1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * CZ.NIC's Turris Omnia LEDs driver
4 *
5 * 2020, 2023, 2024 by Marek Behún <[email protected]>
6 */
7
8 #include <linux/i2c.h>
9 #include <linux/led-class-multicolor.h>
10 #include <linux/module.h>
11 #include <linux/mutex.h>
12 #include <linux/of.h>
13 #include <linux/turris-omnia-mcu-interface.h>
14
15 #define OMNIA_BOARD_LEDS 12
16 #define OMNIA_LED_NUM_CHANNELS 3
17
18 /* MCU controller I2C address 0x2a, needed for detecting MCU features */
19 #define OMNIA_MCU_I2C_ADDR 0x2a
20
21 /**
22 * struct omnia_led - per-LED part of driver private data structure
23 * @mc_cdev: multi-color LED class device
24 * @subled_info: per-channel information
25 * @cached_channels: cached values of per-channel brightness that was sent to the MCU
26 * @on: whether the LED was set on
27 * @hwtrig: whether the LED blinking was offloaded to the MCU
28 * @reg: LED identifier to the MCU
29 */
30 struct omnia_led {
31 struct led_classdev_mc mc_cdev;
32 struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
33 u8 cached_channels[OMNIA_LED_NUM_CHANNELS];
34 bool on, hwtrig;
35 int reg;
36 };
37
38 #define to_omnia_led(l) container_of(l, struct omnia_led, mc_cdev)
39
40 /**
41 * struct omnia_leds - driver private data structure
42 * @client: I2C client device
43 * @lock: mutex to protect cached state
44 * @has_gamma_correction: whether the MCU firmware supports gamma correction
45 * @brightness_knode: kernel node of the "brightness" device sysfs attribute (this is the
46 * driver specific global brightness, not the LED classdev brightness)
47 * @leds: flexible array of per-LED data
48 */
49 struct omnia_leds {
50 struct i2c_client *client;
51 struct mutex lock;
52 bool has_gamma_correction;
53 struct kernfs_node *brightness_knode;
54 struct omnia_led leds[];
55 };
56
omnia_cmd_set_color(const struct i2c_client * client,u8 led,u8 r,u8 g,u8 b)57 static int omnia_cmd_set_color(const struct i2c_client *client, u8 led, u8 r, u8 g, u8 b)
58 {
59 u8 buf[5] = { OMNIA_CMD_LED_COLOR, led, r, g, b };
60
61 return omnia_cmd_write(client, buf, sizeof(buf));
62 }
63
omnia_led_send_color_cmd(const struct i2c_client * client,struct omnia_led * led)64 static int omnia_led_send_color_cmd(const struct i2c_client *client,
65 struct omnia_led *led)
66 {
67 int ret;
68
69 /* Send the color change command */
70 ret = omnia_cmd_set_color(client, led->reg, led->subled_info[0].brightness,
71 led->subled_info[1].brightness, led->subled_info[2].brightness);
72 if (ret < 0)
73 return ret;
74
75 /* Cache the RGB channel brightnesses */
76 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
77 led->cached_channels[i] = led->subled_info[i].brightness;
78
79 return 0;
80 }
81
82 /* Determine if the computed RGB channels are different from the cached ones */
omnia_led_channels_changed(struct omnia_led * led)83 static bool omnia_led_channels_changed(struct omnia_led *led)
84 {
85 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
86 if (led->subled_info[i].brightness != led->cached_channels[i])
87 return true;
88
89 return false;
90 }
91
omnia_led_brightness_set_blocking(struct led_classdev * cdev,enum led_brightness brightness)92 static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
93 enum led_brightness brightness)
94 {
95 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
96 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
97 struct omnia_led *led = to_omnia_led(mc_cdev);
98 int err = 0;
99
100 mutex_lock(&leds->lock);
101
102 /*
103 * Only recalculate RGB brightnesses from intensities if brightness is
104 * non-zero (if it is zero and the LED is in HW blinking mode, we use
105 * max_brightness as brightness). Otherwise we won't be using them and
106 * we can save ourselves some software divisions (Omnia's CPU does not
107 * implement the division instruction).
