target/linux/ixp4xx/patches-4.9/020-gateworks_i2c_pld.patch

   1 --- a/drivers/gpio/Kconfig
   2 +++ b/drivers/gpio/Kconfig
   3 @@ -656,6 +656,14 @@ config GPIO_WS16C48
   4           parameter. The interrupt line numbers for the devices may be
   5           configured via the irq module parameter.
   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 "I2C GPIO expanders"
  18 --- a/drivers/gpio/Makefile
  19 +++ b/drivers/gpio/Makefile
  20 @@ -48,6 +48,7 @@ obj-$(CONFIG_GPIO_F7188X)     += gpio-f7188x
  21  obj-$(CONFIG_GPIO_GE_FPGA)     += gpio-ge.o
  22  obj-$(CONFIG_GPIO_GPIO_MM)     += gpio-gpio-mm.o
  23  obj-$(CONFIG_GPIO_GRGPIO)      += gpio-grgpio.o
  24 +obj-$(CONFIG_GPIO_GW_I2C_PLD)  += gw_i2c_pld.o
  25  obj-$(CONFIG_HTC_EGPIO)                += gpio-htc-egpio.o
  26  obj-$(CONFIG_GPIO_ICH)         += gpio-ich.o
  27  obj-$(CONFIG_GPIO_IOP)         += gpio-iop.o
  28 --- /dev/null
  29 +++ b/drivers/gpio/gw_i2c_pld.c
  30 @@ -0,0 +1,371 @@
  31 +/*
  32 + * Gateworks I2C PLD GPIO expander
  33 + *
  34 + * Copyright (C) 2009 Gateworks Corporation
  35 + *
  36 + * This program is free software; you can redistribute it and/or modify
  37 + * it under the terms of the GNU General Public License as published by
  38 + * the Free Software Foundation; either version 2 of the License, or
  39 + * (at your option) any later version.
  40 + *
  41 + * This program is distributed in the hope that it will be useful,
  42 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  43 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  44 + * GNU General Public License for more details.
  45 + *
  46 + * You should have received a copy of the GNU General Public License
  47 + * along with this program; if not, write to the Free Software
  48 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  49 + */
  50 +
  51 +#include <linux/kernel.h>
  52 +#include <linux/slab.h>
  53 +#include <linux/hardirq.h>
  54 +#include <linux/i2c.h>
  55 +#include <linux/i2c/gw_i2c_pld.h>
  56 +#include <linux/module.h>
  57 +#include <linux/export.h>
  58 +#include <asm/gpio.h>
  59 +#include <mach/hardware.h>
  60 +
  61 +static const struct i2c_device_id gw_i2c_pld_id[] = {
  62 +       { "gw_i2c_pld", 8 },
  63 +       { }
  64 +};
  65 +MODULE_DEVICE_TABLE(i2c, gw_i2c_pld_id);
  66 +
  67 +/*
  68 + * The Gateworks I2C PLD chip only expose one read and one
  69 + * write register.  Writing a "one" bit (to match the reset state) lets
  70 + * that pin be used as an input. It is an open-drain model.
  71 + */
  72 +
  73 +struct gw_i2c_pld {
  74 +       struct gpio_chip        chip;
  75 +       struct i2c_client       *client;
  76 +       unsigned                out;            /* software latch */
  77 +};
  78 +
  79 +/*-------------------------------------------------------------------------*/
  80 +
  81 +/*
  82 + * The Gateworks I2C PLD chip does not properly send the acknowledge bit
  83 + * thus we cannot use standard i2c_smbus functions. We have recreated
  84 + * our own here, but we still use the rt_mutex_lock to lock the i2c_bus
  85 + * as the device still exists on the I2C bus.
