Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | |
| 3 | /* |
| 4 | * LED pattern trigger |
| 5 | * |
| 6 | * Idea discussed with Pavel Machek. Raphael Teysseyre implemented |
| 7 | * the first version, Baolin Wang simplified and improved the approach. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/kernel.h> |
| 11 | #include <linux/leds.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/mutex.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/timer.h> |
| 16 | |
| 17 | #define MAX_PATTERNS 1024 |
| 18 | /* |
| 19 | * When doing gradual dimming, the led brightness will be updated |
| 20 | * every 50 milliseconds. |
| 21 | */ |
| 22 | #define UPDATE_INTERVAL 50 |
| 23 | |
| 24 | struct pattern_trig_data { |
| 25 | struct led_classdev *led_cdev; |
| 26 | struct led_pattern patterns[MAX_PATTERNS]; |
| 27 | struct led_pattern *curr; |
| 28 | struct led_pattern *next; |
| 29 | struct mutex lock; |
| 30 | u32 npatterns; |
| 31 | int repeat; |
| 32 | int last_repeat; |
| 33 | int delta_t; |
| 34 | bool is_indefinite; |
| 35 | bool is_hw_pattern; |
| 36 | struct timer_list timer; |
| 37 | }; |
| 38 | |
| 39 | static void pattern_trig_update_patterns(struct pattern_trig_data *data) |
| 40 | { |
| 41 | data->curr = data->next; |
| 42 | if (!data->is_indefinite && data->curr == data->patterns) |
| 43 | data->repeat--; |
| 44 | |
| 45 | if (data->next == data->patterns + data->npatterns - 1) |
| 46 | data->next = data->patterns; |
| 47 | else |
| 48 | data->next++; |
| 49 | |
| 50 | data->delta_t = 0; |
| 51 | } |
| 52 | |
| 53 | static int pattern_trig_compute_brightness(struct pattern_trig_data *data) |
| 54 | { |
| 55 | int step_brightness; |
| 56 | |
| 57 | /* |
| 58 | * If current tuple's duration is less than the dimming interval, |
| 59 | * we should treat it as a step change of brightness instead of |
| 60 | * doing gradual dimming. |
| 61 | */ |
| 62 | if (data->delta_t == 0 || data->curr->delta_t < UPDATE_INTERVAL) |
| 63 | return data->curr->brightness; |
| 64 | |
| 65 | step_brightness = abs(data->next->brightness - data->curr->brightness); |
| 66 | step_brightness = data->delta_t * step_brightness / data->curr->delta_t; |
| 67 | |
| 68 | if (data->next->brightness > data->curr->brightness) |
| 69 | return data->curr->brightness + step_brightness; |
| 70 | else |
| 71 | return data->curr->brightness - step_brightness; |
| 72 | } |
| 73 | |
| 74 | static void pattern_trig_timer_function(struct timer_list *t) |
| 75 | { |
| 76 | struct pattern_trig_data *data = from_timer(data, t, timer); |
| 77 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 78 | for (;;) { |
| 79 | if (!data->is_indefinite && !data->repeat) |
| 80 | break; |
| 81 | |
| 82 | if (data->curr->brightness == data->next->brightness) { |
| 83 | /* Step change of brightness */ |
| 84 | led_set_brightness(data->led_cdev, |
| 85 | data->curr->brightness); |
| 86 | mod_timer(&data->timer, |
| 87 | jiffies + msecs_to_jiffies(data->curr->delta_t)); |
Pavel Machek | 1b50bb4 | 2018-10-24 22:44:39 +0200 | [diff] [blame] | 88 | if (!data->next->delta_t) { |
| 89 | /* Skip the tuple with zero duration */ |
| 90 | pattern_trig_update_patterns(data); |
| 91 | } |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 92 | /* Select next tuple */ |
| 93 | pattern_trig_update_patterns(data); |
| 94 | } else { |
| 95 | /* Gradual dimming */ |
| 96 | |
| 97 | /* |
| 98 | * If the accumulation time is larger than current |
