target/linux/ixp4xx/patches-2.6.29/020-gateworks_i2c_pld.patch

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