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 /* This is temporary - in 2.6.26 i2c_driver_data should replace it. */
  27 struct pca953x_desc {
  28         char            name[I2C_NAME_SIZE];
  29         unsigned long   driver_data;
  30 };
  31
  32 static const struct pca953x_desc pca953x_descs[] = {
  33         { "pca9534", 8, },
  34         { "pca9535", 16, },
  35         { "pca9536", 4, },
  36         { "pca9537", 4, },
  37         { "pca9538", 8, },
  38         { "pca9539", 16, },
  39         /* REVISIT several pca955x parts should work here too */
  40 };
  41
  42 struct pca953x_chip {
  43         unsigned gpio_start;
  44         uint16_t reg_output;
  45         uint16_t reg_direction;
  46
  47         struct i2c_client *client;
  48         struct gpio_chip gpio_chip;
  49 };
  50
  51 /* NOTE:  we can't currently rely on fault codes to come from SMBus
  52  * calls, so we map all errors to EIO here and return zero otherwise.
  53  */
  54 static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
  55 {
  56         int ret;
  57
  58         if (chip->gpio_chip.ngpio <= 8)
  59                 ret = i2c_smbus_write_byte_data(chip->client, reg, val);
  60         else
  61                 ret = i2c_smbus_write_word_data(chip->client, reg << 1, val);
  62
  63         if (ret < 0) {
  64                 dev_err(&chip->client->dev, "failed writing register\n");
  65                 return -EIO;
  66         }
  67
  68         return 0;
  69 }
  70
  71 static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
  72 {
  73         int ret;
  74
  75         if (chip->gpio_chip.ngpio <= 8)
  76                 ret = i2c_smbus_read_byte_data(chip->client, reg);
  77         else
  78                 ret = i2c_smbus_read_word_data(chip->client, reg << 1);
  79
  80         if (ret < 0) {
  81                 dev_err(&chip->client->dev, "failed reading register\n");
  82                 return -EIO;
  83         }
  84
  85         *val = (uint16_t)ret;
  86         return 0;
  87 }
  88
  89 static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
  90 {
  91         struct pca953x_chip *chip;
  92         uint16_t reg_val;
  93         int ret;
  94
  95         chip = container_of(gc, struct pca953x_chip, gpio_chip);
  96
  97         reg_val = chip->reg_direction | (1u << off);
  98         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
  99         if (ret)
 100                 return ret;
 101
 102         chip->reg_direction = reg_val;
 103         return 0;
 104 }
 105
 106 static int pca953x_gpio_direction_output(struct gpio_chip *gc,
 107                 unsigned off, int val)
 108 {
 109         struct pca953x_chip *chip;
 110         uint16_t reg_val;
 111         int ret;
 112
 113         chip = container_of(gc, struct pca953x_chip, gpio_chip);
 114
 115         /* set output level */
 116         if (val)
 117                 reg_val = chip->reg_output | (1u << off);
 118         else
 119                 reg_val = chip->reg_output & ~(1u << off);
 120
 121         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
 122         if (ret)
 123                 return ret;
 124
 125         chip->reg_output = reg_val;
 126
 127         /* then direction */
 128         reg_val = chip->reg_direction & ~(1u << off);
 129         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
 130         if (ret)
 131                 return ret;
 132
 133         chip->reg_direction = reg_val;
 134         return 0;
 135 }
 136
 137 static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
 138 {
 139         struct pca953x_chip *chip;
 140         uint16_t reg_val;
 141         int ret;
 142
 143         chip = container_of(gc, struct pca953x_chip, gpio_chip);
 144
 145         ret = pca953x_read_reg(chip, PCA953X_INPUT, &reg_val);
 146         if (ret < 0) {
 147                 /* NOTE:  diagnostic already emitted; that's all we should
 148                  * do unless gpio_*_value_cansleep() calls become different
 149                  * from their nonsleeping siblings (and report faults).
