drivers/gpio/max732x.c

   1 /*
   2  *  max732x.c - I2C Port Expander with 8/16 I/O
   3  *
   4  *  Copyright (C) 2007 Marvell International Ltd.
   5  *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
   6  *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
   7  *
   8  *  Derived from drivers/gpio/pca953x.c
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; version 2 of the License.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <linux/string.h>
  19 #include <linux/gpio.h>
  20
  21 #include <linux/i2c.h>
  22 #include <linux/i2c/max732x.h>
  23
  24
  25 /*
  26  * Each port of MAX732x (including MAX7319) falls into one of the
  27  * following three types:
  28  *
  29  *   - Push Pull Output
  30  *   - Input
  31  *   - Open Drain I/O
  32  *
  33  * designated by 'O', 'I' and 'P' individually according to MAXIM's
  34  * datasheets.
  35  *
  36  * There are two groups of I/O ports, each group usually includes
  37  * up to 8 I/O ports, and is accessed by a specific I2C address:
  38  *
  39  *   - Group A : by I2C address 0b'110xxxx
  40  *   - Group B : by I2C address 0b'101xxxx
  41  *
  42  * where 'xxxx' is decided by the connections of pin AD2/AD0.  The
  43  * address used also affects the initial state of output signals.
  44  *
  45  * Within each group of ports, there are five known combinations of
  46  * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
  47  * the detailed organization of these ports.
  48  *
  49  * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
  50  * and GPIOs from GROUP_A are numbered before those from GROUP_B
  51  * (if there are two groups).
  52  *
  53  * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
  54  * they are not supported by this driver.
  55  */
  56
  57 #define PORT_NONE       0x0     /* '/' No Port */
  58 #define PORT_OUTPUT     0x1     /* 'O' Push-Pull, Output Only */
  59 #define PORT_INPUT      0x2     /* 'I' Input Only */
  60 #define PORT_OPENDRAIN  0x3     /* 'P' Open-Drain, I/O */
  61
  62 #define IO_4I4O         0x5AA5  /* O7 O6 I5 I4 I3 I2 O1 O0 */
  63 #define IO_4P4O         0x5FF5  /* O7 O6 P5 P4 P3 P2 O1 O0 */
  64 #define IO_8I           0xAAAA  /* I7 I6 I5 I4 I3 I2 I1 I0 */
  65 #define IO_8P           0xFFFF  /* P7 P6 P5 P4 P3 P2 P1 P0 */
  66 #define IO_8O           0x5555  /* O7 O6 O5 O4 O3 O2 O1 O0 */
  67
  68 #define GROUP_A(x)      ((x) & 0xffff)  /* I2C Addr: 0b'110xxxx */
  69 #define GROUP_B(x)      ((x) << 16)     /* I2C Addr: 0b'101xxxx */
  70
  71 static const struct i2c_device_id max732x_id[] = {
  72         { "max7319", GROUP_A(IO_8I) },
  73         { "max7320", GROUP_B(IO_8O) },
  74         { "max7321", GROUP_A(IO_8P) },
  75         { "max7322", GROUP_A(IO_4I4O) },
  76         { "max7323", GROUP_A(IO_4P4O) },
  77         { "max7324", GROUP_A(IO_8I) | GROUP_B(IO_8O) },
  78         { "max7325", GROUP_A(IO_8P) | GROUP_B(IO_8O) },
  79         { "max7326", GROUP_A(IO_4I4O) | GROUP_B(IO_8O) },
  80         { "max7327", GROUP_A(IO_4P4O) | GROUP_B(IO_8O) },
  81         { },
  82 };
  83 MODULE_DEVICE_TABLE(i2c, max732x_id);
  84
  85 struct max732x_chip {
  86         struct gpio_chip gpio_chip;
  87
  88         struct i2c_client *client;      /* "main" client */
  89         struct i2c_client *client_dummy;
  90         struct i2c_client *client_group_a;
  91         struct i2c_client *client_group_b;
  92
  93         unsigned int    mask_group_a;
  94         unsigned int    dir_input;
  95         unsigned int    dir_output;
  96
  97         struct mutex    lock;
  98         uint8_t         reg_out[2];
  99 };
 100
 101 static int max732x_write(struct max732x_chip *chip, int group_a, uint8_t val)
 102 {
 103         struct i2c_client *client;
 104         int ret;
 105
 106         client = group_a ? chip->client_group_a : chip->client_group_b;
 107         ret = i2c_smbus_write_byte(client, val);
 108         if (ret < 0) {
 109                 dev_err(&client->dev, "failed writing\n");
 110                 return ret;
 111         }
 112
 113         return 0;
 114 }
 115
 116 static int max732x_read(struct max732x_chip *chip, int group_a, uint8_t *val)
 117 {
 118         struct i2c_client *client;
 119         int ret;
 120
 121         client = group_a ? chip->client_group_a : chip->client_group_b;
 122         ret = i2c_smbus_read_byte(client);
 123         if (ret < 0) {
 124                 dev_err(&client->dev, "failed reading\n");
 125                 return ret;
 126         }
 127
 128         *val = (uint8_t)ret;
