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
 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_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
 76static 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 */
155static 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
172static 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}
196static DEVICE_ATTR_RW(brightness);
197
198static struct attribute *omnia_led_controller_attrs[] = {
199	&dev_attr_brightness.attr,
200	NULL,
201};
202ATTRIBUTE_GROUPS(omnia_led_controller);
203
204static int omnia_leds_probe(struct i2c_client *client,
205			    const struct i2c_device_id *id)
206{
207	struct device *dev = &client->dev;
208	struct device_node *np = dev_of_node(dev), *child;
209	struct omnia_leds *leds;
210	struct omnia_led *led;
211	int ret, count;
212
213	count = of_get_available_child_count(np);
214	if (!count) {
215		dev_err(dev, "LEDs are not defined in device tree!\n");
216		return -ENODEV;
217	} else if (count > OMNIA_BOARD_LEDS) {
218		dev_err(dev, "Too many LEDs defined in device tree!\n");
219		return -EINVAL;
220	}
221
222	leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
223	if (!leds)
224		return -ENOMEM;
225
226	leds->client = client;
227	i2c_set_clientdata(client, leds);
228
229	mutex_init(&leds->lock);
230
231	led = &leds->leds[0];
232	for_each_available_child_of_node(np, child) {
233		ret = omnia_led_register(client, led, child);
234		if (ret < 0) {
235			of_node_put(child);
236			return ret;
237		}
238
239		led += ret;
240	}
241
242	return 0;
243}
244
245static void omnia_leds_remove(struct i2c_client *client)
246{
247	u8 buf[5];
248
249	/* put all LEDs into default (HW triggered) mode */
250	i2c_smbus_write_byte_data(client, CMD_LED_MODE,
251				  CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
252
253	/* set all LEDs color to [255, 255, 255] */
254	buf[0] = CMD_LED_COLOR;
255	buf[1] = OMNIA_BOARD_LEDS;
256	buf[2] = 255;
257	buf[3] = 255;
258	buf[4] = 255;
259
260	i2c_master_send(client, buf, 5);
261}
262
263static const struct of_device_id of_omnia_leds_match[] = {
264	{ .compatible = "cznic,turris-omnia-leds", },
265	{},
266};
267
268static const struct i2c_device_id omnia_id[] = {
269	{ "omnia", 0 },
270	{ }
271};
272MODULE_DEVICE_TABLE(i2c, omnia_id);
273
274static struct i2c_driver omnia_leds_driver = {
275	.probe		= omnia_leds_probe,
276	.remove		= omnia_leds_remove,
277	.id_table	= omnia_id,
278	.driver		= {
279		.name	= "leds-turris-omnia",
280		.of_match_table = of_omnia_leds_match,
281		.dev_groups = omnia_led_controller_groups,
282	},
283};
284
285module_i2c_driver(omnia_leds_driver);
286
287MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
288MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
289MODULE_LICENSE("GPL v2");