1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * CZ.NIC's Turris Omnia LEDs driver
4 *
5 * 2020, 2023 by Marek Behún <kabel@kernel.org>
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
14 #define OMNIA_BOARD_LEDS 12
15 #define OMNIA_LED_NUM_CHANNELS 3
16
17 /* MCU controller commands at I2C address 0x2a */
18 #define OMNIA_MCU_I2C_ADDR 0x2a
19
20 #define CMD_GET_STATUS_WORD 0x01
21 #define STS_FEATURES_SUPPORTED BIT(2)
22
23 #define CMD_GET_FEATURES 0x10
24 #define FEAT_LED_GAMMA_CORRECTION BIT(5)
25
26 /* LED controller commands at I2C address 0x2b */
27 #define CMD_LED_MODE 0x03
28 #define CMD_LED_MODE_LED(l) ((l) & 0x0f)
29 #define CMD_LED_MODE_USER 0x10
30
31 #define CMD_LED_STATE 0x04
32 #define CMD_LED_STATE_LED(l) ((l) & 0x0f)
33 #define CMD_LED_STATE_ON 0x10
34
35 #define CMD_LED_COLOR 0x05
36 #define CMD_LED_SET_BRIGHTNESS 0x07
37 #define CMD_LED_GET_BRIGHTNESS 0x08
38
39 #define CMD_SET_GAMMA_CORRECTION 0x30
40 #define CMD_GET_GAMMA_CORRECTION 0x31
41
42 struct omnia_led {
43 struct led_classdev_mc mc_cdev;
44 struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
45 u8 cached_channels[OMNIA_LED_NUM_CHANNELS];
46 bool on, hwtrig;
47 int reg;
48 };
49
50 #define to_omnia_led(l) container_of(l, struct omnia_led, mc_cdev)
51
52 struct omnia_leds {
53 struct i2c_client *client;
54 struct mutex lock;
55 bool has_gamma_correction;
56 struct omnia_led leds[];
57 };
58
omnia_cmd_write_u8(const struct i2c_client * client,u8 cmd,u8 val)59 static int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd, u8 val)
60 {
61 u8 buf[2] = { cmd, val };
62 int ret;
63
64 ret = i2c_master_send(client, buf, sizeof(buf));
65
66 return ret < 0 ? ret : 0;
67 }
68
omnia_cmd_read_raw(struct i2c_adapter * adapter,u8 addr,u8 cmd,void * reply,size_t len)69 static int omnia_cmd_read_raw(struct i2c_adapter *adapter, u8 addr, u8 cmd,
70 void *reply, size_t len)
71 {
72 struct i2c_msg msgs[2];
73 int ret;
74
75 msgs[0].addr = addr;
76 msgs[0].flags = 0;
77 msgs[0].len = 1;
78 msgs[0].buf = &cmd;
79 msgs[1].addr = addr;
80 msgs[1].flags = I2C_M_RD;
81 msgs[1].len = len;
82 msgs[1].buf = reply;
83
84 ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs));
85 if (likely(ret == ARRAY_SIZE(msgs)))
86 return 0;
87 else if (ret < 0)
88 return ret;
89 else
90 return -EIO;
91 }
92
omnia_cmd_read_u8(const struct i2c_client * client,u8 cmd)93 static int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
94 {
95 u8 reply;
96 int err;
97
98 err = omnia_cmd_read_raw(client->adapter, client->addr, cmd, &reply, 1);
99 if (err)
100 return err;
101
102 return reply;
103 }
104
omnia_led_send_color_cmd(const struct i2c_client * client,struct omnia_led * led)105 static int omnia_led_send_color_cmd(const struct i2c_client *client,
106 struct omnia_led *led)
107 {
108 char cmd[5];
109 int ret;
110
111 cmd[0] = CMD_LED_COLOR;
112 cmd[1] = led->reg;
113 cmd[2] = led->subled_info[0].brightness;
114 cmd[3] = led->subled_info[1].brightness;
115 cmd[4] = led->subled_info[2].brightness;
116
117 /* Send the color change command */
118 ret = i2c_master_send(client, cmd, 5);
119 if (ret < 0)
120 return ret;
121
122 /* Cache the RGB channel brightnesses */
123 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
124 led->cached_channels[i] = led->subled_info[i].brightness;
125
126 return 0;
127 }
128
129 /* Determine if the computed RGB channels are different from the cached ones */
omnia_led_channels_changed(struct omnia_led * led)130 static bool omnia_led_channels_changed(struct omnia_led *led)
131 {
132 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
133 if (led->subled_info[i].brightness != led->cached_channels[i])
134 return true;
135
136 return false;
137 }
138
omnia_led_brightness_set_blocking(struct led_classdev * cdev,enum led_brightness brightness)139 static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
140 enum led_brightness brightness)
141 {
142 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
143 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
144 struct omnia_led *led = to_omnia_led(mc_cdev);
145 int err = 0;
146
147 mutex_lock(&leds->lock);
148
149 /*
150 * Only recalculate RGB brightnesses from intensities if brightness is
151 * non-zero (if it is zero and the LED is in HW blinking mode, we use
152 * max_brightness as brightness). Otherwise we won't be using them and
153 * we can save ourselves some software divisions (Omnia's CPU does not
154 * implement the division instruction).
