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 
20 /* register numbers */
21 #define IS31FL319X_SHUTDOWN		0x00
22 #define IS31FL319X_CTRL1		0x01
23 #define IS31FL319X_CTRL2		0x02
24 #define IS31FL319X_CONFIG1		0x03
25 #define IS31FL319X_CONFIG2		0x04
26 #define IS31FL319X_RAMP_MODE		0x05
27 #define IS31FL319X_BREATH_MASK		0x06
28 #define IS31FL319X_PWM(channel)		(0x07 + channel)
29 #define IS31FL319X_DATA_UPDATE		0x10
30 #define IS31FL319X_T0(channel)		(0x11 + channel)
31 #define IS31FL319X_T123_1		0x1a
32 #define IS31FL319X_T123_2		0x1b
33 #define IS31FL319X_T123_3		0x1c
34 #define IS31FL319X_T4(channel)		(0x1d + channel)
35 #define IS31FL319X_TIME_UPDATE		0x26
36 #define IS31FL319X_RESET		0xff
37 
38 #define IS31FL319X_REG_CNT		(IS31FL319X_RESET + 1)
39 
40 #define IS31FL319X_MAX_LEDS		9
41 
42 /* CS (Current Setting) in CONFIG2 register */
43 #define IS31FL319X_CONFIG2_CS_SHIFT	4
44 #define IS31FL319X_CONFIG2_CS_MASK	0x7
45 #define IS31FL319X_CONFIG2_CS_STEP_REF	12
46 
47 #define IS31FL319X_CURRENT_MIN		((u32)5000)
48 #define IS31FL319X_CURRENT_MAX		((u32)40000)
49 #define IS31FL319X_CURRENT_STEP		((u32)5000)
50 #define IS31FL319X_CURRENT_DEFAULT	((u32)20000)
51 
52 /* Audio gain in CONFIG2 register */
53 #define IS31FL319X_AUDIO_GAIN_DB_MAX	((u32)21)
54 #define IS31FL319X_AUDIO_GAIN_DB_STEP	((u32)3)
55 
56 /*
57  * regmap is used as a cache of chip's register space,
58  * to avoid reading back brightness values from chip,
59  * which is known to hang.
60  */
61 struct is31fl319x_chip {
62 	const struct is31fl319x_chipdef *cdef;
63 	struct i2c_client               *client;
64 	struct regmap                   *regmap;
65 	struct mutex                    lock;
66 	u32                             audio_gain_db;
67 
68 	struct is31fl319x_led {
69 		struct is31fl319x_chip  *chip;
70 		struct led_classdev     cdev;
71 		u32                     max_microamp;
72 		bool                    configured;
73 	} leds[IS31FL319X_MAX_LEDS];
74 };
75 
76 struct is31fl319x_chipdef {
77 	int num_leds;
78 };
79 
80 static const struct is31fl319x_chipdef is31fl3190_cdef = {
81 	.num_leds = 1,
82 };
83 
84 static const struct is31fl319x_chipdef is31fl3193_cdef = {
85 	.num_leds = 3,
86 };
87 
88 static const struct is31fl319x_chipdef is31fl3196_cdef = {
89 	.num_leds = 6,
90 };
91 
92 static const struct is31fl319x_chipdef is31fl3199_cdef = {
93 	.num_leds = 9,
94 };
95 
96 static const struct of_device_id of_is31fl319x_match[] = {
97 	{ .compatible = "issi,is31fl3190", .data = &is31fl3190_cdef, },
98 	{ .compatible = "issi,is31fl3191", .data = &is31fl3190_cdef, },
99 	{ .compatible = "issi,is31fl3193", .data = &is31fl3193_cdef, },
100 	{ .compatible = "issi,is31fl3196", .data = &is31fl3196_cdef, },
101 	{ .compatible = "issi,is31fl3199", .data = &is31fl3199_cdef, },
102 	{ .compatible = "si-en,sn3199",    .data = &is31fl3199_cdef, },
103 	{ }
104 };
105 MODULE_DEVICE_TABLE(of, of_is31fl319x_match);
106 
107 static int is31fl319x_brightness_set(struct led_classdev *cdev,
108 				     enum led_brightness brightness)
109 {
110 	struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led,
111 						  cdev);
112 	struct is31fl319x_chip *is31 = led->chip;
113 	int chan = led - is31->leds;
114 	int ret;
115 	int i;
116 	u8 ctrl1 = 0, ctrl2 = 0;
117 