  86 +*/
  87 +
  88 +#define PLD_SCL_GPIO 6
  89 +#define PLD_SDA_GPIO 7
  90 +
  91 +#define SCL_LO()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_LOW)
  92 +#define SCL_HI()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_HIGH)
  93 +#define SCL_EN()  gpio_line_config(PLD_SCL_GPIO, IXP4XX_GPIO_OUT)
  94 +#define SDA_LO()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_LOW)
  95 +#define SDA_HI()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_HIGH)
  96 +#define SDA_EN()  gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_OUT)
  97 +#define SDA_DIS() gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_IN)
  98 +#define SDA_IN(x) gpio_line_get(PLD_SDA_GPIO, &x);
  99 +
 100 +static int i2c_pld_write_byte(int address, int byte)
 101 +{
 102 +       int i;
 103 +
 104 +       address = (address << 1) & ~0x1;
 105 +
 106 +       SDA_HI();
 107 +       SDA_EN();
 108 +       SCL_EN();
 109 +       SCL_HI();
 110 +       SDA_LO();
 111 +       SCL_LO();
 112 +
 113 +       for (i = 7; i >= 0; i--)
 114 +       {
 115 +               if (address & (1 << i))
 116 +                       SDA_HI();
 117 +               else
 118 +                       SDA_LO();
 119 +
 120 +               SCL_HI();
 121 +               SCL_LO();
 122 +       }
 123 +
 124 +       SDA_DIS();
 125 +       SCL_HI();
 126 +       SDA_IN(i);
 127 +       SCL_LO();
 128 +       SDA_EN();
 129 +
 130 +       for (i = 7; i >= 0; i--)
 131 +       {
 132 +               if (byte & (1 << i))
 133 +      SDA_HI();
 134 +               else
 135 +                       SDA_LO();
 136 +               SCL_HI();
 137 +               SCL_LO();
 138 +       }
 139 +
 140 +       SDA_DIS();
 141 +       SCL_HI();
 142 +       SDA_IN(i);
 143 +       SCL_LO();
 144 +
 145 +       SDA_HI();
 146 +       SDA_EN();
 147 +
 148 +       SDA_LO();
 149 +       SCL_HI();
 150 +       SDA_HI();
 151 +       SCL_LO();
 152 +       SCL_HI();
 153 +
 154 +       return 0;
 155 +}
 156 +
 157 +static unsigned int i2c_pld_read_byte(int address)
 158 +{
 159 +       int i = 0, byte = 0;
 160 +       int bit;
 161 +
 162 +       address = (address << 1) | 0x1;
 163 +
 164 +       SDA_HI();
 165 +       SDA_EN();
 166 +       SCL_EN();
 167 +       SCL_HI();
 168 +       SDA_LO();
 169 +       SCL_LO();
 170 +
 171 +       for (i = 7; i >= 0; i--)
 172 +       {
 173 +               if (address & (1 << i))
 174 +                       SDA_HI();
 175 +               else
 176 +                       SDA_LO();
 177 +
 178 +               SCL_HI();
 179 +               SCL_LO();
 180 +       }
 181 +
 182 +       SDA_DIS();
 183 +       SCL_HI();
 184 +       SDA_IN(i);
 185 +       SCL_LO();
 186 +       SDA_EN();
 187 +
 188 +       SDA_DIS();
 189 +       for (i = 7; i >= 0; i--)
 190 +       {
 191 +               SCL_HI();
 192 +               SDA_IN(bit);
 193 +               byte |= bit << i;
 194 +               SCL_LO();
 195 +       }
 196 +
 197 +       SDA_LO();
 198 +       SCL_HI();
 199 +       SDA_HI();
 200 +       SCL_LO();
 201 +       SCL_HI();
 202 +
 203 +       return byte;
 204 +}
 205 +
 206 +
 207 +static int gw_i2c_pld_input8(struct gpio_chip *chip, unsigned offset)
 208 +{
 209 +       int ret;
 210 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 211 +       struct i2c_adapter *adap = gpio->client->adapter;
 212 +
 213 +       if (in_atomic() || irqs_disabled()) {
 214 +               ret = rt_mutex_trylock(&adap->bus_lock);
 215 +               if (!ret)
 216 +                       /* I2C activity is ongoing. */
 217 +                       return -EAGAIN;
 218 +       } else {
 219 +               rt_mutex_lock(&adap->bus_lock);
 220 +       }
 221 +
 222 +       gpio->out |= (1 << offset);
 223 +
 224 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 225 +
