drivers/gpio/pca953x.c

   1 /*
   2  *  pca953x.c - 4/8/16 bit I/O ports
   3  *
   4  *  Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
   5  *  Copyright (C) 2007 Marvell International Ltd.
   6  *
   7  *  Derived from drivers/i2c/chips/pca9539.c
   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; version 2 of the License.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/i2c.h>
  17 #include <linux/i2c/pca953x.h>
  18
  19 #include <asm/gpio.h>
  20
  21 #define PCA953X_INPUT          0
  22 #define PCA953X_OUTPUT         1
  23 #define PCA953X_INVERT         2
  24 #define PCA953X_DIRECTION      3
  25
  26 static const struct i2c_device_id pca953x_id[] = {
  27         { "pca9534", 8, },
  28         { "pca9535", 16, },
  29         { "pca9536", 4, },
  30         { "pca9537", 4, },
  31         { "pca9538", 8, },
  32         { "pca9539", 16, },
  33         { "pca9554", 8, },
  34         { "pca9555", 16, },
  35         { "pca9557", 8, },
  36
  37         { "max7310", 8, },
  38         { "pca6107", 8, },
  39         { "tca6408", 8, },
  40         { "tca6416", 16, },
  41         /* NYET:  { "tca6424", 24, }, */
  42         { }
  43 };
  44 MODULE_DEVICE_TABLE(i2c, pca953x_id);
  45
  46 struct pca953x_chip {
  47         unsigned gpio_start;
  48         uint16_t reg_output;
  49         uint16_t reg_direction;
  50
  51         struct i2c_client *client;
  52         struct gpio_chip gpio_chip;
  53 };
  54
  55 static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
  56 {
  57         int ret;
  58
  59         if (chip->gpio_chip.ngpio <= 8)
  60                 ret = i2c_smbus_write_byte_data(chip->client, reg, val);
  61         else
  62                 ret = i2c_smbus_write_word_data(chip->client, reg << 1, val);
  63
  64         if (ret < 0) {
  65                 dev_err(&chip->client->dev, "failed writing register\n");
  66                 return ret;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
  73 {
  74         int ret;
  75
  76         if (chip->gpio_chip.ngpio <= 8)
  77                 ret = i2c_smbus_read_byte_data(chip->client, reg);
  78         else
  79                 ret = i2c_smbus_read_word_data(chip->client, reg << 1);
  80
  81         if (ret < 0) {
  82                 dev_err(&chip->client->dev, "failed reading register\n");
  83                 return ret;
  84         }
  85
  86         *val = (uint16_t)ret;
  87         return 0;
  88 }
  89
  90 static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
  91 {
  92         struct pca953x_chip *chip;
  93         uint16_t reg_val;
  94         int ret;
  95
  96         chip = container_of(gc, struct pca953x_chip, gpio_chip);
  97
  98         reg_val = chip->reg_direction | (1u << off);
  99         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
 100         if (ret)
 101                 return ret;
 102
 103         chip->reg_direction = reg_val;
 104         return 0;
 105 }
 106
 107 static int pca953x_gpio_direction_output(struct gpio_chip *gc,
 108                 unsigned off, int val)
 109 {
 110         struct pca953x_chip *chip;
 111         uint16_t reg_val;
 112         int ret;
 113
 114         chip = container_of(gc, struct pca953x_chip, gpio_chip);
 115
 116         /* set output level */
 117         if (val)
 118                 reg_val = chip->reg_output | (1u << off);
 119         else
 120                 reg_val = chip->reg_output & ~(1u << off);
 121
 122         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
 123         if (ret)
 124                 return ret;
 125
 126         chip->reg_output = reg_val;
 127
 128         /* then direction */
 129         reg_val = chip->reg_direction & ~(1u << off);
 130         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
 131         if (ret)
 132                 return ret;
 133
 134         chip->reg_direction = reg_val;
 135         return 0;
 136 }
 137
 138 static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
 139 {
 140         struct pca953x_chip *chip;
 141         uint16_t reg_val;
 142         int ret;
 143
 144         chip = container_of(gc, struct pca953x_chip, gpio_chip);
 145
 146         ret = pca953x_read_reg(chip, PCA953X_INPUT, &reg_val);
 147         if (ret < 0) {
 148                 /* NOTE:  diagnostic already emitted; that's all we should
 149                  * do unless gpio_*_value_cansleep() calls become different
 150                  * from their nonsleeping siblings (and report faults).
