target/linux/ixp4xx/patches-3.10/020-gateworks_i2c_pld.patch

   1 --- a/drivers/gpio/Kconfig
   2 +++ b/drivers/gpio/Kconfig
   3 @@ -625,6 +625,14 @@ config GPIO_RDC321X
   4           Support for the RDC R321x SoC GPIOs over southbridge
   5           PCI configuration space.
   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  comment "SPI GPIO expanders:"
  16
  17  config GPIO_MAX7301
  18 --- a/drivers/gpio/Makefile
  19 +++ b/drivers/gpio/Makefile
  20 @@ -87,3 +87,4 @@ obj-$(CONFIG_GPIO_WM831X)     += gpio-wm831x
  21  obj-$(CONFIG_GPIO_WM8350)      += gpio-wm8350.o
  22  obj-$(CONFIG_GPIO_WM8994)      += gpio-wm8994.o
  23  obj-$(CONFIG_GPIO_XILINX)      += gpio-xilinx.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 +1,373 @@
  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 +
  57 +static const struct i2c_device_id gw_i2c_pld_id[] = {
  58 +       { "gw_i2c_pld", 8 },
  59 +       { }
  60 +};
  61 +MODULE_DEVICE_TABLE(i2c, gw_i2c_pld_id);
  62 +
  63 +/*
  64 + * The Gateworks I2C PLD chip only expose one read and one
  65 + * write register.  Writing a "one" bit (to match the reset state) lets
  66 + * that pin be used as an input. It is an open-drain model.
  67 + */
  68 +
  69 +struct gw_i2c_pld {
  70 +       struct gpio_chip        chip;
  71 +       struct i2c_client       *client;
  72 +       unsigned                out;            /* software latch */
  73 +};
  74 +
  75 +/*-------------------------------------------------------------------------*/
  76 +
  77 +/*
  78 + * The Gateworks I2C PLD chip does not properly send the acknowledge bit
  79 + * thus we cannot use standard i2c_smbus functions. We have recreated
  80 + * our own here, but we still use the rt_mutex_lock to lock the i2c_bus
  81 + * as the device still exists on the I2C bus.
  82 +*/
  83 +
  84 +#define PLD_SCL_GPIO 6
  85 +#define PLD_SDA_GPIO 7
  86 +
  87 +#define SCL_LO()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_LOW)
  88 +#define SCL_HI()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_HIGH)
  89 +#define SCL_EN()  gpio_line_config(PLD_SCL_GPIO, IXP4XX_GPIO_OUT)
  90 +#define SDA_LO()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_LOW)
  91 +#define SDA_HI()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_HIGH)
  92 +#define SDA_EN()  gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_OUT)
  93 +#define SDA_DIS() gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_IN)
  94 +#define SDA_IN(x) gpio_line_get(PLD_SDA_GPIO, &x);
  95 +
  96 +static int i2c_pld_write_byte(int address, int byte)
  97 +{
  98 +       int i;
  99 +
 100 +       address = (address << 1) & ~0x1;
 101 +
 102 +       SDA_HI();
 103 +       SDA_EN();
 104 +       SCL_EN();
 105 +       SCL_HI();
 106 +       SDA_LO();
 107 +       SCL_LO();
 108 +
 109 +       for (i = 7; i >= 0; i--)
 110 +       {
 111 +               if (address & (1 << i))
 112 +                       SDA_HI();
 113 +               else
 114 +                       SDA_LO();
 115 +
 116 +               SCL_HI();
 117 +               SCL_LO();
 118 +       }
 119 +
 120 +       SDA_DIS();
 121 +       SCL_HI();
 122 +       SDA_IN(i);
 123 +       SCL_LO();
 124 +       SDA_EN();
 125 +
 126 +       for (i = 7; i >= 0; i--)
 127 +       {
 128 +               if (byte & (1 << i))
 129 +      SDA_HI();
 130 +               else
 131 +                       SDA_LO();
 132 +               SCL_HI();
 133 +               SCL_LO();
 134 +       }
 135 +
 136 +       SDA_DIS();
 137 +       SCL_HI();
 138 +       SDA_IN(i);
 139 +       SCL_LO();
 140 +
 141 +       SDA_HI();
 142 +       SDA_EN();
 143 +
 144 +       SDA_LO();
 145 +       SCL_HI();
 146 +       SDA_HI();
 147 +       SCL_LO();
 148 +       SCL_HI();
 149 +
 150 +       return 0;
 151 +}
 152 +
 153 +static unsigned int i2c_pld_read_byte(int address)
 154 +{
 155 +       int i = 0, byte = 0;
 156 +       int bit;
 157 +
 158 +       address = (address << 1) | 0x1;
 159 +
 160 +       SDA_HI();
 161 +       SDA_EN();
 162 +       SCL_EN();
 163 +       SCL_HI();
 164 +       SDA_LO();
 165 +       SCL_LO();
 166 +
 167 +       for (i = 7; i >= 0; i--)
 168 +       {
 169 +               if (address & (1 << i))
 170 +                       SDA_HI();
 171 +               else
 172 +                       SDA_LO();
 173 +
 174 +               SCL_HI();
 175 +               SCL_LO();
 176 +       }
 177 +
 178 +       SDA_DIS();
 179 +       SCL_HI();
 180 +       SDA_IN(i);
 181 +       SCL_LO();
 182 +       SDA_EN();
 183 +
 184 +       SDA_DIS();
 185 +       for (i = 7; i >= 0; i--)
 186 +       {
 187 +               SCL_HI();
 188 +               SDA_IN(bit);
 189 +               byte |= bit << i;