| 99 | * tuple's duration, we should go next one and re-check |
| 100 | * if we repeated done. |
| 101 | */ |
| 102 | if (data->delta_t > data->curr->delta_t) { |
| 103 | pattern_trig_update_patterns(data); |
| 104 | continue; |
| 105 | } |
| 106 | |
| 107 | led_set_brightness(data->led_cdev, |
| 108 | pattern_trig_compute_brightness(data)); |
| 109 | mod_timer(&data->timer, |
| 110 | jiffies + msecs_to_jiffies(UPDATE_INTERVAL)); |
| 111 | |
| 112 | /* Accumulate the gradual dimming time */ |
| 113 | data->delta_t += UPDATE_INTERVAL; |
| 114 | } |
| 115 | |
| 116 | break; |
| 117 | } |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 118 | } |
| 119 | |
| 120 | static int pattern_trig_start_pattern(struct led_classdev *led_cdev) |
| 121 | { |
| 122 | struct pattern_trig_data *data = led_cdev->trigger_data; |
| 123 | |
| 124 | if (!data->npatterns) |
| 125 | return 0; |
| 126 | |
| 127 | if (data->is_hw_pattern) { |
| 128 | return led_cdev->pattern_set(led_cdev, data->patterns, |
| 129 | data->npatterns, data->repeat); |
| 130 | } |
| 131 | |
| 132 | /* At least 2 tuples for software pattern. */ |
| 133 | if (data->npatterns < 2) |
| 134 | return -EINVAL; |
| 135 | |
| 136 | data->delta_t = 0; |
| 137 | data->curr = data->patterns; |
| 138 | data->next = data->patterns + 1; |
| 139 | data->timer.expires = jiffies; |
| 140 | add_timer(&data->timer); |
| 141 | |
| 142 | return 0; |
| 143 | } |
| 144 | |
| 145 | static ssize_t repeat_show(struct device *dev, struct device_attribute *attr, |
| 146 | char *buf) |
| 147 | { |
| 148 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 149 | struct pattern_trig_data *data = led_cdev->trigger_data; |
| 150 | int repeat; |
| 151 | |
| 152 | mutex_lock(&data->lock); |
| 153 | |
| 154 | repeat = data->last_repeat; |
| 155 | |
| 156 | mutex_unlock(&data->lock); |
| 157 | |
ye xingchen | 3f6fb1c | 2022-12-01 16:11:24 +0800 | [diff] [blame] | 158 | return sysfs_emit(buf, "%d\n", repeat); |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 159 | } |
| 160 | |
| 161 | static ssize_t repeat_store(struct device *dev, struct device_attribute *attr, |
| 162 | const char *buf, size_t count) |
| 163 | { |
| 164 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 165 | struct pattern_trig_data *data = led_cdev->trigger_data; |
| 166 | int err, res; |
| 167 | |
| 168 | err = kstrtos32(buf, 10, &res); |
| 169 | if (err) |
| 170 | return err; |
| 171 | |
| 172 | /* Number 0 and negative numbers except -1 are invalid. */ |
| 173 | if (res < -1 || res == 0) |
| 174 | return -EINVAL; |
| 175 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 176 | mutex_lock(&data->lock); |
| 177 | |
Baolin Wang | 3a40cfe | 2018-11-07 13:42:58 +0800 | [diff] [blame] | 178 | del_timer_sync(&data->timer); |
| 179 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 180 | if (data->is_hw_pattern) |
| 181 | led_cdev->pattern_clear(led_cdev); |
| 182 | |
| 183 | data->last_repeat = data->repeat = res; |
| 184 | /* -1 means repeat indefinitely */ |
| 185 | if (data->repeat == -1) |
| 186 | data->is_indefinite = true; |
| 187 | else |
| 188 | data->is_indefinite = false; |
| 189 | |
| 190 | err = pattern_trig_start_pattern(led_cdev); |
| 191 | |
| 192 | mutex_unlock(&data->lock); |
| 193 | return err < 0 ? err : count; |
| 194 | } |
| 195 | |
| 196 | static DEVICE_ATTR_RW(repeat); |
| 197 | |
