1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2015-16 Golden Delicious Computers
4 *
5 * Author: Nikolaus Schaller <hns@goldelico.com>
6 *
7 * LED driver for the IS31FL319{0,1,3,6,9} to drive 1, 3, 6 or 9 light
8 * effect LEDs.
9 */
10
11#include <linux/err.h>
12#include <linux/i2c.h>
13#include <linux/leds.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/of_device.h>
17#include <linux/regmap.h>
18#include <linux/slab.h>
19#include <linux/delay.h>
20#include <linux/gpio/consumer.h>
21
22/* register numbers */
23#define IS31FL319X_SHUTDOWN		0x00
24#define IS31FL319X_CTRL1		0x01
25#define IS31FL319X_CTRL2		0x02
26#define IS31FL319X_CONFIG1		0x03
27#define IS31FL319X_CONFIG2		0x04
28#define IS31FL319X_RAMP_MODE		0x05
29#define IS31FL319X_BREATH_MASK		0x06
30#define IS31FL319X_PWM(channel)		(0x07 + channel)
31#define IS31FL319X_DATA_UPDATE		0x10
32#define IS31FL319X_T0(channel)		(0x11 + channel)
33#define IS31FL319X_T123_1		0x1a
34#define IS31FL319X_T123_2		0x1b
35#define IS31FL319X_T123_3		0x1c
36#define IS31FL319X_T4(channel)		(0x1d + channel)
37#define IS31FL319X_TIME_UPDATE		0x26
38#define IS31FL319X_RESET		0xff
39
40#define IS31FL319X_REG_CNT		(IS31FL319X_RESET + 1)
41
42#define IS31FL319X_MAX_LEDS		9
43
44/* CS (Current Setting) in CONFIG2 register */
45#define IS31FL319X_CONFIG2_CS_SHIFT	4
46#define IS31FL319X_CONFIG2_CS_MASK	0x7
47#define IS31FL319X_CONFIG2_CS_STEP_REF	12
48
49#define IS31FL319X_CURRENT_MIN		((u32)5000)
50#define IS31FL319X_CURRENT_MAX		((u32)40000)
51#define IS31FL319X_CURRENT_STEP		((u32)5000)
52#define IS31FL319X_CURRENT_DEFAULT	((u32)20000)
53
54/* Audio gain in CONFIG2 register */
55#define IS31FL319X_AUDIO_GAIN_DB_MAX	((u32)21)
56#define IS31FL319X_AUDIO_GAIN_DB_STEP	((u32)3)
57
58/*
59 * regmap is used as a cache of chip's register space,
60 * to avoid reading back brightness values from chip,
61 * which is known to hang.
62 */
63struct is31fl319x_chip {
64	const struct is31fl319x_chipdef *cdef;
65	struct i2c_client               *client;
66	struct gpio_desc		*shutdown_gpio;
67	struct regmap                   *regmap;
68	struct mutex                    lock;
69	u32                             audio_gain_db;
70
71	struct is31fl319x_led {
72		struct is31fl319x_chip  *chip;
73		struct led_classdev     cdev;
74		u32                     max_microamp;
75		bool                    configured;
76	} leds[IS31FL319X_MAX_LEDS];
77};
78
79struct is31fl319x_chipdef {
80	int num_leds;
81};
82
83static const struct is31fl319x_chipdef is31fl3190_cdef = {
84	.num_leds = 1,
85};
86
87static const struct is31fl319x_chipdef is31fl3193_cdef = {
88	.num_leds = 3,
89};
90
91static const struct is31fl319x_chipdef is31fl3196_cdef = {
92	.num_leds = 6,
93};
94
95static const struct is31fl319x_chipdef is31fl3199_cdef = {
96	.num_leds = 9,
97};
98
99static const struct of_device_id of_is31fl319x_match[] = {
100	{ .compatible = "issi,is31fl3190", .data = &is31fl3190_cdef, },
101	{ .compatible = "issi,is31fl3191", .data = &is31fl3190_cdef, },
102	{ .compatible = "issi,is31fl3193", .data = &is31fl3193_cdef, },
103	{ .compatible = "issi,is31fl3196", .data = &is31fl3196_cdef, },
104	{ .compatible = "issi,is31fl3199", .data = &is31fl3199_cdef, },
105	{ .compatible = "si-en,sn3199",    .data = &is31fl3199_cdef, },
106	{ }
107};
108MODULE_DEVICE_TABLE(of, of_is31fl319x_match);
109
