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_MULTI) {
102		dev_warn(dev,
103			 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_MULTI\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	of_property_read_string(np, "linux,default-trigger", &cdev->default_trigger);
125
126	/* put the LED into software mode */
127	ret = i2c_smbus_write_byte_data(client, CMD_LED_MODE,
128					CMD_LED_MODE_LED(led->reg) |
129					CMD_LED_MODE_USER);
130	if (ret < 0) {
131		dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np, ret);
132		return ret;
133	}
134
135	/* disable the LED */
136	ret = i2c_smbus_write_byte_data(client, CMD_LED_STATE, CMD_LED_STATE_LED(led->reg));
137	if (ret < 0) {
138		dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
139		return ret;
140	}
141
142	ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev, &init_data);
143	if (ret < 0) {
144		dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
145		return ret;
146	}
147
148	return 1;
149}
150
151/*
152 * On the front panel of the Turris Omnia router there is also a button which
153 * can be used to control the intensity of all the LEDs at once, so that if they
154 * are too bright, user can dim them.
155 * The microcontroller cycles between 8 levels of this global brightness (from
156 * 100% to 0%), but this setting can have any integer value between 0 and 100.
157 * It is therefore convenient to be able to change this setting from software.
158 * We expose this setting via a sysfs attribute file called "brightness". This
159 * file lives in the device directory of the LED controller, not an individual
160 * LED, so it should not confuse users.
161 */
162static ssize_t brightness_show(struct device *dev, struct device_attribute *a, char *buf)
163{
164	struct i2c_client *client = to_i2c_client(dev);
165	struct omnia_leds *leds = i2c_get_clientdata(client);
166	int ret;
167
168	mutex_lock(&leds->lock);
169	ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
170	mutex_unlock(&leds->lock);
171
172	if (ret < 0)
173		return ret;
174
175	return sprintf(buf, "%d\n", ret);
176}
177
178static ssize_t brightness_store(struct device *dev, struct device_attribute *a, const char *buf,
179				size_t count)
180{
181	struct i2c_client *client = to_i2c_client(dev);
182	struct omnia_leds *leds = i2c_get_clientdata(client);
183	unsigned int brightness;
184	int ret;
185
186	if (sscanf(buf, "%u", &brightness) != 1)
187		return -EINVAL;
188
189	if (brightness > 100)
190		return -EINVAL;
191
192	mutex_lock(&leds->lock);
193	ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS, (u8) brightness);
194	mutex_unlock(&leds->lock);
195
196	if (ret < 0)
197		return ret;
198
199	return count;
200}
201static DEVICE_ATTR_RW(brightness);
202
203static struct attribute *omnia_led_controller_attrs[] = {
204	&dev_attr_brightness.attr,
205	NULL,
206};
207ATTRIBUTE_GROUPS(omnia_led_controller);
208
209static int omnia_leds_probe(struct i2c_client *client,
210			    const struct i2c_device_id *id)
211{
212	struct device *dev = &client->dev;
213	struct device_node *np = dev->of_node, *child;
214	struct omnia_leds *leds;
215	struct omnia_led *led;
216	int ret, count;
217
218	count = of_get_available_child_count(np);
219	if (!count) {
220		dev_err(dev, "LEDs are not defined in device tree!\n");
221		return -ENODEV;
222	} else if (count > OMNIA_BOARD_LEDS) {
223		dev_err(dev, "Too many LEDs defined in device tree!\n");
224		return -EINVAL;
225	}
226
227	leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
228	if (!leds)
229		return -ENOMEM;
230
231	leds->client = client;
232	i2c_set_clientdata(client, leds);
233
234	mutex_init(&leds->lock);
235
236	led = &leds->leds[0];
237	for_each_available_child_of_node(np, child) {
238		ret = omnia_led_register(client, led, child);
239		if (ret < 0)
240			return ret;
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};
280
281static struct i2c_driver omnia_leds_driver = {
282	.probe		= omnia_leds_probe,
283	.remove		= omnia_leds_remove,
284	.id_table	= omnia_id,
285	.driver		= {
286		.name	= "leds-turris-omnia",
287		.of_match_table = of_omnia_leds_match,
288	},
289};
290
291module_i2c_driver(omnia_leds_driver);
292
293MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");
294MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
295MODULE_LICENSE("GPL v2");