target/linux/ixp4xx/patches-2.6.28/020-gateworks_i2c_pld.patch

   1 --- /dev/null
   2 +++ b/drivers/gpio/gw_i2c_pld.c
   3 @@ -0,0 +1,370 @@
   4 +/*
   5 + * Gateworks I2C PLD GPIO expander
   6 + *
   7 + * Copyright (C) 2009 Gateworks Corporation
   8 + *
   9 + * This program is free software; you can redistribute it and/or modify
  10 + * it under the terms of the GNU General Public License as published by
  11 + * the Free Software Foundation; either version 2 of the License, or
  12 + * (at your option) any later version.
  13 + *
  14 + * This program is distributed in the hope that it will be useful,
  15 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 + * GNU General Public License for more details.
  18 + *
  19 + * You should have received a copy of the GNU General Public License
  20 + * along with this program; if not, write to the Free Software
  21 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 + */
  23 +
  24 +#include <linux/kernel.h>
  25 +#include <linux/slab.h>
  26 +#include <linux/i2c.h>
  27 +#include <linux/i2c/gw_i2c_pld.h>
  28 +#include <asm/gpio.h>
  29 +
  30 +static const struct i2c_device_id gw_i2c_pld_id[] = {
  31 +       { "gw_i2c_pld", 8 },
  32 +       { }
  33 +};
  34 +MODULE_DEVICE_TABLE(i2c, gw_i2c_pld_id);
  35 +
  36 +/*
  37 + * The Gateworks I2C PLD chip only expose one read and one
  38 + * write register.  Writing a "one" bit (to match the reset state) lets
  39 + * that pin be used as an input. It is an open-drain model.
  40 + */
  41 +
  42 +struct gw_i2c_pld {
  43 +       struct gpio_chip        chip;
  44 +       struct i2c_client       *client;
  45 +       unsigned                out;            /* software latch */
  46 +};
  47 +
  48 +/*-------------------------------------------------------------------------*/
  49 +
  50 +/*
  51 + * The Gateworks I2C PLD chip does not properly send the acknowledge bit
  52 + * thus we cannot use standard i2c_smbus functions. We have recreated
  53 + * our own here, but we still use the mutex_lock to lock the i2c_bus
  54 + * as the device still exists on the I2C bus.
  55 +*/
  56 +
  57 +#define PLD_SCL_GPIO 6
  58 +#define PLD_SDA_GPIO 7
  59 +
  60 +#define SCL_LO()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_LOW)
  61 +#define SCL_HI()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_HIGH)
  62 +#define SCL_EN()  gpio_line_config(PLD_SCL_GPIO, IXP4XX_GPIO_OUT)
  63 +#define SDA_LO()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_LOW)
  64 +#define SDA_HI()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_HIGH)
  65 +#define SDA_EN()  gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_OUT)
  66 +#define SDA_DIS() gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_IN)
  67 +#define SDA_IN(x) gpio_line_get(PLD_SDA_GPIO, &x);
  68 +
  69 +static int i2c_pld_write_byte(int address, int byte)
  70 +{
  71 +       int i;
  72 +
  73 +       address = (address << 1) & ~0x1;
  74 +
  75 +       SDA_HI();
  76 +       SDA_EN();
  77 +       SCL_EN();
  78 +       SCL_HI();
  79 +       SDA_LO();
  80 +       SCL_LO();
  81 +
  82 +       for (i = 7; i >= 0; i--)
  83 +       {
  84 +               if (address & (1 << i))
  85 +                       SDA_HI();
  86 +               else
