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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> | |
31 | #include <linux/leds.h> | |
32 | #include <linux/mutex.h> | |
33 | #include <linux/workqueue.h> | |
34 | #include <linux/leds-lp3944.h> | |
35 | ||
36 | /* Read Only Registers */ | |
37 | #define LP3944_REG_INPUT1 0x00 /* LEDs 0-7 InputRegister (Read Only) */ | |
38 | #define LP3944_REG_REGISTER1 0x01 /* None (Read Only) */ | |
39 | ||
40 | #define LP3944_REG_PSC0 0x02 /* Frequency Prescaler 0 (R/W) */ | |
41 | #define LP3944_REG_PWM0 0x03 /* PWM Register 0 (R/W) */ | |
42 | #define LP3944_REG_PSC1 0x04 /* Frequency Prescaler 1 (R/W) */ | |
43 | #define LP3944_REG_PWM1 0x05 /* PWM Register 1 (R/W) */ | |
44 | #define LP3944_REG_LS0 0x06 /* LEDs 0-3 Selector (R/W) */ | |
45 | #define LP3944_REG_LS1 0x07 /* LEDs 4-7 Selector (R/W) */ | |
46 | ||
47 | /* These registers are not used to control leds in LP3944, they can store | |
48 | * arbitrary values which the chip will ignore. | |
49 | */ | |
50 | #define LP3944_REG_REGISTER8 0x08 | |
51 | #define LP3944_REG_REGISTER9 0x09 | |
52 | ||
53 | #define LP3944_DIM0 0 | |
54 | #define LP3944_DIM1 1 | |
55 | ||
56 | /* period in ms */ | |
57 | #define LP3944_PERIOD_MIN 0 | |
58 | #define LP3944_PERIOD_MAX 1600 | |
59 | ||
60 | /* duty cycle is a percentage */ | |
61 | #define LP3944_DUTY_CYCLE_MIN 0 | |
62 | #define LP3944_DUTY_CYCLE_MAX 100 | |
63 | ||
64 | #define ldev_to_led(c) container_of(c, struct lp3944_led_data, ldev) | |
65 | ||
66 | /* Saved data */ | |
67 | struct lp3944_led_data { | |
68 | u8 id; | |
69 | enum lp3944_type type; | |
70 | enum lp3944_status status; | |
71 | struct led_classdev ldev; | |
72 | struct i2c_client *client; | |
73 | struct work_struct work; | |
74 | }; | |
75 | ||
76 | struct lp3944_data { | |
77 | struct mutex lock; | |
78 | struct i2c_client *client; | |
79 | struct lp3944_led_data leds[LP3944_LEDS_MAX]; | |
80 | }; | |
81 | ||
82 | static int lp3944_reg_read(struct i2c_client *client, u8 reg, u8 *value) | |
83 | { | |
84 | int tmp; | |
85 | ||
86 | tmp = i2c_smbus_read_byte_data(client, reg); | |
87 | if (tmp < 0) | |
88 | return -EINVAL; | |
89 | ||
90 | *value = tmp; | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static int lp3944_reg_write(struct i2c_client *client, u8 reg, u8 value) | |
96 | { | |
97 | return i2c_smbus_write_byte_data(client, reg, value); | |
98 | } | |
99 | ||
100 | /** | |
101 | * Set the period for DIM status | |
102 | * | |
103 | * @client: the i2c client | |
104 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
105 | * @period: period of a blink, that is a on/off cycle, expressed in ms. | |
106 | */ | |
107 | static int lp3944_dim_set_period(struct i2c_client *client, u8 dim, u16 period) | |
108 | { | |
109 | u8 psc_reg; | |
110 | u8 psc_value; | |
111 | int err; | |
112 | ||
113 | if (dim == LP3944_DIM0) | |
114 | psc_reg = LP3944_REG_PSC0; | |
115 | else if (dim == LP3944_DIM1) | |
116 | psc_reg = LP3944_REG_PSC1; | |
117 | else | |
118 | return -EINVAL; | |
119 | ||
120 | /* Convert period to Prescaler value */ | |
121 | if (period > LP3944_PERIOD_MAX) | |
122 | return -EINVAL; | |
123 | ||
124 | psc_value = (period * 255) / LP3944_PERIOD_MAX; | |
125 | ||
126 | err = lp3944_reg_write(client, psc_reg, psc_value); | |
127 | ||
128 | return err; | |
129 | } | |
130 | ||
131 | /** | |
132 | * Set the duty cycle for DIM status | |
133 | * | |
134 | * @client: the i2c client | |