108 */
109 if (brightness || led->hwtrig) {
110 led_mc_calc_color_components(mc_cdev, brightness ?:
111 cdev->max_brightness);
112
113 /*
114 * Send color command only if brightness is non-zero and the RGB
115 * channel brightnesses changed.
116 */
117 if (omnia_led_channels_changed(led))
118 err = omnia_led_send_color_cmd(leds->client, led);
119 }
120
121 /*
122 * Send on/off state change only if (bool)brightness changed and the LED
123 * is not being blinked by HW.
124 */
125 if (!err && !led->hwtrig && !brightness != !led->on) {
126 u8 state = OMNIA_CMD_LED_STATE_LED(led->reg);
127
128 if (brightness)
129 state |= OMNIA_CMD_LED_STATE_ON;
130
131 err = omnia_cmd_write_u8(leds->client, OMNIA_CMD_LED_STATE, state);
132 if (!err)
133 led->on = !!brightness;
134 }
135
136 mutex_unlock(&leds->lock);
137
138 return err;
139 }
140
141 static struct led_hw_trigger_type omnia_hw_trigger_type;
142
omnia_hwtrig_activate(struct led_classdev * cdev)143 static int omnia_hwtrig_activate(struct led_classdev *cdev)
144 {
145 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
146 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
147 struct omnia_led *led = to_omnia_led(mc_cdev);
148 int err = 0;
149
150 mutex_lock(&leds->lock);
151
152 if (!led->on) {
153 /*
154 * If the LED is off (brightness was set to 0), the last
155 * configured color was not necessarily sent to the MCU.
156 * Recompute with max_brightness and send if needed.
157 */
158 led_mc_calc_color_components(mc_cdev, cdev->max_brightness);
159
160 if (omnia_led_channels_changed(led))
161 err = omnia_led_send_color_cmd(leds->client, led);
162 }
163
164 if (!err) {
165 /* Put the LED into MCU controlled mode */
166 err = omnia_cmd_write_u8(leds->client, OMNIA_CMD_LED_MODE,
167 OMNIA_CMD_LED_MODE_LED(led->reg));
168 if (!err)
169 led->hwtrig = true;
170 }
171
172 mutex_unlock(&leds->lock);
173
174 return err;
175 }
176
omnia_hwtrig_deactivate(struct led_classdev * cdev)177 static void omnia_hwtrig_deactivate(struct led_classdev *cdev)
178 {
179 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
180 struct omnia_led *led = to_omnia_led(lcdev_to_mccdev(cdev));
181 int err;
182
183 mutex_lock(&leds->lock);
184
185 led->hwtrig = false;
186
187 /* Put the LED into software mode */
188 err = omnia_cmd_write_u8(leds->client, OMNIA_CMD_LED_MODE,
189 OMNIA_CMD_LED_MODE_LED(led->reg) | OMNIA_CMD_LED_MODE_USER);
190
191 mutex_unlock(&leds->lock);
192
193 if (err)
194 dev_err(cdev->dev, "Cannot put LED to software mode: %i\n",
195 err);
196 }
197
198 static struct led_trigger omnia_hw_trigger = {
199 .name = "omnia-mcu",
200 .activate = omnia_hwtrig_activate,
201 .deactivate = omnia_hwtrig_deactivate,
202 .trigger_type = &omnia_hw_trigger_type,
203 };
204
omnia_led_register(struct i2c_client * client,struct omnia_led * led,struct device_node * np)205 static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
206 struct device_node *np)
207 {
208 struct led_init_data init_data = {};
209 struct device *dev = &client->dev;
210 struct led_classdev *cdev;
211 int ret, color;
212
213 ret = of_property_read_u32(np, "reg", &led->reg);
214 if (ret || led->reg >= OMNIA_BOARD_LEDS) {
215 dev_warn(dev,
216 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
217 np, OMNIA_BOARD_LEDS - 1);
218 return 0;
219 }
220
221 ret = of_property_read_u32(np, "color", &color);
222 if (ret || color != LED_COLOR_ID_RGB) {
223 dev_warn(dev,
224 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
225 np);
226 return 0;
227 }
228
229 led->subled_info[0].color_index = LED_COLOR_ID_RED;
230 led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
231 led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
232
233 /* Initial color is white */
234 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i) {
235 led->subled_info[i].intensity = 255;
236 led->subled_info[i].brightness = 255;
237 led->subled_info[i].channel = i;
238 }
239
240 led->mc_cdev.subled_info = led->subled_info;
241 led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
242
243 init_data.fwnode = &np->fwnode;
244
245 cdev = &led->mc_cdev.led_cdev;
246 cdev->max_brightness = 255;
247 cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
248 cdev->trigger_type = &omnia_hw_trigger_type;
249 /*
250 * Use the omnia-mcu trigger as the default trigger. It may be rewritten
251 * by LED class from the linux,default-trigger property.
