target/linux/ixp4xx/patches-4.1/020-gateworks_i2c_pld.patch

   1 --- a/drivers/gpio/Kconfig
   2 +++ b/drivers/gpio/Kconfig
   3 @@ -647,6 +647,14 @@ config GPIO_SX150X
   4           8 bits:  sx1508q
   5           16 bits: sx1509q
   6
   7 +config GPIO_GW_I2C_PLD
   8 +       tristate "Gateworks I2C PLD GPIO Expander"
   9 +       depends on I2C
  10 +       help
  11 +               Say yes here to provide access to the Gateworks I2C PLD GPIO
  12 +               Expander. This is used at least on the GW2358-4.
  13 +
  14 +
  15  endmenu
  16
  17  menu "MFD GPIO expanders"
  18 --- a/drivers/gpio/Makefile
  19 +++ b/drivers/gpio/Makefile
  20 @@ -112,3 +112,4 @@ obj-$(CONFIG_GPIO_XILINX)   += gpio-xilinx
  21  obj-$(CONFIG_GPIO_XTENSA)      += gpio-xtensa.o
  22  obj-$(CONFIG_GPIO_ZEVIO)       += gpio-zevio.o
  23  obj-$(CONFIG_GPIO_ZYNQ)                += gpio-zynq.o
  24 +obj-$(CONFIG_GPIO_GW_I2C_PLD)  += gw_i2c_pld.o
  25 --- /dev/null
  26 +++ b/drivers/gpio/gw_i2c_pld.c
  27 @@ -0,0 +1,371 @@
  28 +/*
  29 + * Gateworks I2C PLD GPIO expander
  30 + *
  31 + * Copyright (C) 2009 Gateworks Corporation
  32 + *
  33 + * This program is free software; you can redistribute it and/or modify
  34 + * it under the terms of the GNU General Public License as published by
  35 + * the Free Software Foundation; either version 2 of the License, or
  36 + * (at your option) any later version.
  37 + *
  38 + * This program is distributed in the hope that it will be useful,
  39 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  40 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  41 + * GNU General Public License for more details.
  42 + *
  43 + * You should have received a copy of the GNU General Public License
  44 + * along with this program; if not, write to the Free Software
  45 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  46 + */
  47 +
  48 +#include <linux/kernel.h>
  49 +#include <linux/slab.h>
  50 +#include <linux/hardirq.h>
  51 +#include <linux/i2c.h>
  52 +#include <linux/i2c/gw_i2c_pld.h>
  53 +#include <linux/module.h>
  54 +#include <linux/export.h>
  55 +#include <asm/gpio.h>
  56 +#include <mach/hardware.h>
  57 +
  58 +static const struct i2c_device_id gw_i2c_pld_id[] = {
  59 +       { "gw_i2c_pld", 8 },
  60 +       { }
  61 +};
  62 +MODULE_DEVICE_TABLE(i2c, gw_i2c_pld_id);
  63 +
  64 +/*
  65 + * The Gateworks I2C PLD chip only expose one read and one
  66 + * write register.  Writing a "one" bit (to match the reset state) lets
  67 + * that pin be used as an input. It is an open-drain model.
  68 + */
  69 +
  70 +struct gw_i2c_pld {
  71 +       struct gpio_chip        chip;
  72 +       struct i2c_client       *client;
  73 +       unsigned                out;            /* software latch */
  74 +};
  75 +
  76 +/*-------------------------------------------------------------------------*/
  77 +
  78 +/*
  79 + * The Gateworks I2C PLD chip does not properly send the acknowledge bit
  80 + * thus we cannot use standard i2c_smbus functions. We have recreated
  81 + * our own here, but we still use the rt_mutex_lock to lock the i2c_bus
  82 + * as the device still exists on the I2C bus.
