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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
5054d39e AO |
2 | /* |
3 | * leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip | |
4 | * | |
5 | * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it> | |
5054d39e AO |
6 | */ |
7 | ||
8 | /* | |
9 | * I2C driver for National Semiconductor LP3944 Funlight Chip | |
10 | * http://www.national.com/pf/LP/LP3944.html | |
11 | * | |
12 | * This helper chip can drive up to 8 leds, with two programmable DIM modes; | |
13 | * it could even be used as a gpio expander but this driver assumes it is used | |
14 | * as a led controller. | |
15 | * | |
16 | * The DIM modes are used to set _blink_ patterns for leds, the pattern is | |
17 | * specified supplying two parameters: | |
18 | * - period: from 0s to 1.6s | |
19 | * - duty cycle: percentage of the period the led is on, from 0 to 100 | |
20 | * | |
21 | * LP3944 can be found on Motorola A910 smartphone, where it drives the rgb | |
22 | * leds, the camera flash light and the displays backlights. | |
23 | */ | |
24 | ||
25 | #include <linux/module.h> | |
26 | #include <linux/i2c.h> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
5054d39e AO |
28 | #include <linux/leds.h> |
29 | #include <linux/mutex.h> | |
5054d39e AO |
30 | #include <linux/leds-lp3944.h> |
31 | ||
32 | /* Read Only Registers */ | |
33 | #define LP3944_REG_INPUT1 0x00 /* LEDs 0-7 InputRegister (Read Only) */ | |
34 | #define LP3944_REG_REGISTER1 0x01 /* None (Read Only) */ | |
35 | ||
36 | #define LP3944_REG_PSC0 0x02 /* Frequency Prescaler 0 (R/W) */ | |
37 | #define LP3944_REG_PWM0 0x03 /* PWM Register 0 (R/W) */ | |
38 | #define LP3944_REG_PSC1 0x04 /* Frequency Prescaler 1 (R/W) */ | |
39 | #define LP3944_REG_PWM1 0x05 /* PWM Register 1 (R/W) */ | |
40 | #define LP3944_REG_LS0 0x06 /* LEDs 0-3 Selector (R/W) */ | |
41 | #define LP3944_REG_LS1 0x07 /* LEDs 4-7 Selector (R/W) */ | |
42 | ||
43 | /* These registers are not used to control leds in LP3944, they can store | |
44 | * arbitrary values which the chip will ignore. | |
45 | */ | |
46 | #define LP3944_REG_REGISTER8 0x08 | |
47 | #define LP3944_REG_REGISTER9 0x09 | |
48 | ||
49 | #define LP3944_DIM0 0 | |
50 | #define LP3944_DIM1 1 | |
51 | ||
52 | /* period in ms */ | |
53 | #define LP3944_PERIOD_MIN 0 | |
54 | #define LP3944_PERIOD_MAX 1600 | |
55 | ||
56 | /* duty cycle is a percentage */ | |
57 | #define LP3944_DUTY_CYCLE_MIN 0 | |
58 | #define LP3944_DUTY_CYCLE_MAX 100 | |
59 | ||
60 | #define ldev_to_led(c) container_of(c, struct lp3944_led_data, ldev) | |
61 | ||
62 | /* Saved data */ | |
63 | struct lp3944_led_data { | |
64 | u8 id; | |
65 | enum lp3944_type type; | |
5054d39e AO |
66 | struct led_classdev ldev; |
67 | struct i2c_client *client; | |
5054d39e AO |
68 | }; |
69 | ||
70 | struct lp3944_data { | |
71 | struct mutex lock; | |
72 | struct i2c_client *client; | |
73 | struct lp3944_led_data leds[LP3944_LEDS_MAX]; | |
74 | }; | |
