target/linux/ixp4xx/patches-3.3/020-gateworks_i2c_pld.patch

   1 --- /dev/null
   2 +++ b/drivers/gpio/gw_i2c_pld.c
   3 @@ -0,0 +1,373 @@
   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 <linux/module.h>
  30 +#include <linux/export.h>
  31 +#include <asm/gpio.h>
  32 +
  33 +static const struct i2c_device_id gw_i2c_pld_id[] = {
  34 +       { "gw_i2c_pld", 8 },
  35 +       { }
  36 +};
  37 +MODULE_DEVICE_TABLE(i2c, gw_i2c_pld_id);
  38 +
  39 +/*
  40 + * The Gateworks I2C PLD chip only expose one read and one
  41 + * write register.  Writing a "one" bit (to match the reset state) lets
  42 + * that pin be used as an input. It is an open-drain model.
  43 + */
  44 +
  45 +struct gw_i2c_pld {
  46 +       struct gpio_chip        chip;
  47 +       struct i2c_client       *client;
  48 +       unsigned                out;            /* software latch */
  49 +};
  50 +
  51 +/*-------------------------------------------------------------------------*/
  52 +
  53 +/*
  54 + * The Gateworks I2C PLD chip does not properly send the acknowledge bit
  55 + * thus we cannot use standard i2c_smbus functions. We have recreated
  56 + * our own here, but we still use the rt_mutex_lock to lock the i2c_bus
  57 + * as the device still exists on the I2C bus.
  58 +*/
  59 +
  60 +#define PLD_SCL_GPIO 6
  61 +#define PLD_SDA_GPIO 7
  62 +
  63 +#define SCL_LO()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_LOW)
  64 +#define SCL_HI()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_HIGH)
  65 +#define SCL_EN()  gpio_line_config(PLD_SCL_GPIO, IXP4XX_GPIO_OUT)
  66 +#define SDA_LO()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_LOW)
  67 +#define SDA_HI()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_HIGH)
  68 +#define SDA_EN()  gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_OUT)
  69 +#define SDA_DIS() gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_IN)
  70 +#define SDA_IN(x) gpio_line_get(PLD_SDA_GPIO, &x);
  71 +
  72 +static int i2c_pld_write_byte(int address, int byte)
  73 +{
  74 +       int i;
  75 +
  76 +       address = (address << 1) & ~0x1;
  77 +
  78 +       SDA_HI();
  79 +       SDA_EN();
  80 +       SCL_EN();
  81 +       SCL_HI();
  82 +       SDA_LO();
  83 +       SCL_LO();
  84 +
  85 +       for (i = 7; i >= 0; i--)
  86 +       {
  87 +               if (address & (1 << i))
  88 +                       SDA_HI();
  89 +               else
  90 +                       SDA_LO();
  91 +
  92 +               SCL_HI();
  93 +               SCL_LO();
  94 +       }
  95 +
  96 +       SDA_DIS();
  97 +       SCL_HI();
  98 +       SDA_IN(i);
  99 +       SCL_LO();
 100 +       SDA_EN();
 101 +
 102 +       for (i = 7; i >= 0; i--)
 103 +       {
 104 +               if (byte & (1 << i))
 105 +      SDA_HI();
 106 +               else
 107 +                       SDA_LO();
 108 +               SCL_HI();
 109 +               SCL_LO();
 110 +       }
 111 +
 112 +       SDA_DIS();
 113 +       SCL_HI();
 114 +       SDA_IN(i);
 115 +       SCL_LO();
 116 +
 117 +       SDA_HI();
 118 +       SDA_EN();
 119 +
 120 +       SDA_LO();
 121 +       SCL_HI();
 122 +       SDA_HI();
 123 +       SCL_LO();
 124 +       SCL_HI();
 125 +
 126 +       return 0;
 127 +}
 128 +
 129 +static unsigned int i2c_pld_read_byte(int address)
 130 +{
 131 +       int i = 0, byte = 0;
 132 +       int bit;
 133 +
 134 +       address = (address << 1) | 0x1;
 135 +
 136 +       SDA_HI();
 137 +       SDA_EN();
 138 +       SCL_EN();
 139 +       SCL_HI();
 140 +       SDA_LO();
 141 +       SCL_LO();
 142 +
 143 +       for (i = 7; i >= 0; i--)
 144 +       {
 145 +               if (address & (1 << i))
 146 +                       SDA_HI();
 147 +               else
 148 +                       SDA_LO();
 149 +
 150 +               SCL_HI();
 151 +               SCL_LO();
 152 +       }
 153 +
 154 +       SDA_DIS();
 155 +       SCL_HI();
 156 +       SDA_IN(i);
 157 +       SCL_LO();
 158 +       SDA_EN();
 159 +
 160 +       SDA_DIS();
 161 +       for (i = 7; i >= 0; i--)