  83 +*/
  84 +
  85 +#define PLD_SCL_GPIO 6
  86 +#define PLD_SDA_GPIO 7
  87 +
  88 +#define SCL_LO()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_LOW)
  89 +#define SCL_HI()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_HIGH)
  90 +#define SCL_EN()  gpio_line_config(PLD_SCL_GPIO, IXP4XX_GPIO_OUT)
  91 +#define SDA_LO()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_LOW)
  92 +#define SDA_HI()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_HIGH)
  93 +#define SDA_EN()  gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_OUT)
  94 +#define SDA_DIS() gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_IN)
  95 +#define SDA_IN(x) gpio_line_get(PLD_SDA_GPIO, &x);
  96 +
  97 +static int i2c_pld_write_byte(int address, int byte)
  98 +{
  99 +       int i;
 100 +
 101 +       address = (address << 1) & ~0x1;
 102 +
 103 +       SDA_HI();
 104 +       SDA_EN();
 105 +       SCL_EN();
 106 +       SCL_HI();
 107 +       SDA_LO();
 108 +       SCL_LO();
 109 +
 110 +       for (i = 7; i >= 0; i--)
 111 +       {
 112 +               if (address & (1 << i))
 113 +                       SDA_HI();
 114 +               else
 115 +                       SDA_LO();
 116 +
 117 +               SCL_HI();
 118 +               SCL_LO();
 119 +       }
 120 +
 121 +       SDA_DIS();
 122 +       SCL_HI();
 123 +       SDA_IN(i);
 124 +       SCL_LO();
 125 +       SDA_EN();
 126 +
 127 +       for (i = 7; i >= 0; i--)
 128 +       {
 129 +               if (byte & (1 << i))
 130 +      SDA_HI();
 131 +               else
 132 +                       SDA_LO();
 133 +               SCL_HI();
 134 +               SCL_LO();
 135 +       }
 136 +
 137 +       SDA_DIS();
 138 +       SCL_HI();
 139 +       SDA_IN(i);
 140 +       SCL_LO();
 141 +
 142 +       SDA_HI();
 143 +       SDA_EN();
 144 +
 145 +       SDA_LO();
 146 +       SCL_HI();
 147 +       SDA_HI();
 148 +       SCL_LO();
 149 +       SCL_HI();
 150 +
 151 +       return 0;
 152 +}
 153 +
 154 +static unsigned int i2c_pld_read_byte(int address)
 155 +{
 156 +       int i = 0, byte = 0;
 157 +       int bit;
 158 +
 159 +       address = (address << 1) | 0x1;
 160 +
 161 +       SDA_HI();
 162 +       SDA_EN();
 163 +       SCL_EN();
 164 +       SCL_HI();
 165 +       SDA_LO();
 166 +       SCL_LO();
 167 +
 168 +       for (i = 7; i >= 0; i--)
 169 +       {
 170 +               if (address & (1 << i))
 171 +                       SDA_HI();
 172 +               else
 173 +                       SDA_LO();
 174 +
 175 +               SCL_HI();
 176 +               SCL_LO();
 177 +       }
 178 +
 179 +       SDA_DIS();
 180 +       SCL_HI();
 181 +       SDA_IN(i);
 182 +       SCL_LO();
 183 +       SDA_EN();
 184 +
 185 +       SDA_DIS();
 186 +       for (i = 7; i >= 0; i--)
 187 +       {
 188 +               SCL_HI();
 189 +               SDA_IN(bit);
 190 +               byte |= bit << i;
 191 +               SCL_LO();
 192 +       }
 193 +
 194 +       SDA_LO();
 195 +       SCL_HI();
 196 +       SDA_HI();
 197 +       SCL_LO();
 198 +       SCL_HI();
 199 +
 200 +       return byte;
 201 +}
 202 +
 203 +
 204 +static int gw_i2c_pld_input8(struct gpio_chip *chip, unsigned offset)
 205 +{
 206 +       int ret;
 207 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 208 +       struct i2c_adapter *adap = gpio->client->adapter;
 209 +
 210 +       if (in_atomic() || irqs_disabled()) {
 211 +               ret = rt_mutex_trylock(&adap->bus_lock);
 212 +               if (!ret)
 213 +                       /* I2C activity is ongoing. */
 214 +                       return -EAGAIN;
 215 +       } else {
 216 +               rt_mutex_lock(&adap->bus_lock);
 217 +       }
 218 +
 219 +       gpio->out |= (1 << offset);
 220 +
 221 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 222 +
 223 +       rt_mutex_unlock(&adap->bus_lock);
 224 +
 225 +       return ret;
 226 +}
 227 +
 228 +static int gw_i2c_pld_get8(struct gpio_chip *chip, unsigned offset)
 229 +{
 230 +       int ret;
 231 +       s32     value;
 232 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 233 +       struct i2c_adapter *adap = gpio->client->adapter;
 234 +
 235 +       if (in_atomic() || irqs_disabled()) {
 236 +               ret = rt_mutex_trylock(&adap->bus_lock);
 237 +               if (!ret)
 238 +                       /* I2C activity is ongoing. */
 239 +                       return -EAGAIN;
 240 +       } else {
 241 +               rt_mutex_lock(&adap->bus_lock);
 242 +       }
 243 +
 244 +       value = i2c_pld_read_byte(gpio->client->addr);
 245 +
 246 +       rt_mutex_unlock(&adap->bus_lock);
 247 +
 248 +       return (value < 0) ? 0 : (value & (1 << offset));
 249 +}
 250 +
 251 +static int gw_i2c_pld_output8(struct gpio_chip *chip, unsigned offset, int value)
 252 +{
 253 +       int ret;
 254 +
 255 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 256 +       struct i2c_adapter *adap = gpio->client->adapter;
