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_dev *indio_dev; 34 struct iio_chan_spec *chan; 35 struct iio_chan_spec_ext_info *ext_info; 36 struct mux_child *child; 37 u32 delay_us; 38 }; 39 40 static int iio_mux_select(struct mux *mux, int idx) 41 { 42 struct mux_child *child = &mux->child[idx]; 43 struct iio_chan_spec const *chan = &mux->chan[idx]; 44 int ret; 45 int i; 46 47 ret = mux_control_select_delay(mux->control, chan->channel, 48 mux->delay_us); 49 if (ret < 0) { 50 mux->cached_state = -1; 51 return ret; 52 } 53 54 if (mux->cached_state == chan->channel) 55 return 0; 56 57 if (chan->ext_info) { 58 for (i = 0; chan->ext_info[i].name; ++i) { 59 const char *attr = chan->ext_info[i].name; 60 struct mux_ext_info_cache *cache; 61 62 cache = &child->ext_info_cache[i]; 63 64 if (cache->size < 0) 65 continue; 66 67 ret = iio_write_channel_ext_info(mux->parent, attr, 68 cache->data, 69 cache->size); 70 71 if (ret < 0) { 72 mux_control_deselect(mux->control); 73 mux->cached_state = -1; 74 return ret; 75 } 76 } 77 } 78 mux->cached_state = chan->channel; 79 80 return 0; 81 } 82 83 static void iio_mux_deselect(struct mux *mux) 84 { 85 mux_control_deselect(mux->control); 86 } 87 88 static int mux_read_raw(struct iio_dev *indio_dev, 89 struct iio_chan_spec const *chan, 90 int *val, int *val2, long mask) 91 { 92 struct mux *mux = iio_priv(indio_dev); 93 int idx = chan - mux->chan; 94 int ret; 95 96 ret = iio_mux_select(mux, idx); 97 if (ret < 0) 98 return ret; 99 100 switch (mask) { 101 case IIO_CHAN_INFO_RAW: 102 ret = iio_read_channel_raw(mux->parent, val); 103 break; 104 105 case IIO_CHAN_INFO_SCALE: 106 ret = iio_read_channel_scale(mux->parent, val, val2); 107 break; 108 109 default: 110 ret = -EINVAL; 111 } 112 113 iio_mux_deselect(mux); 114 115 return ret; 116 } 117 118 static int mux_read_avail(struct iio_dev *indio_dev, 119 struct iio_chan_spec const *chan, 120 const int **vals, int *type, int *length, 121 long mask) 122 { 123 struct mux *mux = iio_priv(indio_dev); 124 int idx = chan - mux->chan; 125 int ret; 126 127 ret = iio_mux_select(mux, idx); 128 if (ret < 0) 129 return ret; 130 131 switch (mask) { 132 case IIO_CHAN_INFO_RAW: 133 *type = IIO_VAL_INT; 134 ret = iio_read_avail_channel_raw(mux->parent, vals, length); 135 break; 136 137 default: 138 ret = -EINVAL; 139 } 140 141 iio_mux_deselect(mux); 142 143 return ret; 144 } 145 146 static int mux_write_raw(struct iio_dev *indio_dev, 147 struct iio_chan_spec const *chan, 148 int val, int val2, long mask) 149 { 150 struct mux *mux = iio_priv(indio_dev); 151 int idx = chan - mux->chan; 152 int ret; 153 154 ret = iio_mux_select(mux, idx); 155 if (ret < 0) 156 return ret; 157 158 switch (mask) { 159 case IIO_CHAN_INFO_RAW: 160 ret = iio_write_channel_raw(mux->parent, val); 161 break; 162 163 default: 164 ret = -EINVAL; 165 } 166 167 iio_mux_deselect(mux); 168 169 return ret; 170 } 171 172 static const struct iio_info mux_info = { 173 .read_raw = mux_read_raw, 174 .read_avail = mux_read_avail, 175 .write_raw = mux_write_raw, 176 }; 177 178 static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private, 179 struct iio_chan_spec const *chan, char *buf) 180 { 181 struct mux *mux = iio_priv(indio_dev); 182 int idx = chan - mux->chan; 183 ssize_t ret; 184 185 ret = iio_mux_select(mux, idx); 186 if (ret < 0) 187 return ret; 188 189 ret = iio_read_channel_ext_info(mux->parent, 190 mux->ext_info[private].name, 191 buf); 192 193 iio_mux_deselect(mux); 194 195 return ret; 196 } 197 198 