 151                  */
 152                 return 0;
 153         }
 154
 155         return (reg_val & (1u << off)) ? 1 : 0;
 156 }
 157
 158 static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
 159 {
 160         struct pca953x_chip *chip;
 161         uint16_t reg_val;
 162         int ret;
 163
 164         chip = container_of(gc, struct pca953x_chip, gpio_chip);
 165
 166         if (val)
 167                 reg_val = chip->reg_output | (1u << off);
 168         else
 169                 reg_val = chip->reg_output & ~(1u << off);
 170
 171         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
 172         if (ret)
 173                 return;
 174
 175         chip->reg_output = reg_val;
 176 }
 177
 178 static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
 179 {
 180         struct gpio_chip *gc;
 181
 182         gc = &chip->gpio_chip;
 183
 184         gc->direction_input  = pca953x_gpio_direction_input;
 185         gc->direction_output = pca953x_gpio_direction_output;
 186         gc->get = pca953x_gpio_get_value;
 187         gc->set = pca953x_gpio_set_value;
 188         gc->can_sleep = 1;
 189
 190         gc->base = chip->gpio_start;
 191         gc->ngpio = gpios;
 192         gc->label = chip->client->name;
 193         gc->dev = &chip->client->dev;
 194         gc->owner = THIS_MODULE;
 195 }
 196
 197 static int __devinit pca953x_probe(struct i2c_client *client,
 198                                    const struct i2c_device_id *id)
 199 {
 200         struct pca953x_platform_data *pdata;
 201         struct pca953x_chip *chip;
 202         int ret;
 203
 204         pdata = client->dev.platform_data;
 205         if (pdata == NULL) {
 206                 dev_dbg(&client->dev, "no platform data\n");
 207                 return -EINVAL;
 208         }
 209
 210         chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
 211         if (chip == NULL)
 212                 return -ENOMEM;
 213
 214         chip->client = client;
 215
 216         chip->gpio_start = pdata->gpio_base;
 217
 218         /* initialize cached registers from their original values.
 219          * we can't share this chip with another i2c master.
 220          */
 221         pca953x_setup_gpio(chip, id->driver_data);
 222
 223         ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
 224         if (ret)
 225                 goto out_failed;
 226
 227         ret = pca953x_read_reg(chip, PCA953X_DIRECTION, &chip->reg_direction);
 228         if (ret)
 229                 goto out_failed;
 230
 231         /* set platform specific polarity inversion */
 232         ret = pca953x_write_reg(chip, PCA953X_INVERT, pdata->invert);
 233         if (ret)
 234                 goto out_failed;
 235
 236
 237         ret = gpiochip_add(&chip->gpio_chip);
 238         if (ret)
 239                 goto out_failed;
 240
 241         if (pdata->setup) {
 242                 ret = pdata->setup(client, chip->gpio_chip.base,
 243                                 chip->gpio_chip.ngpio, pdata->context);
 244                 if (ret < 0)
 245                         dev_warn(&client->dev, "setup failed, %d\n", ret);
 246         }
 247
 248         i2c_set_clientdata(client, chip);
 249         return 0;
 250
 251 out_failed:
 252         kfree(chip);
 253         return ret;
 254 }
 255
 256 static int pca953x_remove(struct i2c_client *client)
 257 {
 258         struct pca953x_platform_data *pdata = client->dev.platform_data;
 259         struct pca953x_chip *chip = i2c_get_clientdata(client);
 260         int ret = 0;
 261
 262         if (pdata->teardown) {
 263                 ret = pdata->teardown(client, chip->gpio_chip.base,
 264                                 chip->gpio_chip.ngpio, pdata->context);
 265                 if (ret < 0) {
 266                         dev_err(&client->dev, "%s failed, %d\n",
 267                                         "teardown", ret);
 268                         return ret;
 269                 }
 270         }
 271
 272         ret = gpiochip_remove(&chip->gpio_chip);
 273         if (ret) {
 274                 dev_err(&client->dev, "%s failed, %d\n",
 275                                 "gpiochip_remove()", ret);
 276                 return ret;
 277         }
 278
 279         kfree(chip);
 280         return 0;
 281 }
 282
 283 static struct i2c_driver pca953x_driver = {
 284         .driver = {
 285                 .name   = "pca953x",
 286         },
 287         .probe          = pca953x_probe,
 288         .remove         = pca953x_remove,
 289         .id_table       = pca953x_id,
 290 };
 291
 292 static int __init pca953x_init(void)
 293 {
 294         return i2c_add_driver(&pca953x_driver);
 295 }
 296 /* register after i2c postcore initcall and before
 297  * subsys initcalls that may rely on these GPIOs
 298  */
 299 subsys_initcall(pca953x_init);
 300
 301 static void __exit pca953x_exit(void)
 302 {
 303         i2c_del_driver(&pca953x_driver);
 304 }
 305 module_exit(pca953x_exit);
 306
 307 MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
 308 MODULE_DESCRIPTION("GPIO expander driver for PCA953x");
 309 MODULE_LICENSE("GPL");