 190 +               SCL_LO();
 191 +       }
 192 +
 193 +       SDA_LO();
 194 +       SCL_HI();
 195 +       SDA_HI();
 196 +       SCL_LO();
 197 +       SCL_HI();
 198 +
 199 +       return byte;
 200 +}
 201 +
 202 +
 203 +static int gw_i2c_pld_input8(struct gpio_chip *chip, unsigned offset)
 204 +{
 205 +       int ret;
 206 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 207 +       struct i2c_adapter *adap = gpio->client->adapter;
 208 +
 209 +       if (in_atomic() || irqs_disabled()) {
 210 +               ret = rt_mutex_trylock(&adap->bus_lock);
 211 +               if (!ret)
 212 +                       /* I2C activity is ongoing. */
 213 +                       return -EAGAIN;
 214 +       } else {
 215 +               rt_mutex_lock(&adap->bus_lock);
 216 +       }
 217 +
 218 +       gpio->out |= (1 << offset);
 219 +
 220 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 221 +
 222 +       rt_mutex_unlock(&adap->bus_lock);
 223 +
 224 +       return ret;
 225 +}
 226 +
 227 +static int gw_i2c_pld_get8(struct gpio_chip *chip, unsigned offset)
 228 +{
 229 +       int ret;
 230 +       s32     value;
 231 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 232 +       struct i2c_adapter *adap = gpio->client->adapter;
 233 +
 234 +       if (in_atomic() || irqs_disabled()) {
 235 +               ret = rt_mutex_trylock(&adap->bus_lock);
 236 +               if (!ret)
 237 +                       /* I2C activity is ongoing. */
 238 +                       return -EAGAIN;
 239 +       } else {
 240 +               rt_mutex_lock(&adap->bus_lock);
 241 +       }
 242 +
 243 +       value = i2c_pld_read_byte(gpio->client->addr);
 244 +
 245 +       rt_mutex_unlock(&adap->bus_lock);
 246 +
 247 +       return (value < 0) ? 0 : (value & (1 << offset));
 248 +}
 249 +
 250 +static int gw_i2c_pld_output8(struct gpio_chip *chip, unsigned offset, int value)
 251 +{
 252 +       int ret;
 253 +
 254 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 255 +       struct i2c_adapter *adap = gpio->client->adapter;
 256 +
 257 +       unsigned bit = 1 << offset;
 258 +
 259 +       if (in_atomic() || irqs_disabled()) {
 260 +               ret = rt_mutex_trylock(&adap->bus_lock);
 261 +               if (!ret)
 262 +                       /* I2C activity is ongoing. */
 263 +                       return -EAGAIN;
 264 +       } else {
 265 +               rt_mutex_lock(&adap->bus_lock);
 266 +       }
 267 +
 268 +
 269 +       if (value)
 270 +               gpio->out |= bit;
 271 +       else
 272 +               gpio->out &= ~bit;
 273 +
 274 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 275 +
 276 +       rt_mutex_unlock(&adap->bus_lock);
 277 +
 278 +       return ret;
 279 +}
 280 +
 281 +static void gw_i2c_pld_set8(struct gpio_chip *chip, unsigned offset, int value)
 282 +{
 283 +       gw_i2c_pld_output8(chip, offset, value);
 284 +}
 285 +
 286 +/*-------------------------------------------------------------------------*/
 287 +
 288 +static int gw_i2c_pld_probe(struct i2c_client *client,
 289 +                        const struct i2c_device_id *id)
 290 +{
 291 +       struct gw_i2c_pld_platform_data *pdata;
 292 +       struct gw_i2c_pld *gpio;
 293 +       int status;
 294 +
 295 +       pdata = client->dev.platform_data;
 296 +       if (!pdata)
 297 +               return -ENODEV;
 298 +
 299 +       /* Allocate, initialize, and register this gpio_chip. */
 300 +       gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
 301 +       if (!gpio)
 302 +               return -ENOMEM;
 303 +
 304 +       gpio->chip.base = pdata->gpio_base;
 305 +       gpio->chip.can_sleep = 1;
 306 +       gpio->chip.dev = &client->dev;
 307 +       gpio->chip.owner = THIS_MODULE;
 308 +
 309 +       gpio->chip.ngpio = pdata->nr_gpio;
 310 +       gpio->chip.direction_input = gw_i2c_pld_input8;
 311 +       gpio->chip.get = gw_i2c_pld_get8;
 312 +       gpio->chip.direction_output = gw_i2c_pld_output8;
 313 +       gpio->chip.set = gw_i2c_pld_set8;
 314 +
 315 +       gpio->chip.label = client->name;
 316 +
 317 +       gpio->client = client;
 318 +       i2c_set_clientdata(client, gpio);
 319 +
 320 +       gpio->out = 0xFF;
 321 +
 322 +       status = gpiochip_add(&gpio->chip);
 323 +       if (status < 0)
 324 +               goto fail;
 325 +
 326 +       dev_info(&client->dev, "gpios %d..%d on a %s%s\n",
 327 +                       gpio->chip.base,
 328 +                       gpio->chip.base + gpio->chip.ngpio - 1,
 329 +                       client->name,
 330 +                       client->irq ? " (irq ignored)" : "");
 331 +
 332 +       /* Let platform code set up the GPIOs and their users.
