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 #include <linux/regulator/consumer.h> 22 23 #include <linux/iio/iio.h> 24 #include <linux/iio/sysfs.h> 25 26 #include <linux/iio/dac/mcp4725.h> 27 28 #define MCP4725_DRV_NAME "mcp4725" 29 30 struct mcp4725_data { 31 struct i2c_client *client; 32 u16 dac_value; 33 bool powerdown; 34 unsigned powerdown_mode; 35 struct regulator *vdd_reg; 36 }; 37 38 static int mcp4725_suspend(struct device *dev) 39 { 40 struct mcp4725_data *data = iio_priv(i2c_get_clientdata( 41 to_i2c_client(dev))); 42 u8 outbuf[2]; 43 44 outbuf[0] = (data->powerdown_mode + 1) << 4; 45 outbuf[1] = 0; 46 data->powerdown = true; 47 48 return i2c_master_send(data->client, outbuf, 2); 49 } 50 51 static int mcp4725_resume(struct device *dev) 52 { 53 struct mcp4725_data *data = iio_priv(i2c_get_clientdata( 54 to_i2c_client(dev))); 55 u8 outbuf[2]; 56 57 /* restore previous DAC value */ 58 outbuf[0] = (data->dac_value >> 8) & 0xf; 59 outbuf[1] = data->dac_value & 0xff; 60 data->powerdown = false; 61 62 return i2c_master_send(data->client, outbuf, 2); 63 } 64 65 #ifdef CONFIG_PM_SLEEP 66 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume); 67 #define MCP4725_PM_OPS (&mcp4725_pm_ops) 68 #else 69 #define MCP4725_PM_OPS NULL 70 #endif 71 72 static ssize_t mcp4725_store_eeprom(struct device *dev, 73 struct device_attribute *attr, const char *buf, size_t len) 74 { 75 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 76 struct mcp4725_data *data = iio_priv(indio_dev); 77 int tries = 20; 78 u8 inoutbuf[3]; 79 bool state; 80 int ret; 81 82 ret = strtobool(buf, &state); 83 if (ret < 0) 84 return ret; 85 86 if (!state) 87 return 0; 88 89 inoutbuf[0] = 0x60; /* write EEPROM */ 90 inoutbuf[1] = data->dac_value >> 4; 91 inoutbuf[2] = (data->dac_value & 0xf) << 4; 92 93 ret = i2c_master_send(data->client, inoutbuf, 3); 94 if (ret < 0) 95 return ret; 96 else if (ret != 3) 97 return -EIO; 98 99 /* wait for write complete, takes up to 50ms */ 100 while (tries--) { 101 msleep(20); 102 ret = i2c_master_recv(data->client, inoutbuf, 3); 103 if (ret < 0) 104 return ret; 105 else if (ret != 3) 106 return -EIO; 107 108 if (inoutbuf[0] & 0x80) 109 break; 110 } 111 112 if (tries < 0) { 113 dev_err(&data->client->dev, 114 "mcp4725_store_eeprom() failed, incomplete\n"); 115 return -EIO; 116 } 117 118 return len; 119 } 120 121 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0); 122 123 static struct attribute *mcp4725_attributes[] = { 124 &iio_dev_attr_store_eeprom.dev_attr.attr, 125 NULL, 126 }; 127 128 static const struct attribute_group mcp4725_attribute_group = { 129 .attrs = mcp4725_attributes, 130 }; 131 132 static const char * const mcp4725_powerdown_modes[] = { 133 "1kohm_to_gnd", 134 "100kohm_to_gnd", 135 "500kohm_to_gnd" 136 }; 137 138 static const char * const mcp4726_powerdown_modes[] = { 139 "1kohm_to_gnd", 140 "125kohm_to_gnd", 141 "640kohm_to_gnd" 142 }; 143 144 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev, 145 const struct iio_chan_spec *chan) 146 { 147 struct mcp4725_data *data = iio_priv(indio_dev); 148 149 return data->powerdown_mode; 150 } 151 152 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev, 153 const struct iio_chan_spec *chan, unsigned mode) 154 { 155 struct mcp4725_data *data = iio_priv(indio_dev); 156 157 data->powerdown_mode = mode; 158 159 return 0; 160 } 161 162 