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5054d39e AO |
1 | /* |
2 | * leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip | |
3 | * | |
4 | * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | */ | |
11 | ||
12 | /* | |
13 | * I2C driver for National Semiconductor LP3944 Funlight Chip | |
14 | * http://www.national.com/pf/LP/LP3944.html | |
15 | * | |
16 | * This helper chip can drive up to 8 leds, with two programmable DIM modes; | |
17 | * it could even be used as a gpio expander but this driver assumes it is used | |
18 | * as a led controller. | |
19 | * | |
20 | * The DIM modes are used to set _blink_ patterns for leds, the pattern is | |
21 | * specified supplying two parameters: | |
22 | * - period: from 0s to 1.6s | |
23 | * - duty cycle: percentage of the period the led is on, from 0 to 100 | |
24 | * | |
25 | * LP3944 can be found on Motorola A910 smartphone, where it drives the rgb | |
26 | * leds, the camera flash light and the displays backlights. | |
27 | */ | |
28 | ||
29 | #include <linux/module.h> | |
30 | #include <linux/i2c.h> | |
5a0e3ad6 | 31 | #include <linux/slab.h> |
5054d39e AO |
32 | #include <linux/leds.h> |
33 | #include <linux/mutex.h> | |
34 | #include <linux/workqueue.h> | |
35 | #include <linux/leds-lp3944.h> | |
36 | ||
37 | /* Read Only Registers */ | |
38 | #define LP3944_REG_INPUT1 0x00 /* LEDs 0-7 InputRegister (Read Only) */ | |
39 | #define LP3944_REG_REGISTER1 0x01 /* None (Read Only) */ | |
40 | ||
41 | #define LP3944_REG_PSC0 0x02 /* Frequency Prescaler 0 (R/W) */ | |
42 | #define LP3944_REG_PWM0 0x03 /* PWM Register 0 (R/W) */ | |
43 | #define LP3944_REG_PSC1 0x04 /* Frequency Prescaler 1 (R/W) */ | |
44 | #define LP3944_REG_PWM1 0x05 /* PWM Register 1 (R/W) */ | |
45 | #define LP3944_REG_LS0 0x06 /* LEDs 0-3 Selector (R/W) */ | |
46 | #define LP3944_REG_LS1 0x07 /* LEDs 4-7 Selector (R/W) */ | |
47 | ||
48 | /* These registers are not used to control leds in LP3944, they can store | |
49 | * arbitrary values which the chip will ignore. | |
50 | */ | |
51 | #define LP3944_REG_REGISTER8 0x08 | |
52 | #define LP3944_REG_REGISTER9 0x09 | |
53 | ||
54 | #define LP3944_DIM0 0 | |
55 | #define LP3944_DIM1 1 | |
56 | ||
57 | /* period in ms */ | |
58 | #define LP3944_PERIOD_MIN 0 | |
59 | #define LP3944_PERIOD_MAX 1600 | |
60 | ||
61 | /* duty cycle is a percentage */ | |
62 | #define LP3944_DUTY_CYCLE_MIN 0 | |
63 | #define LP3944_DUTY_CYCLE_MAX 100 | |
64 | ||
65 | #define ldev_to_led(c) container_of(c, struct lp3944_led_data, ldev) | |
66 | ||
67 | /* Saved data */ | |
68 | struct lp3944_led_data { | |
69 | u8 id; | |
70 | enum lp3944_type type; | |
71 | enum lp3944_status status; | |
72 | struct led_classdev ldev; | |
73 | struct i2c_client *client; | |
74 | struct work_struct work; | |
75 | }; | |
76 | ||
77 | struct lp3944_data { | |
78 | struct mutex lock; | |
79 | struct i2c_client *client; | |
80 | struct lp3944_led_data leds[LP3944_LEDS_MAX]; | |
81 | }; | |
82 | ||
83 | static int lp3944_reg_read(struct i2c_client *client, u8 reg, u8 *value) | |
84 | { | |
85 | int tmp; | |
86 | ||
87 | tmp = i2c_smbus_read_byte_data(client, reg); | |
88 | if (tmp < 0) | |
4401e487 | 89 | return tmp; |
5054d39e AO |
90 | |
91 | *value = tmp; | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
96 | static int lp3944_reg_write(struct i2c_client *client, u8 reg, u8 value) | |
97 | { | |
98 | return i2c_smbus_write_byte_data(client, reg, value); | |
99 | } | |
100 | ||
101 | /** | |
102 | * Set the period for DIM status | |
103 | * | |
104 | * @client: the i2c client | |
105 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
106 | * @period: period of a blink, that is a on/off cycle, expressed in ms. | |