 333 +        * Now is the first time anyone could use them.
 334 +        */
 335 +       if (pdata->setup) {
 336 +               status = pdata->setup(client,
 337 +                               gpio->chip.base, gpio->chip.ngpio,
 338 +                               pdata->context);
 339 +               if (status < 0)
 340 +                       dev_warn(&client->dev, "setup --> %d\n", status);
 341 +       }
 342 +
 343 +       return 0;
 344 +
 345 +fail:
 346 +       dev_dbg(&client->dev, "probe error %d for '%s'\n",
 347 +                       status, client->name);
 348 +       kfree(gpio);
 349 +       return status;
 350 +}
 351 +
 352 +static int gw_i2c_pld_remove(struct i2c_client *client)
 353 +{
 354 +       struct gw_i2c_pld_platform_data *pdata = client->dev.platform_data;
 355 +       struct gw_i2c_pld *gpio = i2c_get_clientdata(client);
 356 +       int                             status = 0;
 357 +
 358 +       if (pdata->teardown) {
 359 +               status = pdata->teardown(client,
 360 +                               gpio->chip.base, gpio->chip.ngpio,
 361 +                               pdata->context);
 362 +               if (status < 0) {
 363 +                       dev_err(&client->dev, "%s --> %d\n",
 364 +                                       "teardown", status);
 365 +                       return status;
 366 +               }
 367 +       }
 368 +
 369 +       status = gpiochip_remove(&gpio->chip);
 370 +       if (status == 0)
 371 +               kfree(gpio);
 372 +       else
 373 +               dev_err(&client->dev, "%s --> %d\n", "remove", status);
 374 +       return status;
 375 +}
 376 +
 377 +static struct i2c_driver gw_i2c_pld_driver = {
 378 +       .driver = {
 379 +               .name   = "gw_i2c_pld",
 380 +               .owner  = THIS_MODULE,
 381 +       },
 382 +       .probe  = gw_i2c_pld_probe,
 383 +       .remove = gw_i2c_pld_remove,
 384 +       .id_table = gw_i2c_pld_id,
 385 +};
 386 +
 387 +static int __init gw_i2c_pld_init(void)
 388 +{
 389 +       return i2c_add_driver(&gw_i2c_pld_driver);
 390 +}
 391 +module_init(gw_i2c_pld_init);
 392 +
 393 +static void __exit gw_i2c_pld_exit(void)
 394 +{
 395 +       i2c_del_driver(&gw_i2c_pld_driver);
 396 +}
 397 +module_exit(gw_i2c_pld_exit);
 398 +
 399 +MODULE_LICENSE("GPL");
 400 +MODULE_AUTHOR("Chris Lang");
 401 --- /dev/null
 402 +++ b/include/linux/i2c/gw_i2c_pld.h
 403 @@ -0,0 +1,20 @@
 404 +#ifndef __LINUX_GW_I2C_PLD_H
 405 +#define __LINUX_GW_I2C_PLD_H
 406 +
 407 +/**
 408 + * The Gateworks I2C PLD Implements an additional 8 bits of GPIO through the PLD
 409 + */
 410 +
 411 +struct gw_i2c_pld_platform_data {
 412 +       unsigned gpio_base;
 413 +       unsigned nr_gpio;
 414 +       int             (*setup)(struct i2c_client *client,
 415 +                                       int gpio, unsigned ngpio,
 416 +                                       void *context);
 417 +       int             (*teardown)(struct i2c_client *client,
 418 +                                       int gpio, unsigned ngpio,
 419 +                                       void *context);
 420 +       void            *context;
 421 +};
 422 +
 423 +#endif /* __LINUX_GW_I2C_PLD_H */