static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private, 199 struct iio_chan_spec const *chan, 200 const char *buf, size_t len) 201 { 202 struct device *dev = indio_dev->dev.parent; 203 struct mux *mux = iio_priv(indio_dev); 204 int idx = chan - mux->chan; 205 char *new; 206 ssize_t ret; 207 208 if (len >= PAGE_SIZE) 209 return -EINVAL; 210 211 ret = iio_mux_select(mux, idx); 212 if (ret < 0) 213 return ret; 214 215 new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL); 216 if (!new) { 217 iio_mux_deselect(mux); 218 return -ENOMEM; 219 } 220 221 new[len] = 0; 222 223 ret = iio_write_channel_ext_info(mux->parent, 224 mux->ext_info[private].name, 225 buf, len); 226 if (ret < 0) { 227 iio_mux_deselect(mux); 228 devm_kfree(dev, new); 229 return ret; 230 } 231 232 devm_kfree(dev, mux->child[idx].ext_info_cache[private].data); 233 mux->child[idx].ext_info_cache[private].data = new; 234 mux->child[idx].ext_info_cache[private].size = len; 235 236 iio_mux_deselect(mux); 237 238 return ret; 239 } 240 241 static int mux_configure_channel(struct device *dev, struct mux *mux, 242 u32 state, const char *label, int idx) 243 { 244 struct mux_child *child = &mux->child[idx]; 245 struct iio_chan_spec *chan = &mux->chan[idx]; 246 struct iio_chan_spec const *pchan = mux->parent->channel; 247 char *page = NULL; 248 int num_ext_info; 249 int i; 250 int ret; 251 252 chan->indexed = 1; 253 chan->output = pchan->output; 254 chan->datasheet_name = label; 255 chan->ext_info = mux->ext_info; 256 257 ret = iio_get_channel_type(mux->parent, &chan->type); 258 if (ret < 0) { 259 dev_err(dev, "failed to get parent channel type\n"); 260 return ret; 261 } 262 263 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW)) 264 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW); 265 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE)) 266 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE); 267 268 if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW)) 269 chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW); 270 271 if (state >= mux_control_states(mux->control)) { 272 dev_err(dev, "too many channels\n"); 273 return -EINVAL; 274 } 275 276 chan->channel = state; 277 278 num_ext_info = iio_get_channel_ext_info_count(mux->parent); 279 if (num_ext_info) { 280 page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL); 281 if (!page) 282 return -ENOMEM; 283 } 284 child->ext_info_cache = devm_kcalloc(dev, 285 num_ext_info, 286 sizeof(*child->ext_info_cache), 287 GFP_KERNEL); 288 if (!child->ext_info_cache) 289 return -ENOMEM; 290 291 for (i = 0; i < num_ext_info; ++i) { 292 child->ext_info_cache[i].size = -1; 293 294 if (!pchan->ext_info[i].write) 295 continue; 296 if (!pchan->ext_info[i].read) 297 continue; 298 299 ret = iio_read_channel_ext_info(mux->parent, 300 mux->ext_info[i].name, 301 page); 302 if (ret < 0) { 303 dev_err(dev, "failed to get ext_info '%s'\n", 304 pchan->ext_info[i].name); 305 return ret; 306 } 307 if (ret >= PAGE_SIZE) { 308 dev_err(dev, "too large ext_info '%s'\n", 309 pchan->ext_info[i].name); 310 return -EINVAL; 311 } 312 313 child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1, 314 GFP_KERNEL); 315 if (!child->ext_info_cache[i].data) 316 return -ENOMEM; 317 318 child->ext_info_cache[i].data[ret] = 0; 319 child->ext_info_cache[i].size = ret; 320 } 321 322 if (page) 323 devm_kfree(dev, page); 324 325 return 0; 326 } 327 328 static int mux_probe(struct platform_device *pdev) 329 { 330 struct device *dev = &pdev->dev; 331 struct iio_dev *indio_dev; 332 struct iio_channel *parent; 