118 	dev_dbg(&is31->client->dev, "%s %d: %d\n", __func__, chan, brightness);
119 
120 	mutex_lock(&is31->lock);
121 
122 	/* update PWM register */
123 	ret = regmap_write(is31->regmap, IS31FL319X_PWM(chan), brightness);
124 	if (ret < 0)
125 		goto out;
126 
127 	/* read current brightness of all PWM channels */
128 	for (i = 0; i < is31->cdef->num_leds; i++) {
129 		unsigned int pwm_value;
130 		bool on;
131 
132 		/*
133 		 * since neither cdev nor the chip can provide
134 		 * the current setting, we read from the regmap cache
135 		 */
136 
137 		ret = regmap_read(is31->regmap, IS31FL319X_PWM(i), &pwm_value);
138 		dev_dbg(&is31->client->dev, "%s read %d: ret=%d: %d\n",
139 			__func__, i, ret, pwm_value);
140 		on = ret >= 0 && pwm_value > LED_OFF;
141 
142 		if (i < 3)
143 			ctrl1 |= on << i;       /* 0..2 => bit 0..2 */
144 		else if (i < 6)
145 			ctrl1 |= on << (i + 1); /* 3..5 => bit 4..6 */
146 		else
147 			ctrl2 |= on << (i - 6); /* 6..8 => bit 0..2 */
148 	}
149 
150 	if (ctrl1 > 0 || ctrl2 > 0) {
151 		dev_dbg(&is31->client->dev, "power up %02x %02x\n",
152 			ctrl1, ctrl2);
153 		regmap_write(is31->regmap, IS31FL319X_CTRL1, ctrl1);
154 		regmap_write(is31->regmap, IS31FL319X_CTRL2, ctrl2);
155 		/* update PWMs */
156 		regmap_write(is31->regmap, IS31FL319X_DATA_UPDATE, 0x00);
157 		/* enable chip from shut down */
158 		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
159 	} else {
160 		dev_dbg(&is31->client->dev, "power down\n");
161 		/* shut down (no need to clear CTRL1/2) */
162 		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
163 	}
164 
165 out:
166 	mutex_unlock(&is31->lock);
167 
168 	return ret;
169 }
170 
171 static int is31fl319x_parse_child_dt(const struct device *dev,
172 				     const struct device_node *child,
173 				     struct is31fl319x_led *led)
174 {
175 	struct led_classdev *cdev = &led->cdev;
176 	int ret;
177 
178 	if (of_property_read_string(child, "label", &cdev->name))
179 		cdev->name = child->name;
180 
181 	ret = of_property_read_string(child, "linux,default-trigger",
182 				      &cdev->default_trigger);
183 	if (ret < 0 && ret != -EINVAL) /* is optional */
184 		return ret;
185 
186 	led->max_microamp = IS31FL319X_CURRENT_DEFAULT;
187 	ret = of_property_read_u32(child, "led-max-microamp",
188 				   &led->max_microamp);
189 	if (!ret) {
190 		if (led->max_microamp < IS31FL319X_CURRENT_MIN)
191 			return -EINVAL;	/* not supported */
192 		led->max_microamp = min(led->max_microamp,
193 					  IS31FL319X_CURRENT_MAX);
194 	}
195 
196 	return 0;
197 }
198 
199 static int is31fl319x_parse_dt(struct device *dev,
200 			       struct is31fl319x_chip *is31)
201 {
202 	struct device_node *np = dev->of_node, *child;
203 	const struct of_device_id *of_dev_id;
204 	int count;
205 	int ret;
206 
207 	if (!np)
208 		return -ENODEV;
209 
210 	of_dev_id = of_match_device(of_is31fl319x_match, dev);
211 	if (!of_dev_id) {
212 		dev_err(dev, "Failed to match device with supported chips\n");
213 		return -EINVAL;
214 	}
215 
216 	is31->cdef = of_dev_id->data;
217 
218 	count = of_get_child_count(np);
219 
220 	dev_dbg(dev, "probe %s with %d leds defined in DT\n",
221 		of_dev_id->compatible, count);
222 
223 	if (!count || count > is31->cdef->num_leds) {
224 		dev_err(dev, "Number of leds defined must be between 1 and %u\n",
