Eric Miao | bbcd6d5 | 2008-07-25 01:46:14 -0700 | [diff] [blame] | 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), ®_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; |
Ben Dooks | a342d21 | 2009-01-15 13:50:45 -0800 | [diff] [blame^] | 270 | if (pdata == NULL) { |
| 271 | dev_dbg(&client->dev, "no platform data\n"); |
| 272 | return -EINVAL; |
| 273 | } |
Eric Miao | bbcd6d5 | 2008-07-25 01:46:14 -0700 | [diff] [blame] | 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 | } |
David Brownell | 2f8d119 | 2008-10-15 22:03:13 -0700 | [diff] [blame] | 377 | /* register after i2c postcore initcall and before |
| 378 | * subsys initcalls that may rely on these GPIOs |
| 379 | */ |
| 380 | subsys_initcall(max732x_init); |
Eric Miao | bbcd6d5 | 2008-07-25 01:46:14 -0700 | [diff] [blame] | 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"); |