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#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
30struct omnia_led {
31	struct led_classdev_mc mc_cdev;
32	struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
33	int reg;
34};
35
36#define to_omnia_led(l)		container_of(l, struct omnia_led, mc_cdev)
37
38struct omnia_leds {
39	struct i2c_client *client;
40	struct mutex lock;
41	struct omnia_led leds[];
42};
43
44static int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd, u8 val)
45{
46	u8 buf[2] = { cmd, val };
47
48	return i2c_master_send(client, buf, sizeof(buf));
49}
50
51static int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
52{
53	struct i2c_msg msgs[2];
54	u8 reply;
55	int ret;
56
57	msgs[0].addr = client->addr;
58	msgs[0].flags = 0;
59	msgs[0].len = 1;
60	msgs[0].buf = &cmd;
61	msgs[1].addr = client->addr;
62	msgs[1].flags = I2C_M_RD;
63	msgs[1].len = 1;
64	msgs[1].buf = &reply;
65
66	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
67	if (likely(ret == ARRAY_SIZE(msgs)))
68		return reply;
69	else if (ret < 0)
70		return ret;
71	else
72		return -EIO;
73}
74
75static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
76					     enum led_brightness brightness)
77{
78	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
79	struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
80	struct omnia_led *led = to_omnia_led(mc_cdev);
81	u8 buf[5], state;
82	int ret;
83
84	mutex_lock(&leds->lock);
85
86	led_mc_calc_color_components(&led->mc_cdev, brightness);
87
88	buf[0] = CMD_LED_COLOR;
89	buf[1] = led->reg;
90	buf[2] = mc_cdev->subled_info[0].brightness;
91	buf[3] = mc_cdev->subled_info[1].brightness;
92	buf[4] = mc_cdev->subled_info[2].brightness;
93
94	state = CMD_LED_STATE_LED(led->reg);
95	if (buf[2] || buf[3] || buf[4])
96		state |= CMD_LED_STATE_ON;
97
98	ret = omnia_cmd_write_u8(leds->client, CMD_LED_STATE, state);
99	if (ret >= 0 && (state & CMD_LED_STATE_ON))
100		ret = i2c_master_send(leds->client, buf, 5);
101
102	mutex_unlock(&leds->lock);
103
104	return ret;
105}
106
107static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
108			      struct device_node *np)
109{
110	struct led_init_data init_data = {};
111	struct device *dev = &client->dev;
112	struct led_classdev *cdev;
113	int ret, color;
114
115	ret = of_property_read_u32(np, "reg", &led->reg);
116	if (ret || led->reg >= OMNIA_BOARD_LEDS) {
117		dev_warn(dev,
118			 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
119			 np, OMNIA_BOARD_LEDS - 1);
120		return 0;
121	}
122
123	ret = of_property_read_u32(np, "color", &color);
124	if (ret || color != LED_COLOR_ID_RGB) {
125		dev_warn(dev,
126			 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
127			 np);
128		return 0;
129	}
130
131	led->subled_info[0].color_index = LED_COLOR_ID_RED;
132	led->subled_info[0].channel = 0;
133	led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
134	led->subled_info[1].channel = 1;
135	led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
136	led->subled_info[2].channel = 2;
137
138	led->mc_cdev.subled_info = led->subled_info;
139	led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
140
141	init_data.fwnode = &np->fwnode;
142
143	cdev = &led->mc_cdev.led_cdev;
144	cdev->max_brightness = 255;
145	cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
146
147	/* put the LED into software mode */
148	ret = omnia_cmd_write_u8(client, CMD_LED_MODE,
149				 CMD_LED_MODE_LED(led->reg) |
150				 CMD_LED_MODE_USER);
151	if (ret < 0) {
152		dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
153			ret);
154		return ret;
155	}
156
157	/* disable the LED */
158	ret = omnia_cmd_write_u8(client, CMD_LED_STATE,
159				 CMD_LED_STATE_LED(led->reg));
160	if (ret < 0) {
161		dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
162		return ret;
163	}
164
165	ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
166							&init_data);
167	if (ret < 0) {
168		dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
169		return ret;
170	}
171
172	return 1;
173}
174
175/*
176 * On the front panel of the Turris Omnia router there is also a button which
177 * can be used to control the intensity of all the LEDs at once, so that if they
178 * are too bright, user can dim them.
