1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * IIO multiplexer driver 4 * 5 * Copyright (C) 2017 Axentia Technologies AB 6 * 7 * Author: Peter Rosin <peda@axentia.se> 8 */ 9 10 #include <linux/err.h> 11 #include <linux/iio/consumer.h> 12 #include <linux/iio/iio.h> 13 #include <linux/mod_devicetable.h> 14 #include <linux/module.h> 15 #include <linux/mutex.h> 16 #include <linux/mux/consumer.h> 17 #include <linux/platform_device.h> 18 #include <linux/property.h> 19 20 struct mux_ext_info_cache { 21 char *data; 22 ssize_t size; 23 }; 24 25 struct mux_child { 26 struct mux_ext_info_cache *ext_info_cache; 27 }; 28 29 struct mux { 30 int cached_state; 31 struct mux_control *control; 32 struct iio_channel *parent; 33 struct iio_chan_spec *chan; 34 struct iio_chan_spec_ext_info *ext_info; 35 struct mux_child *child; 36 u32 delay_us; 37 }; 38 39 static int iio_mux_select(struct mux *mux, int idx) 40 { 41 struct mux_child *child = &mux->child[idx]; 42 struct iio_chan_spec const *chan = &mux->chan[idx]; 43 int ret; 44 int i; 45 46 ret = mux_control_select_delay(mux->control, chan->channel, 47 mux->delay_us); 48 if (ret < 0) { 49 mux->cached_state = -1; 50 return ret; 51 } 52 53 if (mux->cached_state == chan->channel) 54 return 0; 55 56 if (chan->ext_info) { 57 for (i = 0; chan->ext_info[i].name; ++i) { 58 const char *attr = chan->ext_info[i].name; 59 struct mux_ext_info_cache *cache; 60 61 cache = &child->ext_info_cache[i]; 62 63 if (cache->size < 0) 64 continue; 65 66 ret = iio_write_channel_ext_info(mux->parent, attr, 67 cache->data, 68 cache->size); 69 70 if (ret < 0) { 71 mux_control_deselect(mux->control); 72 mux->cached_state = -1; 73 return ret; 74 } 75 } 76 } 77 mux->cached_state = chan->channel; 78 79 return 0; 80 } 81 82 static void iio_mux_deselect(struct mux *mux) 83 { 84 mux_control_deselect(mux->control); 85 } 86 87 static int mux_read_raw(struct iio_dev *indio_dev, 88 struct iio_chan_spec const *chan, 89 int *val, int *val2, long mask) 90 { 91 struct mux *mux = iio_priv(indio_dev); 92 int idx = chan - mux->chan; 93 int ret; 94 95 ret = iio_mux_select(mux, idx); 96 if (ret < 0) 97 return ret; 98 99 switch (mask) { 100 case IIO_CHAN_INFO_RAW: 101 ret = iio_read_channel_raw(mux->parent, val); 102 break; 103 104 case IIO_CHAN_INFO_SCALE: 105 ret = iio_read_channel_scale(mux->parent, val, val2); 106 break; 107 108 default: 109 ret = -EINVAL; 110 } 111 112 iio_mux_deselect(mux); 113 114 return ret; 115 } 116 117 static int mux_read_avail(struct iio_dev *indio_dev, 118 struct iio_chan_spec const *chan, 119 const int **vals, int *type, int *length, 120 long mask) 121 { 122 struct mux *mux = iio_priv(indio_dev); 123 int idx = chan - mux->chan; 124 int ret; 125 126 ret = iio_mux_select(mux, idx); 127 if (ret < 0) 128 return ret; 129 130 switch (mask) { 131 case IIO_CHAN_INFO_RAW: 132 *type = IIO_VAL_INT; 133 ret = iio_read_avail_channel_raw(mux->parent, vals, length); 134 break; 135 136 default: 137 ret = -EINVAL; 138 } 139 140 iio_mux_deselect(mux); 141 142 return ret; 143 } 144 145 static int mux_write_raw(struct iio_dev *indio_dev, 146 struct iio_chan_spec const *chan, 147 int val, int val2, long mask) 148 { 149 struct mux *mux = iio_priv(indio_dev); 150 int idx = chan - mux->chan; 151 int ret; 152 153 ret = iio_mux_select(mux, idx); 154 if (ret < 0) 155 return ret; 156 157 switch (mask) { 158 case IIO_CHAN_INFO_RAW: 159 ret = iio_write_channel_raw(mux->parent, val); 160 break; 161 162 default: 163 ret = -EINVAL; 164 } 165 166 iio_mux_deselect(mux); 167 168 return ret; 169 } 170 171 static const struct iio_info mux_info = { 172 .read_raw = mux_read_raw, 173 .read_avail = mux_read_avail, 174 .write_raw = mux_write_raw, 175 }; 176 177 