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev, 163 uintptr_t private, const struct iio_chan_spec *chan, char *buf) 164 { 165 struct mcp4725_data *data = iio_priv(indio_dev); 166 167 return sprintf(buf, "%d\n", data->powerdown); 168 } 169 170 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev, 171 uintptr_t private, const struct iio_chan_spec *chan, 172 const char *buf, size_t len) 173 { 174 struct mcp4725_data *data = iio_priv(indio_dev); 175 bool state; 176 int ret; 177 178 ret = strtobool(buf, &state); 179 if (ret) 180 return ret; 181 182 if (state) 183 ret = mcp4725_suspend(&data->client->dev); 184 else 185 ret = mcp4725_resume(&data->client->dev); 186 if (ret < 0) 187 return ret; 188 189 return len; 190 } 191 192 enum { 193 MCP4725, 194 MCP4726, 195 }; 196 197 static const struct iio_enum mcp472x_powerdown_mode_enum[] = { 198 [MCP4725] = { 199 .items = mcp4725_powerdown_modes, 200 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes), 201 .get = mcp4725_get_powerdown_mode, 202 .set = mcp4725_set_powerdown_mode, 203 }, 204 [MCP4726] = { 205 .items = mcp4726_powerdown_modes, 206 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes), 207 .get = mcp4725_get_powerdown_mode, 208 .set = mcp4725_set_powerdown_mode, 209 }, 210 }; 211 212 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = { 213 { 214 .name = "powerdown", 215 .read = mcp4725_read_powerdown, 216 .write = mcp4725_write_powerdown, 217 .shared = IIO_SEPARATE, 218 }, 219 IIO_ENUM("powerdown_mode", IIO_SEPARATE, 220 &mcp472x_powerdown_mode_enum[MCP4725]), 221 IIO_ENUM_AVAILABLE("powerdown_mode", 222 &mcp472x_powerdown_mode_enum[MCP4725]), 223 { }, 224 }; 225 226 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = { 227 { 228 .name = "powerdown", 229 .read = mcp4725_read_powerdown, 230 .write = mcp4725_write_powerdown, 231 .shared = IIO_SEPARATE, 232 }, 233 IIO_ENUM("powerdown_mode", IIO_SEPARATE, 234 &mcp472x_powerdown_mode_enum[MCP4726]), 235 IIO_ENUM_AVAILABLE("powerdown_mode", 236 &mcp472x_powerdown_mode_enum[MCP4726]), 237 { }, 238 }; 239 240 static const struct iio_chan_spec mcp472x_channel[] = { 241 [MCP4725] = { 242 .type = IIO_VOLTAGE, 243 .indexed = 1, 244 .output = 1, 245 .channel = 0, 246 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 247 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 248 .ext_info = mcp4725_ext_info, 249 }, 250 [MCP4726] = { 251 .type = IIO_VOLTAGE, 252 .indexed = 1, 253 .output = 1, 254 .channel = 0, 255 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 256 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 257 .ext_info = mcp4726_ext_info, 258 }, 259 }; 260 261 static int mcp4725_set_value(struct iio_dev *indio_dev, int val) 262 { 263 struct mcp4725_data *data = iio_priv(indio_dev); 264 u8 outbuf[2]; 265 int ret; 266 267 if (val >= (1 << 12) || val < 0) 268 return -EINVAL; 269 270 outbuf[0] = (val >> 8) & 0xf; 271 outbuf[1] = val & 0xff; 272 273 ret = i2c_master_send(data->client, outbuf, 2); 274 if (ret < 0) 275 return ret; 276 else if (ret != 2) 277 return -EIO; 278 else 279 return 0; 280 } 281 282 static int mcp4725_read_raw(struct iio_dev *indio_dev, 283 struct iio_chan_spec const *chan, 284 int *val, int *val2, long mask) 285 { 286 struct mcp4725_data *data = iio_priv(indio_dev); 287 int ret; 288 289 switch (mask) { 290 case IIO_CHAN_INFO_RAW: 291 *val = data->dac_value; 292 return IIO_VAL_INT; 