1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * iio/dac/max5821.c 4 * Copyright (C) 2014 Philippe Reynes 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/module.h> 9 #include <linux/i2c.h> 10 #include <linux/iio/iio.h> 11 #include <linux/regulator/consumer.h> 12 13 #define MAX5821_MAX_DAC_CHANNELS 2 14 15 /* command bytes */ 16 #define MAX5821_LOAD_DAC_A_IN_REG_B 0x00 17 #define MAX5821_LOAD_DAC_B_IN_REG_A 0x10 18 #define MAX5821_EXTENDED_COMMAND_MODE 0xf0 19 #define MAX5821_READ_DAC_A_COMMAND 0xf1 20 #define MAX5821_READ_DAC_B_COMMAND 0xf2 21 22 #define MAX5821_EXTENDED_POWER_UP 0x00 23 #define MAX5821_EXTENDED_POWER_DOWN_MODE0 0x01 24 #define MAX5821_EXTENDED_POWER_DOWN_MODE1 0x02 25 #define MAX5821_EXTENDED_POWER_DOWN_MODE2 0x03 26 #define MAX5821_EXTENDED_DAC_A 0x04 27 #define MAX5821_EXTENDED_DAC_B 0x08 28 29 enum max5821_device_ids { 30 ID_MAX5821, 31 }; 32 33 struct max5821_data { 34 struct i2c_client *client; 35 unsigned short vref_mv; 36 bool powerdown[MAX5821_MAX_DAC_CHANNELS]; 37 u8 powerdown_mode[MAX5821_MAX_DAC_CHANNELS]; 38 struct mutex lock; 39 }; 40 41 static const char * const max5821_powerdown_modes[] = { 42 "three_state", 43 "1kohm_to_gnd", 44 "100kohm_to_gnd", 45 }; 46 47 enum { 48 MAX5821_THREE_STATE, 49 MAX5821_1KOHM_TO_GND, 50 MAX5821_100KOHM_TO_GND 51 }; 52 53 static int max5821_get_powerdown_mode(struct iio_dev *indio_dev, 54 const struct iio_chan_spec *chan) 55 { 56 struct max5821_data *st = iio_priv(indio_dev); 57 58 return st->powerdown_mode[chan->channel]; 59 } 60 61 static int max5821_set_powerdown_mode(struct iio_dev *indio_dev, 62 const struct iio_chan_spec *chan, 63 unsigned int mode) 64 { 65 struct max5821_data *st = iio_priv(indio_dev); 66 67 st->powerdown_mode[chan->channel] = mode; 68 69 return 0; 70 } 71 72 static const struct iio_enum max5821_powerdown_mode_enum = { 73 .items = max5821_powerdown_modes, 74 .num_items = ARRAY_SIZE(max5821_powerdown_modes), 75 .get = max5821_get_powerdown_mode, 76 .set = max5821_set_powerdown_mode, 77 }; 78 79 static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev, 80 uintptr_t private, 81 const struct iio_chan_spec *chan, 82 char *buf) 83 { 84 struct max5821_data *st = iio_priv(indio_dev); 85 86 return sysfs_emit(buf, "%d\n", st->powerdown[chan->channel]); 87 } 88 89 static int max5821_sync_powerdown_mode(struct max5821_data *data, 90 const struct iio_chan_spec *chan) 91 { 92 u8 outbuf[2]; 93 94 outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE; 95 96 if (chan->channel == 0) 97 outbuf[1] = MAX5821_EXTENDED_DAC_A; 98 else 99 outbuf[1] = MAX5821_EXTENDED_DAC_B; 100 101 if (data->powerdown[chan->channel]) 102 outbuf[1] |= data->powerdown_mode[chan->channel] + 1; 103 else 104 outbuf[1] |= MAX5821_EXTENDED_POWER_UP; 105 106 return i2c_master_send(data->client, outbuf, 2); 107 } 108 109 static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev, 110 uintptr_t private, 111 const struct iio_chan_spec *chan, 112 const char *buf, size_t len) 113 { 114 struct max5821_data *data = iio_priv(indio_dev); 115 bool powerdown; 116 int ret; 117 118 ret = kstrtobool(buf, &powerdown); 119 if (ret) 