 257 +
 258 +       unsigned bit = 1 << offset;
 259 +
 260 +       if (in_atomic() || irqs_disabled()) {
 261 +               ret = rt_mutex_trylock(&adap->bus_lock);
 262 +               if (!ret)
 263 +                       /* I2C activity is ongoing. */
 264 +                       return -EAGAIN;
 265 +       } else {
 266 +               rt_mutex_lock(&adap->bus_lock);
 267 +       }
 268 +
 269 +
 270 +       if (value)
 271 +               gpio->out |= bit;
 272 +       else
 273 +               gpio->out &= ~bit;
 274 +
 275 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 276 +
 277 +       rt_mutex_unlock(&adap->bus_lock);
 278 +
 279 +       return ret;
 280 +}
 281 +
 282 +static void gw_i2c_pld_set8(struct gpio_chip *chip, unsigned offset, int value)
 283 +{
 284 +       gw_i2c_pld_output8(chip, offset, value);
 285 +}
 286 +
 287 +/*-------------------------------------------------------------------------*/
 288 +
 289 +static int gw_i2c_pld_probe(struct i2c_client *client,
 290 +                        const struct i2c_device_id *id)
 291 +{
 292 +       struct gw_i2c_pld_platform_data *pdata;
 293 +       struct gw_i2c_pld *gpio;
 294 +       int status;
 295 +
 296 +       pdata = client->dev.platform_data;
 297 +       if (!pdata)
 298 +               return -ENODEV;
 299 +
 300 +       /* Allocate, initialize, and register this gpio_chip. */
 301 +       gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
 302 +       if (!gpio)
 303 +               return -ENOMEM;
 304 +
 305 +       gpio->chip.base = pdata->gpio_base;
 306 +       gpio->chip.can_sleep = 1;
 307 +       gpio->chip.dev = &client->dev;
 308 +       gpio->chip.owner = THIS_MODULE;
 309 +
 310 +       gpio->chip.ngpio = pdata->nr_gpio;
 311 +       gpio->chip.direction_input = gw_i2c_pld_input8;
 312 +       gpio->chip.get = gw_i2c_pld_get8;
 313 +       gpio->chip.direction_output = gw_i2c_pld_output8;
 314 +       gpio->chip.set = gw_i2c_pld_set8;
 315 +
 316 +       gpio->chip.label = client->name;
 317 +
 318 +       gpio->client = client;
 319 +       i2c_set_clientdata(client, gpio);
 320 +
 321 +       gpio->out = 0xFF;
 322 +
 323 +       status = gpiochip_add(&gpio->chip);
 324 +       if (status < 0)
 325 +               goto fail;
 326 +
 327 +       dev_info(&client->dev, "gpios %d..%d on a %s%s\n",
 328 +                       gpio->chip.base,
 329 +                       gpio->chip.base + gpio->chip.ngpio - 1,
 330 +                       client->name,
 331 +                       client->irq ? " (irq ignored)" : "");
 332 +
 333 +       /* Let platform code set up the GPIOs and their users.
 334 +        * Now is the first time anyone could use them.
 335 +        */
 336 +       if (pdata->setup) {
 337 +               status = pdata->setup(client,
 338 +                               gpio->chip.base, gpio->chip.ngpio,
 339 +                               pdata->context);
 340 +               if (status < 0)
 341 +                       dev_warn(&client->dev, "setup --> %d\n", status);
 342 +       }
 343 +
 344 +       return 0;
 345 +
 346 +fail:
 347 +       dev_dbg(&client->dev, "probe error %d for '%s'\n",
 348 +                       status, client->name);
 349 +       kfree(gpio);
 350 +       return status;
 351 +}
 352 +
 353 +static int gw_i2c_pld_remove(struct i2c_client *client)
 354 +{
 355 +       struct gw_i2c_pld_platform_data *pdata = client->dev.platform_data;
 356 +       struct gw_i2c_pld *gpio = i2c_get_clientdata(client);
 357 +       int                             status = 0;
 358 +
 359 +       if (pdata->teardown) {
 360 +               status = pdata->teardown(client,
 361 +                               gpio->chip.base, gpio->chip.ngpio,
 362 +                               pdata->context);
 363 +               if (status < 0) {
 364 +                       dev_err(&client->dev, "%s --> %d\n",
 365 +                                       "teardown", status);
 366 +                       return status;
 367 +               }
 368 +       }
 369 +
 370 +       gpiochip_remove(&gpio->chip);
 371 +       kfree(gpio);
 372 +       return 0;
 373 +}
 374 +
 375 +static struct i2c_driver gw_i2c_pld_driver = {
 376 +       .driver = {
 377 +               .name   = "gw_i2c_pld",
 378 +               .owner  = THIS_MODULE,
 379 +       },
 380 +       .probe  = gw_i2c_pld_probe,
 381 +       .remove = gw_i2c_pld_remove,
 382 +       .id_table = gw_i2c_pld_id,
 383 +};
 384 +
 385 +static int __init gw_i2c_pld_init(void)
 386 +{
 387 +       return i2c_add_driver(&gw_i2c_pld_driver);
 388 +}
 389 +module_init(gw_i2c_pld_init);
 390 +
 391 +static void __exit gw_i2c_pld_exit(void)
 392 +{
 393 +       i2c_del_driver(&gw_i2c_pld_driver);
 394 +}
 395 +module_exit(gw_i2c_pld_exit);
 396 +
 397 +MODULE_LICENSE("GPL");
 398 +MODULE_AUTHOR("Chris Lang");
 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 */