1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * CZ.NIC's Turris Omnia LEDs driver
4  *
5  * 2020 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 
30 struct 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 
38 struct omnia_leds {
39 	struct i2c_client *client;
40 	struct mutex lock;
41 	struct omnia_led leds[];
42 };
43 
44 static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
45 					     enum led_brightness brightness)
46 {
47 	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
48 	struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
49 	struct omnia_led *led = to_omnia_led(mc_cdev);
50 	u8 buf[5], state;
51 	int ret;
52 
53 	mutex_lock(&leds->lock);
54 
55 	led_mc_calc_color_components(&led->mc_cdev, brightness);
56 
57 	buf[0] = CMD_LED_COLOR;
58 	buf[1] = led->reg;
59 	buf[2] = mc_cdev->subled_info[0].brightness;
60 	buf[3] = mc_cdev->subled_info[1].brightness;
61 	buf[4] = mc_cdev->subled_info[2].brightness;
62 
63 	state = CMD_LED_STATE_LED(led->reg);
64 	if (buf[2] || buf[3] || buf[4])
65 		state |= CMD_LED_STATE_ON;
66 
67 	ret = i2c_smbus_write_byte_data(leds->client, CMD_LED_STATE, state);
68 	if (ret >= 0 && (state & CMD_LED_STATE_ON))
69 		ret = i2c_master_send(leds->client, buf, 5);
70 
71 	mutex_unlock(&leds->lock);
72 
73 	return ret;
74 }
75 
76 static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
77 			      struct device_node *np)
78 {
79 	struct led_init_data init_data = {};
80 	struct device *dev = &client->dev;
81 	struct led_classdev *cdev;
82 	int ret, color;
83 
84 	ret = of_property_read_u32(np, "reg", &led->reg);
85 	if (ret || led->reg >= OMNIA_BOARD_LEDS) {
86 		dev_warn(dev,
87 			 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
88 			 np, OMNIA_BOARD_LEDS - 1);
89 		return 0;
90 	}
91 
92 	ret = of_property_read_u32(np, "color", &color);
93 	if (ret || color != LED_COLOR_ID_RGB) {
94 		dev_warn(dev,
95 			 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
96 			 np);
97 		return 0;
98 	}
99 
100 	led->subled_info[0].color_index = LED_COLOR_ID_RED;
101 	led->subled_info[0].channel = 0;
102 	led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
103 	led->subled_info[1].channel = 1;
104 	led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
105 	led->subled_info[2].channel = 2;
106 
107 	led->mc_cdev.subled_info = led->subled_info;
108 	led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
109 
110 	init_data.fwnode = &np->fwnode;
111 
112 	cdev = &led->mc_cdev.led_cdev;
113 	cdev->max_brightness = 255;
114 	cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
115 
116 	/* put the LED into software mode */
117 	ret = i2c_smbus_write_byte_data(client, CMD_LED_MODE,
118 					CMD_LED_MODE_LED(led->reg) |
119 					CMD_LED_MODE_USER);
120 	if (ret < 0) {
121 		dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
122 			ret);
123 		return ret;
124 	}
125 
126 	/* disable the LED */
127 	ret = i2c_smbus_write_byte_data(client, CMD_LED_STATE,
128 					CMD_LED_STATE_LED(led->reg));
129 	if (ret < 0) {
130 		dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
131 		return ret;
132 	}
133 
134 	ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
135 							&init_data);
136 	if (ret < 0) {
137 		dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
138 		return ret;
139 	}
140 
141 	return 1;
142 }
143 
144 /*
145  * On the front panel of the Turris Omnia router there is also a button which
146  * can be used to control the intensity of all the LEDs at once, so that if they
147  * are too bright, user can dim them.
148  * The microcontroller cycles between 8 levels of this global brightness (from
149  * 100% to 0%), but this setting can have any integer value between 0 and 100.
150  * It is therefore convenient to be able to change this setting from software.
151  * We expose this setting via a sysfs attribute file called "brightness". This
152  * file lives in the device directory of the LED controller, not an individual
153  * LED, so it should not confuse users.
