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 #include "leds.h"
14
15 #define OMNIA_BOARD_LEDS 12
16 #define OMNIA_LED_NUM_CHANNELS 3
17
18 /* MCU controller commands at I2C address 0x2a */
19 #define OMNIA_MCU_I2C_ADDR 0x2a
20
21 #define CMD_GET_STATUS_WORD 0x01
22 #define STS_FEATURES_SUPPORTED BIT(2)
23
24 #define CMD_GET_FEATURES 0x10
25 #define FEAT_LED_GAMMA_CORRECTION BIT(5)
26
27 /* LED controller commands at I2C address 0x2b */
28 #define CMD_LED_MODE 0x03
29 #define CMD_LED_MODE_LED(l) ((l) & 0x0f)
30 #define CMD_LED_MODE_USER 0x10
31
32 #define CMD_LED_STATE 0x04
33 #define CMD_LED_STATE_LED(l) ((l) & 0x0f)
34 #define CMD_LED_STATE_ON 0x10
35
36 #define CMD_LED_COLOR 0x05
37 #define CMD_LED_SET_BRIGHTNESS 0x07
38 #define CMD_LED_GET_BRIGHTNESS 0x08
39
40 #define CMD_SET_GAMMA_CORRECTION 0x30
41 #define CMD_GET_GAMMA_CORRECTION 0x31
42
43 struct omnia_led {
44 struct led_classdev_mc mc_cdev;
45 struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
46 u8 cached_channels[OMNIA_LED_NUM_CHANNELS];
47 bool on, hwtrig;
48 int reg;
49 };
50
51 #define to_omnia_led(l) container_of(l, struct omnia_led, mc_cdev)
52
53 struct omnia_leds {
54 struct i2c_client *client;
55 struct mutex lock;
56 bool has_gamma_correction;
57 struct omnia_led leds[];
58 };
59
omnia_cmd_write_u8(const struct i2c_client * client,u8 cmd,u8 val)60 static int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd, u8 val)
61 {
62 u8 buf[2] = { cmd, val };
63 int ret;
64
65 ret = i2c_master_send(client, buf, sizeof(buf));
66
67 return ret < 0 ? ret : 0;
68 }
69
omnia_cmd_read_raw(struct i2c_adapter * adapter,u8 addr,u8 cmd,void * reply,size_t len)70 static int omnia_cmd_read_raw(struct i2c_adapter *adapter, u8 addr, u8 cmd,
71 void *reply, size_t len)
72 {
73 struct i2c_msg msgs[2];
74 int ret;
75
76 msgs[0].addr = addr;
77 msgs[0].flags = 0;
78 msgs[0].len = 1;
79 msgs[0].buf = &cmd;
80 msgs[1].addr = addr;
81 msgs[1].flags = I2C_M_RD;
82 msgs[1].len = len;
83 msgs[1].buf = reply;
84
85 ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs));
86 if (likely(ret == ARRAY_SIZE(msgs)))
87 return 0;
88 else if (ret < 0)
89 return ret;
90 else
91 return -EIO;
92 }
93
omnia_cmd_read_u8(const struct i2c_client * client,u8 cmd)94 static int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
95 {
96 u8 reply;
97 int err;
98
99 err = omnia_cmd_read_raw(client->adapter, client->addr, cmd, &reply, 1);
100 if (err)
101 return err;
102
103 return reply;
104 }
105
omnia_led_send_color_cmd(const struct i2c_client * client,struct omnia_led * led)106 static int omnia_led_send_color_cmd(const struct i2c_client *client,
107 struct omnia_led *led)
108 {
109 char cmd[5];
110 int ret;
111
112 cmd[0] = CMD_LED_COLOR;
113 cmd[1] = led->reg;
114 cmd[2] = led->subled_info[0].brightness;
115 cmd[3] = led->subled_info[1].brightness;
116 cmd[4] = led->subled_info[2].brightness;
117
118 /* Send the color change command */
119 ret = i2c_master_send(client, cmd, 5);
120 if (ret < 0)
121 return ret;
122
123 /* Cache the RGB channel brightnesses */
124 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
125 led->cached_channels[i] = led->subled_info[i].brightness;
126
127 return 0;
128 }
129
130 /* Determine if the computed RGB channels are different from the cached ones */
omnia_led_channels_changed(struct omnia_led * led)131 static bool omnia_led_channels_changed(struct omnia_led *led)
132 {
133 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
134 if (led->subled_info[i].brightness != led->cached_channels[i])
135 return true;
136
137 return false;
138 }
139
omnia_led_brightness_set_blocking(struct led_classdev * cdev,enum led_brightness brightness)140 static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
141 enum led_brightness brightness)
142 {
143 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
144 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
145 struct omnia_led *led = to_omnia_led(mc_cdev);
146 int err = 0;
147
148 mutex_lock(&leds->lock);
149
150 /*
151 * Only recalculate RGB brightnesses from intensities if brightness is
152 * non-zero (if it is zero and the LED is in HW blinking mode, we use
153 * max_brightness as brightness). Otherwise we won't be using them and
154 * we can save ourselves some software divisions (Omnia's CPU does not
155 * implement the division instruction).
