drivers/gpio/mcp23s08.c

   1 /*
   2  * mcp23s08.c - SPI gpio expander driver
   3  */
   4
   5 #include <linux/kernel.h>
   6 #include <linux/device.h>
   7 #include <linux/workqueue.h>
   8 #include <linux/mutex.h>
   9 #include <linux/gpio.h>
  10 #include <linux/spi/spi.h>
  11 #include <linux/spi/mcp23s08.h>
  12 #include <linux/slab.h>
  13
  14
  15 /* Registers are all 8 bits wide.
  16  *
  17  * The mcp23s17 has twice as many bits, and can be configured to work
  18  * with either 16 bit registers or with two adjacent 8 bit banks.
  19  *
  20  * Also, there are I2C versions of both chips.
  21  */
  22 #define MCP_IODIR       0x00            /* init/reset:  all ones */
  23 #define MCP_IPOL        0x01
  24 #define MCP_GPINTEN     0x02
  25 #define MCP_DEFVAL      0x03
  26 #define MCP_INTCON      0x04
  27 #define MCP_IOCON       0x05
  28 #       define IOCON_SEQOP      (1 << 5)
  29 #       define IOCON_HAEN       (1 << 3)
  30 #       define IOCON_ODR        (1 << 2)
  31 #       define IOCON_INTPOL     (1 << 1)
  32 #define MCP_GPPU        0x06
  33 #define MCP_INTF        0x07
  34 #define MCP_INTCAP      0x08
  35 #define MCP_GPIO        0x09
  36 #define MCP_OLAT        0x0a
  37
  38 struct mcp23s08 {
  39         struct spi_device       *spi;
  40         u8                      addr;
  41
  42         u8                      cache[11];
  43         /* lock protects the cached values */
  44         struct mutex            lock;
  45
  46         struct gpio_chip        chip;
  47
  48         struct work_struct      work;
  49 };
  50
  51 /* A given spi_device can represent up to four mcp23s08 chips
  52  * sharing the same chipselect but using different addresses
  53  * (e.g. chips #0 and #3 might be populated, but not #1 or $2).
  54  * Driver data holds all the per-chip data.
  55  */
  56 struct mcp23s08_driver_data {
  57         unsigned                ngpio;
  58         struct mcp23s08         *mcp[4];
  59         struct mcp23s08         chip[];
  60 };
  61
  62 static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
  63 {
  64         u8      tx[2], rx[1];
  65         int     status;
  66
  67         tx[0] = mcp->addr | 0x01;
  68         tx[1] = reg;
  69         status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
  70         return (status < 0) ? status : rx[0];
  71 }
  72
  73 static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, u8 val)
  74 {
  75         u8      tx[3];
  76
  77         tx[0] = mcp->addr;
  78         tx[1] = reg;
  79         tx[2] = val;
  80         return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
  81 }
  82
  83 static int
  84 mcp23s08_read_regs(struct mcp23s08 *mcp, unsigned reg, u8 *vals, unsigned n)
  85 {
  86         u8      tx[2];
  87
  88         if ((n + reg) > sizeof mcp->cache)
  89                 return -EINVAL;
  90         tx[0] = mcp->addr | 0x01;
  91         tx[1] = reg;
  92         return spi_write_then_read(mcp->spi, tx, sizeof tx, vals, n);
  93 }
  94
  95 /*----------------------------------------------------------------------*/
  96
  97 static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
  98 {
  99         struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
 100         int status;
 101
 102         mutex_lock(&mcp->lock);
 103         mcp->cache[MCP_IODIR] |= (1 << offset);
 104         status = mcp23s08_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
 105         mutex_unlock(&mcp->lock);
 106         return status;
 107 }
 108
 109 static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
 110 {
 111         struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
 112         int status;
 113
 114         mutex_lock(&mcp->lock);
 115
 116         /* REVISIT reading this clears any IRQ ... */
 117         status = mcp23s08_read(mcp, MCP_GPIO);
 118         if (status < 0)
 119                 status = 0;
 120         else {
 121                 mcp->cache[MCP_GPIO] = status;
 122                 status = !!(status & (1 << offset));
 123         }
 124         mutex_unlock(&mcp->lock);
 125         return status;
 126 }
 127
 128 static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, int value)
 129 {
 130         u8 olat = mcp->cache[MCP_OLAT];
 131
 132         if (value)
 133                 olat |= mask;
 134         else
 135                 olat &= ~mask;
 136         mcp->cache[MCP_OLAT] = olat;
 137         return mcp23s08_write(mcp, MCP_OLAT, olat);
 138 }
 139
 140 static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
 141 {
 142         struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
 143         u8 mask = 1 << offset;
 144
 145         mutex_lock(&mcp->lock);
 146         __mcp23s08_set(mcp, mask, value);
 147         mutex_unlock(&mcp->lock);
 148 }
 149
 150 static int
 151 mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
 152 {
 153         struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
 154         u8 mask = 1 << offset;
 155         int status;
 156
 157         mutex_lock(&mcp->lock);
 158         status = __mcp23s08_set(mcp, mask, value);
 159         if (status == 0) {
 160                 mcp->cache[MCP_IODIR] &= ~mask;
 161                 status = mcp23s08_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
 162         }
 163         mutex_unlock(&mcp->lock);
 164         return status;
 165 }
 166
 167 /*----------------------------------------------------------------------*/
 168
 169 #ifdef CONFIG_DEBUG_FS
 170
 171 #include <linux/seq_file.h>
 172
 173 /*
 174  * This shows more info than the generic gpio dump code:
 175  * pullups, deglitching, open drain drive.
