leds-turris-omnia.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * CZ.NIC's Turris Omnia LEDs driver
  4 *
  5 * 2020, 2023, 2024 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 <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 */
 30struct 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 */
 49struct 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
 57static 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
 64static 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 */
 83static 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
 92static 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
141static struct led_hw_trigger_type omnia_hw_trigger_type;
142
143static 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
177static 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
198static 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
205static 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 */
290static 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
304static 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}
321static DEVICE_ATTR_RW(brightness);
322
323static 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
340static 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}
359static DEVICE_ATTR_RW(gamma_correction);
360
361static struct attribute *omnia_led_controller_attrs[] = {
362	&dev_attr_brightness.attr,
363	&dev_attr_gamma_correction.attr,
364	NULL
365};
366ATTRIBUTE_GROUPS(omnia_led_controller);
367
368static 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
387static 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
395static 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
421static 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
441static 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
452static 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
468static 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
519static 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
528static const struct of_device_id of_omnia_leds_match[] = {
529	{ .compatible = "cznic,turris-omnia-leds", },
530	{ }
531};
532MODULE_DEVICE_TABLE(of, of_omnia_leds_match);
533
534static const struct i2c_device_id omnia_id[] = {
535	{ "omnia" },
536	{ }
537};
538MODULE_DEVICE_TABLE(i2c, omnia_id);
539
540static 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
551module_i2c_driver(omnia_leds_driver);
552
553MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
554MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
555MODULE_LICENSE("GPL v2");