333 struct mux *mux; 334 const char **labels; 335 int all_children; 336 int children; 337 u32 state; 338 int sizeof_ext_info; 339 int sizeof_priv; 340 int i; 341 int ret; 342 343 parent = devm_iio_channel_get(dev, "parent"); 344 if (IS_ERR(parent)) 345 return dev_err_probe(dev, PTR_ERR(parent), 346 "failed to get parent channel\n"); 347 348 sizeof_ext_info = iio_get_channel_ext_info_count(parent); 349 if (sizeof_ext_info) { 350 sizeof_ext_info += 1; /* one extra entry for the sentinel */ 351 sizeof_ext_info *= sizeof(*mux->ext_info); 352 } 353 354 all_children = device_property_string_array_count(dev, "channels"); 355 if (all_children < 0) 356 return all_children; 357 358 labels = devm_kmalloc_array(dev, all_children, sizeof(*labels), GFP_KERNEL); 359 if (!labels) 360 return -ENOMEM; 361 362 ret = device_property_read_string_array(dev, "channels", labels, all_children); 363 if (ret < 0) 364 return ret; 365 366 children = 0; 367 for (state = 0; state < all_children; state++) { 368 if (*labels[state]) 369 children++; 370 } 371 if (children <= 0) { 372 dev_err(dev, "not even a single child\n"); 373 return -EINVAL; 374 } 375 376 sizeof_priv = sizeof(*mux); 377 sizeof_priv += sizeof(*mux->child) * children; 378 sizeof_priv += sizeof(*mux->chan) * children; 379 sizeof_priv += sizeof_ext_info; 380 381 indio_dev = devm_iio_device_alloc(dev, sizeof_priv); 382 if (!indio_dev) 383 return -ENOMEM; 384 385 mux = iio_priv(indio_dev); 386 mux->child = (struct mux_child *)(mux + 1); 387 mux->chan = (struct iio_chan_spec *)(mux->child + children); 388 389 platform_set_drvdata(pdev, indio_dev); 390 391 mux->parent = parent; 392 mux->cached_state = -1; 393 394 mux->delay_us = 0; 395 device_property_read_u32(dev, "settle-time-us", &mux->delay_us); 396 397 indio_dev->name = dev_name(dev); 398 indio_dev->info = &mux_info; 399 indio_dev->modes = INDIO_DIRECT_MODE; 400 indio_dev->channels = mux->chan; 401 indio_dev->num_channels = children; 402 if (sizeof_ext_info) { 403 mux->ext_info = devm_kmemdup(dev, 404 parent->channel->ext_info, 405 sizeof_ext_info, GFP_KERNEL); 406 if (!mux->ext_info) 407 return -ENOMEM; 408 409 for (i = 0; mux->ext_info[i].name; ++i) { 410 if (parent->channel->ext_info[i].read) 411 mux->ext_info[i].read = mux_read_ext_info; 412 if (parent->channel->ext_info[i].write) 413 mux->ext_info[i].write = mux_write_ext_info; 414 mux->ext_info[i].private = i; 415 } 416 } 417 418 mux->control = devm_mux_control_get(dev, NULL); 419 if (IS_ERR(mux->control)) { 420 if (PTR_ERR(mux->control) != -EPROBE_DEFER) 421 dev_err(dev, "failed to get control-mux\n"); 422 return PTR_ERR(mux->control); 423 } 424 425 i = 0; 426 for (state = 0; state < all_children; state++) { 427 if (!*labels[state]) 428 continue; 429 430 ret = mux_configure_channel(dev, mux, state, labels[state], i++); 431 if (ret < 0) 432 return ret; 433 } 434 435 ret = devm_iio_device_register(dev, indio_dev); 436 if (ret) { 437 dev_err(dev, "failed to register iio device\n"); 438 return ret; 439 } 440 441 return 0; 442 } 443 444 static const struct of_device_id mux_match[] = { 445 { .compatible = "io-channel-mux" }, 446 { /* sentinel */ } 447 }; 448 MODULE_DEVICE_TABLE(of, mux_match); 449 450 static struct platform_driver mux_driver = { 451 .probe = mux_probe, 452 .driver = { 453 .name = "iio-mux", 454 .of_match_table = mux_match, 455 }, 456 }; 457 module_platform_driver(mux_driver); 458 459 MODULE_DESCRIPTION("IIO multiplexer driver"); 460 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 461 MODULE_LICENSE("GPL v2"); 462