155 */
156 if (brightness || led->hwtrig) {
157 led_mc_calc_color_components(mc_cdev, brightness ?:
158 cdev->max_brightness);
159
160 /*
161 * Send color command only if brightness is non-zero and the RGB
162 * channel brightnesses changed.
163 */
164 if (omnia_led_channels_changed(led))
165 err = omnia_led_send_color_cmd(leds->client, led);
166 }
167
168 /*
169 * Send on/off state change only if (bool)brightness changed and the LED
170 * is not being blinked by HW.
171 */
172 if (!err && !led->hwtrig && !brightness != !led->on) {
173 u8 state = CMD_LED_STATE_LED(led->reg);
174
175 if (brightness)
176 state |= CMD_LED_STATE_ON;
177
178 err = omnia_cmd_write_u8(leds->client, CMD_LED_STATE, state);
179 if (!err)
180 led->on = !!brightness;
181 }
182
183 mutex_unlock(&leds->lock);
184
185 return err;
186 }
187
188 static struct led_hw_trigger_type omnia_hw_trigger_type;
189
omnia_hwtrig_activate(struct led_classdev * cdev)190 static int omnia_hwtrig_activate(struct led_classdev *cdev)
191 {
192 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
193 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
194 struct omnia_led *led = to_omnia_led(mc_cdev);
195 int err = 0;
196
197 mutex_lock(&leds->lock);
198
199 if (!led->on) {
200 /*
201 * If the LED is off (brightness was set to 0), the last
202 * configured color was not necessarily sent to the MCU.
203 * Recompute with max_brightness and send if needed.
204 */
205 led_mc_calc_color_components(mc_cdev, cdev->max_brightness);
206
207 if (omnia_led_channels_changed(led))
208 err = omnia_led_send_color_cmd(leds->client, led);
209 }
210
211 if (!err) {
212 /* Put the LED into MCU controlled mode */
213 err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
214 CMD_LED_MODE_LED(led->reg));
215 if (!err)
216 led->hwtrig = true;
217 }
218
219 mutex_unlock(&leds->lock);
220
221 return err;
222 }
223
omnia_hwtrig_deactivate(struct led_classdev * cdev)224 static void omnia_hwtrig_deactivate(struct led_classdev *cdev)
225 {
226 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
227 struct omnia_led *led = to_omnia_led(lcdev_to_mccdev(cdev));
228 int err;
229
230 mutex_lock(&leds->lock);
231
232 led->hwtrig = false;
233
234 /* Put the LED into software mode */
235 err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
236 CMD_LED_MODE_LED(led->reg) |
237 CMD_LED_MODE_USER);
238
239 mutex_unlock(&leds->lock);
240
241 if (err)
242 dev_err(cdev->dev, "Cannot put LED to software mode: %i\n",
243 err);
244 }
245
246 static struct led_trigger omnia_hw_trigger = {
247 .name = "omnia-mcu",
248 .activate = omnia_hwtrig_activate,
249 .deactivate = omnia_hwtrig_deactivate,
250 .trigger_type = &omnia_hw_trigger_type,
251 };
252
omnia_led_register(struct i2c_client * client,struct omnia_led * led,struct device_node * np)253 static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
254 struct device_node *np)
255 {
256 struct led_init_data init_data = {};
257 struct device *dev = &client->dev;
258 struct led_classdev *cdev;
259 int ret, color;
260
261 ret = of_property_read_u32(np, "reg", &led->reg);
262 if (ret || led->reg >= OMNIA_BOARD_LEDS) {
263 dev_warn(dev,
264 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
265 np, OMNIA_BOARD_LEDS - 1);
266 return 0;
267 }
268
269 ret = of_property_read_u32(np, "color", &color);
270 if (ret || color != LED_COLOR_ID_RGB) {
271 dev_warn(dev,
272 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
273 np);
274 return 0;
275 }
276
277 led->subled_info[0].color_index = LED_COLOR_ID_RED;
278 led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
279 led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
280
281 /* Initial color is white */
282 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i) {
283 led->subled_info[i].intensity = 255;
284 led->subled_info[i].brightness = 255;
285 led->subled_info[i].channel = i;
286 }
287
288 led->mc_cdev.subled_info = led->subled_info;
289 led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
290
291 init_data.fwnode = &np->fwnode;
292
293 cdev = &led->mc_cdev.led_cdev;
294 cdev->max_brightness = 255;
295 cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
296 cdev->trigger_type = &omnia_hw_trigger_type;
297 /*
298 * Use the omnia-mcu trigger as the default trigger. It may be rewritten
299 * by LED class from the linux,default-trigger property.