156 */
157 if (brightness || led->hwtrig) {
158 led_mc_calc_color_components(mc_cdev, brightness ?:
159 cdev->max_brightness);
160
161 /*
162 * Send color command only if brightness is non-zero and the RGB
163 * channel brightnesses changed.
164 */
165 if (omnia_led_channels_changed(led))
166 err = omnia_led_send_color_cmd(leds->client, led);
167 }
168
169 /*
170 * Send on/off state change only if (bool)brightness changed and the LED
171 * is not being blinked by HW.
172 */
173 if (!err && !led->hwtrig && !brightness != !led->on) {
174 u8 state = CMD_LED_STATE_LED(led->reg);
175
176 if (brightness)
177 state |= CMD_LED_STATE_ON;
178
179 err = omnia_cmd_write_u8(leds->client, CMD_LED_STATE, state);
180 if (!err)
181 led->on = !!brightness;
182 }
183
184 mutex_unlock(&leds->lock);
185
186 return err;
187 }
188
189 static struct led_hw_trigger_type omnia_hw_trigger_type;
190
omnia_hwtrig_activate(struct led_classdev * cdev)191 static int omnia_hwtrig_activate(struct led_classdev *cdev)
192 {
193 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
194 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
195 struct omnia_led *led = to_omnia_led(mc_cdev);
196 int err = 0;
197
198 mutex_lock(&leds->lock);
199
200 if (!led->on) {
201 /*
202 * If the LED is off (brightness was set to 0), the last
203 * configured color was not necessarily sent to the MCU.
204 * Recompute with max_brightness and send if needed.
205 */
206 led_mc_calc_color_components(mc_cdev, cdev->max_brightness);
207
208 if (omnia_led_channels_changed(led))
209 err = omnia_led_send_color_cmd(leds->client, led);
210 }
211
212 if (!err) {
213 /* Put the LED into MCU controlled mode */
214 err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
215 CMD_LED_MODE_LED(led->reg));
216 if (!err)
217 led->hwtrig = true;
218 }
219
220 mutex_unlock(&leds->lock);
221
222 return err;
223 }
224
omnia_hwtrig_deactivate(struct led_classdev * cdev)225 static void omnia_hwtrig_deactivate(struct led_classdev *cdev)
226 {
227 struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
228 struct omnia_led *led = to_omnia_led(lcdev_to_mccdev(cdev));
229 int err;
230
231 mutex_lock(&leds->lock);
232
233 led->hwtrig = false;
234
235 /* Put the LED into software mode */
236 err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
237 CMD_LED_MODE_LED(led->reg) |
238 CMD_LED_MODE_USER);
239
240 mutex_unlock(&leds->lock);
241
242 if (err)
243 dev_err(cdev->dev, "Cannot put LED to software mode: %i\n",
244 err);
245 }
246
247 static struct led_trigger omnia_hw_trigger = {
248 .name = "omnia-mcu",
249 .activate = omnia_hwtrig_activate,
250 .deactivate = omnia_hwtrig_deactivate,
251 .trigger_type = &omnia_hw_trigger_type,
252 };
253
omnia_led_register(struct i2c_client * client,struct omnia_led * led,struct device_node * np)254 static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
255 struct device_node *np)
256 {
257 struct led_init_data init_data = {};
258 struct device *dev = &client->dev;
259 struct led_classdev *cdev;
260 int ret, color;
261
262 ret = of_property_read_u32(np, "reg", &led->reg);
263 if (ret || led->reg >= OMNIA_BOARD_LEDS) {
264 dev_warn(dev,
265 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
266 np, OMNIA_BOARD_LEDS - 1);
267 return 0;
268 }
269
270 ret = of_property_read_u32(np, "color", &color);
271 if (ret || color != LED_COLOR_ID_RGB) {
272 dev_warn(dev,
273 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
274 np);
275 return 0;
276 }
277
278 led->subled_info[0].color_index = LED_COLOR_ID_RED;
279 led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
280 led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
281
282 /* Initial color is white */
283 for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i) {
284 led->subled_info[i].intensity = 255;
285 led->subled_info[i].brightness = 255;
286 led->subled_info[i].channel = i;
287 }
288
289 led->mc_cdev.subled_info = led->subled_info;
290 led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
291
292 init_data.fwnode = &np->fwnode;
293
294 cdev = &led->mc_cdev.led_cdev;
295 cdev->max_brightness = 255;
296 cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
297 cdev->trigger_type = &omnia_hw_trigger_type;
298 /*
299 * Use the omnia-mcu trigger as the default trigger. It may be rewritten
300 * by LED class from the linux,default-trigger property.
