1 /* 2 * IIO multiplexer driver 3 * 4 * Copyright (C) 2017 Axentia Technologies AB 5 * 6 * Author: Peter Rosin <peda@axentia.se> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/err.h> 14 #include <linux/iio/consumer.h> 15 #include <linux/iio/iio.h> 16 #include <linux/module.h> 17 #include <linux/mutex.h> 18 #include <linux/mux/consumer.h> 19 #include <linux/of.h> 20 #include <linux/platform_device.h> 21 22 struct mux_ext_info_cache { 23 char *data; 24 ssize_t size; 25 }; 26 27 struct mux_child { 28 struct mux_ext_info_cache *ext_info_cache; 29 }; 30 31 struct mux { 32 int cached_state; 33 struct mux_control *control; 34 struct iio_channel *parent; 35 struct iio_dev *indio_dev; 36 struct iio_chan_spec *chan; 37 struct iio_chan_spec_ext_info *ext_info; 38 struct mux_child *child; 39 }; 40 41 static int iio_mux_select(struct mux *mux, int idx) 42 { 43 struct mux_child *child = &mux->child[idx]; 44 struct iio_chan_spec const *chan = &mux->chan[idx]; 45 int ret; 46 int i; 47 48 ret = mux_control_select(mux->control, chan->channel); 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 /* 329 * Same as of_property_for_each_string(), but also keeps track of the 330 * index of each string. 331 */ 332 #define of_property_for_each_string_index(np, propname, prop, s, i) \ 333 for (prop = of_find_property(np, propname, NULL), \ 334 s = of_prop_next_string(prop, NULL), \ 335 i = 0; \ 336 s; \ 337 s = of_prop_next_string(prop, s), \ 338 i++) 339 340 static int mux_probe(struct platform_device *pdev) 341 { 342 struct device *dev = &pdev->dev; 343 struct device_node *np = pdev->dev.of_node; 344 struct iio_dev *indio_dev; 345 struct iio_channel *parent; 346 struct mux *mux; 347 struct property *prop; 348 const char *label; 349 u32 state; 350 int sizeof_ext_info; 351 int children; 352 int sizeof_priv; 353 int i; 354 int ret; 355 356 if (!np) 357 return -ENODEV; 358 359 parent = devm_iio_channel_get(dev, "parent"); 360 if (IS_ERR(parent)) { 361 if (PTR_ERR(parent) != -EPROBE_DEFER) 362 dev_err(dev, "failed to get parent channel\n"); 363 return PTR_ERR(parent); 364 } 365 366 sizeof_ext_info = iio_get_channel_ext_info_count(parent); 367 if (sizeof_ext_info) { 368 sizeof_ext_info += 1; /* one extra entry for the sentinel */ 369 sizeof_ext_info *= sizeof(*mux->ext_info); 370 } 371 372 children = 0; 373 of_property_for_each_string(np, "channels", prop, label) { 374 if (*label) 375 children++; 376 } 377 if (children <= 0) { 378 dev_err(dev, "not even a single child\n"); 379 return -EINVAL; 380 } 381 382 sizeof_priv = sizeof(*mux); 383 sizeof_priv += sizeof(*mux->child) * children; 384 sizeof_priv += sizeof(*mux->chan) * children; 385 sizeof_priv += sizeof_ext_info; 386 387 indio_dev = devm_iio_device_alloc(dev, sizeof_priv); 388 if (!indio_dev) 389 return -ENOMEM; 390 391 mux = iio_priv(indio_dev); 392 mux->child = (struct mux_child *)(mux + 1); 393 mux->chan = (struct iio_chan_spec *)(mux->child + children); 394 395 platform_set_drvdata(pdev, indio_dev); 396 397 mux->parent = parent; 398 mux->cached_state = -1; 399 400 indio_dev->name = dev_name(dev); 401 indio_dev->dev.parent = dev; 402 indio_dev->info = &mux_info; 403 indio_dev->modes = INDIO_DIRECT_MODE; 404 indio_dev->channels = mux->chan; 405 indio_dev->num_channels = children; 406 if (sizeof_ext_info) { 407 mux->ext_info = devm_kmemdup(dev, 408 parent->channel->ext_info, 409 sizeof_ext_info, GFP_KERNEL); 410 if (!mux->ext_info) 411 return -ENOMEM; 412 413 for (i = 0; mux->ext_info[i].name; ++i) { 414 if (parent->channel->ext_info[i].read) 415 mux->ext_info[i].read = mux_read_ext_info; 416 if (parent->channel->ext_info[i].write) 417 mux->ext_info[i].write = mux_write_ext_info; 418 mux->ext_info[i].private = i; 419 } 420 } 421 422 mux->control = devm_mux_control_get(dev, NULL); 423 if (IS_ERR(mux->control)) { 424 if (PTR_ERR(mux->control) != -EPROBE_DEFER) 425 dev_err(dev, "failed to get control-mux\n"); 426 return PTR_ERR(mux->control); 427 } 428 429 i = 0; 430 of_property_for_each_string_index(np, "channels", prop, label, state) { 431 if (!*label) 432 continue; 433 434 ret = mux_configure_channel(dev, mux, state, label, i++); 435 if (ret < 0) 436 return ret; 437 } 438 439 ret = devm_iio_device_register(dev, indio_dev); 440 if (ret) { 441 dev_err(dev, "failed to register iio device\n"); 442 return ret; 443 } 444 445 return 0; 446 } 447 448 static const struct of_device_id mux_match[] = { 449 { .compatible = "io-channel-mux" }, 450 { /* sentinel */ } 451 }; 452 MODULE_DEVICE_TABLE(of, mux_match); 453 454 static struct platform_driver mux_driver = { 455 .probe = mux_probe, 456 .driver = { 457 .name = "iio-mux", 458 .of_match_table = mux_match, 459 }, 460 }; 461 module_platform_driver(mux_driver); 462 463 MODULE_DESCRIPTION("IIO multiplexer driver"); 464 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 465 MODULE_LICENSE("GPL v2"); 466