179 * The microcontroller cycles between 8 levels of this global brightness (from
180 * 100% to 0%), but this setting can have any integer value between 0 and 100.
181 * It is therefore convenient to be able to change this setting from software.
182 * We expose this setting via a sysfs attribute file called "brightness". This
183 * file lives in the device directory of the LED controller, not an individual
184 * LED, so it should not confuse users.
185 */
186static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
187			       char *buf)
188{
189	struct i2c_client *client = to_i2c_client(dev);
190	int ret;
191
192	ret = omnia_cmd_read_u8(client, CMD_LED_GET_BRIGHTNESS);
193
194	if (ret < 0)
195		return ret;
196
197	return sysfs_emit(buf, "%d\n", ret);
198}
199
200static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
201				const char *buf, size_t count)
202{
203	struct i2c_client *client = to_i2c_client(dev);
204	unsigned long brightness;
205	int ret;
206
207	if (kstrtoul(buf, 10, &brightness))
208		return -EINVAL;
209
210	if (brightness > 100)
211		return -EINVAL;
212
213	ret = omnia_cmd_write_u8(client, CMD_LED_SET_BRIGHTNESS, brightness);
214
215	return ret < 0 ? ret : count;
216}
217static DEVICE_ATTR_RW(brightness);
218
219static struct attribute *omnia_led_controller_attrs[] = {
220	&dev_attr_brightness.attr,
221	NULL,
222};
223ATTRIBUTE_GROUPS(omnia_led_controller);
224
225static int omnia_leds_probe(struct i2c_client *client)
226{
227	struct device *dev = &client->dev;
228	struct device_node *np = dev_of_node(dev), *child;
229	struct omnia_leds *leds;
230	struct omnia_led *led;
231	int ret, count;
232
233	count = of_get_available_child_count(np);
234	if (!count) {
235		dev_err(dev, "LEDs are not defined in device tree!\n");
236		return -ENODEV;
237	} else if (count > OMNIA_BOARD_LEDS) {
238		dev_err(dev, "Too many LEDs defined in device tree!\n");
239		return -EINVAL;
240	}
241
242	leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
243	if (!leds)
244		return -ENOMEM;
245
246	leds->client = client;
247	i2c_set_clientdata(client, leds);
248
249	mutex_init(&leds->lock);
250
251	led = &leds->leds[0];
252	for_each_available_child_of_node(np, child) {
253		ret = omnia_led_register(client, led, child);
254		if (ret < 0) {
255			of_node_put(child);
256			return ret;
257		}
258
259		led += ret;
260	}
261
262	return 0;
263}
264
265static void omnia_leds_remove(struct i2c_client *client)
266{
267	u8 buf[5];
268
269	/* put all LEDs into default (HW triggered) mode */
270	omnia_cmd_write_u8(client, CMD_LED_MODE,
271			   CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
272
273	/* set all LEDs color to [255, 255, 255] */
274	buf[0] = CMD_LED_COLOR;
275	buf[1] = OMNIA_BOARD_LEDS;
276	buf[2] = 255;
277	buf[3] = 255;
278	buf[4] = 255;
279
280	i2c_master_send(client, buf, 5);
281}
282
283static const struct of_device_id of_omnia_leds_match[] = {
284	{ .compatible = "cznic,turris-omnia-leds", },
285	{},
286};
287
288static const struct i2c_device_id omnia_id[] = {
289	{ "omnia", 0 },
290	{ }
291};
292MODULE_DEVICE_TABLE(i2c, omnia_id);
293
294static struct i2c_driver omnia_leds_driver = {
295	.probe		= omnia_leds_probe,
296	.remove		= omnia_leds_remove,
297	.id_table	= omnia_id,
298	.driver		= {
299		.name	= "leds-turris-omnia",
300		.of_match_table = of_omnia_leds_match,
301		.dev_groups = omnia_led_controller_groups,
302	},
303};
304
305module_i2c_driver(omnia_leds_driver);
306
307MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
308MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
309MODULE_LICENSE("GPL v2");
310