135 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
136 | * @duty_cycle: percentage of a period during which a led is ON | |
137 | */ | |
138 | static int lp3944_dim_set_dutycycle(struct i2c_client *client, u8 dim, | |
139 | u8 duty_cycle) | |
140 | { | |
141 | u8 pwm_reg; | |
142 | u8 pwm_value; | |
143 | int err; | |
144 | ||
145 | if (dim == LP3944_DIM0) | |
146 | pwm_reg = LP3944_REG_PWM0; | |
147 | else if (dim == LP3944_DIM1) | |
148 | pwm_reg = LP3944_REG_PWM1; | |
149 | else | |
150 | return -EINVAL; | |
151 | ||
152 | /* Convert duty cycle to PWM value */ | |
153 | if (duty_cycle > LP3944_DUTY_CYCLE_MAX) | |
154 | return -EINVAL; | |
155 | ||
156 | pwm_value = (duty_cycle * 255) / LP3944_DUTY_CYCLE_MAX; | |
157 | ||
158 | err = lp3944_reg_write(client, pwm_reg, pwm_value); | |
159 | ||
160 | return err; | |
161 | } | |
162 | ||
163 | /** | |
164 | * Set the led status | |
165 | * | |
166 | * @led: a lp3944_led_data structure | |
167 | * @status: one of LP3944_LED_STATUS_OFF | |
168 | * LP3944_LED_STATUS_ON | |
169 | * LP3944_LED_STATUS_DIM0 | |
170 | * LP3944_LED_STATUS_DIM1 | |
171 | */ | |
172 | static int lp3944_led_set(struct lp3944_led_data *led, u8 status) | |
173 | { | |
174 | struct lp3944_data *data = i2c_get_clientdata(led->client); | |
175 | u8 id = led->id; | |
176 | u8 reg; | |
177 | u8 val = 0; | |
178 | int err; | |
179 | ||
180 | dev_dbg(&led->client->dev, "%s: %s, status before normalization:%d\n", | |
181 | __func__, led->ldev.name, status); | |
182 | ||
183 | switch (id) { | |
184 | case LP3944_LED0: | |
185 | case LP3944_LED1: | |
186 | case LP3944_LED2: | |
187 | case LP3944_LED3: | |
188 | reg = LP3944_REG_LS0; | |
189 | break; | |
190 | case LP3944_LED4: | |
191 | case LP3944_LED5: | |
192 | case LP3944_LED6: | |
193 | case LP3944_LED7: | |
194 | id -= LP3944_LED4; | |
195 | reg = LP3944_REG_LS1; | |
196 | break; | |
197 | default: | |
198 | return -EINVAL; | |
199 | } | |
200 | ||
201 | if (status > LP3944_LED_STATUS_DIM1) | |
202 | return -EINVAL; | |
203 | ||
204 | /* invert only 0 and 1, leave unchanged the other values, | |
205 | * remember we are abusing status to set blink patterns | |
206 | */ | |
207 | if (led->type == LP3944_LED_TYPE_LED_INVERTED && status < 2) | |
208 | status = 1 - status; | |
209 | ||
210 | mutex_lock(&data->lock); | |
211 | lp3944_reg_read(led->client, reg, &val); | |
212 | ||
213 | val &= ~(LP3944_LED_STATUS_MASK << (id << 1)); | |
214 | val |= (status << (id << 1)); | |
215 | ||
216 | dev_dbg(&led->client->dev, "%s: %s, reg:%d id:%d status:%d val:%#x\n", | |
217 | __func__, led->ldev.name, reg, id, status, val); | |
218 | ||
219 | /* set led status */ | |
220 | err = lp3944_reg_write(led->client, reg, val); | |
221 | mutex_unlock(&data->lock); | |
222 | ||
223 | return err; | |
224 | } | |
225 | ||
226 | static int lp3944_led_set_blink(struct led_classdev *led_cdev, | |
227 | unsigned long *delay_on, | |
228 | unsigned long *delay_off) | |
229 | { | |
230 | struct lp3944_led_data *led = ldev_to_led(led_cdev); | |
231 | u16 period; | |
232 | u8 duty_cycle; | |
233 | int err; | |
234 | ||
235 | /* units are in ms */ | |
236 | if (*delay_on + *delay_off > LP3944_PERIOD_MAX) | |
237 | return -EINVAL; | |
238 | ||
239 | if (*delay_on == 0 && *delay_off == 0) { | |
240 | /* Special case: the leds subsystem requires a default user | |
241 | * friendly blink pattern for the LED. Let's blink the led | |
242 | * slowly (1Hz). | |
243 | */ | |