107 | */ | |
108 | static int lp3944_dim_set_period(struct i2c_client *client, u8 dim, u16 period) | |
109 | { | |
110 | u8 psc_reg; | |
111 | u8 psc_value; | |
112 | int err; | |
113 | ||
114 | if (dim == LP3944_DIM0) | |
115 | psc_reg = LP3944_REG_PSC0; | |
116 | else if (dim == LP3944_DIM1) | |
117 | psc_reg = LP3944_REG_PSC1; | |
118 | else | |
119 | return -EINVAL; | |
120 | ||
121 | /* Convert period to Prescaler value */ | |
122 | if (period > LP3944_PERIOD_MAX) | |
123 | return -EINVAL; | |
124 | ||
125 | psc_value = (period * 255) / LP3944_PERIOD_MAX; | |
126 | ||
127 | err = lp3944_reg_write(client, psc_reg, psc_value); | |
128 | ||
129 | return err; | |
130 | } | |
131 | ||
132 | /** | |
133 | * Set the duty cycle for DIM status | |
134 | * | |
135 | * @client: the i2c client | |
136 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
137 | * @duty_cycle: percentage of a period during which a led is ON | |
138 | */ | |
139 | static int lp3944_dim_set_dutycycle(struct i2c_client *client, u8 dim, | |
140 | u8 duty_cycle) | |
141 | { | |
142 | u8 pwm_reg; | |
143 | u8 pwm_value; | |
144 | int err; | |
145 | ||
146 | if (dim == LP3944_DIM0) | |
147 | pwm_reg = LP3944_REG_PWM0; | |
148 | else if (dim == LP3944_DIM1) | |
149 | pwm_reg = LP3944_REG_PWM1; | |
150 | else | |
151 | return -EINVAL; | |
152 | ||
153 | /* Convert duty cycle to PWM value */ | |
154 | if (duty_cycle > LP3944_DUTY_CYCLE_MAX) | |
155 | return -EINVAL; | |
156 | ||
157 | pwm_value = (duty_cycle * 255) / LP3944_DUTY_CYCLE_MAX; | |
158 | ||
159 | err = lp3944_reg_write(client, pwm_reg, pwm_value); | |
160 | ||
161 | return err; | |
162 | } | |
163 | ||
164 | /** | |
165 | * Set the led status | |
166 | * | |
167 | * @led: a lp3944_led_data structure | |
168 | * @status: one of LP3944_LED_STATUS_OFF | |
169 | * LP3944_LED_STATUS_ON | |
170 | * LP3944_LED_STATUS_DIM0 | |
171 | * LP3944_LED_STATUS_DIM1 | |
172 | */ | |
173 | static int lp3944_led_set(struct lp3944_led_data *led, u8 status) | |
174 | { | |
175 | struct lp3944_data *data = i2c_get_clientdata(led->client); | |
176 | u8 id = led->id; | |
177 | u8 reg; | |
178 | u8 val = 0; | |
179 | int err; | |
180 | ||
181 | dev_dbg(&led->client->dev, "%s: %s, status before normalization:%d\n", | |
182 | __func__, led->ldev.name, status); | |
183 | ||
184 | switch (id) { | |
185 | case LP3944_LED0: | |
186 | case LP3944_LED1: | |
187 | case LP3944_LED2: | |
188 | case LP3944_LED3: | |
189 | reg = LP3944_REG_LS0; | |
190 | break; | |
191 | case LP3944_LED4: | |
192 | case LP3944_LED5: | |
193 | case LP3944_LED6: | |
194 | case LP3944_LED7: | |
195 | id -= LP3944_LED4; | |
196 | reg = LP3944_REG_LS1; | |
197 | break; | |
198 | default: | |
199 | return -EINVAL; | |
200 | } | |
201 | ||
202 | if (status > LP3944_LED_STATUS_DIM1) | |
203 | return -EINVAL; | |
204 | ||
205 | /* invert only 0 and 1, leave unchanged the other values, | |
206 | * remember we are abusing status to set blink patterns | |
207 | */ | |
208 | if (led->type == LP3944_LED_TYPE_LED_INVERTED && status < 2) | |
209 | status = 1 - status; | |
210 | ||
211 | mutex_lock(&data->lock); | |
212 | lp3944_reg_read(led->client, reg, &val); | |
213 | ||
214 | val &= ~(LP3944_LED_STATUS_MASK << (id << 1)); | |
215 | val |= (status << (id << 1)); | |
216 | ||
217 | dev_dbg(&led->client->dev, "%s: %s, reg:%d id:%d status:%d val:%#x\n", | |
218 | __func__, led->ldev.name, reg, id, status, val); | |
219 | ||
220 | /* set led status */ | |
221 | err = lp3944_reg_write(led->client, reg, val); | |
222 | mutex_unlock(&data->lock); | |
223 | ||
224 | return err; | |
225 | } | |
226 | ||
227 | static int lp3944_led_set_blink(struct led_classdev *led_cdev, | |
228 | unsigned long *delay_on, | |