252 */
253 cdev->default_trigger = omnia_hw_trigger.name;
254
255 /* Put the LED into software mode */
256 ret = omnia_cmd_write_u8(client, OMNIA_CMD_LED_MODE, OMNIA_CMD_LED_MODE_LED(led->reg) |
257 OMNIA_CMD_LED_MODE_USER);
258 if (ret)
259 return dev_err_probe(dev, ret, "Cannot set LED %pOF to software mode\n", np);
260
261 /* Disable the LED */
262 ret = omnia_cmd_write_u8(client, OMNIA_CMD_LED_STATE, OMNIA_CMD_LED_STATE_LED(led->reg));
263 if (ret)
264 return dev_err_probe(dev, ret, "Cannot set LED %pOF brightness\n", np);
265
266 /* Set initial color and cache it */
267 ret = omnia_led_send_color_cmd(client, led);
268 if (ret < 0)
269 return dev_err_probe(dev, ret, "Cannot set LED %pOF initial color\n", np);
270
271 ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
272 &init_data);
273 if (ret < 0)
274 return dev_err_probe(dev, ret, "Cannot register LED %pOF\n", np);
275
276 return 1;
277 }
278
279 /*
280 * On the front panel of the Turris Omnia router there is also a button which
281 * can be used to control the intensity of all the LEDs at once, so that if they
282 * are too bright, user can dim them.
283 * The microcontroller cycles between 8 levels of this global brightness (from
284 * 100% to 0%), but this setting can have any integer value between 0 and 100.
285 * It is therefore convenient to be able to change this setting from software.
286 * We expose this setting via a sysfs attribute file called "brightness". This
287 * file lives in the device directory of the LED controller, not an individual
288 * LED, so it should not confuse users.
289 */
brightness_show(struct device * dev,struct device_attribute * a,char * buf)290 static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
291 char *buf)
292 {
293 struct i2c_client *client = to_i2c_client(dev);
294 u8 reply;
295 int err;
296
297 err = omnia_cmd_read_u8(client, OMNIA_CMD_GET_BRIGHTNESS, &reply);
298 if (err < 0)
299 return err;
300
301 return sysfs_emit(buf, "%d\n", reply);
302 }
303
brightness_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)304 static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
305 const char *buf, size_t count)
306 {
307 struct i2c_client *client = to_i2c_client(dev);
308 unsigned long brightness;
309 int err;
310
311 if (kstrtoul(buf, 10, &brightness))
312 return -EINVAL;
313
314 if (brightness > 100)
315 return -EINVAL;
316
317 err = omnia_cmd_write_u8(client, OMNIA_CMD_SET_BRIGHTNESS, brightness);
318
319 return err ?: count;
320 }
321 static DEVICE_ATTR_RW(brightness);
322
gamma_correction_show(struct device * dev,struct device_attribute * a,char * buf)323 static ssize_t gamma_correction_show(struct device *dev,
324 struct device_attribute *a, char *buf)
325 {
326 struct i2c_client *client = to_i2c_client(dev);
327 struct omnia_leds *leds = i2c_get_clientdata(client);
328 u8 reply = 0;
329 int err;
330
331 if (leds->has_gamma_correction) {
332 err = omnia_cmd_read_u8(client, OMNIA_CMD_GET_GAMMA_CORRECTION, &reply);
333 if (err < 0)
334 return err;
335 }
336
337 return sysfs_emit(buf, "%d\n", !!reply);
338 }
339
gamma_correction_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)340 static ssize_t gamma_correction_store(struct device *dev,