  87 +                       SDA_LO();
  88 +
  89 +               SCL_HI();
  90 +               SCL_LO();
  91 +       }
  92 +
  93 +       SDA_DIS();
  94 +       SCL_HI();
  95 +       SDA_IN(i);
  96 +       SCL_LO();
  97 +       SDA_EN();
  98 +
  99 +       for (i = 7; i >= 0; i--)
 100 +       {
 101 +               if (byte & (1 << i))
 102 +      SDA_HI();
 103 +               else
 104 +                       SDA_LO();
 105 +               SCL_HI();
 106 +               SCL_LO();
 107 +       }
 108 +
 109 +       SDA_DIS();
 110 +       SCL_HI();
 111 +       SDA_IN(i);
 112 +       SCL_LO();
 113 +
 114 +       SDA_HI();
 115 +       SDA_EN();
 116 +
 117 +       SDA_LO();
 118 +       SCL_HI();
 119 +       SDA_HI();
 120 +       SCL_LO();
 121 +       SCL_HI();
 122 +
 123 +       return 0;
 124 +}
 125 +
 126 +static unsigned int i2c_pld_read_byte(int address)
 127 +{
 128 +       int i = 0, byte = 0;
 129 +       int bit;
 130 +
 131 +       address = (address << 1) | 0x1;
 132 +
 133 +       SDA_HI();
 134 +       SDA_EN();
 135 +       SCL_EN();
 136 +       SCL_HI();
 137 +       SDA_LO();
 138 +       SCL_LO();
 139 +
 140 +       for (i = 7; i >= 0; i--)
 141 +       {
 142 +               if (address & (1 << i))
 143 +                       SDA_HI();
 144 +               else
 145 +                       SDA_LO();
 146 +
 147 +               SCL_HI();
 148 +               SCL_LO();
 149 +       }
 150 +
 151 +       SDA_DIS();
 152 +       SCL_HI();
 153 +       SDA_IN(i);
 154 +       SCL_LO();
 155 +       SDA_EN();
 156 +
 157 +       SDA_DIS();
 158 +       for (i = 7; i >= 0; i--)
 159 +       {
 160 +               SCL_HI();
 161 +               SDA_IN(bit);
 162 +               byte |= bit << i;
 163 +               SCL_LO();
 164 +       }
 165 +
 166 +       SDA_LO();
 167 +       SCL_HI();
 168 +       SDA_HI();
 169 +       SCL_LO();
 170 +       SCL_HI();
 171 +
 172 +       return byte;
 173 +}
 174 +
 175 +
 176 +static int gw_i2c_pld_input8(struct gpio_chip *chip, unsigned offset)
 177 +{
 178 +       int ret;
 179 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 180 +       struct i2c_adapter *adap = gpio->client->adapter;
 181 +
 182 +       if (in_atomic() || irqs_disabled()) {
 183 +               ret = mutex_trylock(&adap->bus_lock);
 184 +               if (!ret)
 185 +                       /* I2C activity is ongoing. */
 186 +                       return -EAGAIN;
 187 +       } else {
 188 +               mutex_lock_nested(&adap->bus_lock, adap->level);
 189 +       }
 190 +
 191 +       gpio->out |= (1 << offset);
 192 +
 193 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 194 +
 195 +       mutex_unlock(&adap->bus_lock);
 196 +
 197 +       return ret;
 198 +}
 199 +
 200 +static int gw_i2c_pld_get8(struct gpio_chip *chip, unsigned offset)
 201 +{
 202 +       int ret;
 203 +       s32     value;
 204 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 205 +       struct i2c_adapter *adap = gpio->client->adapter;
 206 +
 207 +       if (in_atomic() || irqs_disabled()) {
 208 +               ret = mutex_trylock(&adap->bus_lock);
 209 +               if (!ret)
 210 +                       /* I2C activity is ongoing. */
 211 +                       return -EAGAIN;