| 198 | static ssize_t pattern_trig_show_patterns(struct pattern_trig_data *data, |
| 199 | char *buf, bool hw_pattern) |
| 200 | { |
| 201 | ssize_t count = 0; |
| 202 | int i; |
| 203 | |
| 204 | mutex_lock(&data->lock); |
| 205 | |
| 206 | if (!data->npatterns || (data->is_hw_pattern ^ hw_pattern)) |
| 207 | goto out; |
| 208 | |
| 209 | for (i = 0; i < data->npatterns; i++) { |
| 210 | count += scnprintf(buf + count, PAGE_SIZE - count, |
| 211 | "%d %u ", |
| 212 | data->patterns[i].brightness, |
| 213 | data->patterns[i].delta_t); |
| 214 | } |
| 215 | |
| 216 | buf[count - 1] = '\n'; |
| 217 | |
| 218 | out: |
| 219 | mutex_unlock(&data->lock); |
| 220 | return count; |
| 221 | } |
| 222 | |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 223 | static int pattern_trig_store_patterns_string(struct pattern_trig_data *data, |
| 224 | const char *buf, size_t count) |
| 225 | { |
| 226 | int ccount, cr, offset = 0; |
| 227 | |
| 228 | while (offset < count - 1 && data->npatterns < MAX_PATTERNS) { |
| 229 | cr = 0; |
Pavel Machek | feff727 | 2020-07-24 12:43:47 +0200 | [diff] [blame] | 230 | ccount = sscanf(buf + offset, "%u %u %n", |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 231 | &data->patterns[data->npatterns].brightness, |
| 232 | &data->patterns[data->npatterns].delta_t, &cr); |
Pavel Machek | feff727 | 2020-07-24 12:43:47 +0200 | [diff] [blame] | 233 | |
| 234 | if (ccount != 2 || |
| 235 | data->patterns[data->npatterns].brightness > data->led_cdev->max_brightness) { |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 236 | data->npatterns = 0; |
| 237 | return -EINVAL; |
| 238 | } |
| 239 | |
| 240 | offset += cr; |
| 241 | data->npatterns++; |
| 242 | } |
| 243 | |
| 244 | return 0; |
| 245 | } |
| 246 | |
| 247 | static int pattern_trig_store_patterns_int(struct pattern_trig_data *data, |
| 248 | const u32 *buf, size_t count) |
| 249 | { |
| 250 | unsigned int i; |
| 251 | |
| 252 | for (i = 0; i < count; i += 2) { |
| 253 | data->patterns[data->npatterns].brightness = buf[i]; |
| 254 | data->patterns[data->npatterns].delta_t = buf[i + 1]; |
| 255 | data->npatterns++; |
| 256 | } |
| 257 | |
| 258 | return 0; |
| 259 | } |
| 260 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 261 | static ssize_t pattern_trig_store_patterns(struct led_classdev *led_cdev, |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 262 | const char *buf, const u32 *buf_int, |
| 263 | size_t count, bool hw_pattern) |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 264 | { |
| 265 | struct pattern_trig_data *data = led_cdev->trigger_data; |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 266 | int err = 0; |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 267 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 268 | mutex_lock(&data->lock); |
| 269 | |
Baolin Wang | 3a40cfe | 2018-11-07 13:42:58 +0800 | [diff] [blame] | 270 | del_timer_sync(&data->timer); |
| 271 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 272 | if (data->is_hw_pattern) |
| 273 | led_cdev->pattern_clear(led_cdev); |
| 274 | |
| 275 | data->is_hw_pattern = hw_pattern; |
| 276 | data->npatterns = 0; |
| 277 | |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 278 | if (buf) |
| 279 | err = pattern_trig_store_patterns_string(data, buf, count); |
| 280 | else |
| 281 | err = pattern_trig_store_patterns_int(data, buf_int, count); |
| 282 | if (err) |