110static int is31fl319x_brightness_set(struct led_classdev *cdev,
111				     enum led_brightness brightness)
112{
113	struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led,
114						  cdev);
115	struct is31fl319x_chip *is31 = led->chip;
116	int chan = led - is31->leds;
117	int ret;
118	int i;
119	u8 ctrl1 = 0, ctrl2 = 0;
120
121	dev_dbg(&is31->client->dev, "%s %d: %d\n", __func__, chan, brightness);
122
123	mutex_lock(&is31->lock);
124
125	/* update PWM register */
126	ret = regmap_write(is31->regmap, IS31FL319X_PWM(chan), brightness);
127	if (ret < 0)
128		goto out;
129
130	/* read current brightness of all PWM channels */
131	for (i = 0; i < is31->cdef->num_leds; i++) {
132		unsigned int pwm_value;
133		bool on;
134
135		/*
136		 * since neither cdev nor the chip can provide
137		 * the current setting, we read from the regmap cache
138		 */
139
140		ret = regmap_read(is31->regmap, IS31FL319X_PWM(i), &pwm_value);
141		dev_dbg(&is31->client->dev, "%s read %d: ret=%d: %d\n",
142			__func__, i, ret, pwm_value);
143		on = ret >= 0 && pwm_value > LED_OFF;
144
145		if (i < 3)
146			ctrl1 |= on << i;       /* 0..2 => bit 0..2 */
147		else if (i < 6)
148			ctrl1 |= on << (i + 1); /* 3..5 => bit 4..6 */
149		else
150			ctrl2 |= on << (i - 6); /* 6..8 => bit 0..2 */
151	}
152
153	if (ctrl1 > 0 || ctrl2 > 0) {
154		dev_dbg(&is31->client->dev, "power up %02x %02x\n",
155			ctrl1, ctrl2);
156		regmap_write(is31->regmap, IS31FL319X_CTRL1, ctrl1);
157		regmap_write(is31->regmap, IS31FL319X_CTRL2, ctrl2);
158		/* update PWMs */
159		regmap_write(is31->regmap, IS31FL319X_DATA_UPDATE, 0x00);
160		/* enable chip from shut down */
161		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
162	} else {
163		dev_dbg(&is31->client->dev, "power down\n");
164		/* shut down (no need to clear CTRL1/2) */
165		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
166	}
167
168out:
169	mutex_unlock(&is31->lock);
170
171	return ret;
172}
173
174static int is31fl319x_parse_child_dt(const struct device *dev,
175				     const struct device_node *child,
176				     struct is31fl319x_led *led)
177{
178	struct led_classdev *cdev = &led->cdev;
179	int ret;
180
181	if (of_property_read_string(child, "label", &cdev->name))
182		cdev->name = child->name;
183
184	ret = of_property_read_string(child, "linux,default-trigger",
185				      &cdev->default_trigger);
186	if (ret < 0 && ret != -EINVAL) /* is optional */
187		return ret;
188
189	led->max_microamp = IS31FL319X_CURRENT_DEFAULT;
190	ret = of_property_read_u32(child, "led-max-microamp",
191				   &led->max_microamp);
192	if (!ret) {
193		if (led->max_microamp < IS31FL319X_CURRENT_MIN)
194			return -EINVAL;	/* not supported */
195		led->max_microamp = min(led->max_microamp,
196					  IS31FL319X_CURRENT_MAX);
197	}
198
199	return 0;
200}
201
202static int is31fl319x_parse_dt(struct device *dev,
203			       struct is31fl319x_chip *is31)
204{
205	struct device_node *np = dev_of_node(dev), *child;
206	int count;
207	int ret;
208
209	if (!np)
210		return -ENODEV;
211
212	is31->shutdown_gpio = devm_gpiod_get_optional(dev,
213						"shutdown",
214						GPIOD_OUT_HIGH);
215	if (IS_ERR(is31->shutdown_gpio)) {
216		ret = PTR_ERR(is31->shutdown_gpio);
217		dev_err(dev, "Failed to get shutdown gpio: %d\n", ret);
218		return ret;
219	}
220
221	is31->cdef = device_get_match_data(dev);
222