 129         return 0;
 130 }
 131
 132 static inline int is_group_a(struct max732x_chip *chip, unsigned off)
 133 {
 134         return (1u << off) & chip->mask_group_a;
 135 }
 136
 137 static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
 138 {
 139         struct max732x_chip *chip;
 140         uint8_t reg_val;
 141         int ret;
 142
 143         chip = container_of(gc, struct max732x_chip, gpio_chip);
 144
 145         ret = max732x_read(chip, is_group_a(chip, off), &reg_val);
 146         if (ret < 0)
 147                 return 0;
 148
 149         return reg_val & (1u << (off & 0x7));
 150 }
 151
 152 static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
 153 {
 154         struct max732x_chip *chip;
 155         uint8_t reg_out, mask = 1u << (off & 0x7);
 156         int ret;
 157
 158         chip = container_of(gc, struct max732x_chip, gpio_chip);
 159
 160         mutex_lock(&chip->lock);
 161
 162         reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
 163         reg_out = (val) ? reg_out | mask : reg_out & ~mask;
 164
 165         ret = max732x_write(chip, is_group_a(chip, off), reg_out);
 166         if (ret < 0)
 167                 goto out;
 168
 169         /* update the shadow register then */
 170         if (off > 7)
 171                 chip->reg_out[1] = reg_out;
 172         else
 173                 chip->reg_out[0] = reg_out;
 174 out:
 175         mutex_unlock(&chip->lock);
 176 }
 177
 178 static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
 179 {
 180         struct max732x_chip *chip;
 181         unsigned int mask = 1u << off;
 182
 183         chip = container_of(gc, struct max732x_chip, gpio_chip);
 184
 185         if ((mask & chip->dir_input) == 0) {
 186                 dev_dbg(&chip->client->dev, "%s port %d is output only\n",
 187                         chip->client->name, off);
 188                 return -EACCES;
 189         }
 190
 191         return 0;
 192 }
 193
 194 static int max732x_gpio_direction_output(struct gpio_chip *gc,
 195                 unsigned off, int val)
 196 {
 197         struct max732x_chip *chip;
 198         unsigned int mask = 1u << off;
 199
 200         chip = container_of(gc, struct max732x_chip, gpio_chip);
 201
 202         if ((mask & chip->dir_output) == 0) {
 203                 dev_dbg(&chip->client->dev, "%s port %d is input only\n",
 204                         chip->client->name, off);
 205                 return -EACCES;
 206         }
 207
 208         max732x_gpio_set_value(gc, off, val);
 209         return 0;
 210 }
 211
 212 static int __devinit max732x_setup_gpio(struct max732x_chip *chip,
 213                                         const struct i2c_device_id *id,
 214                                         unsigned gpio_start)
 215 {
 216         struct gpio_chip *gc = &chip->gpio_chip;
 217         uint32_t id_data = id->driver_data;
 218         int i, port = 0;
 219
 220         for (i = 0; i < 16; i++, id_data >>= 2) {
 221                 unsigned int mask = 1 << port;
 222
 223                 switch (id_data & 0x3) {
 224                 case PORT_OUTPUT:
 225                         chip->dir_output |= mask;
 226                         break;
 227                 case PORT_INPUT:
 228                         chip->dir_input |= mask;
 229                         break;
 230                 case PORT_OPENDRAIN:
 231                         chip->dir_output |= mask;
 232                         chip->dir_input |= mask;
 233                         break;
 234                 default:
 235                         continue;
 236                 }
 237
 238                 if (i < 8)
 239                         chip->mask_group_a |= mask;
 240                 port++;
 241         }
 242
 243         if (chip->dir_input)
 244                 gc->direction_input = max732x_gpio_direction_input;
 245         if (chip->dir_output) {
 246                 gc->direction_output = max732x_gpio_direction_output;
 247                 gc->set = max732x_gpio_set_value;
 248         }
 249         gc->get = max732x_gpio_get_value;
 250         gc->can_sleep = 1;
 251
 252         gc->base = gpio_start;
 253         gc->ngpio = port;
 254         gc->label = chip->client->name;
 255         gc->owner = THIS_MODULE;
 256
 257         return port;
 258 }
 259
 260 static int __devinit max732x_probe(struct i2c_client *client,
 261                                    const struct i2c_device_id *id)
 262 {
 263         struct max732x_platform_data *pdata;