| 283 | goto out; |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 284 | |
| 285 | err = pattern_trig_start_pattern(led_cdev); |
| 286 | if (err) |
| 287 | data->npatterns = 0; |
| 288 | |
| 289 | out: |
| 290 | mutex_unlock(&data->lock); |
| 291 | return err < 0 ? err : count; |
| 292 | } |
| 293 | |
| 294 | static ssize_t pattern_show(struct device *dev, struct device_attribute *attr, |
| 295 | char *buf) |
| 296 | { |
| 297 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 298 | struct pattern_trig_data *data = led_cdev->trigger_data; |
| 299 | |
| 300 | return pattern_trig_show_patterns(data, buf, false); |
| 301 | } |
| 302 | |
| 303 | static ssize_t pattern_store(struct device *dev, struct device_attribute *attr, |
| 304 | const char *buf, size_t count) |
| 305 | { |
| 306 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 307 | |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 308 | return pattern_trig_store_patterns(led_cdev, buf, NULL, count, false); |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 309 | } |
| 310 | |
| 311 | static DEVICE_ATTR_RW(pattern); |
| 312 | |
| 313 | static ssize_t hw_pattern_show(struct device *dev, |
| 314 | struct device_attribute *attr, char *buf) |
| 315 | { |
| 316 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 317 | struct pattern_trig_data *data = led_cdev->trigger_data; |
| 318 | |
| 319 | return pattern_trig_show_patterns(data, buf, true); |
| 320 | } |
| 321 | |
| 322 | static ssize_t hw_pattern_store(struct device *dev, |
| 323 | struct device_attribute *attr, |
| 324 | const char *buf, size_t count) |
| 325 | { |
| 326 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 327 | |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 328 | return pattern_trig_store_patterns(led_cdev, buf, NULL, count, true); |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 329 | } |
| 330 | |
| 331 | static DEVICE_ATTR_RW(hw_pattern); |
| 332 | |
| 333 | static umode_t pattern_trig_attrs_mode(struct kobject *kobj, |
| 334 | struct attribute *attr, int index) |
| 335 | { |
Tian Tao | 5fe09e1 | 2021-03-22 10:37:16 +0800 | [diff] [blame] | 336 | struct device *dev = kobj_to_dev(kobj); |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 337 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 338 | |
| 339 | if (attr == &dev_attr_repeat.attr || attr == &dev_attr_pattern.attr) |
| 340 | return attr->mode; |
| 341 | else if (attr == &dev_attr_hw_pattern.attr && led_cdev->pattern_set) |
| 342 | return attr->mode; |
| 343 | |
| 344 | return 0; |
| 345 | } |
| 346 | |
| 347 | static struct attribute *pattern_trig_attrs[] = { |
| 348 | &dev_attr_pattern.attr, |
| 349 | &dev_attr_hw_pattern.attr, |
| 350 | &dev_attr_repeat.attr, |
| 351 | NULL |
| 352 | }; |
| 353 | |
| 354 | static const struct attribute_group pattern_trig_group = { |
| 355 | .attrs = pattern_trig_attrs, |
| 356 | .is_visible = pattern_trig_attrs_mode, |
| 357 | }; |
| 358 | |
| 359 | static const struct attribute_group *pattern_trig_groups[] = { |
| 360 | &pattern_trig_group, |
| 361 | NULL, |
| 362 | }; |
| 363 | |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 364 | static void pattern_init(struct led_classdev *led_cdev) |
| 365 | { |
| 366 | unsigned int size = 0; |
| 367 | u32 *pattern; |
| 368 | int err; |
| 369 | |
| 370 | pattern = led_get_default_pattern(led_cdev, &size); |
| 371 | if (!pattern) |
| 372 | return; |
| 373 | |
| 374 | if (size % 2) { |