341 struct device_attribute *a,
342 const char *buf, size_t count)
343 {
344 struct i2c_client *client = to_i2c_client(dev);
345 struct omnia_leds *leds = i2c_get_clientdata(client);
346 bool val;
347 int err;
348
349 if (!leds->has_gamma_correction)
350 return -EOPNOTSUPP;
351
352 if (kstrtobool(buf, &val) < 0)
353 return -EINVAL;
354
355 err = omnia_cmd_write_u8(client, OMNIA_CMD_SET_GAMMA_CORRECTION, val);
356
357 return err ?: count;
358 }
359 static DEVICE_ATTR_RW(gamma_correction);
360
361 static struct attribute *omnia_led_controller_attrs[] = {
362 &dev_attr_brightness.attr,
363 &dev_attr_gamma_correction.attr,
364 NULL,
365 };
366 ATTRIBUTE_GROUPS(omnia_led_controller);
367
omnia_brightness_changed_threaded_fn(int irq,void * data)368 static irqreturn_t omnia_brightness_changed_threaded_fn(int irq, void *data)
369 {
370 struct omnia_leds *leds = data;
371
372 if (unlikely(!leds->brightness_knode)) {
373 /*
374 * Note that sysfs_get_dirent() may sleep. This is okay, because we are in threaded
375 * context.
376 */
377 leds->brightness_knode = sysfs_get_dirent(leds->client->dev.kobj.sd, "brightness");
378 if (!leds->brightness_knode)
379 return IRQ_NONE;
380 }
381
382 sysfs_notify_dirent(leds->brightness_knode);
383
384 return IRQ_HANDLED;
385 }
386
omnia_brightness_knode_put(void * data)387 static void omnia_brightness_knode_put(void *data)
388 {
389 struct omnia_leds *leds = data;
390
391 if (leds->brightness_knode)
392 sysfs_put(leds->brightness_knode);
393 }
394
omnia_request_brightness_irq(struct omnia_leds * leds)395 static int omnia_request_brightness_irq(struct omnia_leds *leds)
396 {
397 struct device *dev = &leds->client->dev;
398 int ret;
399
400 if (!leds->client->irq) {
401 dev_info(dev,
402 "Brightness change interrupt supported by MCU firmware but not described in device-tree\n");
403
404 return 0;
405 }
406
407 /*
408 * Registering the brightness_knode destructor before requesting the IRQ ensures that on
409 * removal the brightness_knode sysfs node is put only after the IRQ is freed.
410 * This is needed because the interrupt handler uses the knode.
411 */
412 ret = devm_add_action(dev, omnia_brightness_knode_put, leds);
413 if (ret < 0)
414 return ret;
415
416 return devm_request_threaded_irq(dev, leds->client->irq, NULL,
417 omnia_brightness_changed_threaded_fn, IRQF_ONESHOT,
418 "leds-turris-omnia", leds);
419 }
420
omnia_mcu_get_features(const struct i2c_client * mcu_client)421 static int omnia_mcu_get_features(const struct i2c_client *mcu_client)
422 {
423 u16 reply;
424 int err;
425
426 err = omnia_cmd_read_u16(mcu_client, OMNIA_CMD_GET_STATUS_WORD, &reply);
427 if (err)
428 return err;
429
430 /* Check whether MCU firmware supports the OMNIA_CMD_GET_FEAUTRES command */
431 if (!(reply & OMNIA_STS_FEATURES_SUPPORTED))
432 return 0;
433
434 err = omnia_cmd_read_u16(mcu_client, OMNIA_CMD_GET_FEATURES, &reply);
435 if (err)
436 return err;
437
438 return reply;
439 }
440
omnia_match_mcu_client(struct device * dev,const void * data)441 static int omnia_match_mcu_client(struct device *dev, const void *data)
442 {
443 struct i2c_client *client;
444
445 client = i2c_verify_client(dev);
446 if (!client)
447 return 0;
448
