1// SPDX-License-Identifier: GPL-2.0+
2//
3// Driver for Panasonic AN30259A 3-channel LED driver
4//
5// Copyright (c) 2018 Simon Shields <simon@lineageos.org>
6//
7// Datasheet:
8// https://www.alliedelec.com/m/d/a9d2b3ee87c2d1a535a41dd747b1c247.pdf
9
10#include <linux/i2c.h>
11#include <linux/leds.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/of.h>
15#include <linux/regmap.h>
16
17#define AN30259A_MAX_LEDS 3
18
19#define AN30259A_REG_SRESET 0x00
20#define AN30259A_LED_SRESET BIT(0)
21
22/* LED power registers */
23#define AN30259A_REG_LED_ON 0x01
24#define AN30259A_LED_EN(x) BIT((x) - 1)
25#define AN30259A_LED_SLOPE(x) BIT(((x) - 1) + 4)
26
27#define AN30259A_REG_LEDCC(x) (0x03 + ((x) - 1))
28
29/* slope control registers */
30#define AN30259A_REG_SLOPE(x) (0x06 + ((x) - 1))
31#define AN30259A_LED_SLOPETIME1(x) (x)
32#define AN30259A_LED_SLOPETIME2(x) ((x) << 4)
33
34#define AN30259A_REG_LEDCNT1(x) (0x09 + (4 * ((x) - 1)))
35#define AN30259A_LED_DUTYMAX(x) ((x) << 4)
36#define AN30259A_LED_DUTYMID(x) (x)
37
38#define AN30259A_REG_LEDCNT2(x) (0x0A + (4 * ((x) - 1)))
39#define AN30259A_LED_DELAY(x) ((x) << 4)
40#define AN30259A_LED_DUTYMIN(x) (x)
41
42/* detention time control (length of each slope step) */
43#define AN30259A_REG_LEDCNT3(x) (0x0B + (4 * ((x) - 1)))
44#define AN30259A_LED_DT1(x) (x)
45#define AN30259A_LED_DT2(x) ((x) << 4)
46
47#define AN30259A_REG_LEDCNT4(x) (0x0C + (4 * ((x) - 1)))
48#define AN30259A_LED_DT3(x) (x)
49#define AN30259A_LED_DT4(x) ((x) << 4)
50
51#define AN30259A_REG_MAX 0x14
52
53#define AN30259A_BLINK_MAX_TIME 7500 /* ms */
54#define AN30259A_SLOPE_RESOLUTION 500 /* ms */
55
56#define AN30259A_NAME "an30259a"
57
58#define STATE_OFF 0
59#define STATE_KEEP 1
60#define STATE_ON 2
61
62struct an30259a;
63
64struct an30259a_led {
65	struct an30259a *chip;
66	struct fwnode_handle *fwnode;
67	struct led_classdev cdev;
68	u32 num;
69	u32 default_state;
70	bool sloping;
71};
72
73struct an30259a {
74	struct mutex mutex; /* held when writing to registers */
75	struct i2c_client *client;
76	struct an30259a_led leds[AN30259A_MAX_LEDS];
77	struct regmap *regmap;
78	int num_leds;
79};
80
81static int an30259a_brightness_set(struct led_classdev *cdev,
82				   enum led_brightness brightness)
83{
84	struct an30259a_led *led;
85	int ret;
86	unsigned int led_on;
87
88	led = container_of(cdev, struct an30259a_led, cdev);
89	mutex_lock(&led->chip->mutex);
90
91	ret = regmap_read(led->chip->regmap, AN30259A_REG_LED_ON, &led_on);
92	if (ret)
93		goto error;
94
95	switch (brightness) {
96	case LED_OFF:
97		led_on &= ~AN30259A_LED_EN(led->num);
98		led_on &= ~AN30259A_LED_SLOPE(led->num);
99		led->sloping = false;
100		break;
101	default:
102		led_on |= AN30259A_LED_EN(led->num);
103		if (led->sloping)
104			led_on |= AN30259A_LED_SLOPE(led->num);
105		ret = regmap_write(led->chip->regmap,
106				   AN30259A_REG_LEDCNT1(led->num),
107				   AN30259A_LED_DUTYMAX(0xf) |
108				   AN30259A_LED_DUTYMID(0xf));
109		if (ret)
110			goto error;
111		break;
112	}
113
114	ret = regmap_write(led->chip->regmap, AN30259A_REG_LED_ON, led_on);
115	if (ret)
116		goto error;
117
118	ret = regmap_write(led->chip->regmap, AN30259A_REG_LEDCC(led->num),
119			   brightness);
120
121error:
122	mutex_unlock(&led->chip->mutex);