225 			is31->cdef->num_leds);
226 		return -ENODEV;
227 	}
228 
229 	for_each_child_of_node(np, child) {
230 		struct is31fl319x_led *led;
231 		u32 reg;
232 
233 		ret = of_property_read_u32(child, "reg", &reg);
234 		if (ret) {
235 			dev_err(dev, "Failed to read led 'reg' property\n");
236 			goto put_child_node;
237 		}
238 
239 		if (reg < 1 || reg > is31->cdef->num_leds) {
240 			dev_err(dev, "invalid led reg %u\n", reg);
241 			ret = -EINVAL;
242 			goto put_child_node;
243 		}
244 
245 		led = &is31->leds[reg - 1];
246 
247 		if (led->configured) {
248 			dev_err(dev, "led %u is already configured\n", reg);
249 			ret = -EINVAL;
250 			goto put_child_node;
251 		}
252 
253 		ret = is31fl319x_parse_child_dt(dev, child, led);
254 		if (ret) {
255 			dev_err(dev, "led %u DT parsing failed\n", reg);
256 			goto put_child_node;
257 		}
258 
259 		led->configured = true;
260 	}
261 
262 	is31->audio_gain_db = 0;
263 	ret = of_property_read_u32(np, "audio-gain-db", &is31->audio_gain_db);
264 	if (!ret)
265 		is31->audio_gain_db = min(is31->audio_gain_db,
266 					  IS31FL319X_AUDIO_GAIN_DB_MAX);
267 
268 	return 0;
269 
270 put_child_node:
271 	of_node_put(child);
272 	return ret;
273 }
274 
275 static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
276 { /* we have no readable registers */
277 	return false;
278 }
279 
280 static bool is31fl319x_volatile_reg(struct device *dev, unsigned int reg)
281 { /* volatile registers are not cached */
282 	switch (reg) {
283 	case IS31FL319X_DATA_UPDATE:
284 	case IS31FL319X_TIME_UPDATE:
285 	case IS31FL319X_RESET:
286 		return true; /* always write-through */
287 	default:
288 		return false;
289 	}
290 }
291 
292 static const struct reg_default is31fl319x_reg_defaults[] = {
293 	{ IS31FL319X_CONFIG1, 0x00},
294 	{ IS31FL319X_CONFIG2, 0x00},
295 	{ IS31FL319X_PWM(0), 0x00},
296 	{ IS31FL319X_PWM(1), 0x00},
297 	{ IS31FL319X_PWM(2), 0x00},
298 	{ IS31FL319X_PWM(3), 0x00},
299 	{ IS31FL319X_PWM(4), 0x00},
300 	{ IS31FL319X_PWM(5), 0x00},
301 	{ IS31FL319X_PWM(6), 0x00},
302 	{ IS31FL319X_PWM(7), 0x00},
303 	{ IS31FL319X_PWM(8), 0x00},
304 };
305 
306 static struct regmap_config regmap_config = {
307 	.reg_bits = 8,
308 	.val_bits = 8,
309 	.max_register = IS31FL319X_REG_CNT,
310 	.cache_type = REGCACHE_FLAT,
311 	.readable_reg = is31fl319x_readable_reg,
312 	.volatile_reg = is31fl319x_volatile_reg,
313 	.reg_defaults = is31fl319x_reg_defaults,
314 	.num_reg_defaults = ARRAY_SIZE(is31fl319x_reg_defaults),
315 };
316 
317 static inline int is31fl319x_microamp_to_cs(struct device *dev, u32 microamp)
318 { /* round down to nearest supported value (range check done by caller) */
319 	u32 step = microamp / IS31FL319X_CURRENT_STEP;
320 
321 	return ((IS31FL319X_CONFIG2_CS_STEP_REF - step) &
322 		IS31FL319X_CONFIG2_CS_MASK) <<
323 		IS31FL319X_CONFIG2_CS_SHIFT; /* CS encoding */
324 }
325 
326 static inline int is31fl319x_db_to_gain(u32 dezibel)
327 { /* round down to nearest supported value (range check done by caller) */
328 	return dezibel / IS31FL319X_AUDIO_GAIN_DB_STEP;
329 }
330 
331 static int is31fl319x_probe(struct i2c_client *client,
332 			    const struct i2c_device_id *id)
333 {
334 	struct is31fl319x_chip *is31;
335 	struct device *dev = &client->dev;
336 	struct i2c_adapter *adapter = to_i2c_adapter(dev->parent);