293 case IIO_CHAN_INFO_SCALE: 294 ret = regulator_get_voltage(data->vdd_reg); 295 if (ret < 0) 296 return ret; 297 298 *val = ret / 1000; 299 *val2 = 12; 300 return IIO_VAL_FRACTIONAL_LOG2; 301 } 302 return -EINVAL; 303 } 304 305 static int mcp4725_write_raw(struct iio_dev *indio_dev, 306 struct iio_chan_spec const *chan, 307 int val, int val2, long mask) 308 { 309 struct mcp4725_data *data = iio_priv(indio_dev); 310 int ret; 311 312 switch (mask) { 313 case IIO_CHAN_INFO_RAW: 314 ret = mcp4725_set_value(indio_dev, val); 315 data->dac_value = val; 316 break; 317 default: 318 ret = -EINVAL; 319 break; 320 } 321 322 return ret; 323 } 324 325 static const struct iio_info mcp4725_info = { 326 .read_raw = mcp4725_read_raw, 327 .write_raw = mcp4725_write_raw, 328 .attrs = &mcp4725_attribute_group, 329 .driver_module = THIS_MODULE, 330 }; 331 332 static int mcp4725_probe(struct i2c_client *client, 333 const struct i2c_device_id *id) 334 { 335 struct mcp4725_data *data; 336 struct iio_dev *indio_dev; 337 struct mcp4725_platform_data *pdata = dev_get_platdata(&client->dev); 338 u8 inbuf[3]; 339 u8 pd; 340 int err; 341 342 if (!pdata) { 343 dev_err(&client->dev, "invalid platform data"); 344 return -EINVAL; 345 } 346 347 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 348 if (indio_dev == NULL) 349 return -ENOMEM; 350 data = iio_priv(indio_dev); 351 i2c_set_clientdata(client, indio_dev); 352 data->client = client; 353 354 data->vdd_reg = devm_regulator_get(&client->dev, "vdd"); 355 if (IS_ERR(data->vdd_reg)) 356 return PTR_ERR(data->vdd_reg); 357 358 err = regulator_enable(data->vdd_reg); 359 if (err) 360 return err; 361 362 indio_dev->dev.parent = &client->dev; 363 indio_dev->name = id->name; 364 indio_dev->info = &mcp4725_info; 365 indio_dev->channels = &mcp472x_channel[id->driver_data]; 366 indio_dev->num_channels = 1; 367 indio_dev->modes = INDIO_DIRECT_MODE; 368 369 /* read current DAC value */ 370 err = i2c_master_recv(client, inbuf, 3); 371 if (err < 0) { 372 dev_err(&client->dev, "failed to read DAC value"); 373 goto err_disable_vdd_reg; 374 } 375 pd = (inbuf[0] >> 1) & 0x3; 376 data->powerdown = pd > 0 ? true : false; 377 data->powerdown_mode = pd ? pd - 1 : 2; /* largest register to gnd */ 378 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); 379 380 err = iio_device_register(indio_dev); 381 if (err) 382 goto err_disable_vdd_reg; 383 384 return 0; 385 386 387 err_disable_vdd_reg: 388 regulator_disable(data->vdd_reg); 389 390 return err; 391 } 392 393 static int mcp4725_remove(struct i2c_client *client) 394 { 395 struct iio_dev *indio_dev = i2c_get_clientdata(client); 396 struct mcp4725_data *data = iio_priv(indio_dev); 397 398 iio_device_unregister(indio_dev); 399 400 regulator_disable(data->vdd_reg); 401 402 return 0; 403 } 404 405 static const struct i2c_device_id mcp4725_id[] = { 406 { "mcp4725", MCP4725 }, 407 { "mcp4726", MCP4726 }, 408 { } 409 }; 410 MODULE_DEVICE_TABLE(i2c, mcp4725_id); 411 412 static struct i2c_driver mcp4725_driver = { 413 .driver = { 414 .name = MCP4725_DRV_NAME, 415 .pm = MCP4725_PM_OPS, 416 }, 417 .probe = mcp4725_probe, 418 .remove = mcp4725_remove, 419 .id_table = mcp4725_id, 420 }; 421 module_i2c_driver(mcp4725_driver); 422 423 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); 424 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC"); 425 MODULE_LICENSE("GPL"); 426