75 | ||
76 | static int lp3944_reg_read(struct i2c_client *client, u8 reg, u8 *value) | |
77 | { | |
78 | int tmp; | |
79 | ||
80 | tmp = i2c_smbus_read_byte_data(client, reg); | |
81 | if (tmp < 0) | |
4401e487 | 82 | return tmp; |
5054d39e AO |
83 | |
84 | *value = tmp; | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | static int lp3944_reg_write(struct i2c_client *client, u8 reg, u8 value) | |
90 | { | |
91 | return i2c_smbus_write_byte_data(client, reg, value); | |
92 | } | |
93 | ||
94 | /** | |
9933bde2 | 95 | * lp3944_dim_set_period() - Set the period for DIM status |
5054d39e AO |
96 | * |
97 | * @client: the i2c client | |
98 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
99 | * @period: period of a blink, that is a on/off cycle, expressed in ms. | |
100 | */ | |
101 | static int lp3944_dim_set_period(struct i2c_client *client, u8 dim, u16 period) | |
102 | { | |
103 | u8 psc_reg; | |
104 | u8 psc_value; | |
105 | int err; | |
106 | ||
107 | if (dim == LP3944_DIM0) | |
108 | psc_reg = LP3944_REG_PSC0; | |
109 | else if (dim == LP3944_DIM1) | |
110 | psc_reg = LP3944_REG_PSC1; | |
111 | else | |
112 | return -EINVAL; | |
113 | ||
114 | /* Convert period to Prescaler value */ | |
115 | if (period > LP3944_PERIOD_MAX) | |
116 | return -EINVAL; | |
117 | ||
118 | psc_value = (period * 255) / LP3944_PERIOD_MAX; | |
119 | ||
120 | err = lp3944_reg_write(client, psc_reg, psc_value); | |
121 | ||
122 | return err; | |
123 | } | |
124 | ||
125 | /** | |
9933bde2 | 126 | * lp3944_dim_set_dutycycle - Set the duty cycle for DIM status |
5054d39e AO |
127 | * |
128 | * @client: the i2c client | |
129 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
130 | * @duty_cycle: percentage of a period during which a led is ON | |
131 | */ | |
132 | static int lp3944_dim_set_dutycycle(struct i2c_client *client, u8 dim, | |
133 | u8 duty_cycle) | |
134 | { | |
135 | u8 pwm_reg; | |
136 | u8 pwm_value; | |
137 | int err; | |
138 | ||
139 | if (dim == LP3944_DIM0) | |
140 | pwm_reg = LP3944_REG_PWM0; | |
141 | else if (dim == LP3944_DIM1) | |
142 | pwm_reg = LP3944_REG_PWM1; | |
143 | else | |
144 | return -EINVAL; | |
145 | ||
146 | /* Convert duty cycle to PWM value */ | |
147 | if (duty_cycle > LP3944_DUTY_CYCLE_MAX) | |
148 | return -EINVAL; | |
149 | ||
150 | pwm_value = (duty_cycle * 255) / LP3944_DUTY_CYCLE_MAX; | |
151 | ||
152 | err = lp3944_reg_write(client, pwm_reg, pwm_value); | |
153 | ||
154 | return err; | |
155 | } | |
156 | ||
157 | /** | |
9933bde2 | 158 | * lp3944_led_set() - Set the led status |
5054d39e AO |
159 | * |
160 | * @led: a lp3944_led_data structure | |
161 | * @status: one of LP3944_LED_STATUS_OFF | |
162 | * LP3944_LED_STATUS_ON | |
163 | * LP3944_LED_STATUS_DIM0 | |
164 | * LP3944_LED_STATUS_DIM1 | |
165 | */ | |
166 | static int lp3944_led_set(struct lp3944_led_data *led, u8 status) | |
167 | { | |
168 | struct lp3944_data *data = i2c_get_clientdata(led->client); | |
169 | u8 id = led->id; | |
170 | u8 reg; | |
