rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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 | .driver_module = THIS_MODULE, |
| 177 | }; |
| 178 | |
| 179 | static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private, |
| 180 | struct iio_chan_spec const *chan, char *buf) |
| 181 | { |
| 182 | struct mux *mux = iio_priv(indio_dev); |
| 183 | int idx = chan - mux->chan; |
| 184 | ssize_t ret; |
| 185 | |
| 186 | ret = iio_mux_select(mux, idx); |
| 187 | if (ret < 0) |
| 188 | return ret; |
| 189 | |
| 190 | ret = iio_read_channel_ext_info(mux->parent, |
| 191 | mux->ext_info[private].name, |
| 192 | buf); |
| 193 | |
| 194 | iio_mux_deselect(mux); |
| 195 | |
| 196 | return ret; |
| 197 | } |
| 198 | |
| 199 | static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private, |
| 200 | struct iio_chan_spec const *chan, |
| 201 | const char *buf, size_t len) |
| 202 | { |
| 203 | struct device *dev = indio_dev->dev.parent; |
| 204 | struct mux *mux = iio_priv(indio_dev); |
| 205 | int idx = chan - mux->chan; |
| 206 | char *new; |
| 207 | ssize_t ret; |
| 208 | |
| 209 | if (len >= PAGE_SIZE) |
| 210 | return -EINVAL; |
| 211 | |
| 212 | ret = iio_mux_select(mux, idx); |
| 213 | if (ret < 0) |
| 214 | return ret; |
| 215 | |
| 216 | new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL); |
| 217 | if (!new) { |
| 218 | iio_mux_deselect(mux); |
| 219 | return -ENOMEM; |
| 220 | } |
| 221 | |
| 222 | new[len] = 0; |
| 223 | |
| 224 | ret = iio_write_channel_ext_info(mux->parent, |
| 225 | mux->ext_info[private].name, |
| 226 | buf, len); |
| 227 | if (ret < 0) { |
| 228 | iio_mux_deselect(mux); |
| 229 | devm_kfree(dev, new); |
| 230 | return ret; |
| 231 | } |
| 232 | |
| 233 | devm_kfree(dev, mux->child[idx].ext_info_cache[private].data); |
| 234 | mux->child[idx].ext_info_cache[private].data = new; |
| 235 | mux->child[idx].ext_info_cache[private].size = len; |
| 236 | |
| 237 | iio_mux_deselect(mux); |
| 238 | |
| 239 | return ret; |
| 240 | } |
| 241 | |
| 242 | static int mux_configure_channel(struct device *dev, struct mux *mux, |
| 243 | u32 state, const char *label, int idx) |
| 244 | { |
| 245 | struct mux_child *child = &mux->child[idx]; |
| 246 | struct iio_chan_spec *chan = &mux->chan[idx]; |
| 247 | struct iio_chan_spec const *pchan = mux->parent->channel; |
| 248 | char *page = NULL; |
| 249 | int num_ext_info; |
| 250 | int i; |
| 251 | int ret; |
| 252 | |
| 253 | chan->indexed = 1; |
| 254 | chan->output = pchan->output; |
| 255 | chan->datasheet_name = label; |
| 256 | chan->ext_info = mux->ext_info; |
| 257 | |
| 258 | ret = iio_get_channel_type(mux->parent, &chan->type); |
| 259 | if (ret < 0) { |
| 260 | dev_err(dev, "failed to get parent channel type\n"); |
| 261 | return ret; |
| 262 | } |
| 263 | |
| 264 | if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW)) |
| 265 | chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW); |
| 266 | if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE)) |
| 267 | chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE); |
| 268 | |
| 269 | if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW)) |
| 270 | chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW); |
| 271 | |
| 272 | if (state >= mux_control_states(mux->control)) { |
| 273 | dev_err(dev, "too many channels\n"); |
| 274 | return -EINVAL; |
| 275 | } |
| 276 | |
| 277 | chan->channel = state; |
| 278 | |
| 279 | num_ext_info = iio_get_channel_ext_info_count(mux->parent); |
| 280 | if (num_ext_info) { |
| 281 | page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL); |
| 282 | if (!page) |
| 283 | return -ENOMEM; |
| 284 | } |
| 285 | child->ext_info_cache = devm_kzalloc(dev, |
| 286 | sizeof(*child->ext_info_cache) * |
| 287 | num_ext_info, 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"); |