154  */
155 static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
156 			       char *buf)
157 {
158 	struct i2c_client *client = to_i2c_client(dev);
159 	struct omnia_leds *leds = i2c_get_clientdata(client);
160 	int ret;
161 
162 	mutex_lock(&leds->lock);
163 	ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
164 	mutex_unlock(&leds->lock);
165 
166 	if (ret < 0)
167 		return ret;
168 
169 	return sprintf(buf, "%d\n", ret);
170 }
171 
172 static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
173 				const char *buf, size_t count)
174 {
175 	struct i2c_client *client = to_i2c_client(dev);
176 	struct omnia_leds *leds = i2c_get_clientdata(client);
177 	unsigned long brightness;
178 	int ret;
179 
180 	if (kstrtoul(buf, 10, &brightness))
181 		return -EINVAL;
182 
183 	if (brightness > 100)
184 		return -EINVAL;
185 
186 	mutex_lock(&leds->lock);
187 	ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS,
188 					(u8)brightness);
189 	mutex_unlock(&leds->lock);
190 
191 	if (ret < 0)
192 		return ret;
193 
194 	return count;
195 }
196 static DEVICE_ATTR_RW(brightness);
197 
198 static struct attribute *omnia_led_controller_attrs[] = {
199 	&dev_attr_brightness.attr,
200 	NULL,
201 };
202 ATTRIBUTE_GROUPS(omnia_led_controller);
203 
204 static int omnia_leds_probe(struct i2c_client *client)
205 {
206 	struct device *dev = &client->dev;
207 	struct device_node *np = dev_of_node(dev), *child;
208 	struct omnia_leds *leds;
209 	struct omnia_led *led;
210 	int ret, count;
211 
212 	count = of_get_available_child_count(np);
213 	if (!count) {
214 		dev_err(dev, "LEDs are not defined in device tree!\n");
215 		return -ENODEV;
216 	} else if (count > OMNIA_BOARD_LEDS) {
217 		dev_err(dev, "Too many LEDs defined in device tree!\n");
218 		return -EINVAL;
219 	}
220 
221 	leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
222 	if (!leds)
223 		return -ENOMEM;
224 
225 	leds->client = client;
226 	i2c_set_clientdata(client, leds);
227 
228 	mutex_init(&leds->lock);
229 
230 	led = &leds->leds[0];
231 	for_each_available_child_of_node(np, child) {
232 		ret = omnia_led_register(client, led, child);
233 		if (ret < 0) {
234 			of_node_put(child);
235 			return ret;
236 		}
237 
238 		led += ret;
239 	}
240 
241 	return 0;
242 }
243 
244 static void omnia_leds_remove(struct i2c_client *client)
245 {
246 	u8 buf[5];
247 
248 	/* put all LEDs into default (HW triggered) mode */
249 	i2c_smbus_write_byte_data(client, CMD_LED_MODE,
250 				  CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
251 
252 	/* set all LEDs color to [255, 255, 255] */
253 	buf[0] = CMD_LED_COLOR;
254 	buf[1] = OMNIA_BOARD_LEDS;
255 	buf[2] = 255;
256 	buf[3] = 255;
257 	buf[4] = 255;
258 
259 	i2c_master_send(client, buf, 5);
260 }
261 
262 static const struct of_device_id of_omnia_leds_match[] = {
263 	{ .compatible = "cznic,turris-omnia-leds", },
264 	{},
265 };
266 
267 static const struct i2c_device_id omnia_id[] = {
268 	{ "omnia", 0 },
269 	{ }
270 };
271 MODULE_DEVICE_TABLE(i2c, omnia_id);
272 
273 static struct i2c_driver omnia_leds_driver = {
274 	.probe_new	= omnia_leds_probe,
275 	.remove		= omnia_leds_remove,
276 	.id_table	= omnia_id,
277 	.driver		= {
278 		.name	= "leds-turris-omnia",
279 		.of_match_table = of_omnia_leds_match,
280 		.dev_groups = omnia_led_controller_groups,
281 	},
282 };
283 
284 module_i2c_driver(omnia_leds_driver);
285 
286 MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
287 MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
288 MODULE_LICENSE("GPL v2");
289