300 */
301 cdev->default_trigger = omnia_hw_trigger.name;
302
303 /* put the LED into software mode */
304 ret = omnia_cmd_write_u8(client, CMD_LED_MODE,
305 CMD_LED_MODE_LED(led->reg) |
306 CMD_LED_MODE_USER);
307 if (ret) {
308 dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
309 ret);
310 return ret;
311 }
312
313 /* disable the LED */
314 ret = omnia_cmd_write_u8(client, CMD_LED_STATE,
315 CMD_LED_STATE_LED(led->reg));
316 if (ret) {
317 dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
318 return ret;
319 }
320
321 /* Set initial color and cache it */
322 ret = omnia_led_send_color_cmd(client, led);
323 if (ret < 0) {
324 dev_err(dev, "Cannot set LED %pOF initial color: %i\n", np,
325 ret);
326 return ret;
327 }
328
329 ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
330 &init_data);
331 if (ret < 0) {
332 dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
333 return ret;
334 }
335
336 return 1;
337 }
338
339 /*
340 * On the front panel of the Turris Omnia router there is also a button which
341 * can be used to control the intensity of all the LEDs at once, so that if they
342 * are too bright, user can dim them.
343 * The microcontroller cycles between 8 levels of this global brightness (from
344 * 100% to 0%), but this setting can have any integer value between 0 and 100.
345 * It is therefore convenient to be able to change this setting from software.
346 * We expose this setting via a sysfs attribute file called "brightness". This
347 * file lives in the device directory of the LED controller, not an individual
348 * LED, so it should not confuse users.
349 */
brightness_show(struct device * dev,struct device_attribute * a,char * buf)350 static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
351 char *buf)
352 {
353 struct i2c_client *client = to_i2c_client(dev);
354 int ret;
355
356 ret = omnia_cmd_read_u8(client, CMD_LED_GET_BRIGHTNESS);
357
358 if (ret < 0)
359 return ret;
360
361 return sysfs_emit(buf, "%d\n", ret);
362 }
363
brightness_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)364 static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
365 const char *buf, size_t count)
366 {
367 struct i2c_client *client = to_i2c_client(dev);
368 unsigned long brightness;
369 int err;
370
371 if (kstrtoul(buf, 10, &brightness))
372 return -EINVAL;
373
374 if (brightness > 100)
375 return -EINVAL;
376
377 err = omnia_cmd_write_u8(client, CMD_LED_SET_BRIGHTNESS, brightness);
378
379 return err ?: count;
380 }
381 static DEVICE_ATTR_RW(brightness);
382
gamma_correction_show(struct device * dev,struct device_attribute * a,char * buf)383 static ssize_t gamma_correction_show(struct device *dev,
384 struct device_attribute *a, char *buf)
385 {
386 struct i2c_client *client = to_i2c_client(dev);
387 struct omnia_leds *leds = i2c_get_clientdata(client);
388 int ret;
389
390 if (leds->has_gamma_correction) {
391 ret = omnia_cmd_read_u8(client, CMD_GET_GAMMA_CORRECTION);
392 if (ret < 0)
393 return ret;
394 } else {
395 ret = 0;
396 }
397
398 return sysfs_emit(buf, "%d\n", !!ret);
399 }
400
gamma_correction_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)401 static ssize_t gamma_correction_store(struct device *dev,
402 struct device_attribute *a,
403 const char *buf, size_t count)
404 {
405 struct i2c_client *client = to_i2c_client(dev);
406 struct omnia_leds *leds = i2c_get_clientdata(client);
407 bool val;
