drivers/iio/dac/mcp4725.c

   1 /*
   2  * mcp4725.c - Support for Microchip MCP4725/6
   3  *
   4  * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
   5  *
   6  * Based on max517 by Roland Stigge <stigge@antcom.de>
   7  *
   8  * This file is subject to the terms and conditions of version 2 of
   9  * the GNU General Public License.  See the file COPYING in the main
  10  * directory of this archive for more details.
  11  *
  12  * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
  13  * (7-bit I2C slave address 0x60, the three LSBs can be configured in
  14  * hardware)
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/i2c.h>
  19 #include <linux/err.h>
  20 #include <linux/delay.h>
  21
  22 #include <linux/iio/iio.h>
  23 #include <linux/iio/sysfs.h>
  24
  25 #include <linux/iio/dac/mcp4725.h>
  26
  27 #define MCP4725_DRV_NAME "mcp4725"
  28
  29 struct mcp4725_data {
  30         struct i2c_client *client;
  31         u16 vref_mv;
  32         u16 dac_value;
  33         bool powerdown;
  34         unsigned powerdown_mode;
  35 };
  36
  37 static int mcp4725_suspend(struct device *dev)
  38 {
  39         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  40                 to_i2c_client(dev)));
  41         u8 outbuf[2];
  42
  43         outbuf[0] = (data->powerdown_mode + 1) << 4;
  44         outbuf[1] = 0;
  45         data->powerdown = true;
  46
  47         return i2c_master_send(data->client, outbuf, 2);
  48 }
  49
  50 static int mcp4725_resume(struct device *dev)
  51 {
  52         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  53                 to_i2c_client(dev)));
  54         u8 outbuf[2];
  55
  56         /* restore previous DAC value */
  57         outbuf[0] = (data->dac_value >> 8) & 0xf;
  58         outbuf[1] = data->dac_value & 0xff;
  59         data->powerdown = false;
  60
  61         return i2c_master_send(data->client, outbuf, 2);
  62 }
  63
  64 #ifdef CONFIG_PM_SLEEP
  65 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
  66 #define MCP4725_PM_OPS (&mcp4725_pm_ops)
  67 #else
  68 #define MCP4725_PM_OPS NULL
  69 #endif
  70
  71 static ssize_t mcp4725_store_eeprom(struct device *dev,
  72         struct device_attribute *attr, const char *buf, size_t len)
  73 {
  74         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  75         struct mcp4725_data *data = iio_priv(indio_dev);
  76         int tries = 20;
  77         u8 inoutbuf[3];
  78         bool state;
  79         int ret;
  80
  81         ret = strtobool(buf, &state);
  82         if (ret < 0)
  83                 return ret;
  84
  85         if (!state)
  86                 return 0;
  87
  88         inoutbuf[0] = 0x60; /* write EEPROM */
  89         inoutbuf[1] = data->dac_value >> 4;
  90         inoutbuf[2] = (data->dac_value & 0xf) << 4;
  91
  92         ret = i2c_master_send(data->client, inoutbuf, 3);
  93         if (ret < 0)
  94                 return ret;
  95         else if (ret != 3)
  96                 return -EIO;
  97
  98         /* wait for write complete, takes up to 50ms */
  99         while (tries--) {
 100                 msleep(20);
 101                 ret = i2c_master_recv(data->client, inoutbuf, 3);
 102                 if (ret < 0)
 103                         return ret;
 104                 else if (ret != 3)
 105                         return -EIO;
 106
 107                 if (inoutbuf[0] & 0x80)
 108                         break;
 109         }
 110
 111         if (tries < 0) {
 112                 dev_err(&data->client->dev,
 113                         "mcp4725_store_eeprom() failed, incomplete\n");
 114                 return -EIO;
 115         }
 116
 117         return len;
 118 }
 119
 120 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
 121
 122 static struct attribute *mcp4725_attributes[] = {
 123         &iio_dev_attr_store_eeprom.dev_attr.attr,
 124         NULL,
 125 };
 126
 127 static const struct attribute_group mcp4725_attribute_group = {
 128         .attrs = mcp4725_attributes,
 129 };
 130
 131 static const char * const mcp4725_powerdown_modes[] = {
 132         "1kohm_to_gnd",
 133         "100kohm_to_gnd",
 134         "500kohm_to_gnd"
 135 };
 136
 137 static const char * const mcp4726_powerdown_modes[] = {
 138         "1kohm_to_gnd",
 139         "125kohm_to_gnd",
 140         "640kohm_to_gnd"
 141 };
 142
 143 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