449 return client->addr == OMNIA_MCU_I2C_ADDR;
450 }
451
omnia_find_mcu_and_get_features(struct device * dev)452 static int omnia_find_mcu_and_get_features(struct device *dev)
453 {
454 struct device *mcu_dev;
455 int ret;
456
457 mcu_dev = device_find_child(dev->parent, NULL, omnia_match_mcu_client);
458 if (!mcu_dev)
459 return -ENODEV;
460
461 ret = omnia_mcu_get_features(i2c_verify_client(mcu_dev));
462
463 put_device(mcu_dev);
464
465 return ret;
466 }
467
omnia_leds_probe(struct i2c_client * client)468 static int omnia_leds_probe(struct i2c_client *client)
469 {
470 struct device *dev = &client->dev;
471 struct device_node *np = dev_of_node(dev);
472 struct omnia_leds *leds;
473 struct omnia_led *led;
474 int ret, count;
475
476 count = of_get_available_child_count(np);
477 if (count == 0)
478 return dev_err_probe(dev, -ENODEV, "LEDs are not defined in device tree!\n");
479 if (count > OMNIA_BOARD_LEDS)
480 return dev_err_probe(dev, -EINVAL, "Too many LEDs defined in device tree!\n");
481
482 leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
483 if (!leds)
484 return -ENOMEM;
485
486 leds->client = client;
487 i2c_set_clientdata(client, leds);
488
489 ret = omnia_find_mcu_and_get_features(dev);
490 if (ret < 0)
491 return dev_err_probe(dev, ret, "Cannot determine MCU supported features\n");
492
493 leds->has_gamma_correction = ret & OMNIA_FEAT_LED_GAMMA_CORRECTION;
494
495 if (ret & OMNIA_FEAT_BRIGHTNESS_INT) {
496 ret = omnia_request_brightness_irq(leds);
497 if (ret < 0)
498 return dev_err_probe(dev, ret, "Cannot request brightness IRQ\n");
499 }
500
501 mutex_init(&leds->lock);
502
503 ret = devm_led_trigger_register(dev, &omnia_hw_trigger);
504 if (ret < 0)
505 return dev_err_probe(dev, ret, "Cannot register private LED trigger\n");
506
507 led = &leds->leds[0];
508 for_each_available_child_of_node_scoped(np, child) {
509 ret = omnia_led_register(client, led, child);
510 if (ret < 0)
511 return ret;
512
513 led += ret;
514 }
515
516 return 0;
517 }
518
omnia_leds_remove(struct i2c_client * client)519 static void omnia_leds_remove(struct i2c_client *client)
520 {
521 /* Put all LEDs into default (HW triggered) mode */
522 omnia_cmd_write_u8(client, OMNIA_CMD_LED_MODE, OMNIA_CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
523
524 /* Set all LEDs color to [255, 255, 255] */
525 omnia_cmd_set_color(client, OMNIA_BOARD_LEDS, 255, 255, 255);
526 }
527
528 static const struct of_device_id of_omnia_leds_match[] = {
529 { .compatible = "cznic,turris-omnia-leds", },
530 {},
531 };
532 MODULE_DEVICE_TABLE(of, of_omnia_leds_match);
533
534 static const struct i2c_device_id omnia_id[] = {
535 { "omnia" },
536 { }
537 };
538 MODULE_DEVICE_TABLE(i2c, omnia_id);
539
540 static struct i2c_driver omnia_leds_driver = {
541 .probe = omnia_leds_probe,
542 .remove = omnia_leds_remove,
543 .id_table = omnia_id,
544 .driver = {
545 .name = "leds-turris-omnia",
546 .of_match_table = of_omnia_leds_match,
547 .dev_groups = omnia_led_controller_groups,
548 },
549 };
550
551 module_i2c_driver(omnia_leds_driver);
552
553 MODULE_AUTHOR("Marek Behun <[email protected]>");
554 MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
555 MODULE_LICENSE("GPL v2");
556