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"); 398