 412
 413 out_disable:
 414         stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 415         gpiochip_remove(&stmpe_gpio->chip);
 416 out_free:
 417         kfree(stmpe_gpio);
 418         return ret;
 419 }
 420
 421 static int stmpe_gpio_remove(struct platform_device *pdev)
 422 {
 423         struct stmpe_gpio *stmpe_gpio = platform_get_drvdata(pdev);
 424         struct stmpe *stmpe = stmpe_gpio->stmpe;
 425
 426         gpiochip_remove(&stmpe_gpio->chip);
 427         stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 428         kfree(stmpe_gpio);
 429
 430         return 0;
 431 }
 432
 433 static struct platform_driver stmpe_gpio_driver = {
 434         .driver.name    = "stmpe-gpio",
 435         .driver.owner   = THIS_MODULE,
 436         .probe          = stmpe_gpio_probe,
 437         .remove         = stmpe_gpio_remove,
 438 };
 439
 440 static int __init stmpe_gpio_init(void)
 441 {
 442         return platform_driver_register(&stmpe_gpio_driver);
 443 }
 444 subsys_initcall(stmpe_gpio_init);
 445
 446 static void __exit stmpe_gpio_exit(void)
 447 {
 448         platform_driver_unregister(&stmpe_gpio_driver);
 449 }
 450 module_exit(stmpe_gpio_exit);
 451
 452 MODULE_LICENSE("GPL v2");
 453 MODULE_DESCRIPTION("STMPExxxx GPIO driver");
 454 MODULE_AUTHOR("Rabin Vincent <rabin.vincent@stericsson.com>");