xref: /linux/drivers/leds/leds-turris-omnia.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
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 
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 
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 
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 
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 */
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 
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 
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 
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 
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  */
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 
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 
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 
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 
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 
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 
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