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 */
63 struct 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
79 struct is31fl319x_chipdef {
80 int num_leds;
81 };
82
83 static const struct is31fl319x_chipdef is31fl3190_cdef = {
84 .num_leds = 1,
85 };
86
87 static const struct is31fl319x_chipdef is31fl3193_cdef = {
88 .num_leds = 3,
89 };
90
91 static const struct is31fl319x_chipdef is31fl3196_cdef = {
92 .num_leds = 6,
93 };
94
95 static const struct is31fl319x_chipdef is31fl3199_cdef = {
96 .num_leds = 9,
97 };
98
99 static 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 };
108 MODULE_DEVICE_TABLE(of, of_is31fl319x_match);
109
is31fl319x_brightness_set(struct led_classdev * cdev,enum led_brightness brightness)110 static 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
168 out:
169 mutex_unlock(&is31->lock);
170
171 return ret;
172 }
173
is31fl319x_parse_child_dt(const struct device * dev,const struct device_node * child,struct is31fl319x_led * led)174 static 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
is31fl319x_parse_dt(struct device * dev,struct is31fl319x_chip * is31)202 static 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", ®);
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
274 put_child_node:
275 of_node_put(child);
276 return ret;
277 }
278
is31fl319x_readable_reg(struct device * dev,unsigned int reg)279 static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
280 { /* we have no readable registers */
281 return false;
282 }
283
is31fl319x_volatile_reg(struct device * dev,unsigned int reg)284 static 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
296 static 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
310 static 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
is31fl319x_microamp_to_cs(struct device * dev,u32 microamp)321 static 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
is31fl319x_db_to_gain(u32 dezibel)330 static 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
is31fl319x_probe(struct i2c_client * client,const struct i2c_device_id * id)335 static 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, ®map_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
412 free_mutex:
413 mutex_destroy(&is31->lock);
414 return err;
415 }
416
is31fl319x_remove(struct i2c_client * client)417 static 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 */
429 static const struct i2c_device_id is31fl319x_id[] = {
430 { "is31fl3190" },
431 { "is31fl3191" },
432 { "is31fl3193" },
433 { "is31fl3196" },
434 { "is31fl3199" },
435 { "sn3199" },
436 {},
437 };
438 MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
439
440 static 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
450 module_i2c_driver(is31fl319x_driver);
451
452 MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
453 MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
454 MODULE_DESCRIPTION("IS31FL319X LED driver");
455 MODULE_LICENSE("GPL v2");
456