229 | unsigned long *delay_off) | |
230 | { | |
231 | struct lp3944_led_data *led = ldev_to_led(led_cdev); | |
232 | u16 period; | |
233 | u8 duty_cycle; | |
234 | int err; | |
235 | ||
236 | /* units are in ms */ | |
237 | if (*delay_on + *delay_off > LP3944_PERIOD_MAX) | |
238 | return -EINVAL; | |
239 | ||
240 | if (*delay_on == 0 && *delay_off == 0) { | |
241 | /* Special case: the leds subsystem requires a default user | |
242 | * friendly blink pattern for the LED. Let's blink the led | |
243 | * slowly (1Hz). | |
244 | */ | |
245 | *delay_on = 500; | |
246 | *delay_off = 500; | |
247 | } | |
248 | ||
249 | period = (*delay_on) + (*delay_off); | |
250 | ||
251 | /* duty_cycle is the percentage of period during which the led is ON */ | |
252 | duty_cycle = 100 * (*delay_on) / period; | |
253 | ||
254 | /* invert duty cycle for inverted leds, this has the same effect of | |
255 | * swapping delay_on and delay_off | |
256 | */ | |
257 | if (led->type == LP3944_LED_TYPE_LED_INVERTED) | |
258 | duty_cycle = 100 - duty_cycle; | |
259 | ||
260 | /* NOTE: using always the first DIM mode, this means that all leds | |
261 | * will have the same blinking pattern. | |
262 | * | |
263 | * We could find a way later to have two leds blinking in hardware | |
264 | * with different patterns at the same time, falling back to software | |
265 | * control for the other ones. | |
266 | */ | |
267 | err = lp3944_dim_set_period(led->client, LP3944_DIM0, period); | |
268 | if (err) | |
269 | return err; | |
270 | ||
271 | err = lp3944_dim_set_dutycycle(led->client, LP3944_DIM0, duty_cycle); | |
272 | if (err) | |
273 | return err; | |
274 | ||
275 | dev_dbg(&led->client->dev, "%s: OK hardware accelerated blink!\n", | |
276 | __func__); | |
277 | ||
278 | led->status = LP3944_LED_STATUS_DIM0; | |
279 | schedule_work(&led->work); | |
280 | ||
281 | return 0; | |
282 | } | |
283 | ||
284 | static void lp3944_led_set_brightness(struct led_classdev *led_cdev, | |
285 | enum led_brightness brightness) | |
286 | { | |
287 | struct lp3944_led_data *led = ldev_to_led(led_cdev); | |
288 | ||
289 | dev_dbg(&led->client->dev, "%s: %s, %d\n", | |
290 | __func__, led_cdev->name, brightness); | |
291 | ||
292 | led->status = brightness; | |
293 | schedule_work(&led->work); | |
294 | } | |
295 | ||
296 | static void lp3944_led_work(struct work_struct *work) | |
297 | { | |
298 | struct lp3944_led_data *led; | |
299 | ||
300 | led = container_of(work, struct lp3944_led_data, work); | |
301 | lp3944_led_set(led, led->status); | |
302 | } | |
303 | ||
304 | static int lp3944_configure(struct i2c_client *client, | |
305 | struct lp3944_data *data, | |
306 | struct lp3944_platform_data *pdata) | |
307 | { | |
308 | int i, err = 0; | |
309 | ||
310 | for (i = 0; i < pdata->leds_size; i++) { | |
311 | struct lp3944_led *pled = &pdata->leds[i]; | |
312 | struct lp3944_led_data *led = &data->leds[i]; | |
313 | led->client = client; | |
314 | led->id = i; | |
315 | ||
316 | switch (pled->type) { | |
317 | ||
318 | case LP3944_LED_TYPE_LED: | |
319 | case LP3944_LED_TYPE_LED_INVERTED: | |
320 | led->type = pled->type; | |
321 | led->status = pled->status; | |
322 | led->ldev.name = pled->name; | |
323 | led->ldev.max_brightness = 1; | |
324 | led->ldev.brightness_set = lp3944_led_set_brightness; | |
325 | led->ldev.blink_set = lp3944_led_set_blink; | |
326 | led->ldev.flags = LED_CORE_SUSPENDRESUME; | |
327 | ||
328 | INIT_WORK(&led->work, lp3944_led_work); | |
329 | err = led_classdev_register(&client->dev, &led->ldev); | |
330 | if (err < 0) { | |
331 | dev_err(&client->dev, | |
332 | "couldn't register LED %s\n", | |
333 | led->ldev.name); | |
334 | goto exit; | |
335 | } | |
336 | ||
