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