 162 +       {
 163 +               SCL_HI();
 164 +               SDA_IN(bit);
 165 +               byte |= bit << i;
 166 +               SCL_LO();
 167 +       }
 168 +
 169 +       SDA_LO();
 170 +       SCL_HI();
 171 +       SDA_HI();
 172 +       SCL_LO();
 173 +       SCL_HI();
 174 +
 175 +       return byte;
 176 +}
 177 +
 178 +
 179 +static int gw_i2c_pld_input8(struct gpio_chip *chip, unsigned offset)
 180 +{
 181 +       int ret;
 182 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 183 +       struct i2c_adapter *adap = gpio->client->adapter;
 184 +
 185 +       if (in_atomic() || irqs_disabled()) {
 186 +               ret = rt_mutex_trylock(&adap->bus_lock);
 187 +               if (!ret)
 188 +                       /* I2C activity is ongoing. */
 189 +                       return -EAGAIN;
 190 +       } else {
 191 +               rt_mutex_lock(&adap->bus_lock);
 192 +       }
 193 +
 194 +       gpio->out |= (1 << offset);
 195 +
 196 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 197 +
 198 +       rt_mutex_unlock(&adap->bus_lock);
 199 +
 200 +       return ret;
 201 +}
 202 +
 203 +static int gw_i2c_pld_get8(struct gpio_chip *chip, unsigned offset)
 204 +{
 205 +       int ret;
 206 +       s32     value;
 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 +       value = i2c_pld_read_byte(gpio->client->addr);
 220 +
 221 +       rt_mutex_unlock(&adap->bus_lock);
 222 +
 223 +       return (value < 0) ? 0 : (value & (1 << offset));
 224 +}
 225 +
 226 +static int gw_i2c_pld_output8(struct gpio_chip *chip, unsigned offset, int value)
 227 +{
 228 +       int ret;
 229 +
 230 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 231 +       struct i2c_adapter *adap = gpio->client->adapter;
 232 +
 233 +       unsigned bit = 1 << offset;
 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 +
 245 +       if (value)
 246 +               gpio->out |= bit;
 247 +       else
 248 +               gpio->out &= ~bit;
 249 +
 250 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 251 +
 252 +       rt_mutex_unlock(&adap->bus_lock);
 253 +
 254 +       return ret;
 255 +}
 256 +
 257 +static void gw_i2c_pld_set8(struct gpio_chip *chip, unsigned offset, int value)
 258 +{
 259 +       gw_i2c_pld_output8(chip, offset, value);
 260 +}
 261 +
 262 +/*-------------------------------------------------------------------------*/
 263 +
 264 +static int gw_i2c_pld_probe(struct i2c_client *client,
 265 +                        const struct i2c_device_id *id)
 266 +{
 267 +       struct gw_i2c_pld_platform_data *pdata;
 268 +       struct gw_i2c_pld *gpio;
 269 +       int status;
 270 +
 271 +       pdata = client->dev.platform_data;
 272 +       if (!pdata)
 273 +               return -ENODEV;
 274 +
 275 +       /* Allocate, initialize, and register this gpio_chip. */
 276 +       gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
 277 +       if (!gpio)
 278 +               return -ENOMEM;
 279 +
 280 +       gpio->chip.base = pdata->gpio_base;
 281 +       gpio->chip.can_sleep = 1;
 282 +       gpio->chip.dev = &client->dev;
 283 +       gpio->chip.owner = THIS_MODULE;
 284 +
 285 +       gpio->chip.ngpio = pdata->nr_gpio;
 286 +       gpio->chip.direction_input = gw_i2c_pld_input8;
 287 +       gpio->chip.get = gw_i2c_pld_get8;
 288 +       gpio->chip.direction_output = gw_i2c_pld_output8;
 289 +       gpio->chip.set = gw_i2c_pld_set8;
 290 +
 291 +       gpio->chip.label = client->name;
 292 +
 293 +       gpio->client = client;
 294 +       i2c_set_clientdata(client, gpio);
 295 +
 296 +       gpio->out = 0xFF;
 297 +
 298 +       status = gpiochip_add(&gpio->chip);
 299 +       if (status < 0)
 300 +               goto fail;
 301 +
 302 +       dev_info(&client->dev, "gpios %d..%d on a %s%s\n",
 303 +                       gpio->chip.base,
 304 +                       gpio->chip.base + gpio->chip.ngpio - 1,
 305 +                       client->name,
 306 +                       client->irq ? " (irq ignored)" : "");
 307 +
 308 +       /* Let platform code set up the GPIOs and their users.