 264         struct max732x_chip *chip;
 265         struct i2c_client *c;
 266         uint16_t addr_a, addr_b;
 267         int ret, nr_port;
 268
 269         pdata = client->dev.platform_data;
 270         if (pdata == NULL) {
 271                 dev_dbg(&client->dev, "no platform data\n");
 272                 return -EINVAL;
 273         }
 274
 275         chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
 276         if (chip == NULL)
 277                 return -ENOMEM;
 278         chip->client = client;
 279
 280         nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
 281
 282         addr_a = (client->addr & 0x0f) | 0x60;
 283         addr_b = (client->addr & 0x0f) | 0x50;
 284
 285         switch (client->addr & 0x70) {
 286         case 0x60:
 287                 chip->client_group_a = client;
 288                 if (nr_port > 7) {
 289                         c = i2c_new_dummy(client->adapter, addr_b);
 290                         chip->client_group_b = chip->client_dummy = c;
 291                 }
 292                 break;
 293         case 0x50:
 294                 chip->client_group_b = client;
 295                 if (nr_port > 7) {
 296                         c = i2c_new_dummy(client->adapter, addr_a);
 297                         chip->client_group_a = chip->client_dummy = c;
 298                 }
 299                 break;
 300         default:
 301                 dev_err(&client->dev, "invalid I2C address specified %02x\n",
 302                                 client->addr);
 303                 ret = -EINVAL;
 304                 goto out_failed;
 305         }
 306
 307         mutex_init(&chip->lock);
 308
 309         max732x_read(chip, is_group_a(chip, 0), &chip->reg_out[0]);
 310         if (nr_port > 7)
 311                 max732x_read(chip, is_group_a(chip, 8), &chip->reg_out[1]);
 312
 313         ret = gpiochip_add(&chip->gpio_chip);
 314         if (ret)
 315                 goto out_failed;
 316
 317         if (pdata->setup) {
 318                 ret = pdata->setup(client, chip->gpio_chip.base,
 319                                 chip->gpio_chip.ngpio, pdata->context);
 320                 if (ret < 0)
 321                         dev_warn(&client->dev, "setup failed, %d\n", ret);
 322         }
 323
 324         i2c_set_clientdata(client, chip);
 325         return 0;
 326
 327 out_failed:
 328         kfree(chip);
 329         return ret;
 330 }
 331
 332 static int __devexit max732x_remove(struct i2c_client *client)
 333 {
 334         struct max732x_platform_data *pdata = client->dev.platform_data;
 335         struct max732x_chip *chip = i2c_get_clientdata(client);
 336         int ret;
 337
 338         if (pdata->teardown) {
 339                 ret = pdata->teardown(client, chip->gpio_chip.base,
 340                                 chip->gpio_chip.ngpio, pdata->context);
 341                 if (ret < 0) {
 342                         dev_err(&client->dev, "%s failed, %d\n",
 343                                         "teardown", ret);
 344                         return ret;
 345                 }
 346         }
 347
 348         ret = gpiochip_remove(&chip->gpio_chip);
 349         if (ret) {
 350                 dev_err(&client->dev, "%s failed, %d\n",
 351                                 "gpiochip_remove()", ret);
 352                 return ret;
 353         }
 354
 355         /* unregister any dummy i2c_client */
 356         if (chip->client_dummy)
 357                 i2c_unregister_device(chip->client_dummy);
 358
 359         kfree(chip);
 360         return 0;
 361 }
 362
 363 static struct i2c_driver max732x_driver = {
 364         .driver = {
 365                 .name   = "max732x",
 366                 .owner  = THIS_MODULE,
 367         },
 368         .probe          = max732x_probe,
 369         .remove         = __devexit_p(max732x_remove),
 370         .id_table       = max732x_id,
 371 };
 372
 373 static int __init max732x_init(void)
 374 {
 375         return i2c_add_driver(&max732x_driver);
 376 }
 377 /* register after i2c postcore initcall and before
 378  * subsys initcalls that may rely on these GPIOs
 379  */
 380 subsys_initcall(max732x_init);
 381
 382 static void __exit max732x_exit(void)
 383 {
 384         i2c_del_driver(&max732x_driver);
 385 }
 386 module_exit(max732x_exit);
 387
 388 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
 389 MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
 390 MODULE_LICENSE("GPL");