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_kzalloc(dev, 285 sizeof(*child->ext_info_cache) * 286 num_ext_info, 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 /* 328 * Same as of_property_for_each_string(), but also keeps track of the 329 * index of each string. 330 */ 331 #define of_property_for_each_string_index(np, propname, prop, s, i) \ 332 for (prop = of_find_property(np, propname, NULL), \ 333 s = of_prop_next_string(prop, NULL), \ 334 i = 0; \ 335 s; \ 336 s = of_prop_next_string(prop, s), \ 337 i++) 338 339 static int mux_probe(struct platform_device *pdev) 340 { 341 struct device *dev = &pdev->dev; 342 struct device_node *np = pdev->dev.of_node; 343 struct iio_dev *indio_dev; 344 struct iio_channel *parent; 345 struct mux *mux; 346 struct property *prop; 347 const char *label; 348 u32 state; 349 int sizeof_ext_info; 350 int children; 351 int sizeof_priv; 352 int i; 353 int ret; 354 355 if (!np) 356 return -ENODEV; 357 358 parent = devm_iio_channel_get(dev, "parent"); 359 if (IS_ERR(parent)) { 360 if (PTR_ERR(parent) != -EPROBE_DEFER) 361 dev_err(dev, "failed to get parent channel\n"); 362 return PTR_ERR(parent); 363 } 364 365 sizeof_ext_info = iio_get_channel_ext_info_count(parent); 366 if (sizeof_ext_info) { 367 sizeof_ext_info += 1; /* one extra entry for the sentinel */ 368 sizeof_ext_info *= sizeof(*mux->ext_info); 369 } 370 371 children = 0; 372 of_property_for_each_string(np, "channels", prop, label) { 373 if (*label) 374 children++; 375 } 376 if (children <= 0) { 377 dev_err(dev, "not even a single child\n"); 378 return -EINVAL; 379 } 380 381 sizeof_priv = sizeof(*mux); 382 sizeof_priv += sizeof(*mux->child) * children; 383 sizeof_priv += sizeof(*mux->chan) * children; 384 sizeof_priv += sizeof_ext_info; 385 386 indio_dev = devm_iio_device_alloc(dev, sizeof_priv); 387 if (!indio_dev) 388 return -ENOMEM; 389 390 mux = iio_priv(indio_dev); 391 mux->child = (struct mux_child *)(mux + 1); 392 mux->chan = (struct iio_chan_spec *)(mux->child + children); 393 394 platform_set_drvdata(pdev, indio_dev); 395 396 mux->parent = parent; 397 mux->cached_state = -1; 398 399 indio_dev->name = dev_name(dev); 400 indio_dev->dev.parent = dev; 401 indio_dev->info = &mux_info; 402 indio_dev->modes = INDIO_DIRECT_MODE; 403 indio_dev->channels = mux->chan; 404 indio_dev->num_channels = children; 405 if (sizeof_ext_info) { 406 mux->ext_info = devm_kmemdup(dev, 407 parent->channel->ext_info, 408 sizeof_ext_info, GFP_KERNEL); 409 if (!mux->ext_info) 410 return -ENOMEM; 411 412 for (i = 0; mux->ext_info[i].name; ++i) { 413 if (parent->channel->ext_info[i].read) 414 mux->ext_info[i].read = mux_read_ext_info; 415 if (parent->channel->ext_info[i].write) 416 mux->ext_info[i].write = mux_write_ext_info; 417 mux->ext_info[i].private = i; 418 } 419 } 420 421 mux->control = devm_mux_control_get(dev, NULL); 422 if (IS_ERR(mux->control)) { 423 if (PTR_ERR(mux->control) != -EPROBE_DEFER) 424 dev_err(dev, "failed to get control-mux\n"); 425 return PTR_ERR(mux->control); 426 } 427 428 i = 0; 429 of_property_for_each_string_index(np, "channels", prop, label, state) { 430 if (!*label) 431 continue; 432 433 ret = mux_configure_channel(dev, mux, state, label, i++); 434 if (ret < 0) 435 return ret; 436 } 437 438 ret = devm_iio_device_register(dev, indio_dev); 439 if (ret) { 440 dev_err(dev, "failed to register iio device\n"); 441 return ret; 442 } 443 444 return 0; 445 } 446 447 static const struct of_device_id mux_match[] = { 448 { .compatible = "io-channel-mux" }, 449 { /* sentinel */ } 450 }; 451 MODULE_DEVICE_TABLE(of, mux_match); 452 453 static struct platform_driver mux_driver = { 454 .probe = mux_probe, 455 .driver = { 456 .name = "iio-mux", 457 .of_match_table = mux_match, 458 }, 459 }; 460 module_platform_driver(mux_driver); 461 462 MODULE_DESCRIPTION("IIO multiplexer driver"); 463 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 464 MODULE_LICENSE("GPL v2"); 465