 212 +       } else {
 213 +               mutex_lock_nested(&adap->bus_lock, adap->level);
 214 +       }
 215 +
 216 +       value = i2c_pld_read_byte(gpio->client->addr);
 217 +
 218 +       mutex_unlock(&adap->bus_lock);
 219 +
 220 +       return (value < 0) ? 0 : (value & (1 << offset));
 221 +}
 222 +
 223 +static int gw_i2c_pld_output8(struct gpio_chip *chip, unsigned offset, int value)
 224 +{
 225 +       int ret;
 226 +
 227 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 228 +       struct i2c_adapter *adap = gpio->client->adapter;
 229 +
 230 +       unsigned bit = 1 << offset;
 231 +
 232 +       if (in_atomic() || irqs_disabled()) {
 233 +               ret = mutex_trylock(&adap->bus_lock);
 234 +               if (!ret)
 235 +                       /* I2C activity is ongoing. */
 236 +                       return -EAGAIN;
 237 +       } else {
 238 +               mutex_lock_nested(&adap->bus_lock, adap->level);
 239 +       }
 240 +
 241 +
 242 +       if (value)
 243 +               gpio->out |= bit;
 244 +       else
 245 +               gpio->out &= ~bit;
 246 +
 247 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 248 +
 249 +       mutex_unlock(&adap->bus_lock);
 250 +
 251 +       return ret;
 252 +}
 253 +
 254 +static void gw_i2c_pld_set8(struct gpio_chip *chip, unsigned offset, int value)
 255 +{
 256 +       gw_i2c_pld_output8(chip, offset, value);
 257 +}
 258 +
 259 +/*-------------------------------------------------------------------------*/
 260 +
 261 +static int gw_i2c_pld_probe(struct i2c_client *client,
 262 +                        const struct i2c_device_id *id)
 263 +{
 264 +       struct gw_i2c_pld_platform_data *pdata;
 265 +       struct gw_i2c_pld *gpio;
 266 +       int status;
 267 +
 268 +       pdata = client->dev.platform_data;
 269 +       if (!pdata)
 270 +               return -ENODEV;
 271 +
 272 +       /* Allocate, initialize, and register this gpio_chip. */
 273 +       gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
 274 +       if (!gpio)
 275 +               return -ENOMEM;
 276 +
 277 +       gpio->chip.base = pdata->gpio_base;
 278 +       gpio->chip.can_sleep = 1;
 279 +       gpio->chip.dev = &client->dev;
 280 +       gpio->chip.owner = THIS_MODULE;
 281 +
 282 +       gpio->chip.ngpio = pdata->nr_gpio;
 283 +       gpio->chip.direction_input = gw_i2c_pld_input8;
 284 +       gpio->chip.get = gw_i2c_pld_get8;
 285 +       gpio->chip.direction_output = gw_i2c_pld_output8;
 286 +       gpio->chip.set = gw_i2c_pld_set8;
 287 +
 288 +       gpio->chip.label = client->name;
 289 +
 290 +       gpio->client = client;
 291 +       i2c_set_clientdata(client, gpio);
 292 +
 293 +       gpio->out = 0xFF;
 294 +
 295 +       status = gpiochip_add(&gpio->chip);
 296 +       if (status < 0)
 297 +               goto fail;
 298 +
 299 +       dev_info(&client->dev, "gpios %d..%d on a %s%s\n",
 300 +                       gpio->chip.base,
 301 +                       gpio->chip.base + gpio->chip.ngpio - 1,
 302 +                       client->name,
 303 +                       client->irq ? " (irq ignored)" : "");
 304 +
 305 +       /* Let platform code set up the GPIOs and their users.
 306 +        * Now is the first time anyone could use them.