171 | u8 val = 0; | |
172 | int err; | |
173 | ||
174 | dev_dbg(&led->client->dev, "%s: %s, status before normalization:%d\n", | |
175 | __func__, led->ldev.name, status); | |
176 | ||
177 | switch (id) { | |
178 | case LP3944_LED0: | |
179 | case LP3944_LED1: | |
180 | case LP3944_LED2: | |
181 | case LP3944_LED3: | |
182 | reg = LP3944_REG_LS0; | |
183 | break; | |
184 | case LP3944_LED4: | |
185 | case LP3944_LED5: | |
186 | case LP3944_LED6: | |
187 | case LP3944_LED7: | |
188 | id -= LP3944_LED4; | |
189 | reg = LP3944_REG_LS1; | |
190 | break; | |
191 | default: | |
192 | return -EINVAL; | |
193 | } | |
194 | ||
195 | if (status > LP3944_LED_STATUS_DIM1) | |
196 | return -EINVAL; | |
197 | ||
c9eec908 AO |
198 | /* |
199 | * Invert status only when it's < 2 (i.e. 0 or 1) which means it's | |
200 | * controlling the on/off state directly. | |
201 | * When, instead, status is >= 2 don't invert it because it would mean | |
202 | * to mess with the hardware blinking mode. | |
5054d39e AO |
203 | */ |
204 | if (led->type == LP3944_LED_TYPE_LED_INVERTED && status < 2) | |
205 | status = 1 - status; | |
206 | ||
207 | mutex_lock(&data->lock); | |
208 | lp3944_reg_read(led->client, reg, &val); | |
209 | ||
210 | val &= ~(LP3944_LED_STATUS_MASK << (id << 1)); | |
211 | val |= (status << (id << 1)); | |
212 | ||
213 | dev_dbg(&led->client->dev, "%s: %s, reg:%d id:%d status:%d val:%#x\n", | |
214 | __func__, led->ldev.name, reg, id, status, val); | |
215 | ||
216 | /* set led status */ | |
217 | err = lp3944_reg_write(led->client, reg, val); | |
218 | mutex_unlock(&data->lock); | |
219 | ||
220 | return err; | |
221 | } | |
222 | ||
223 | static int lp3944_led_set_blink(struct led_classdev *led_cdev, | |
224 | unsigned long *delay_on, | |
225 | unsigned long *delay_off) | |
226 | { | |
227 | struct lp3944_led_data *led = ldev_to_led(led_cdev); | |
228 | u16 period; | |
229 | u8 duty_cycle; | |
230 | int err; | |
231 | ||
232 | /* units are in ms */ | |
233 | if (*delay_on + *delay_off > LP3944_PERIOD_MAX) | |
234 | return -EINVAL; | |
235 | ||
236 | if (*delay_on == 0 && *delay_off == 0) { | |
237 | /* Special case: the leds subsystem requires a default user | |
238 | * friendly blink pattern for the LED. Let's blink the led | |
239 | * slowly (1Hz). | |
240 | */ | |
241 | *delay_on = 500; | |
242 | *delay_off = 500; | |
243 | } | |
244 | ||
245 | period = (*delay_on) + (*delay_off); | |
246 | ||
247 | /* duty_cycle is the percentage of period during which the led is ON */ | |
248 | duty_cycle = 100 * (*delay_on) / period; | |
249 | ||
250 | /* invert duty cycle for inverted leds, this has the same effect of | |
251 | * swapping delay_on and delay_off | |
252 | */ | |
253 | if (led->type == LP3944_LED_TYPE_LED_INVERTED) | |
254 | duty_cycle = 100 - duty_cycle; | |
255 | ||
256 | /* NOTE: using always the first DIM mode, this means that all leds | |
257 | * will have the same blinking pattern. | |
258 | * | |