223	count = of_get_available_child_count(np);
224
225	dev_dbg(dev, "probing with %d leds defined in DT\n", count);
226
227	if (!count || count > is31->cdef->num_leds) {
228		dev_err(dev, "Number of leds defined must be between 1 and %u\n",
229			is31->cdef->num_leds);
230		return -ENODEV;
231	}
232
233	for_each_available_child_of_node(np, child) {
234		struct is31fl319x_led *led;
235		u32 reg;
236
237		ret = of_property_read_u32(child, "reg", &reg);
238		if (ret) {
239			dev_err(dev, "Failed to read led 'reg' property\n");
240			goto put_child_node;
241		}
242
243		if (reg < 1 || reg > is31->cdef->num_leds) {
244			dev_err(dev, "invalid led reg %u\n", reg);
245			ret = -EINVAL;
246			goto put_child_node;
247		}
248
249		led = &is31->leds[reg - 1];
250
251		if (led->configured) {
252			dev_err(dev, "led %u is already configured\n", reg);
253			ret = -EINVAL;
254			goto put_child_node;
255		}
256
257		ret = is31fl319x_parse_child_dt(dev, child, led);
258		if (ret) {
259			dev_err(dev, "led %u DT parsing failed\n", reg);
260			goto put_child_node;
261		}
262
263		led->configured = true;
264	}
265
266	is31->audio_gain_db = 0;
267	ret = of_property_read_u32(np, "audio-gain-db", &is31->audio_gain_db);
268	if (!ret)
269		is31->audio_gain_db = min(is31->audio_gain_db,
270					  IS31FL319X_AUDIO_GAIN_DB_MAX);
271
272	return 0;
273
274put_child_node:
275	of_node_put(child);
276	return ret;
277}
278
279static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
280{ /* we have no readable registers */
281	return false;
282}
283
284static bool is31fl319x_volatile_reg(struct device *dev, unsigned int reg)
285{ /* volatile registers are not cached */
286	switch (reg) {
287	case IS31FL319X_DATA_UPDATE:
288	case IS31FL319X_TIME_UPDATE:
289	case IS31FL319X_RESET:
290		return true; /* always write-through */
291	default:
292		return false;
293	}
294}
295
296static const struct reg_default is31fl319x_reg_defaults[] = {
297	{ IS31FL319X_CONFIG1, 0x00},
298	{ IS31FL319X_CONFIG2, 0x00},
299	{ IS31FL319X_PWM(0), 0x00},
300	{ IS31FL319X_PWM(1), 0x00},
301	{ IS31FL319X_PWM(2), 0x00},
302	{ IS31FL319X_PWM(3), 0x00},
303	{ IS31FL319X_PWM(4), 0x00},
304	{ IS31FL319X_PWM(5), 0x00},
305	{ IS31FL319X_PWM(6), 0x00},
306	{ IS31FL319X_PWM(7), 0x00},
307	{ IS31FL319X_PWM(8), 0x00},
308};
309
310static struct regmap_config regmap_config = {
311	.reg_bits = 8,
312	.val_bits = 8,
313	.max_register = IS31FL319X_REG_CNT,
314	.cache_type = REGCACHE_FLAT,
315	.readable_reg = is31fl319x_readable_reg,
316	.volatile_reg = is31fl319x_volatile_reg,
317	.reg_defaults = is31fl319x_reg_defaults,
318	.num_reg_defaults = ARRAY_SIZE(is31fl319x_reg_defaults),
319};
320
321static inline int is31fl319x_microamp_to_cs(struct device *dev, u32 microamp)
322{ /* round down to nearest supported value (range check done by caller) */
323	u32 step = microamp / IS31FL319X_CURRENT_STEP;
324
325	return ((IS31FL319X_CONFIG2_CS_STEP_REF - step) &
326		IS31FL319X_CONFIG2_CS_MASK) <<
327		IS31FL319X_CONFIG2_CS_SHIFT; /* CS encoding */
328}
329
330static inline int is31fl319x_db_to_gain(u32 dezibel)
331{ /* round down to nearest supported value (range check done by caller) */
332	return dezibel / IS31FL319X_AUDIO_GAIN_DB_STEP;
333}
334
335static int is31fl319x_probe(struct i2c_client *client,
336			    const struct i2c_device_id *id)
337{
338	struct is31fl319x_chip *is31;