 144         const struct iio_chan_spec *chan)
 145 {
 146         struct mcp4725_data *data = iio_priv(indio_dev);
 147
 148         return data->powerdown_mode;
 149 }
 150
 151 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
 152         const struct iio_chan_spec *chan, unsigned mode)
 153 {
 154         struct mcp4725_data *data = iio_priv(indio_dev);
 155
 156         data->powerdown_mode = mode;
 157
 158         return 0;
 159 }
 160
 161 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
 162         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 163 {
 164         struct mcp4725_data *data = iio_priv(indio_dev);
 165
 166         return sprintf(buf, "%d\n", data->powerdown);
 167 }
 168
 169 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
 170          uintptr_t private, const struct iio_chan_spec *chan,
 171          const char *buf, size_t len)
 172 {
 173         struct mcp4725_data *data = iio_priv(indio_dev);
 174         bool state;
 175         int ret;
 176
 177         ret = strtobool(buf, &state);
 178         if (ret)
 179                 return ret;
 180
 181         if (state)
 182                 ret = mcp4725_suspend(&data->client->dev);
 183         else
 184                 ret = mcp4725_resume(&data->client->dev);
 185         if (ret < 0)
 186                 return ret;
 187
 188         return len;
 189 }
 190
 191 enum {
 192         MCP4725,
 193         MCP4726,
 194 };
 195
 196 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
 197         [MCP4725] = {
 198                 .items = mcp4725_powerdown_modes,
 199                 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
 200                 .get = mcp4725_get_powerdown_mode,
 201                 .set = mcp4725_set_powerdown_mode,
 202         },
 203         [MCP4726] = {
 204                 .items = mcp4726_powerdown_modes,
 205                 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
 206                 .get = mcp4725_get_powerdown_mode,
 207                 .set = mcp4725_set_powerdown_mode,
 208         },
 209 };
 210
 211 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
 212         {
 213                 .name = "powerdown",
 214                 .read = mcp4725_read_powerdown,
 215                 .write = mcp4725_write_powerdown,
 216                 .shared = IIO_SEPARATE,
 217         },
 218         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 219                         &mcp472x_powerdown_mode_enum[MCP4725]),
 220         IIO_ENUM_AVAILABLE("powerdown_mode",
 221                         &mcp472x_powerdown_mode_enum[MCP4725]),
 222         { },
 223 };
 224
 225 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
 226         {
 227                 .name = "powerdown",
 228                 .read = mcp4725_read_powerdown,
 229                 .write = mcp4725_write_powerdown,
 230                 .shared = IIO_SEPARATE,
 231         },
 232         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 233                         &mcp472x_powerdown_mode_enum[MCP4726]),
 234         IIO_ENUM_AVAILABLE("powerdown_mode",
 235                         &mcp472x_powerdown_mode_enum[MCP4726]),
 236         { },
 237 };
 238
 239 static const struct iio_chan_spec mcp472x_channel[] = {
 240         [MCP4725] = {
 241                 .type           = IIO_VOLTAGE,
 242                 .indexed        = 1,
 243                 .output         = 1,
 244                 .channel        = 0,
 245                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 246                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 247                 .ext_info       = mcp4725_ext_info,
 248         },
 249         [MCP4726] = {
 250                 .type           = IIO_VOLTAGE,
 251                 .indexed        = 1,
 252                 .output         = 1,
 253                 .channel        = 0,
 254                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 255                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 256                 .ext_info       = mcp4726_ext_info,
 257         },
 258 };
 259
 260 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
 261 {
 262         struct mcp4725_data *data = iio_priv(indio_dev);
 263         u8 outbuf[2];
 264         int ret;
 265
 266         if (val >= (1 << 12) || val < 0)
 267                 return -EINVAL;
 268
 269         outbuf[0] = (val >> 8) & 0xf;