259 | * We could find a way later to have two leds blinking in hardware | |
260 | * with different patterns at the same time, falling back to software | |
261 | * control for the other ones. | |
262 | */ | |
263 | err = lp3944_dim_set_period(led->client, LP3944_DIM0, period); | |
264 | if (err) | |
265 | return err; | |
266 | ||
267 | err = lp3944_dim_set_dutycycle(led->client, LP3944_DIM0, duty_cycle); | |
268 | if (err) | |
269 | return err; | |
270 | ||
271 | dev_dbg(&led->client->dev, "%s: OK hardware accelerated blink!\n", | |
272 | __func__); | |
273 | ||
525d6a65 | 274 | lp3944_led_set(led, LP3944_LED_STATUS_DIM0); |
5054d39e AO |
275 | |
276 | return 0; | |
277 | } | |
278 | ||
525d6a65 | 279 | static int lp3944_led_set_brightness(struct led_classdev *led_cdev, |
5054d39e AO |
280 | enum led_brightness brightness) |
281 | { | |
282 | struct lp3944_led_data *led = ldev_to_led(led_cdev); | |
283 | ||
284 | dev_dbg(&led->client->dev, "%s: %s, %d\n", | |
285 | __func__, led_cdev->name, brightness); | |
286 | ||
525d6a65 | 287 | return lp3944_led_set(led, !!brightness); |
5054d39e AO |
288 | } |
289 | ||
290 | static int lp3944_configure(struct i2c_client *client, | |
291 | struct lp3944_data *data, | |
292 | struct lp3944_platform_data *pdata) | |
293 | { | |
294 | int i, err = 0; | |
295 | ||
296 | for (i = 0; i < pdata->leds_size; i++) { | |
297 | struct lp3944_led *pled = &pdata->leds[i]; | |
298 | struct lp3944_led_data *led = &data->leds[i]; | |
299 | led->client = client; | |
300 | led->id = i; | |
301 | ||
302 | switch (pled->type) { | |
303 | ||
304 | case LP3944_LED_TYPE_LED: | |
305 | case LP3944_LED_TYPE_LED_INVERTED: | |
306 | led->type = pled->type; | |
5054d39e AO |
307 | led->ldev.name = pled->name; |
308 | led->ldev.max_brightness = 1; | |
525d6a65 AL |
309 | led->ldev.brightness_set_blocking = |
310 | lp3944_led_set_brightness; | |
5054d39e AO |
311 | led->ldev.blink_set = lp3944_led_set_blink; |
312 | led->ldev.flags = LED_CORE_SUSPENDRESUME; | |
313 | ||
5054d39e AO |
314 | err = led_classdev_register(&client->dev, &led->ldev); |
315 | if (err < 0) { | |
316 | dev_err(&client->dev, | |
317 | "couldn't register LED %s\n", | |
318 | led->ldev.name); | |
319 | goto exit; | |
320 | } | |
321 | ||
322 | /* to expose the default value to userspace */ | |
7f14e6b9 | 323 | led->ldev.brightness = |
525d6a65 | 324 | (enum led_brightness) pled->status; |
5054d39e AO |
325 | |
326 | /* Set the default led status */ | |
525d6a65 | 327 | err = lp3944_led_set(led, pled->status); |
5054d39e AO |
328 | if (err < 0) { |
329 | dev_err(&client->dev, | |
330 | "%s couldn't set STATUS %d\n", | |
525d6a65 | 331 | led->ldev.name, pled->status); |
5054d39e AO |
332 | goto exit; |
333 | } | |
334 | break; | |
335 | ||
336 | case LP3944_LED_TYPE_NONE: | |
337 | default: | |
338 | break; | |
339 | ||
340 | } | |
341 | } | |
342 | return 0; | |
343 | ||
344 | exit: | |
345 | if (i > 0) | |
346 | for (i = i - 1; i >= 0; i--) | |
347 | switch (pdata->leds[i].type) { | |