120 return ret; 121 122 data->powerdown[chan->channel] = powerdown; 123 124 ret = max5821_sync_powerdown_mode(data, chan); 125 if (ret < 0) 126 return ret; 127 128 return len; 129 } 130 131 static const struct iio_chan_spec_ext_info max5821_ext_info[] = { 132 { 133 .name = "powerdown", 134 .read = max5821_read_dac_powerdown, 135 .write = max5821_write_dac_powerdown, 136 .shared = IIO_SEPARATE, 137 }, 138 IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum), 139 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &max5821_powerdown_mode_enum), 140 { }, 141 }; 142 143 #define MAX5821_CHANNEL(chan) { \ 144 .type = IIO_VOLTAGE, \ 145 .indexed = 1, \ 146 .output = 1, \ 147 .channel = (chan), \ 148 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 149 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \ 150 .ext_info = max5821_ext_info, \ 151 } 152 153 static const struct iio_chan_spec max5821_channels[] = { 154 MAX5821_CHANNEL(0), 155 MAX5821_CHANNEL(1) 156 }; 157 158 static const u8 max5821_read_dac_command[] = { 159 MAX5821_READ_DAC_A_COMMAND, 160 MAX5821_READ_DAC_B_COMMAND 161 }; 162 163 static const u8 max5821_load_dac_command[] = { 164 MAX5821_LOAD_DAC_A_IN_REG_B, 165 MAX5821_LOAD_DAC_B_IN_REG_A 166 }; 167 168 static int max5821_get_value(struct iio_dev *indio_dev, 169 int *val, int channel) 170 { 171 struct max5821_data *data = iio_priv(indio_dev); 172 struct i2c_client *client = data->client; 173 u8 outbuf[1]; 174 u8 inbuf[2]; 175 int ret; 176 177 if ((channel != 0) && (channel != 1)) 178 return -EINVAL; 179 180 outbuf[0] = max5821_read_dac_command[channel]; 181 182 mutex_lock(&data->lock); 183 184 ret = i2c_master_send(client, outbuf, 1); 185 if (ret < 0) { 186 mutex_unlock(&data->lock); 187 return ret; 188 } else if (ret != 1) { 189 mutex_unlock(&data->lock); 190 return -EIO; 191 } 192 193 ret = i2c_master_recv(client, inbuf, 2); 194 if (ret < 0) { 195 mutex_unlock(&data->lock); 196 return ret; 197 } else if (ret != 2) { 198 mutex_unlock(&data->lock); 199 return -EIO; 200 } 201 202 mutex_unlock(&data->lock); 203 204 *val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2); 205 206 return IIO_VAL_INT; 207 } 208 209 static int max5821_set_value(struct iio_dev *indio_dev, 210 int val, int channel) 211 { 212 struct max5821_data *data = iio_priv(indio_dev); 213 struct i2c_client *client = data->client; 214 u8 outbuf[2]; 215 int ret; 216 217 if ((val < 0) || (val > 1023)) 218 return -EINVAL; 219 220 if ((channel != 0) && (channel != 1)) 221 return -EINVAL; 222 223 outbuf[0] = max5821_load_dac_command[channel]; 224 outbuf[0] |= val >> 6; 225 outbuf[1] = (val & 0x3f) << 2; 226 227 ret = i2c_master_send(client, outbuf, 2); 228 if (ret < 0) 229 return ret; 230 else if (ret != 2) 231 return -EIO; 232 else 233 return 0; 234 } 235 236 static int max5821_read_raw(struct iio_dev *indio_dev, 237 struct iio_chan_spec const *chan, 238 int *val, int *val2, long mask) 239 { 240 struct max5821_data *data = iio_priv(indio_dev); 241 242 switch (mask) { 243 case IIO_CHAN_INFO_RAW: 244 return max5821_get_value(indio_dev, val, chan->channel); 245 case IIO_CHAN_INFO_SCALE: 246 *val = data->vref_mv; 247 *val2 = 10; 248 return IIO_VAL_FRACTIONAL_LOG2; 249 default: 250 return -EINVAL; 251 } 252 } 253 254 static int max5821_write_raw(struct iio_dev *indio_dev, 255 struct iio_chan_spec const *chan, 256 int val, int val2, long mask) 257 { 258 if (val2 != 0) 259 return -EINVAL; 260 261 switch (mask) { 262 case IIO_CHAN_INFO_RAW: 263 return max5821_set_value(indio_dev, val, chan->channel); 264 default: 265 return -EINVAL; 266 } 267 } 268 269 static int max5821_suspend(struct device *dev) 270 { 271 u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE, 272 MAX5821_EXTENDED_DAC_A | 273 MAX5821_EXTENDED_DAC_B | 274 MAX5821_EXTENDED_POWER_DOWN_MODE2 }; 275 276 return i2c_master_send(to_i2c_client(dev), outbuf, 2); 277 } 278 279 static int max5821_resume(struct device *dev) 280 { 281 u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE, 282 MAX5821_EXTENDED_DAC_A | 283 MAX5821_EXTENDED_DAC_B | 284 MAX5821_EXTENDED_POWER_UP }; 285 286 return i2c_master_send(to_i2c_client(dev), outbuf, 2); 287 } 288 289 static DEFINE_SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend, 290 max5821_resume); 291 292 static const struct iio_info max5821_info = { 293 .read_raw = max5821_read_raw, 294 .write_raw = max5821_write_raw, 295 }; 296 297 static int max5821_probe(struct i2c_client *client) 298 { 299 const struct i2c_device_id *id = i2c_client_get_device_id(client); 300 struct max5821_data *data; 301 struct iio_dev *indio_dev; 302 u32 tmp; 303 int ret; 304 305 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 306 if (!indio_dev) 307 return -ENOMEM; 308 data = iio_priv(indio_dev); 309 data->client = client; 310 mutex_init(&data->lock); 311 312 /* max5821 start in powerdown mode 100Kohm to ground */ 313 for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) { 314 data->powerdown[tmp] = true; 315 data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND; 316 } 317 318 ret = devm_regulator_get_enable_read_voltage(&client->dev, "vref"); 319 if (ret) 320 return dev_err_probe(&client->dev, ret, 321 "Failed to get vref regulator voltage\n"); 322 323 data->vref_mv = ret / 1000; 324 325 indio_dev->name = id->name; 326 indio_dev->num_channels = ARRAY_SIZE(max5821_channels); 327 indio_dev->channels = max5821_channels; 328 indio_dev->modes = INDIO_DIRECT_MODE; 329 indio_dev->info = &max5821_info; 330 331 return devm_iio_device_register(&client->dev, indio_dev); 332 } 333 334 static const struct i2c_device_id max5821_id[] = { 335 { "max5821", ID_MAX5821 }, 336 { } 337 }; 338 MODULE_DEVICE_TABLE(i2c, max5821_id); 339 340 static const struct of_device_id max5821_of_match[] = { 341 { .compatible = "maxim,max5821" }, 342 { } 343 }; 344 MODULE_DEVICE_TABLE(of, max5821_of_match); 345 346 static struct i2c_driver max5821_driver = { 347 .driver = { 348 .name = "max5821", 349 .of_match_table = max5821_of_match, 350 .pm = pm_sleep_ptr(&max5821_pm_ops), 351 }, 352 .probe = max5821_probe, 353 .id_table = max5821_id, 354 }; 355 module_i2c_driver(max5821_driver); 356 357 MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>"); 358 MODULE_DESCRIPTION("MAX5821 DAC"); 359 MODULE_LICENSE("GPL v2"); 360