339	struct device *dev = &client->dev;
340	int err;
341	int i = 0;
342	u32 aggregated_led_microamp = IS31FL319X_CURRENT_MAX;
343
344	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
345		return -EIO;
346
347	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
348	if (!is31)
349		return -ENOMEM;
350
351	mutex_init(&is31->lock);
352
353	err = is31fl319x_parse_dt(&client->dev, is31);
354	if (err)
355		goto free_mutex;
356
357	if (is31->shutdown_gpio) {
358		gpiod_direction_output(is31->shutdown_gpio, 0);
359		mdelay(5);
360		gpiod_direction_output(is31->shutdown_gpio, 1);
361	}
362
363	is31->client = client;
364	is31->regmap = devm_regmap_init_i2c(client, &regmap_config);
365	if (IS_ERR(is31->regmap)) {
366		dev_err(&client->dev, "failed to allocate register map\n");
367		err = PTR_ERR(is31->regmap);
368		goto free_mutex;
369	}
370
371	i2c_set_clientdata(client, is31);
372
373	/* check for write-reply from chip (we can't read any registers) */
374	err = regmap_write(is31->regmap, IS31FL319X_RESET, 0x00);
375	if (err < 0) {
376		dev_err(&client->dev, "no response from chip write: err = %d\n",
377			err);
378		err = -EIO; /* does not answer */
379		goto free_mutex;
380	}
381
382	/*
383	 * Kernel conventions require per-LED led-max-microamp property.
384	 * But the chip does not allow to limit individual LEDs.
385	 * So we take minimum from all subnodes for safety of hardware.
386	 */
387	for (i = 0; i < is31->cdef->num_leds; i++)
388		if (is31->leds[i].configured &&
389		    is31->leds[i].max_microamp < aggregated_led_microamp)
390			aggregated_led_microamp = is31->leds[i].max_microamp;
391
392	regmap_write(is31->regmap, IS31FL319X_CONFIG2,
393		     is31fl319x_microamp_to_cs(dev, aggregated_led_microamp) |
394		     is31fl319x_db_to_gain(is31->audio_gain_db));
395
396	for (i = 0; i < is31->cdef->num_leds; i++) {
397		struct is31fl319x_led *led = &is31->leds[i];
398
399		if (!led->configured)
400			continue;
401
402		led->chip = is31;
403		led->cdev.brightness_set_blocking = is31fl319x_brightness_set;
404
405		err = devm_led_classdev_register(&client->dev, &led->cdev);
406		if (err < 0)
407			goto free_mutex;
408	}
409
410	return 0;
411
412free_mutex:
413	mutex_destroy(&is31->lock);
414	return err;
415}
416
417static int is31fl319x_remove(struct i2c_client *client)
418{
419	struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
420
421	mutex_destroy(&is31->lock);
422	return 0;
423}
424
425/*
426 * i2c-core (and modalias) requires that id_table be properly filled,
427 * even though it is not used for DeviceTree based instantiation.
428 */
429static const struct i2c_device_id is31fl319x_id[] = {
430	{ "is31fl3190" },
431	{ "is31fl3191" },
432	{ "is31fl3193" },
433	{ "is31fl3196" },
434	{ "is31fl3199" },
435	{ "sn3199" },
436	{},
437};
438MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
439
440static struct i2c_driver is31fl319x_driver = {
441	.driver   = {
442		.name           = "leds-is31fl319x",
443		.of_match_table = of_match_ptr(of_is31fl319x_match),
444	},
445	.probe    = is31fl319x_probe,
446	.remove   = is31fl319x_remove,
447	.id_table = is31fl319x_id,
448};
449
450module_i2c_driver(is31fl319x_driver);
451
452MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
453MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
454MODULE_DESCRIPTION("IS31FL319X LED driver");
455MODULE_LICENSE("GPL v2");
456