1// SPDX-License-Identifier: GPL-2.0
2/*
3 * CZ.NIC's Turris Omnia LEDs driver
4 *
5 * 2020 by Marek Behun <marek.behun@nic.cz>
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#define CMD_LED_MODE			3
19#define CMD_LED_MODE_LED(l)		((l) & 0x0f)
20#define CMD_LED_MODE_USER		0x10
21
22#define CMD_LED_STATE			4
23#define CMD_LED_STATE_LED(l)		((l) & 0x0f)
24#define CMD_LED_STATE_ON		0x10
25
26#define CMD_LED_COLOR			5
27#define CMD_LED_SET_BRIGHTNESS		7
28#define CMD_LED_GET_BRIGHTNESS		8
29
30#define OMNIA_CMD			0
31
32#define OMNIA_CMD_LED_COLOR_LED		1
33#define OMNIA_CMD_LED_COLOR_R		2
34#define OMNIA_CMD_LED_COLOR_G		3
35#define OMNIA_CMD_LED_COLOR_B		4
36#define OMNIA_CMD_LED_COLOR_LEN		5
37
38struct omnia_led {
39	struct led_classdev_mc mc_cdev;
40	struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
41	int reg;
42};
43
44#define to_omnia_led(l)			container_of(l, struct omnia_led, mc_cdev)
45
46struct omnia_leds {
47	struct i2c_client *client;
48	struct mutex lock;
49	struct omnia_led leds[];
50};
51
52static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
53					     enum led_brightness brightness)
54{
55	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
56	struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
57	struct omnia_led *led = to_omnia_led(mc_cdev);
58	u8 buf[OMNIA_CMD_LED_COLOR_LEN], state;
59	int ret;
60
61	mutex_lock(&leds->lock);
62
63	led_mc_calc_color_components(&led->mc_cdev, brightness);
64
65	buf[OMNIA_CMD] = CMD_LED_COLOR;
66	buf[OMNIA_CMD_LED_COLOR_LED] = led->reg;
67	buf[OMNIA_CMD_LED_COLOR_R] = mc_cdev->subled_info[0].brightness;
68	buf[OMNIA_CMD_LED_COLOR_G] = mc_cdev->subled_info[1].brightness;
69	buf[OMNIA_CMD_LED_COLOR_B] = mc_cdev->subled_info[2].brightness;
70
71	state = CMD_LED_STATE_LED(led->reg);
72	if (buf[OMNIA_CMD_LED_COLOR_R] || buf[OMNIA_CMD_LED_COLOR_G] || buf[OMNIA_CMD_LED_COLOR_B])
73		state |= CMD_LED_STATE_ON;
74
75	ret = i2c_smbus_write_byte_data(leds->client, CMD_LED_STATE, state);
76	if (ret >= 0 && (state & CMD_LED_STATE_ON))
77		ret = i2c_master_send(leds->client, buf, 5);
78
79	mutex_unlock(&leds->lock);
80
81	return ret;
82}
83
84static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
85			      struct device_node *np)
86{
87	struct led_init_data init_data = {};
88	struct device *dev = &client->dev;
89	struct led_classdev *cdev;
90	int ret, color;
91
92	ret = of_property_read_u32(np, "reg", &led->reg);
93	if (ret || led->reg >= OMNIA_BOARD_LEDS) {
94		dev_warn(dev,
95			 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
96			 np, OMNIA_BOARD_LEDS - 1);
97		return 0;
98	}
99
100	ret = of_property_read_u32(np, "color", &color);
101	if (ret || color != LED_COLOR_ID_RGB) {
102		dev_warn(dev,
103			 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
104			 np);
105		return 0;
106	}
107
108	led->subled_info[0].color_index = LED_COLOR_ID_RED;
109	led->subled_info[0].channel = 0;
110	led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
111	led->subled_info[1].channel = 1;
112	led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
113	led->subled_info[2].channel = 2;
114
115	led->mc_cdev.subled_info = led->subled_info;
116	led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
117
118	init_data.fwnode = &np->fwnode;
119
120	cdev = &led->mc_cdev.led_cdev;
121	cdev->max_brightness = 255;
122	cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
123
124	/* put the LED into software mode */
125	ret = i2c_smbus_write_byte_data(client, CMD_LED_MODE,
126					CMD_LED_MODE_LED(led->reg) |
127					CMD_LED_MODE_USER);
128	if (ret < 0) {
129		dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np, ret);
130		return ret;
131	}
132
133	/* disable the LED */
134	ret = i2c_smbus_write_byte_data(client, CMD_LED_STATE, CMD_LED_STATE_LED(led->reg));
135	if (ret < 0) {
136		dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
137		return ret;
138	}
139
140	ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev, &init_data);
141	if (ret < 0) {
142		dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
143		return ret;
144	}
145
146	return 1;
147}
148
149/*
150 * On the front panel of the Turris Omnia router there is also a button which
151 * can be used to control the intensity of all the LEDs at once, so that if they
152 * are too bright, user can dim them.