static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private, 178 struct iio_chan_spec const *chan, char *buf) 179 { 180 struct mux *mux = iio_priv(indio_dev); 181 int idx = chan - mux->chan; 182 ssize_t ret; 183 184 ret = iio_mux_select(mux, idx); 185 if (ret < 0) 186 return ret; 187 188 ret = iio_read_channel_ext_info(mux->parent, 189 mux->ext_info[private].name, 190 buf); 191 192 iio_mux_deselect(mux); 193 194 return ret; 195 } 196 197 static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private, 198 struct iio_chan_spec const *chan, 199 const char *buf, size_t len) 200 { 201 struct device *dev = indio_dev->dev.parent; 202 struct mux *mux = iio_priv(indio_dev); 203 int idx = chan - mux->chan; 204 char *new; 205 ssize_t ret; 206 207 if (len >= PAGE_SIZE) 208 return -EINVAL; 209 210 ret = iio_mux_select(mux, idx); 211 if (ret < 0) 212 return ret; 213 214 new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL); 215 if (!new) { 216 iio_mux_deselect(mux); 217 return -ENOMEM; 218 } 219 220 new[len] = 0; 221 222 ret = iio_write_channel_ext_info(mux->parent, 223 mux->ext_info[private].name, 224 buf, len); 225 if (ret < 0) { 226 iio_mux_deselect(mux); 227 devm_kfree(dev, new); 228 return ret; 229 } 230 231 devm_kfree(dev, mux->child[idx].ext_info_cache[private].data); 232 mux->child[idx].ext_info_cache[private].data = new; 233 mux->child[idx].ext_info_cache[private].size = len; 234 235 iio_mux_deselect(mux); 236 237 return ret; 238 } 239 240 static int mux_configure_channel(struct device *dev, struct mux *mux, 241 u32 state, const char *label, int idx) 242 { 243 struct mux_child *child = &mux->child[idx]; 244 struct iio_chan_spec *chan = &mux->chan[idx]; 245 struct iio_chan_spec const *pchan = mux->parent->channel; 246 char *page = NULL; 247 int num_ext_info; 248 int i; 249 int ret; 250 251 chan->indexed = 1; 252 chan->output = pchan->output; 253 chan->datasheet_name = label; 254 chan->ext_info = mux->ext_info; 255 256 ret = iio_get_channel_type(mux->parent, &chan->type); 257 if (ret < 0) { 258 dev_err(dev, "failed to get parent channel type\n"); 259 return ret; 260 } 261 262 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW)) 263 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW); 264 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE)) 265 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE); 266 267 if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW)) 268 chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW); 269 270 if (state >= mux_control_states(mux->control)) { 271 dev_err(dev, "too many channels\n"); 272 return -EINVAL; 273 } 274 275 chan->channel = state; 276 277 num_ext_info = iio_get_channel_ext_info_count(mux->parent); 278 if (num_ext_info) { 279 page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL); 280 if (!page) 281 return -ENOMEM; 282 } 283 child->ext_info_cache = devm_kcalloc(dev, 284 num_ext_info, 285 sizeof(*child->ext_info_cache), 286 GFP_KERNEL); 287 if (!child->ext_info_cache) 288 return -ENOMEM; 289 290 for (i = 0; i < num_ext_info; ++i) { 291 child->ext_info_cache[i].size = -1; 292 293 if (!pchan->ext_info[i].write) 294 continue; 295 if (!pchan->ext_info[i].read) 296 continue; 297 298 ret = iio_read_channel_ext_info(mux->parent, 299 mux->ext_info[i].name, 300 page); 301 if (ret < 0) { 302 dev_err(dev, "failed to get ext_info '%s'\n", 303 pchan->ext_info[i].name); 304 return ret; 305 } 306 if (ret >= PAGE_SIZE) { 307 dev_err(dev, "too large ext_info '%s'\n", 308 pchan->ext_info[i].name); 309 return -EINVAL; 310 } 311 312 child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1, 313 GFP_KERNEL); 314 if (!child->ext_info_cache[i].data) 315 return -ENOMEM; 316 317 child->ext_info_cache[i].data[ret] = 0; 318 child->ext_info_cache[i].size = ret; 319 } 320 321 if (page) 322 devm_kfree(dev, page); 323 324 return 0; 325 } 326 327 static int mux_probe(struct platform_device *pdev) 328 { 329 struct device *dev = &pdev->dev; 330 struct iio_dev *indio_dev; 331 struct iio_channel *parent; 332 struct mux *mux; 333 const char **labels; 334 int all_children; 335 int children; 336 u32 state; 337 int sizeof_ext_info; 338 int sizeof_priv; 339 int i; 340 int ret; 341 342 parent = devm_iio_channel_get(dev, "parent"); 343 if (IS_ERR(parent)) 344 return dev_err_probe(dev, PTR_ERR(parent), 345 "failed to get parent channel\n"); 346 347 sizeof_ext_info = iio_get_channel_ext_info_count(parent); 348 if (sizeof_ext_info) { 349 sizeof_ext_info += 1; /* one extra entry for the sentinel */ 350 sizeof_ext_info *= sizeof(*mux->ext_info); 351 } 352 353 all_children = device_property_string_array_count(dev, "channels"); 354 if (all_children < 0) 355 return all_children; 356 357 labels = devm_kmalloc_array(dev, all_children, sizeof(*labels), GFP_KERNEL); 358 if (!labels) 359 return -ENOMEM; 360 361 ret = device_property_read_string_array(dev, "channels", labels, all_children); 362 if (ret < 0) 363 return ret; 364 365 children = 0; 366 for (state = 0; state < all_children; state++) { 367 if (*labels[state]) 368 children++; 369 } 370 if (children <= 0) { 371 dev_err(dev, "not even a single child\n"); 372 return -EINVAL; 373 } 374 375 sizeof_priv = sizeof(*mux); 376 sizeof_priv += sizeof(*mux->child) * children; 377 sizeof_priv += sizeof(*mux->chan) * children; 378 sizeof_priv += sizeof_ext_info; 379 380 indio_dev = devm_iio_device_alloc(dev, sizeof_priv); 381 if (!indio_dev) 382 return -ENOMEM; 383 384 mux = iio_priv(indio_dev); 385 mux->child = (struct mux_child *)(mux + 1); 386 mux->chan = (struct iio_chan_spec *)(mux->child + children); 387 388 platform_set_drvdata(pdev, indio_dev); 389 390 mux->parent = parent; 391 mux->cached_state = -1; 392 393 mux->delay_us = 0; 394 device_property_read_u32(dev, "settle-time-us", &mux->delay_us); 395 396 indio_dev->name = dev_name(dev); 397 indio_dev->info = &mux_info; 398 indio_dev->modes = INDIO_DIRECT_MODE; 399 indio_dev->channels = mux->chan; 400 indio_dev->num_channels = children; 401 if (sizeof_ext_info) { 402 mux->ext_info = devm_kmemdup(dev, 403 parent->channel->ext_info, 404 sizeof_ext_info, GFP_KERNEL); 405 if (!mux->ext_info) 406 return -ENOMEM; 407 408 for (i = 0; mux->ext_info[i].name; ++i) { 409 if (parent->channel->ext_info[i].read) 410 mux->ext_info[i].read = mux_read_ext_info; 411 if (parent->channel->ext_info[i].write) 412 mux->ext_info[i].write = mux_write_ext_info; 413 mux->ext_info[i].private = i; 414 } 415 } 416 417 mux->control = devm_mux_control_get(dev, NULL); 418 if (IS_ERR(mux->control)) 419 return dev_err_probe(dev, PTR_ERR(mux->control), 420 "failed to get control-mux\n"); 421 422 i = 0; 423 for (state = 0; state < all_children; state++) { 424 if (!*labels[state]) 425 continue; 426 427 ret = mux_configure_channel(dev, mux, state, labels[state], i++); 428 if (ret < 0) 429 return ret; 430 } 431 432 ret = devm_iio_device_register(dev, indio_dev); 433 if (ret) { 434 dev_err(dev, "failed to register iio device\n"); 435 return ret; 436 } 437 438 return 0; 439 } 440 441 static const struct of_device_id mux_match[] = { 442 { .compatible = "io-channel-mux" }, 443 { /* sentinel */ } 444 }; 445 MODULE_DEVICE_TABLE(of, mux_match); 446 447 static struct platform_driver mux_driver = { 448 .probe = mux_probe, 449 .driver = { 450 .name = "iio-mux", 451 .of_match_table = mux_match, 452 }, 453 }; 454 module_platform_driver(mux_driver); 455 456 MODULE_DESCRIPTION("IIO multiplexer driver"); 457 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 458 MODULE_LICENSE("GPL v2"); 459