 226 +       rt_mutex_unlock(&adap->bus_lock);
 227 +
 228 +       return ret;
 229 +}
 230 +
 231 +static int gw_i2c_pld_get8(struct gpio_chip *chip, unsigned offset)
 232 +{
 233 +       int ret;
 234 +       s32     value;
 235 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 236 +       struct i2c_adapter *adap = gpio->client->adapter;
 237 +
 238 +       if (in_atomic() || irqs_disabled()) {
 239 +               ret = rt_mutex_trylock(&adap->bus_lock);
 240 +               if (!ret)
 241 +                       /* I2C activity is ongoing. */
 242 +                       return -EAGAIN;
 243 +       } else {
 244 +               rt_mutex_lock(&adap->bus_lock);
 245 +       }
 246 +
 247 +       value = i2c_pld_read_byte(gpio->client->addr);
 248 +
 249 +       rt_mutex_unlock(&adap->bus_lock);
 250 +
 251 +       return (value < 0) ? 0 : (value & (1 << offset));
 252 +}
 253 +
 254 +static int gw_i2c_pld_output8(struct gpio_chip *chip, unsigned offset, int value)
 255 +{
 256 +       int ret;
 257 +
 258 +       struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
 259 +       struct i2c_adapter *adap = gpio->client->adapter;
 260 +
 261 +       unsigned bit = 1 << offset;
 262 +
 263 +       if (in_atomic() || irqs_disabled()) {
 264 +               ret = rt_mutex_trylock(&adap->bus_lock);
 265 +               if (!ret)
 266 +                       /* I2C activity is ongoing. */
 267 +                       return -EAGAIN;
 268 +       } else {
 269 +               rt_mutex_lock(&adap->bus_lock);
 270 +       }
 271 +
 272 +
 273 +       if (value)
 274 +               gpio->out |= bit;
 275 +       else
 276 +               gpio->out &= ~bit;
 277 +
 278 +       ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
 279 +
 280 +       rt_mutex_unlock(&adap->bus_lock);
 281 +
 282 +       return ret;
 283 +}
 284 +
 285 +static void gw_i2c_pld_set8(struct gpio_chip *chip, unsigned offset, int value)
 286 +{
 287 +       gw_i2c_pld_output8(chip, offset, value);
 288 +}
 289 +
 290 +/*-------------------------------------------------------------------------*/
 291 +
 292 +static int gw_i2c_pld_probe(struct i2c_client *client,
 293 +                        const struct i2c_device_id *id)
 294 +{
 295 +       struct gw_i2c_pld_platform_data *pdata;
 296 +       struct gw_i2c_pld *gpio;
 297 +       int status;
 298 +
 299 +       pdata = client->dev.platform_data;
 300 +       if (!pdata)
 301 +               return -ENODEV;
 302 +
 303 +       /* Allocate, initialize, and register this gpio_chip. */
 304 +       gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
 305 +       if (!gpio)
 306 +               return -ENOMEM;
 307 +
 308 +       gpio->chip.base = pdata->gpio_base;
 309 +       gpio->chip.can_sleep = 1;
 310 +       gpio->chip.dev = &client->dev;
 311 +       gpio->chip.owner = THIS_MODULE;
 312 +
 313 +       gpio->chip.ngpio = pdata->nr_gpio;
 314 +       gpio->chip.direction_input = gw_i2c_pld_input8;
 315 +       gpio->chip.get = gw_i2c_pld_get8;
 316 +       gpio->chip.direction_output = gw_i2c_pld_output8;
 317 +       gpio->chip.set = gw_i2c_pld_set8;
 318 +
 319 +       gpio->chip.label = client->name;
 320 +
 321 +       gpio->client = client;
 322 +       i2c_set_clientdata(client, gpio);
 323 +
 324 +       gpio->out = 0xFF;
 325 +
 326 +       status = gpiochip_add(&gpio->chip);
 327 +       if (status < 0)
 328 +               goto fail;
 329 +
 330 +       dev_info(&client->dev, "gpios %d..%d on a %s%s\n",
 331 +                       gpio->chip.base,
 332 +                       gpio->chip.base + gpio->chip.ngpio - 1,
 333 +                       client->name,
 334 +                       client->irq ? " (irq ignored)" : "");
 335 +
 336 +       /* Let platform code set up the GPIOs and their users.