 307 +        */
 308 +       if (pdata->setup) {
 309 +               status = pdata->setup(client,
 310 +                               gpio->chip.base, gpio->chip.ngpio,
 311 +                               pdata->context);
 312 +               if (status < 0)
 313 +                       dev_warn(&client->dev, "setup --> %d\n", status);
 314 +       }
 315 +
 316 +       return 0;
 317 +
 318 +fail:
 319 +       dev_dbg(&client->dev, "probe error %d for '%s'\n",
 320 +                       status, client->name);
 321 +       kfree(gpio);
 322 +       return status;
 323 +}
 324 +
 325 +static int gw_i2c_pld_remove(struct i2c_client *client)
 326 +{
 327 +       struct gw_i2c_pld_platform_data *pdata = client->dev.platform_data;
 328 +       struct gw_i2c_pld *gpio = i2c_get_clientdata(client);
 329 +       int                             status = 0;
 330 +
 331 +       if (pdata->teardown) {
 332 +               status = pdata->teardown(client,
 333 +                               gpio->chip.base, gpio->chip.ngpio,
 334 +                               pdata->context);
 335 +               if (status < 0) {
 336 +                       dev_err(&client->dev, "%s --> %d\n",
 337 +                                       "teardown", status);
 338 +                       return status;
 339 +               }
 340 +       }
 341 +
 342 +       status = gpiochip_remove(&gpio->chip);
 343 +       if (status == 0)
 344 +               kfree(gpio);
 345 +       else
 346 +               dev_err(&client->dev, "%s --> %d\n", "remove", status);
 347 +       return status;
 348 +}
 349 +
 350 +static struct i2c_driver gw_i2c_pld_driver = {
 351 +       .driver = {
 352 +               .name   = "gw_i2c_pld",
 353 +               .owner  = THIS_MODULE,
 354 +       },
 355 +       .probe  = gw_i2c_pld_probe,
 356 +       .remove = gw_i2c_pld_remove,
 357 +       .id_table = gw_i2c_pld_id,
 358 +};
 359 +
 360 +static int __init gw_i2c_pld_init(void)
 361 +{
 362 +       return i2c_add_driver(&gw_i2c_pld_driver);
 363 +}
 364 +module_init(gw_i2c_pld_init);
 365 +
 366 +static void __exit gw_i2c_pld_exit(void)
 367 +{
 368 +       i2c_del_driver(&gw_i2c_pld_driver);
 369 +}
 370 +module_exit(gw_i2c_pld_exit);
 371 +
 372 +MODULE_LICENSE("GPL");
 373 +MODULE_AUTHOR("Chris Lang");
 374 --- a/drivers/gpio/Kconfig
 375 +++ b/drivers/gpio/Kconfig
 376 @@ -160,6 +160,14 @@ config GPIO_BT8XX
 377
 378           If unsure, say N.
 379
 380 +config GPIO_GW_I2C_PLD
 381 +       tristate "Gateworks I2C PLD GPIO Expander"
 382 +       depends on I2C
 383 +       help
 384 +               Say yes here to provide access to the Gateworks I2C PLD GPIO
 385 +               Expander. This is used at least on the GW2358-4.
 386 +
 387 +
 388  comment "SPI GPIO expanders:"
 389
 390  config GPIO_MAX7301
 391 --- a/drivers/gpio/Makefile
 392 +++ b/drivers/gpio/Makefile
 393 @@ -12,3 +12,4 @@ obj-$(CONFIG_GPIO_PCF857X)    += pcf857x.o
 394  obj-$(CONFIG_GPIO_TWL4030)     += twl4030-gpio.o
 395  obj-$(CONFIG_GPIO_XILINX)      += xilinx_gpio.o
 396  obj-$(CONFIG_GPIO_BT8XX)       += bt8xxgpio.o
 397 +obj-$(CONFIG_GPIO_GW_I2C_PLD)  += gw_i2c_pld.o
 398 --- /dev/null
 399 +++ b/include/linux/i2c/gw_i2c_pld.h
 400 @@ -0,0 +1,20 @@
 401 +#ifndef __LINUX_GW_I2C_PLD_H
 402 +#define __LINUX_GW_I2C_PLD_H
 403 +
 404 +/**
 405 + * The Gateworks I2C PLD Implements an additional 8 bits of GPIO through the PLD
 406 + */
 407 +
 408 +struct gw_i2c_pld_platform_data {
 409 +       unsigned gpio_base;
 410 +       unsigned nr_gpio;
 411 +       int             (*setup)(struct i2c_client *client,
 412 +                                       int gpio, unsigned ngpio,
 413 +                                       void *context);
 414 +       int             (*teardown)(struct i2c_client *client,
 415 +                                       int gpio, unsigned ngpio,
 416 +                                       void *context);
 417 +       void            *context;
 418 +};
 419 +
 420 +#endif /* __LINUX_GW_I2C_PLD_H */