 309 +        * Now is the first time anyone could use them.
 310 +        */
 311 +       if (pdata->setup) {
 312 +               status = pdata->setup(client,
 313 +                               gpio->chip.base, gpio->chip.ngpio,
 314 +                               pdata->context);
 315 +               if (status < 0)
 316 +                       dev_warn(&client->dev, "setup --> %d\n", status);
 317 +       }
 318 +
 319 +       return 0;
 320 +
 321 +fail:
 322 +       dev_dbg(&client->dev, "probe error %d for '%s'\n",
 323 +                       status, client->name);
 324 +       kfree(gpio);
 325 +       return status;
 326 +}
 327 +
 328 +static int gw_i2c_pld_remove(struct i2c_client *client)
 329 +{
 330 +       struct gw_i2c_pld_platform_data *pdata = client->dev.platform_data;
 331 +       struct gw_i2c_pld *gpio = i2c_get_clientdata(client);
 332 +       int                             status = 0;
 333 +
 334 +       if (pdata->teardown) {
 335 +               status = pdata->teardown(client,
 336 +                               gpio->chip.base, gpio->chip.ngpio,
 337 +                               pdata->context);
 338 +               if (status < 0) {
 339 +                       dev_err(&client->dev, "%s --> %d\n",
 340 +                                       "teardown", status);
 341 +                       return status;
 342 +               }
 343 +       }
 344 +
 345 +       status = gpiochip_remove(&gpio->chip);
 346 +       if (status == 0)
 347 +               kfree(gpio);
 348 +       else
 349 +               dev_err(&client->dev, "%s --> %d\n", "remove", status);
 350 +       return status;
 351 +}
 352 +
 353 +static struct i2c_driver gw_i2c_pld_driver = {
 354 +       .driver = {
 355 +               .name   = "gw_i2c_pld",
 356 +               .owner  = THIS_MODULE,
 357 +       },
 358 +       .probe  = gw_i2c_pld_probe,
 359 +       .remove = gw_i2c_pld_remove,
 360 +       .id_table = gw_i2c_pld_id,
 361 +};
 362 +
 363 +static int __init gw_i2c_pld_init(void)
 364 +{
 365 +       return i2c_add_driver(&gw_i2c_pld_driver);
 366 +}
 367 +module_init(gw_i2c_pld_init);
 368 +
 369 +static void __exit gw_i2c_pld_exit(void)
 370 +{
 371 +       i2c_del_driver(&gw_i2c_pld_driver);
 372 +}
 373 +module_exit(gw_i2c_pld_exit);
 374 +
 375 +MODULE_LICENSE("GPL");
 376 +MODULE_AUTHOR("Chris Lang");
 377 --- a/drivers/gpio/Kconfig
 378 +++ b/drivers/gpio/Kconfig
 379 @@ -426,6 +426,14 @@ config GPIO_RDC321X
 380           Support for the RDC R321x SoC GPIOs over southbridge
 381           PCI configuration space.
 382
 383 +config GPIO_GW_I2C_PLD
 384 +       tristate "Gateworks I2C PLD GPIO Expander"
 385 +       depends on I2C
 386 +       help
 387 +               Say yes here to provide access to the Gateworks I2C PLD GPIO
 388 +               Expander. This is used at least on the GW2358-4.
 389 +
 390 +
 391  comment "SPI GPIO expanders:"
 392
 393  config GPIO_MAX7301
 394 --- a/drivers/gpio/Makefile
 395 +++ b/drivers/gpio/Makefile
 396 @@ -61,3 +61,4 @@ obj-$(CONFIG_GPIO_WM831X)     += gpio-wm831x
 397  obj-$(CONFIG_GPIO_WM8350)      += gpio-wm8350.o
 398  obj-$(CONFIG_GPIO_WM8994)      += gpio-wm8994.o
 399  obj-$(CONFIG_GPIO_XILINX)      += gpio-xilinx.o
 400 +obj-$(CONFIG_GPIO_GW_I2C_PLD)  += gw_i2c_pld.o
 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 */