408 int err;
409
410 if (!leds->has_gamma_correction)
411 return -EOPNOTSUPP;
412
413 if (kstrtobool(buf, &val) < 0)
414 return -EINVAL;
415
416 err = omnia_cmd_write_u8(client, CMD_SET_GAMMA_CORRECTION, val);
417
418 return err ?: count;
419 }
420 static DEVICE_ATTR_RW(gamma_correction);
421
422 static struct attribute *omnia_led_controller_attrs[] = {
423 &dev_attr_brightness.attr,
424 &dev_attr_gamma_correction.attr,
425 NULL,
426 };
427 ATTRIBUTE_GROUPS(omnia_led_controller);
428
omnia_mcu_get_features(const struct i2c_client * client)429 static int omnia_mcu_get_features(const struct i2c_client *client)
430 {
431 u16 reply;
432 int err;
433
434 err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
435 CMD_GET_STATUS_WORD, &reply, sizeof(reply));
436 if (err)
437 return err;
438
439 /* Check whether MCU firmware supports the CMD_GET_FEAUTRES command */
440 if (!(le16_to_cpu(reply) & STS_FEATURES_SUPPORTED))
441 return 0;
442
443 err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
444 CMD_GET_FEATURES, &reply, sizeof(reply));
445 if (err)
446 return err;
447
448 return le16_to_cpu(reply);
449 }
450
omnia_leds_probe(struct i2c_client * client)451 static int omnia_leds_probe(struct i2c_client *client)
452 {
453 struct device *dev = &client->dev;
454 struct device_node *np = dev_of_node(dev);
455 struct omnia_leds *leds;
456 struct omnia_led *led;
457 int ret, count;
458
459 count = of_get_available_child_count(np);
460 if (!count) {
461 dev_err(dev, "LEDs are not defined in device tree!\n");
462 return -ENODEV;
463 } else if (count > OMNIA_BOARD_LEDS) {
464 dev_err(dev, "Too many LEDs defined in device tree!\n");
465 return -EINVAL;
466 }
467
468 leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
469 if (!leds)
470 return -ENOMEM;
471
472 leds->client = client;
473 i2c_set_clientdata(client, leds);
474
475 ret = omnia_mcu_get_features(client);
476 if (ret < 0) {
477 dev_err(dev, "Cannot determine MCU supported features: %d\n",
478 ret);
479 return ret;
480 }
481
482 leds->has_gamma_correction = ret & FEAT_LED_GAMMA_CORRECTION;
483 if (!leds->has_gamma_correction) {
484 dev_info(dev,
485 "Your board's MCU firmware does not support the LED gamma correction feature.\n");
486 dev_info(dev,
487 "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
488 }
489
490 mutex_init(&leds->lock);
491
492 ret = devm_led_trigger_register(dev, &omnia_hw_trigger);
493 if (ret < 0) {
494 dev_err(dev, "Cannot register private LED trigger: %d\n", ret);
495 return ret;
496 }
497
498 led = &leds->leds[0];
499 for_each_available_child_of_node_scoped(np, child) {
500 ret = omnia_led_register(client, led, child);
501 if (ret < 0)
502 return ret;
503
504 led += ret;
505 }
506
507 return 0;
508 }
509
omnia_leds_remove(struct i2c_client * client)510 static void omnia_leds_remove(struct i2c_client *client)
511 {
512 u8 buf[5];
513
514 /* put all LEDs into default (HW triggered) mode */
515 omnia_cmd_write_u8(client, CMD_LED_MODE,
516 CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
517
518 /* set all LEDs color to [255, 255, 255] */
519 buf[0] = CMD_LED_COLOR;
520 buf[1] = OMNIA_BOARD_LEDS;
521 buf[2] = 255;
522 buf[3] = 255;
523 buf[4] = 255;
524
525 i2c_master_send(client, buf, 5);
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 <kabel@kernel.org>");
554 MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
555 MODULE_LICENSE("GPL v2");
556