123
124	return ret;
125}
126
127static int an30259a_blink_set(struct led_classdev *cdev,
128			      unsigned long *delay_off, unsigned long *delay_on)
129{
130	struct an30259a_led *led;
131	int ret, num;
132	unsigned int led_on;
133	unsigned long off = *delay_off, on = *delay_on;
134
135	led = container_of(cdev, struct an30259a_led, cdev);
136
137	mutex_lock(&led->chip->mutex);
138	num = led->num;
139
140	/* slope time can only be a multiple of 500ms. */
141	if (off % AN30259A_SLOPE_RESOLUTION || on % AN30259A_SLOPE_RESOLUTION) {
142		ret = -EINVAL;
143		goto error;
144	}
145
146	/* up to a maximum of 7500ms. */
147	if (off > AN30259A_BLINK_MAX_TIME || on > AN30259A_BLINK_MAX_TIME) {
148		ret = -EINVAL;
149		goto error;
150	}
151
152	/* if no blink specified, default to 1 Hz. */
153	if (!off && !on) {
154		*delay_off = off = 500;
155		*delay_on = on = 500;
156	}
157
158	/* convert into values the HW will understand. */
159	off /= AN30259A_SLOPE_RESOLUTION;
160	on /= AN30259A_SLOPE_RESOLUTION;
161
162	/* duty min should be zero (=off), delay should be zero. */
163	ret = regmap_write(led->chip->regmap, AN30259A_REG_LEDCNT2(num),
164			   AN30259A_LED_DELAY(0) | AN30259A_LED_DUTYMIN(0));
165	if (ret)
166		goto error;
167
168	/* reset detention time (no "breathing" effect). */
169	ret = regmap_write(led->chip->regmap, AN30259A_REG_LEDCNT3(num),
170			   AN30259A_LED_DT1(0) | AN30259A_LED_DT2(0));
171	if (ret)
172		goto error;
173	ret = regmap_write(led->chip->regmap, AN30259A_REG_LEDCNT4(num),
174			   AN30259A_LED_DT3(0) | AN30259A_LED_DT4(0));
175	if (ret)
176		goto error;
177
178	/* slope time controls on/off cycle length. */
179	ret = regmap_write(led->chip->regmap, AN30259A_REG_SLOPE(num),
180			   AN30259A_LED_SLOPETIME1(off) |
181			   AN30259A_LED_SLOPETIME2(on));
182	if (ret)
183		goto error;
184
185	/* Finally, enable slope mode. */
186	ret = regmap_read(led->chip->regmap, AN30259A_REG_LED_ON, &led_on);
187	if (ret)
188		goto error;
189
190	led_on |= AN30259A_LED_SLOPE(num) | AN30259A_LED_EN(led->num);
191
192	ret = regmap_write(led->chip->regmap, AN30259A_REG_LED_ON, led_on);
193
194	if (!ret)
195		led->sloping = true;
196error:
197	mutex_unlock(&led->chip->mutex);
198
199	return ret;
200}
201
202static int an30259a_dt_init(struct i2c_client *client,
203			    struct an30259a *chip)
204{
205	struct device_node *np = dev_of_node(&client->dev), *child;
206	int count, ret;
207	int i = 0;
208	const char *str;
209	struct an30259a_led *led;
210
211	count = of_get_available_child_count(np);
212	if (!count || count > AN30259A_MAX_LEDS)
213		return -EINVAL;
214
215	for_each_available_child_of_node(np, child) {
216		u32 source;
217
218		ret = of_property_read_u32(child, "reg", &source);
219		if (ret != 0 || !source || source > AN30259A_MAX_LEDS) {
220			dev_err(&client->dev, "Couldn't read LED address: %d\n",
221				ret);
222			count--;
223			continue;
224		}
225
226		led = &chip->leds[i];
227
228		led->num = source;
229		led->chip = chip;
230		led->fwnode = of_fwnode_handle(child);
231
232		if (!of_property_read_string(child, "default-state", &str)) {
233			if (!strcmp(str, "on"))
234				led->default_state = STATE_ON;
235			else if (!strcmp(str, "keep"))
236				led->default_state = STATE_KEEP;
237			else