153 * The microcontroller cycles between 8 levels of this global brightness (from
154 * 100% to 0%), but this setting can have any integer value between 0 and 100.
155 * It is therefore convenient to be able to change this setting from software.
156 * We expose this setting via a sysfs attribute file called "brightness". This
157 * file lives in the device directory of the LED controller, not an individual
158 * LED, so it should not confuse users.
159 */
160static ssize_t brightness_show(struct device *dev, struct device_attribute *a, char *buf)
161{
162	struct i2c_client *client = to_i2c_client(dev);
163	struct omnia_leds *leds = i2c_get_clientdata(client);
164	int ret;
165
166	mutex_lock(&leds->lock);
167	ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
168	mutex_unlock(&leds->lock);
169
170	if (ret < 0)
171		return ret;
172
173	return sprintf(buf, "%d\n", ret);
174}
175
176static ssize_t brightness_store(struct device *dev, struct device_attribute *a, const char *buf,
177				size_t count)
178{
179	struct i2c_client *client = to_i2c_client(dev);
180	struct omnia_leds *leds = i2c_get_clientdata(client);
181	unsigned int brightness;
182	int ret;
183
184	if (sscanf(buf, "%u", &brightness) != 1)
185		return -EINVAL;
186
187	if (brightness > 100)
188		return -EINVAL;
189
190	mutex_lock(&leds->lock);
191	ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS, (u8) brightness);
192	mutex_unlock(&leds->lock);
193
194	if (ret < 0)
195		return ret;
196
197	return count;
198}
199static DEVICE_ATTR_RW(brightness);
200
201static struct attribute *omnia_led_controller_attrs[] = {
202	&dev_attr_brightness.attr,
203	NULL,
204};
205ATTRIBUTE_GROUPS(omnia_led_controller);
206
207static int omnia_leds_probe(struct i2c_client *client,
208			    const struct i2c_device_id *id)
209{
210	struct device *dev = &client->dev;
211	struct device_node *np = dev_of_node(dev), *child;
212	struct omnia_leds *leds;
213	struct omnia_led *led;
214	int ret, count;
215
216	count = of_get_available_child_count(np);
217	if (!count) {
218		dev_err(dev, "LEDs are not defined in device tree!\n");
219		return -ENODEV;
220	} else if (count > OMNIA_BOARD_LEDS) {
221		dev_err(dev, "Too many LEDs defined in device tree!\n");
222		return -EINVAL;
223	}
224
225	leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
226	if (!leds)
227		return -ENOMEM;
228
229	leds->client = client;
230	i2c_set_clientdata(client, leds);
231
232	mutex_init(&leds->lock);
233
234	led = &leds->leds[0];
235	for_each_available_child_of_node(np, child) {
236		ret = omnia_led_register(client, led, child);
237		if (ret < 0) {
238			of_node_put(child);
239			return ret;
240		}
241
242		led += ret;
243	}
244
245	if (devm_device_add_groups(dev, omnia_led_controller_groups))
246		dev_warn(dev, "Could not add attribute group!\n");
247
248	return 0;
249}
250
251static int omnia_leds_remove(struct i2c_client *client)
252{
253	u8 buf[OMNIA_CMD_LED_COLOR_LEN];
254
255	/* put all LEDs into default (HW triggered) mode */
256	i2c_smbus_write_byte_data(client, CMD_LED_MODE,
257				  CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
258
259	/* set all LEDs color to [255, 255, 255] */
260	buf[OMNIA_CMD] = CMD_LED_COLOR;
261	buf[OMNIA_CMD_LED_COLOR_LED] = OMNIA_BOARD_LEDS;
262	buf[OMNIA_CMD_LED_COLOR_R] = 255;
263	buf[OMNIA_CMD_LED_COLOR_G] = 255;
264	buf[OMNIA_CMD_LED_COLOR_B] = 255;
265
266	i2c_master_send(client, buf, 5);
267
268	return 0;
269}
270
271static const struct of_device_id of_omnia_leds_match[] = {
272	{ .compatible = "cznic,turris-omnia-leds", },
273	{},
274};
275
276static const struct i2c_device_id omnia_id[] = {
277	{ "omnia", 0 },
278	{ }
279};
280MODULE_DEVICE_TABLE(i2c, omnia_id);
281
282static struct i2c_driver omnia_leds_driver = {
283	.probe		= omnia_leds_probe,
284	.remove		= omnia_leds_remove,
285	.id_table	= omnia_id,
286	.driver		= {
287		.name	= "leds-turris-omnia",
288		.of_match_table = of_omnia_leds_match,
289	},
290};
291
292module_i2c_driver(omnia_leds_driver);
293
294MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");
295MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
296MODULE_LICENSE("GPL v2");
297