301 */
302 cdev->default_trigger = omnia_hw_trigger.name;
303
304 /* put the LED into software mode */
305 ret = omnia_cmd_write_u8(client, CMD_LED_MODE,
306 CMD_LED_MODE_LED(led->reg) |
307 CMD_LED_MODE_USER);
308 if (ret) {
309 dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
310 ret);
311 return ret;
312 }
313
314 /* disable the LED */
315 ret = omnia_cmd_write_u8(client, CMD_LED_STATE,
316 CMD_LED_STATE_LED(led->reg));
317 if (ret) {
318 dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
319 return ret;
320 }
321
322 /* Set initial color and cache it */
323 ret = omnia_led_send_color_cmd(client, led);
324 if (ret < 0) {
325 dev_err(dev, "Cannot set LED %pOF initial color: %i\n", np,
326 ret);
327 return ret;
328 }
329
330 ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
331 &init_data);
332 if (ret < 0) {
333 dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
334 return ret;
335 }
336
337 return 1;
338 }
339
340 /*
341 * On the front panel of the Turris Omnia router there is also a button which
342 * can be used to control the intensity of all the LEDs at once, so that if they
343 * are too bright, user can dim them.
344 * The microcontroller cycles between 8 levels of this global brightness (from
345 * 100% to 0%), but this setting can have any integer value between 0 and 100.
346 * It is therefore convenient to be able to change this setting from software.
347 * We expose this setting via a sysfs attribute file called "brightness". This
348 * file lives in the device directory of the LED controller, not an individual
349 * LED, so it should not confuse users.
350 */
brightness_show(struct device * dev,struct device_attribute * a,char * buf)351 static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
352 char *buf)
353 {
354 struct i2c_client *client = to_i2c_client(dev);
355 int ret;
356
357 ret = omnia_cmd_read_u8(client, CMD_LED_GET_BRIGHTNESS);
358
359 if (ret < 0)
360 return ret;
361
362 return sysfs_emit(buf, "%d\n", ret);
363 }
364
brightness_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)365 static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
366 const char *buf, size_t count)
367 {
368 struct i2c_client *client = to_i2c_client(dev);
369 unsigned long brightness;
370 int err;
371
372 if (kstrtoul(buf, 10, &brightness))
373 return -EINVAL;
374
375 if (brightness > 100)
376 return -EINVAL;
377
378 err = omnia_cmd_write_u8(client, CMD_LED_SET_BRIGHTNESS, brightness);
379
380 return err ?: count;
381 }
382 static DEVICE_ATTR_RW(brightness);
383
gamma_correction_show(struct device * dev,struct device_attribute * a,char * buf)384 static ssize_t gamma_correction_show(struct device *dev,
385 struct device_attribute *a, char *buf)
386 {
387 struct i2c_client *client = to_i2c_client(dev);
388 struct omnia_leds *leds = i2c_get_clientdata(client);
389 int ret;
390
391 if (leds->has_gamma_correction) {
392 ret = omnia_cmd_read_u8(client, CMD_GET_GAMMA_CORRECTION);
393 if (ret < 0)
394 return ret;
395 } else {
396 ret = 0;
397 }
398
399 return sysfs_emit(buf, "%d\n", !!ret);
400 }
401
gamma_correction_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)402 static ssize_t gamma_correction_store(struct device *dev,
403 struct device_attribute *a,
404 const char *buf, size_t count)
405 {
406 struct i2c_client *client = to_i2c_client(dev);
407 struct omnia_leds *leds = i2c_get_clientdata(client);
408 bool val;
409 int err;
410
411 if (!leds->has_gamma_correction)
412 return -EOPNOTSUPP;
413
414 if (kstrtobool(buf, &val) < 0)
415 return -EINVAL;
416
417 err = omnia_cmd_write_u8(client, CMD_SET_GAMMA_CORRECTION, val);
418
419 return err ?: count;
420 }
421 static DEVICE_ATTR_RW(gamma_correction);
422