238				led->default_state = STATE_OFF;
239		}
240
241		i++;
242	}
243
244	if (!count)
245		return -EINVAL;
246
247	chip->num_leds = i;
248
249	return 0;
250}
251
252static const struct regmap_config an30259a_regmap_config = {
253	.reg_bits = 8,
254	.val_bits = 8,
255	.max_register = AN30259A_REG_MAX,
256};
257
258static void an30259a_init_default_state(struct an30259a_led *led)
259{
260	struct an30259a *chip = led->chip;
261	int led_on, err;
262
263	switch (led->default_state) {
264	case STATE_ON:
265		led->cdev.brightness = LED_FULL;
266		break;
267	case STATE_KEEP:
268		err = regmap_read(chip->regmap, AN30259A_REG_LED_ON, &led_on);
269		if (err)
270			break;
271
272		if (!(led_on & AN30259A_LED_EN(led->num))) {
273			led->cdev.brightness = LED_OFF;
274			break;
275		}
276		regmap_read(chip->regmap, AN30259A_REG_LEDCC(led->num),
277			    &led->cdev.brightness);
278		break;
279	default:
280		led->cdev.brightness = LED_OFF;
281	}
282
283	an30259a_brightness_set(&led->cdev, led->cdev.brightness);
284}
285
286static int an30259a_probe(struct i2c_client *client)
287{
288	struct an30259a *chip;
289	int i, err;
290
291	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
292	if (!chip)
293		return -ENOMEM;
294
295	err = an30259a_dt_init(client, chip);
296	if (err < 0)
297		return err;
298
299	mutex_init(&chip->mutex);
300	chip->client = client;
301	i2c_set_clientdata(client, chip);
302
303	chip->regmap = devm_regmap_init_i2c(client, &an30259a_regmap_config);
304
305	if (IS_ERR(chip->regmap)) {
306		err = PTR_ERR(chip->regmap);
307		dev_err(&client->dev, "Failed to allocate register map: %d\n",
308			err);
309		goto exit;
310	}
311
312	for (i = 0; i < chip->num_leds; i++) {
313		struct led_init_data init_data = {};
314
315		an30259a_init_default_state(&chip->leds[i]);
316		chip->leds[i].cdev.brightness_set_blocking =
317			an30259a_brightness_set;
318		chip->leds[i].cdev.blink_set = an30259a_blink_set;
319
320		init_data.fwnode = chip->leds[i].fwnode;
321		init_data.devicename = AN30259A_NAME;
322		init_data.default_label = ":";
323
324		err = devm_led_classdev_register_ext(&client->dev,
325						 &chip->leds[i].cdev,
326						 &init_data);
327		if (err < 0)
328			goto exit;
329	}
330	return 0;
331
332exit:
333	mutex_destroy(&chip->mutex);
334	return err;
335}
336
337static int an30259a_remove(struct i2c_client *client)
338{
339	struct an30259a *chip = i2c_get_clientdata(client);
340
341	mutex_destroy(&chip->mutex);
342
343	return 0;
344}
345
346static const struct of_device_id an30259a_match_table[] = {
347	{ .compatible = "panasonic,an30259a", },
348	{ /* sentinel */ },
349};
350
351MODULE_DEVICE_TABLE(of, an30259a_match_table);
352
353static const struct i2c_device_id an30259a_id[] = {
354	{ "an30259a", 0 },
355	{ /* sentinel */ },
356};
357MODULE_DEVICE_TABLE(i2c, an30259a_id);
358
359static struct i2c_driver an30259a_driver = {
360	.driver = {
361		.name = "leds-an30259a",
362		.of_match_table = of_match_ptr(an30259a_match_table),
363	},
364	.probe_new = an30259a_probe,
365	.remove = an30259a_remove,
366	.id_table = an30259a_id,
367};
368
369module_i2c_driver(an30259a_driver);
370
371MODULE_AUTHOR("Simon Shields <simon@lineageos.org>");
372MODULE_DESCRIPTION("AN30259A LED driver");
373MODULE_LICENSE("GPL v2");
374