 150                  */
 151                 return 0;
 152         }
 153
 154         return (reg_val & (1u << off)) ? 1 : 0;
 155 }
 156
 157 static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
 158 {
 159         struct pca953x_chip *chip;
 160         uint16_t reg_val;
 161         int ret;
 162
 163         chip = container_of(gc, struct pca953x_chip, gpio_chip);
 164
 165         if (val)
 166                 reg_val = chip->reg_output | (1u << off);
 167         else
 168                 reg_val = chip->reg_output & ~(1u << off);
 169
 170         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
 171         if (ret)
 172                 return;
 173
 174         chip->reg_output = reg_val;
 175 }
 176
 177 static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
 178 {
 179         struct gpio_chip *gc;
 180
 181         gc = &chip->gpio_chip;
 182
 183         gc->direction_input  = pca953x_gpio_direction_input;
 184         gc->direction_output = pca953x_gpio_direction_output;
 185         gc->get = pca953x_gpio_get_value;
 186         gc->set = pca953x_gpio_set_value;
 187
 188         gc->base = chip->gpio_start;
 189         gc->ngpio = gpios;
 190         gc->label = chip->client->name;
 191 }
 192
 193 static int __devinit pca953x_probe(struct i2c_client *client)
 194 {
 195         struct pca953x_platform_data *pdata;
 196         struct pca953x_chip *chip;
 197         int ret, i;
 198         const struct pca953x_desc *id = NULL;
 199
 200         pdata = client->dev.platform_data;
 201         if (pdata == NULL)
 202                 return -ENODEV;
 203
 204         /* this loop vanishes when we get i2c_device_id */
 205         for (i = 0; i < ARRAY_SIZE(pca953x_descs); i++)
 206                 if (!strcmp(pca953x_descs[i].name, client->name)) {
 207                         id = pca953x_descs + i;
 208                         break;
 209                 }
 210         if (!id)
 211                 return -ENODEV;
 212
 213         chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
 214         if (chip == NULL)
 215                 return -ENOMEM;
 216
 217         chip->client = client;
 218
 219         chip->gpio_start = pdata->gpio_base;
 220
 221         /* initialize cached registers from their original values.
 222          * we can't share this chip with another i2c master.
 223          */
 224         pca953x_setup_gpio(chip, id->driver_data);
 225
 226         ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
 227         if (ret)
 228                 goto out_failed;
 229
 230         ret = pca953x_read_reg(chip, PCA953X_DIRECTION, &chip->reg_direction);
 231         if (ret)
 232                 goto out_failed;
 233
 234         /* set platform specific polarity inversion */
 235         ret = pca953x_write_reg(chip, PCA953X_INVERT, pdata->invert);
 236         if (ret)
 237                 goto out_failed;
 238
 239
 240         ret = gpiochip_add(&chip->gpio_chip);
 241         if (ret)
 242                 goto out_failed;
 243
 244         if (pdata->setup) {
 245                 ret = pdata->setup(client, chip->gpio_chip.base,
 246                                 chip->gpio_chip.ngpio, pdata->context);
 247                 if (ret < 0)
 248                         dev_warn(&client->dev, "setup failed, %d\n", ret);
 249         }
 250
 251         i2c_set_clientdata(client, chip);
 252         return 0;
 253
 254 out_failed:
 255         kfree(chip);
 256         return ret;
 257 }
 258
 259 static int pca953x_remove(struct i2c_client *client)
 260 {
 261         struct pca953x_platform_data *pdata = client->dev.platform_data;
 262         struct pca953x_chip *chip = i2c_get_clientdata(client);
 263         int ret = 0;
 264
 265         if (pdata->teardown) {
 266                 ret = pdata->teardown(client, chip->gpio_chip.base,
 267                                 chip->gpio_chip.ngpio, pdata->context);
 268                 if (ret < 0) {
 269                         dev_err(&client->dev, "%s failed, %d\n",
 270                                         "teardown", ret);
 271                         return ret;
 272                 }
 273         }
 274
 275         ret = gpiochip_remove(&chip->gpio_chip);
 276         if (ret) {
 277                 dev_err(&client->dev, "%s failed, %d\n",
 278                                 "gpiochip_remove()", ret);
 279                 return ret;
 280         }
 281
 282         kfree(chip);
 283         return 0;
 284 }
 285
 286 static struct i2c_driver pca953x_driver = {
 287         .driver = {
 288                 .name   = "pca953x",
 289         },
 290         .probe          = pca953x_probe,
 291         .remove         = pca953x_remove,
 292 };
 293
 294 static int __init pca953x_init(void)
 295 {
 296         return i2c_add_driver(&pca953x_driver);
 297 }
 298 module_init(pca953x_init);
 299
 300 static void __exit pca953x_exit(void)
 301 {
 302         i2c_del_driver(&pca953x_driver);
 303 }
 304 module_exit(pca953x_exit);
 305
 306 MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
 307 MODULE_DESCRIPTION("GPIO expander driver for PCA953x");
 308 MODULE_LICENSE("GPL");