337 	int err;
338 	int i = 0;
339 	u32 aggregated_led_microamp = IS31FL319X_CURRENT_MAX;
340 
341 	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
342 		return -EIO;
343 
344 	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
345 	if (!is31)
346 		return -ENOMEM;
347 
348 	mutex_init(&is31->lock);
349 
350 	err = is31fl319x_parse_dt(&client->dev, is31);
351 	if (err)
352 		goto free_mutex;
353 
354 	is31->client = client;
355 	is31->regmap = devm_regmap_init_i2c(client, &regmap_config);
356 	if (IS_ERR(is31->regmap)) {
357 		dev_err(&client->dev, "failed to allocate register map\n");
358 		err = PTR_ERR(is31->regmap);
359 		goto free_mutex;
360 	}
361 
362 	i2c_set_clientdata(client, is31);
363 
364 	/* check for write-reply from chip (we can't read any registers) */
365 	err = regmap_write(is31->regmap, IS31FL319X_RESET, 0x00);
366 	if (err < 0) {
367 		dev_err(&client->dev, "no response from chip write: err = %d\n",
368 			err);
369 		err = -EIO; /* does not answer */
370 		goto free_mutex;
371 	}
372 
373 	/*
374 	 * Kernel conventions require per-LED led-max-microamp property.
375 	 * But the chip does not allow to limit individual LEDs.
376 	 * So we take minimum from all subnodes for safety of hardware.
377 	 */
378 	for (i = 0; i < is31->cdef->num_leds; i++)
379 		if (is31->leds[i].configured &&
380 		    is31->leds[i].max_microamp < aggregated_led_microamp)
381 			aggregated_led_microamp = is31->leds[i].max_microamp;
382 
383 	regmap_write(is31->regmap, IS31FL319X_CONFIG2,
384 		     is31fl319x_microamp_to_cs(dev, aggregated_led_microamp) |
385 		     is31fl319x_db_to_gain(is31->audio_gain_db));
386 
387 	for (i = 0; i < is31->cdef->num_leds; i++) {
388 		struct is31fl319x_led *led = &is31->leds[i];
389 
390 		if (!led->configured)
391 			continue;
392 
393 		led->chip = is31;
394 		led->cdev.brightness_set_blocking = is31fl319x_brightness_set;
395 
396 		err = devm_led_classdev_register(&client->dev, &led->cdev);
397 		if (err < 0)
398 			goto free_mutex;
399 	}
400 
401 	return 0;
402 
403 free_mutex:
404 	mutex_destroy(&is31->lock);
405 	return err;
406 }
407 
408 static int is31fl319x_remove(struct i2c_client *client)
409 {
410 	struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
411 
412 	mutex_destroy(&is31->lock);
413 	return 0;
414 }
415 
416 /*
417  * i2c-core (and modalias) requires that id_table be properly filled,
418  * even though it is not used for DeviceTree based instantiation.
419  */
420 static const struct i2c_device_id is31fl319x_id[] = {
421 	{ "is31fl3190" },
422 	{ "is31fl3191" },
423 	{ "is31fl3193" },
424 	{ "is31fl3196" },
425 	{ "is31fl3199" },
426 	{ "sn3199" },
427 	{},
428 };
429 MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
430 
431 static struct i2c_driver is31fl319x_driver = {
432 	.driver   = {
433 		.name           = "leds-is31fl319x",
434 		.of_match_table = of_match_ptr(of_is31fl319x_match),
435 	},
436 	.probe    = is31fl319x_probe,
437 	.remove   = is31fl319x_remove,
438 	.id_table = is31fl319x_id,
439 };
440 
441 module_i2c_driver(is31fl319x_driver);
442 
443 MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
444 MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
445 MODULE_DESCRIPTION("IS31FL319X LED driver");
446 MODULE_LICENSE("GPL v2");
447