348 | ||
349 | case LP3944_LED_TYPE_LED: | |
350 | case LP3944_LED_TYPE_LED_INVERTED: | |
351 | led_classdev_unregister(&data->leds[i].ldev); | |
5054d39e AO |
352 | break; |
353 | ||
354 | case LP3944_LED_TYPE_NONE: | |
355 | default: | |
356 | break; | |
357 | } | |
358 | ||
359 | return err; | |
360 | } | |
361 | ||
1ba59160 | 362 | static int lp3944_probe(struct i2c_client *client) |
5054d39e | 363 | { |
87aae1ea JH |
364 | struct lp3944_platform_data *lp3944_pdata = |
365 | dev_get_platdata(&client->dev); | |
5054d39e | 366 | struct lp3944_data *data; |
7e1ce34f | 367 | int err; |
5054d39e AO |
368 | |
369 | if (lp3944_pdata == NULL) { | |
370 | dev_err(&client->dev, "no platform data\n"); | |
371 | return -EINVAL; | |
372 | } | |
373 | ||
374 | /* Let's see whether this adapter can support what we need. */ | |
375 | if (!i2c_check_functionality(client->adapter, | |
376 | I2C_FUNC_SMBUS_BYTE_DATA)) { | |
377 | dev_err(&client->dev, "insufficient functionality!\n"); | |
378 | return -ENODEV; | |
379 | } | |
380 | ||
9813d74f BW |
381 | data = devm_kzalloc(&client->dev, sizeof(struct lp3944_data), |
382 | GFP_KERNEL); | |
5054d39e AO |
383 | if (!data) |
384 | return -ENOMEM; | |
385 | ||
386 | data->client = client; | |
387 | i2c_set_clientdata(client, data); | |
388 | ||
389 | mutex_init(&data->lock); | |
390 | ||
7e1ce34f | 391 | err = lp3944_configure(client, data, lp3944_pdata); |
9813d74f | 392 | if (err < 0) |
7e1ce34f | 393 | return err; |
5054d39e | 394 | |
7e1ce34f | 395 | dev_info(&client->dev, "lp3944 enabled\n"); |
5054d39e AO |
396 | return 0; |
397 | } | |
398 | ||
ed5c2f5f | 399 | static void lp3944_remove(struct i2c_client *client) |
5054d39e | 400 | { |
87aae1ea | 401 | struct lp3944_platform_data *pdata = dev_get_platdata(&client->dev); |
5054d39e AO |
402 | struct lp3944_data *data = i2c_get_clientdata(client); |
403 | int i; | |
404 | ||
405 | for (i = 0; i < pdata->leds_size; i++) | |
406 | switch (data->leds[i].type) { | |
407 | case LP3944_LED_TYPE_LED: | |
408 | case LP3944_LED_TYPE_LED_INVERTED: | |
409 | led_classdev_unregister(&data->leds[i].ldev); | |
5054d39e AO |
410 | break; |
411 | ||
412 | case LP3944_LED_TYPE_NONE: | |
413 | default: | |
414 | break; | |
415 | } | |
5054d39e AO |
416 | } |
417 | ||
418 | /* lp3944 i2c driver struct */ | |
419 | static const struct i2c_device_id lp3944_id[] = { | |
420 | {"lp3944", 0}, | |
421 | {} | |
422 | }; | |
423 | ||
424 | MODULE_DEVICE_TABLE(i2c, lp3944_id); | |
425 | ||
426 | static struct i2c_driver lp3944_driver = { | |
427 | .driver = { | |
428 | .name = "lp3944", | |
429 | }, | |
d9ff8a8e | 430 | .probe = lp3944_probe, |
df07cf81 | 431 | .remove = lp3944_remove, |
5054d39e AO |
432 | .id_table = lp3944_id, |
433 | }; | |
434 | ||
09a0d183 | 435 | module_i2c_driver(lp3944_driver); |
5054d39e AO |
436 | |
437 | MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); | |
438 | MODULE_DESCRIPTION("LP3944 Fun Light Chip"); | |
439 | MODULE_LICENSE("GPL"); |