423 static struct attribute *omnia_led_controller_attrs[] = {
424 &dev_attr_brightness.attr,
425 &dev_attr_gamma_correction.attr,
426 NULL,
427 };
428 ATTRIBUTE_GROUPS(omnia_led_controller);
429
omnia_mcu_get_features(const struct i2c_client * client)430 static int omnia_mcu_get_features(const struct i2c_client *client)
431 {
432 u16 reply;
433 int err;
434
435 err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
436 CMD_GET_STATUS_WORD, &reply, sizeof(reply));
437 if (err)
438 return err;
439
440 /* Check whether MCU firmware supports the CMD_GET_FEAUTRES command */
441 if (!(le16_to_cpu(reply) & STS_FEATURES_SUPPORTED))
442 return 0;
443
444 err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
445 CMD_GET_FEATURES, &reply, sizeof(reply));
446 if (err)
447 return err;
448
449 return le16_to_cpu(reply);
450 }
451
omnia_leds_probe(struct i2c_client * client)452 static int omnia_leds_probe(struct i2c_client *client)
453 {
454 struct device *dev = &client->dev;
455 struct device_node *np = dev_of_node(dev);
456 struct omnia_leds *leds;
457 struct omnia_led *led;
458 int ret, count;
459
460 count = of_get_available_child_count(np);
461 if (!count) {
462 dev_err(dev, "LEDs are not defined in device tree!\n");
463 return -ENODEV;
464 } else if (count > OMNIA_BOARD_LEDS) {
465 dev_err(dev, "Too many LEDs defined in device tree!\n");
466 return -EINVAL;
467 }
468
469 leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
470 if (!leds)
471 return -ENOMEM;
472
473 leds->client = client;
474 i2c_set_clientdata(client, leds);
475
476 ret = omnia_mcu_get_features(client);
477 if (ret < 0) {
478 dev_err(dev, "Cannot determine MCU supported features: %d\n",
479 ret);
480 return ret;
481 }
482
483 leds->has_gamma_correction = ret & FEAT_LED_GAMMA_CORRECTION;
484 if (!leds->has_gamma_correction) {
485 dev_info(dev,
486 "Your board's MCU firmware does not support the LED gamma correction feature.\n");
487 dev_info(dev,
488 "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
489 }
490
491 mutex_init(&leds->lock);
492
493 ret = devm_led_trigger_register(dev, &omnia_hw_trigger);
494 if (ret < 0) {
495 dev_err(dev, "Cannot register private LED trigger: %d\n", ret);
496 return ret;
497 }
498
499 led = &leds->leds[0];
500 for_each_available_child_of_node_scoped(np, child) {
501 ret = omnia_led_register(client, led, child);
502 if (ret < 0)
503 return ret;
504
505 led += ret;
506 }
507
508 return 0;
509 }
510
omnia_leds_remove(struct i2c_client * client)511 static void omnia_leds_remove(struct i2c_client *client)
512 {
513 u8 buf[5];
514
515 /* put all LEDs into default (HW triggered) mode */
516 omnia_cmd_write_u8(client, CMD_LED_MODE,
517 CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
518
519 /* set all LEDs color to [255, 255, 255] */
520 buf[0] = CMD_LED_COLOR;
521 buf[1] = OMNIA_BOARD_LEDS;
522 buf[2] = 255;
523 buf[3] = 255;
524 buf[4] = 255;
525
526 i2c_master_send(client, buf, 5);
527 }
528
529 static const struct of_device_id of_omnia_leds_match[] = {
530 { .compatible = "cznic,turris-omnia-leds", },
531 {},
532 };
533 MODULE_DEVICE_TABLE(of, of_omnia_leds_match);
534
535 static const struct i2c_device_id omnia_id[] = {
536 { "omnia" },
537 { }
538 };
539 MODULE_DEVICE_TABLE(i2c, omnia_id);
540
541 static struct i2c_driver omnia_leds_driver = {
542 .probe = omnia_leds_probe,
543 .remove = omnia_leds_remove,
544 .id_table = omnia_id,
545 .driver = {
546 .name = "leds-turris-omnia",
547 .of_match_table = of_omnia_leds_match,
548 .dev_groups = omnia_led_controller_groups,
549 },
550 };
551
552 module_i2c_driver(omnia_leds_driver);
553
554 MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
555 MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
556 MODULE_LICENSE("GPL v2");
557