 270         outbuf[1] = val & 0xff;
 271
 272         ret = i2c_master_send(data->client, outbuf, 2);
 273         if (ret < 0)
 274                 return ret;
 275         else if (ret != 2)
 276                 return -EIO;
 277         else
 278                 return 0;
 279 }
 280
 281 static int mcp4725_read_raw(struct iio_dev *indio_dev,
 282                            struct iio_chan_spec const *chan,
 283                            int *val, int *val2, long mask)
 284 {
 285         struct mcp4725_data *data = iio_priv(indio_dev);
 286
 287         switch (mask) {
 288         case IIO_CHAN_INFO_RAW:
 289                 *val = data->dac_value;
 290                 return IIO_VAL_INT;
 291         case IIO_CHAN_INFO_SCALE:
 292                 *val = data->vref_mv;
 293                 *val2 = 12;
 294                 return IIO_VAL_FRACTIONAL_LOG2;
 295         }
 296         return -EINVAL;
 297 }
 298
 299 static int mcp4725_write_raw(struct iio_dev *indio_dev,
 300                                struct iio_chan_spec const *chan,
 301                                int val, int val2, long mask)
 302 {
 303         struct mcp4725_data *data = iio_priv(indio_dev);
 304         int ret;
 305
 306         switch (mask) {
 307         case IIO_CHAN_INFO_RAW:
 308                 ret = mcp4725_set_value(indio_dev, val);
 309                 data->dac_value = val;
 310                 break;
 311         default:
 312                 ret = -EINVAL;
 313                 break;
 314         }
 315
 316         return ret;
 317 }
 318
 319 static const struct iio_info mcp4725_info = {
 320         .read_raw = mcp4725_read_raw,
 321         .write_raw = mcp4725_write_raw,
 322         .attrs = &mcp4725_attribute_group,
 323         .driver_module = THIS_MODULE,
 324 };
 325
 326 static int mcp4725_probe(struct i2c_client *client,
 327                          const struct i2c_device_id *id)
 328 {
 329         struct mcp4725_data *data;
 330         struct iio_dev *indio_dev;
 331         struct mcp4725_platform_data *platform_data = client->dev.platform_data;
 332         u8 inbuf[3];
 333         u8 pd;
 334         int err;
 335
 336         if (!platform_data || !platform_data->vref_mv) {
 337                 dev_err(&client->dev, "invalid platform data");
 338                 return -EINVAL;
 339         }
 340
 341         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 342         if (indio_dev == NULL)
 343                 return -ENOMEM;
 344         data = iio_priv(indio_dev);
 345         i2c_set_clientdata(client, indio_dev);
 346         data->client = client;
 347
 348         indio_dev->dev.parent = &client->dev;
 349         indio_dev->name = id->name;
 350         indio_dev->info = &mcp4725_info;
 351         indio_dev->channels = &mcp472x_channel[id->driver_data];
 352         indio_dev->num_channels = 1;
 353         indio_dev->modes = INDIO_DIRECT_MODE;
 354
 355         data->vref_mv = platform_data->vref_mv;
 356
 357         /* read current DAC value */
 358         err = i2c_master_recv(client, inbuf, 3);
 359         if (err < 0) {
 360                 dev_err(&client->dev, "failed to read DAC value");
 361                 return err;
 362         }
 363         pd = (inbuf[0] >> 1) & 0x3;
 364         data->powerdown = pd > 0 ? true : false;
 365         data->powerdown_mode = pd ? pd - 1 : 2; /* largest register to gnd */
 366         data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
 367
 368         return iio_device_register(indio_dev);
 369 }
 370
 371 static int mcp4725_remove(struct i2c_client *client)
 372 {
 373         iio_device_unregister(i2c_get_clientdata(client));
 374         return 0;
 375 }
 376
 377 static const struct i2c_device_id mcp4725_id[] = {
 378         { "mcp4725", MCP4725 },
 379         { "mcp4726", MCP4726 },
 380         { }
 381 };
 382 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
 383
 384 static struct i2c_driver mcp4725_driver = {
 385         .driver = {
 386                 .name   = MCP4725_DRV_NAME,
 387                 .pm     = MCP4725_PM_OPS,
 388         },
 389         .probe          = mcp4725_probe,
 390         .remove         = mcp4725_remove,
 391         .id_table       = mcp4725_id,
 392 };
 393 module_i2c_driver(mcp4725_driver);
 394
 395 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 396 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
 397 MODULE_LICENSE("GPL");