 337 +        * Now is the first time anyone could use them.
 338 +        */
 339 +       if (pdata->setup) {
 340 +               status = pdata->setup(client,
 341 +                               gpio->chip.base, gpio->chip.ngpio,
 342 +                               pdata->context);
 343 +               if (status < 0)
 344 +                       dev_warn(&client->dev, "setup --> %d\n", status);
 345 +       }
 346 +
 347 +       return 0;
 348 +
 349 +fail:
 350 +       dev_dbg(&client->dev, "probe error %d for '%s'\n",
 351 +                       status, client->name);
 352 +       kfree(gpio);
 353 +       return status;
 354 +}
 355 +
 356 +static int gw_i2c_pld_remove(struct i2c_client *client)
 357 +{
 358 +       struct gw_i2c_pld_platform_data *pdata = client->dev.platform_data;
 359 +       struct gw_i2c_pld *gpio = i2c_get_clientdata(client);
 360 +       int                             status = 0;
 361 +
 362 +       if (pdata->teardown) {
 363 +               status = pdata->teardown(client,
 364 +                               gpio->chip.base, gpio->chip.ngpio,
 365 +                               pdata->context);
 366 +               if (status < 0) {
 367 +                       dev_err(&client->dev, "%s --> %d\n",
 368 +                                       "teardown", status);
 369 +                       return status;
 370 +               }
 371 +       }
 372 +
 373 +       gpiochip_remove(&gpio->chip);
 374 +       kfree(gpio);
 375 +       return 0;
 376 +}
 377 +
 378 +static struct i2c_driver gw_i2c_pld_driver = {
 379 +       .driver = {
 380 +               .name   = "gw_i2c_pld",
 381 +               .owner  = THIS_MODULE,
 382 +       },
 383 +       .probe  = gw_i2c_pld_probe,
 384 +       .remove = gw_i2c_pld_remove,
 385 +       .id_table = gw_i2c_pld_id,
 386 +};
 387 +
 388 +static int __init gw_i2c_pld_init(void)
 389 +{
 390 +       return i2c_add_driver(&gw_i2c_pld_driver);
 391 +}
 392 +module_init(gw_i2c_pld_init);
 393 +
 394 +static void __exit gw_i2c_pld_exit(void)
 395 +{
 396 +       i2c_del_driver(&gw_i2c_pld_driver);
 397 +}
 398 +module_exit(gw_i2c_pld_exit);
 399 +
 400 +MODULE_LICENSE("GPL");
 401 +MODULE_AUTHOR("Chris Lang");
 402 --- /dev/null
 403 +++ b/include/linux/i2c/gw_i2c_pld.h
 404 @@ -0,0 +1,20 @@
 405 +#ifndef __LINUX_GW_I2C_PLD_H
 406 +#define __LINUX_GW_I2C_PLD_H
 407 +
 408 +/**
 409 + * The Gateworks I2C PLD Implements an additional 8 bits of GPIO through the PLD
 410 + */
 411 +
 412 +struct gw_i2c_pld_platform_data {
 413 +       unsigned gpio_base;
 414 +       unsigned nr_gpio;
 415 +       int             (*setup)(struct i2c_client *client,
 416 +                                       int gpio, unsigned ngpio,
 417 +                                       void *context);
 418 +       int             (*teardown)(struct i2c_client *client,
 419 +                                       int gpio, unsigned ngpio,
 420 +                                       void *context);
 421 +       void            *context;
 422 +};
 423 +
 424 +#endif /* __LINUX_GW_I2C_PLD_H */