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
is31fl319x_brightness_set(struct led_classdev * cdev,enum led_brightness brightness)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
is31fl319x_parse_child_dt(const struct device * dev,const struct device_node * child,struct is31fl319x_led * led)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
is31fl319x_parse_dt(struct device * dev,struct is31fl319x_chip * is31)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", ®);
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
is31fl319x_readable_reg(struct device * dev,unsigned int reg)275 static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
276 { /* we have no readable registers */
277 return false;
278 }
279
is31fl319x_volatile_reg(struct device * dev,unsigned int reg)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
is31fl319x_microamp_to_cs(struct device * dev,u32 microamp)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
is31fl319x_db_to_gain(u32 dezibel)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
is31fl319x_probe(struct i2c_client * client,const struct i2c_device_id * id)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 int err;
337 int i = 0;
338 u32 aggregated_led_microamp = IS31FL319X_CURRENT_MAX;
339
340 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
341 return -EIO;
342
343 is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
344 if (!is31)
345 return -ENOMEM;
346
347 mutex_init(&is31->lock);
348
349 err = is31fl319x_parse_dt(&client->dev, is31);
350 if (err)
351 goto free_mutex;
352
353 is31->client = client;
354 is31->regmap = devm_regmap_init_i2c(client, ®map_config);
355 if (IS_ERR(is31->regmap)) {
356 dev_err(&client->dev, "failed to allocate register map\n");
357 err = PTR_ERR(is31->regmap);
358 goto free_mutex;
359 }
360
361 i2c_set_clientdata(client, is31);
362
363 /* check for write-reply from chip (we can't read any registers) */
364 err = regmap_write(is31->regmap, IS31FL319X_RESET, 0x00);
365 if (err < 0) {
366 dev_err(&client->dev, "no response from chip write: err = %d\n",
367 err);
368 err = -EIO; /* does not answer */
369 goto free_mutex;
370 }
371
372 /*
373 * Kernel conventions require per-LED led-max-microamp property.
374 * But the chip does not allow to limit individual LEDs.
375 * So we take minimum from all subnodes for safety of hardware.
376 */
377 for (i = 0; i < is31->cdef->num_leds; i++)
378 if (is31->leds[i].configured &&
379 is31->leds[i].max_microamp < aggregated_led_microamp)
380 aggregated_led_microamp = is31->leds[i].max_microamp;
381
382 regmap_write(is31->regmap, IS31FL319X_CONFIG2,
383 is31fl319x_microamp_to_cs(dev, aggregated_led_microamp) |
384 is31fl319x_db_to_gain(is31->audio_gain_db));
385
386 for (i = 0; i < is31->cdef->num_leds; i++) {
387 struct is31fl319x_led *led = &is31->leds[i];
388
389 if (!led->configured)
390 continue;
391
392 led->chip = is31;
393 led->cdev.brightness_set_blocking = is31fl319x_brightness_set;
394
395 err = devm_led_classdev_register(&client->dev, &led->cdev);
396 if (err < 0)
397 goto free_mutex;
398 }
399
400 return 0;
401
402 free_mutex:
403 mutex_destroy(&is31->lock);
404 return err;
405 }
406
is31fl319x_remove(struct i2c_client * client)407 static int is31fl319x_remove(struct i2c_client *client)
408 {
409 struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
410
411 mutex_destroy(&is31->lock);
412 return 0;
413 }
414
415 /*
416 * i2c-core (and modalias) requires that id_table be properly filled,
417 * even though it is not used for DeviceTree based instantiation.
418 */
419 static const struct i2c_device_id is31fl319x_id[] = {
420 { "is31fl3190" },
421 { "is31fl3191" },
422 { "is31fl3193" },
423 { "is31fl3196" },
424 { "is31fl3199" },
425 { "sn3199" },
426 {},
427 };
428 MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
429
430 static struct i2c_driver is31fl319x_driver = {
431 .driver = {
432 .name = "leds-is31fl319x",
433 .of_match_table = of_match_ptr(of_is31fl319x_match),
434 },
435 .probe = is31fl319x_probe,
436 .remove = is31fl319x_remove,
437 .id_table = is31fl319x_id,
438 };
439
440 module_i2c_driver(is31fl319x_driver);
441
442 MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
443 MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
444 MODULE_DESCRIPTION("IS31FL319X LED driver");
445 MODULE_LICENSE("GPL v2");
446