 176  */
 177 static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 178 {
 179         struct mcp23s08 *mcp;
 180         char            bank;
 181         int             t;
 182         unsigned        mask;
 183
 184         mcp = container_of(chip, struct mcp23s08, chip);
 185
 186         /* NOTE: we only handle one bank for now ... */
 187         bank = '0' + ((mcp->addr >> 1) & 0x3);
 188
 189         mutex_lock(&mcp->lock);
 190         t = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
 191         if (t < 0) {
 192                 seq_printf(s, " I/O ERROR %d\n", t);
 193                 goto done;
 194         }
 195
 196         for (t = 0, mask = 1; t < 8; t++, mask <<= 1) {
 197                 const char      *label;
 198
 199                 label = gpiochip_is_requested(chip, t);
 200                 if (!label)
 201                         continue;
 202
 203                 seq_printf(s, " gpio-%-3d P%c.%d (%-12s) %s %s %s",
 204                         chip->base + t, bank, t, label,
 205                         (mcp->cache[MCP_IODIR] & mask) ? "in " : "out",
 206                         (mcp->cache[MCP_GPIO] & mask) ? "hi" : "lo",
 207                         (mcp->cache[MCP_GPPU] & mask) ? "  " : "up");
 208                 /* NOTE:  ignoring the irq-related registers */
 209                 seq_printf(s, "\n");
 210         }
 211 done:
 212         mutex_unlock(&mcp->lock);
 213 }
 214
 215 #else
 216 #define mcp23s08_dbg_show       NULL
 217 #endif
 218
 219 /*----------------------------------------------------------------------*/
 220
 221 static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
 222                 unsigned base, unsigned pullups)
 223 {
 224         struct mcp23s08_driver_data     *data = spi_get_drvdata(spi);
 225         struct mcp23s08                 *mcp = data->mcp[addr];
 226         int                             status;
 227         int                             do_update = 0;
 228
 229         mutex_init(&mcp->lock);
 230
 231         mcp->spi = spi;
 232         mcp->addr = 0x40 | (addr << 1);
 233
 234         mcp->chip.label = "mcp23s08",
 235
 236         mcp->chip.direction_input = mcp23s08_direction_input;
 237         mcp->chip.get = mcp23s08_get;
 238         mcp->chip.direction_output = mcp23s08_direction_output;
 239         mcp->chip.set = mcp23s08_set;
 240         mcp->chip.dbg_show = mcp23s08_dbg_show;
 241
 242         mcp->chip.base = base;
 243         mcp->chip.ngpio = 8;
 244         mcp->chip.can_sleep = 1;
 245         mcp->chip.dev = &spi->dev;
 246         mcp->chip.owner = THIS_MODULE;
 247
 248         /* verify MCP_IOCON.SEQOP = 0, so sequential reads work,
 249          * and MCP_IOCON.HAEN = 1, so we work with all chips.