| 375 | dev_warn(led_cdev->dev, "Expected pattern of tuples\n"); |
| 376 | goto out; |
| 377 | } |
| 378 | |
| 379 | err = pattern_trig_store_patterns(led_cdev, NULL, pattern, size, false); |
| 380 | if (err < 0) |
| 381 | dev_warn(led_cdev->dev, |
| 382 | "Pattern initialization failed with error %d\n", err); |
| 383 | |
| 384 | out: |
| 385 | kfree(pattern); |
| 386 | } |
| 387 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 388 | static int pattern_trig_activate(struct led_classdev *led_cdev) |
| 389 | { |
| 390 | struct pattern_trig_data *data; |
| 391 | |
| 392 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
| 393 | if (!data) |
| 394 | return -ENOMEM; |
| 395 | |
| 396 | if (!!led_cdev->pattern_set ^ !!led_cdev->pattern_clear) { |
| 397 | dev_warn(led_cdev->dev, |
| 398 | "Hardware pattern ops validation failed\n"); |
| 399 | led_cdev->pattern_set = NULL; |
| 400 | led_cdev->pattern_clear = NULL; |
| 401 | } |
| 402 | |
| 403 | data->is_indefinite = true; |
| 404 | data->last_repeat = -1; |
| 405 | mutex_init(&data->lock); |
| 406 | data->led_cdev = led_cdev; |
| 407 | led_set_trigger_data(led_cdev, data); |
| 408 | timer_setup(&data->timer, pattern_trig_timer_function, 0); |
| 409 | led_cdev->activated = true; |
| 410 | |
Krzysztof Kozlowski | aa6fd10 | 2019-01-09 15:44:47 +0100 | [diff] [blame] | 411 | if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) { |
| 412 | pattern_init(led_cdev); |
| 413 | /* |
| 414 | * Mark as initialized even on pattern_init() error because |
| 415 | * any consecutive call to it would produce the same error. |
| 416 | */ |
| 417 | led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER; |
| 418 | } |
| 419 | |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 420 | return 0; |
| 421 | } |
| 422 | |
| 423 | static void pattern_trig_deactivate(struct led_classdev *led_cdev) |
| 424 | { |
| 425 | struct pattern_trig_data *data = led_cdev->trigger_data; |
| 426 | |
| 427 | if (!led_cdev->activated) |
| 428 | return; |
| 429 | |
| 430 | if (led_cdev->pattern_clear) |
| 431 | led_cdev->pattern_clear(led_cdev); |
| 432 | |
Steven Rostedt (Google) | 292a089 | 2022-12-20 13:45:19 -0500 | [diff] [blame] | 433 | timer_shutdown_sync(&data->timer); |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 434 | |
| 435 | led_set_brightness(led_cdev, LED_OFF); |
| 436 | kfree(data); |
| 437 | led_cdev->activated = false; |
| 438 | } |
| 439 | |
| 440 | static struct led_trigger pattern_led_trigger = { |
| 441 | .name = "pattern", |
| 442 | .activate = pattern_trig_activate, |
| 443 | .deactivate = pattern_trig_deactivate, |
| 444 | .groups = pattern_trig_groups, |
| 445 | }; |
| 446 | |
| 447 | static int __init pattern_trig_init(void) |
| 448 | { |
| 449 | return led_trigger_register(&pattern_led_trigger); |
| 450 | } |
| 451 | |
| 452 | static void __exit pattern_trig_exit(void) |
| 453 | { |
| 454 | led_trigger_unregister(&pattern_led_trigger); |
| 455 | } |
| 456 | |
| 457 | module_init(pattern_trig_init); |
| 458 | module_exit(pattern_trig_exit); |
| 459 | |
Pavel Machek | 30d57d5 | 2019-03-10 19:54:40 +0100 | [diff] [blame] | 460 | MODULE_AUTHOR("Raphael Teysseyre <rteysseyre@gmail.com>"); |
| 461 | MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>"); |
Baolin Wang | 5fd752b | 2018-10-11 12:07:14 +0800 | [diff] [blame] | 462 | MODULE_DESCRIPTION("LED Pattern trigger"); |
| 463 | MODULE_LICENSE("GPL v2"); |