337 | /* to expose the default value to userspace */ | |
338 | led->ldev.brightness = led->status; | |
339 | ||
340 | /* Set the default led status */ | |
341 | err = lp3944_led_set(led, led->status); | |
342 | if (err < 0) { | |
343 | dev_err(&client->dev, | |
344 | "%s couldn't set STATUS %d\n", | |
345 | led->ldev.name, led->status); | |
346 | goto exit; | |
347 | } | |
348 | break; | |
349 | ||
350 | case LP3944_LED_TYPE_NONE: | |
351 | default: | |
352 | break; | |
353 | ||
354 | } | |
355 | } | |
356 | return 0; | |
357 | ||
358 | exit: | |
359 | if (i > 0) | |
360 | for (i = i - 1; i >= 0; i--) | |
361 | switch (pdata->leds[i].type) { | |
362 | ||
363 | case LP3944_LED_TYPE_LED: | |
364 | case LP3944_LED_TYPE_LED_INVERTED: | |
365 | led_classdev_unregister(&data->leds[i].ldev); | |
366 | cancel_work_sync(&data->leds[i].work); | |
367 | break; | |
368 | ||
369 | case LP3944_LED_TYPE_NONE: | |
370 | default: | |
371 | break; | |
372 | } | |
373 | ||
374 | return err; | |
375 | } | |
376 | ||
98ea1ea2 | 377 | static int lp3944_probe(struct i2c_client *client, |
5054d39e AO |
378 | const struct i2c_device_id *id) |
379 | { | |
380 | struct lp3944_platform_data *lp3944_pdata = client->dev.platform_data; | |
381 | struct lp3944_data *data; | |
7e1ce34f | 382 | int err; |
5054d39e AO |
383 | |
384 | if (lp3944_pdata == NULL) { | |
385 | dev_err(&client->dev, "no platform data\n"); | |
386 | return -EINVAL; | |
387 | } | |
388 | ||
389 | /* Let's see whether this adapter can support what we need. */ | |
390 | if (!i2c_check_functionality(client->adapter, | |
391 | I2C_FUNC_SMBUS_BYTE_DATA)) { | |
392 | dev_err(&client->dev, "insufficient functionality!\n"); | |
393 | return -ENODEV; | |
394 | } | |
395 | ||
9813d74f BW |
396 | data = devm_kzalloc(&client->dev, sizeof(struct lp3944_data), |
397 | GFP_KERNEL); | |
5054d39e AO |
398 | if (!data) |
399 | return -ENOMEM; | |
400 | ||
401 | data->client = client; | |
402 | i2c_set_clientdata(client, data); | |
403 | ||
404 | mutex_init(&data->lock); | |
405 | ||
7e1ce34f | 406 | err = lp3944_configure(client, data, lp3944_pdata); |
9813d74f | 407 | if (err < 0) |
7e1ce34f | 408 | return err; |
5054d39e | 409 | |
7e1ce34f | 410 | dev_info(&client->dev, "lp3944 enabled\n"); |
5054d39e AO |
411 | return 0; |
412 | } | |
413 | ||
678e8a6b | 414 | static int lp3944_remove(struct i2c_client *client) |
5054d39e AO |
415 | { |
416 | struct lp3944_platform_data *pdata = client->dev.platform_data; | |
417 | struct lp3944_data *data = i2c_get_clientdata(client); | |
418 | int i; | |
419 | ||
420 | for (i = 0; i < pdata->leds_size; i++) | |
421 | switch (data->leds[i].type) { | |
422 | case LP3944_LED_TYPE_LED: | |
423 | case LP3944_LED_TYPE_LED_INVERTED: | |
424 | led_classdev_unregister(&data->leds[i].ldev); | |
425 | cancel_work_sync(&data->leds[i].work); | |
426 | break; | |
427 | ||
428 | case LP3944_LED_TYPE_NONE: | |
429 | default: | |
430 | break; | |
431 | } | |
432 | ||
5054d39e AO |
433 | return 0; |
434 | } | |
435 | ||
436 | /* lp3944 i2c driver struct */ | |
437 | static const struct i2c_device_id lp3944_id[] = { | |
438 | {"lp3944", 0}, | |
439 | {} | |
440 | }; | |
441 | ||
442 | MODULE_DEVICE_TABLE(i2c, lp3944_id); | |
443 | ||
444 | static struct i2c_driver lp3944_driver = { | |
445 | .driver = { | |
446 | .name = "lp3944", | |
447 | }, | |
448 | .probe = lp3944_probe, | |
df07cf81 | 449 | .remove = lp3944_remove, |
5054d39e AO |
450 | .id_table = lp3944_id, |
451 | }; | |
452 | ||
09a0d183 | 453 | module_i2c_driver(lp3944_driver); |
5054d39e AO |
454 | |
455 | MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); | |
456 | MODULE_DESCRIPTION("LP3944 Fun Light Chip"); | |
457 | MODULE_LICENSE("GPL"); |