 250          */
 251         status = mcp23s08_read(mcp, MCP_IOCON);
 252         if (status < 0)
 253                 goto fail;
 254         if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN)) {
 255                 status &= ~IOCON_SEQOP;
 256                 status |= IOCON_HAEN;
 257                 status = mcp23s08_write(mcp, MCP_IOCON, (u8) status);
 258                 if (status < 0)
 259                         goto fail;
 260         }
 261
 262         /* configure ~100K pullups */
 263         status = mcp23s08_write(mcp, MCP_GPPU, pullups);
 264         if (status < 0)
 265                 goto fail;
 266
 267         status = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
 268         if (status < 0)
 269                 goto fail;
 270
 271         /* disable inverter on input */
 272         if (mcp->cache[MCP_IPOL] != 0) {
 273                 mcp->cache[MCP_IPOL] = 0;
 274                 do_update = 1;
 275         }
 276
 277         /* disable irqs */
 278         if (mcp->cache[MCP_GPINTEN] != 0) {
 279                 mcp->cache[MCP_GPINTEN] = 0;
 280                 do_update = 1;
 281         }
 282
 283         if (do_update) {
 284                 u8 tx[4];
 285
 286                 tx[0] = mcp->addr;
 287                 tx[1] = MCP_IPOL;
 288                 memcpy(&tx[2], &mcp->cache[MCP_IPOL], sizeof(tx) - 2);
 289                 status = spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
 290                 if (status < 0)
 291                         goto fail;
 292         }
 293
 294         status = gpiochip_add(&mcp->chip);
 295 fail:
 296         if (status < 0)
 297                 dev_dbg(&spi->dev, "can't setup chip %d, --> %d\n",
 298                                 addr, status);
 299         return status;
 300 }
 301
 302 static int mcp23s08_probe(struct spi_device *spi)
 303 {
 304         struct mcp23s08_platform_data   *pdata;
 305         unsigned                        addr;
 306         unsigned                        chips = 0;
 307         struct mcp23s08_driver_data     *data;
 308         int                             status;
 309         unsigned                        base;
 310
 311         pdata = spi->dev.platform_data;
 312         if (!pdata || !gpio_is_valid(pdata->base)) {
 313                 dev_dbg(&spi->dev, "invalid or missing platform data\n");
 314                 return -EINVAL;
 315         }
 316
 317         for (addr = 0; addr < 4; addr++) {
 318                 if (!pdata->chip[addr].is_present)
 319                         continue;
 320                 chips++;
 321         }
 322         if (!chips)
 323                 return -ENODEV;
 324
 325         data = kzalloc(sizeof *data + chips * sizeof(struct mcp23s08),
 326                         GFP_KERNEL);
 327         if (!data)
 328                 return -ENOMEM;
 329         spi_set_drvdata(spi, data);
 330
 331         base = pdata->base;
 332         for (addr = 0; addr < 4; addr++) {
 333                 if (!pdata->chip[addr].is_present)
 334                         continue;
 335                 chips--;
 336                 data->mcp[addr] = &data->chip[chips];
 337                 status = mcp23s08_probe_one(spi, addr, base,
 338                                 pdata->chip[addr].pullups);
 339                 if (status < 0)
 340                         goto fail;
 341                 base += 8;
 342         }
 343         data->ngpio = base - pdata->base;
 344
 345         /* NOTE:  these chips have a relatively sane IRQ framework, with
 346          * per-signal masking and level/edge triggering.  It's not yet
 347          * handled here...
 348          */
 349
 350         if (pdata->setup) {
 351                 status = pdata->setup(spi,
 352                                 pdata->base, data->ngpio,
 353                                 pdata->context);
 354                 if (status < 0)
 355                         dev_dbg(&spi->dev, "setup --> %d\n", status);
 356         }
 357
 358         return 0;
 359
 360 fail:
 361         for (addr = 0; addr < 4; addr++) {
 362                 int tmp;
 363
 364                 if (!data->mcp[addr])
 365                         continue;
 366                 tmp = gpiochip_remove(&data->mcp[addr]->chip);
 367                 if (tmp < 0)
 368                         dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
 369         }
 370         kfree(data);
 371         return status;
 372 }
 373
 374 static int mcp23s08_remove(struct spi_device *spi)
 375 {
 376         struct mcp23s08_driver_data     *data = spi_get_drvdata(spi);
 377         struct mcp23s08_platform_data   *pdata = spi->dev.platform_data;
 378         unsigned                        addr;
 379         int                             status = 0;
 380
 381         if (pdata->teardown) {
 382                 status = pdata->teardown(spi,
 383                                 pdata->base, data->ngpio,
 384                                 pdata->context);
 385                 if (status < 0) {
 386                         dev_err(&spi->dev, "%s --> %d\n", "teardown", status);
 387                         return status;
 388                 }
 389         }
 390
 391         for (addr = 0; addr < 4; addr++) {
 392                 int tmp;
 393
 394                 if (!data->mcp[addr])
 395                         continue;
 396
 397                 tmp = gpiochip_remove(&data->mcp[addr]->chip);
 398                 if (tmp < 0) {
 399                         dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
 400                         status = tmp;
 401                 }
 402         }
 403         if (status == 0)
 404                 kfree(data);
 405         return status;
 406 }
 407
 408 static struct spi_driver mcp23s08_driver = {
 409         .probe          = mcp23s08_probe,
 410         .remove         = mcp23s08_remove,
 411         .driver = {
 412                 .name   = "mcp23s08",
 413                 .owner  = THIS_MODULE,
 414         },
 415 };
 416
 417 /*----------------------------------------------------------------------*/
 418
 419 static int __init mcp23s08_init(void)
 420 {
 421         return spi_register_driver(&mcp23s08_driver);
 422 }
 423 /* register after spi postcore initcall and before
 424  * subsys initcalls that may rely on these GPIOs
 425  */
 426 subsys_initcall(mcp23s08_init);
 427
 428 static void __exit mcp23s08_exit(void)
 429 {
 430         spi_unregister_driver(&mcp23s08_driver);
 431 }
 432 module_exit(mcp23s08_exit);
 433
 434 MODULE_LICENSE("GPL");
 435 MODULE_ALIAS("spi:mcp23s08");