244 | *delay_on = 500; | |
245 | *delay_off = 500; | |
246 | } | |
247 | ||
248 | period = (*delay_on) + (*delay_off); | |
249 | ||
250 | /* duty_cycle is the percentage of period during which the led is ON */ | |
251 | duty_cycle = 100 * (*delay_on) / period; | |
252 | ||
253 | /* invert duty cycle for inverted leds, this has the same effect of | |
254 | * swapping delay_on and delay_off | |
255 | */ | |
256 | if (led->type == LP3944_LED_TYPE_LED_INVERTED) | |
257 | duty_cycle = 100 - duty_cycle; | |
258 | ||
259 | /* NOTE: using always the first DIM mode, this means that all leds | |
260 | * will have the same blinking pattern. | |
261 | * | |
262 | * We could find a way later to have two leds blinking in hardware | |
263 | * with different patterns at the same time, falling back to software | |
264 | * control for the other ones. | |
265 | */ | |
266 | err = lp3944_dim_set_period(led->client, LP3944_DIM0, period); | |
267 | if (err) | |
268 | return err; | |
269 | ||
270 | err = lp3944_dim_set_dutycycle(led->client, LP3944_DIM0, duty_cycle); | |
271 | if (err) | |
272 | return err; | |
273 | ||
274 | dev_dbg(&led->client->dev, "%s: OK hardware accelerated blink!\n", | |
275 | __func__); | |
276 | ||
277 | led->status = LP3944_LED_STATUS_DIM0; | |
278 | schedule_work(&led->work); | |
279 | ||
280 | return 0; | |
281 | } | |
282 | ||
283 | static void lp3944_led_set_brightness(struct led_classdev *led_cdev, | |
284 | enum led_brightness brightness) | |
285 | { | |
286 | struct lp3944_led_data *led = ldev_to_led(led_cdev); | |
287 | ||
288 | dev_dbg(&led->client->dev, "%s: %s, %d\n", | |
289 | __func__, led_cdev->name, brightness); | |
290 | ||
291 | led->status = brightness; | |
292 | schedule_work(&led->work); | |
293 | } | |
294 | ||
295 | static void lp3944_led_work(struct work_struct *work) | |
296 | { | |
297 | struct lp3944_led_data *led; | |
298 | ||
299 | led = container_of(work, struct lp3944_led_data, work); | |
300 | lp3944_led_set(led, led->status); | |
301 | } | |
302 | ||
303 | static int lp3944_configure(struct i2c_client *client, | |
304 | struct lp3944_data *data, | |
305 | struct lp3944_platform_data *pdata) | |
306 | { | |
307 | int i, err = 0; | |
308 | ||
309 | for (i = 0; i < pdata->leds_size; i++) { | |
310 | struct lp3944_led *pled = &pdata->leds[i]; | |
311 | struct lp3944_led_data *led = &data->leds[i]; | |
312 | led->client = client; | |
313 | led->id = i; | |
314 | ||
315 | switch (pled->type) { | |
316 | ||
317 | case LP3944_LED_TYPE_LED: | |
318 | case LP3944_LED_TYPE_LED_INVERTED: | |
319 | led->type = pled->type; | |
320 | led->status = pled->status; | |
321 | led->ldev.name = pled->name; | |
322 | led->ldev.max_brightness = 1; | |
323 | led->ldev.brightness_set = lp3944_led_set_brightness; | |
324 | led->ldev.blink_set = lp3944_led_set_blink; | |
325 | led->ldev.flags = LED_CORE_SUSPENDRESUME; | |
326 | ||
327 | INIT_WORK(&led->work, lp3944_led_work); | |
328 | err = led_classdev_register(&client->dev, &led->ldev); | |
329 | if (err < 0) { | |
330 | dev_err(&client->dev, | |
331 | "couldn't register LED %s\n", | |
332 | led->ldev.name); | |
333 | goto exit; | |
334 | } | |
335 | ||
336 | /* to expose the default value to userspace */ | |
337 | led->ldev.brightness = led->status; | |
338 | ||
339 | /* Set the default led status */ | |
340 | err = lp3944_led_set(led, led->status); | |
341 | if (err < 0) { | |
342 | dev_err(&client->dev, | |
343 | "%s couldn't set STATUS %d\n", | |
344 | led->ldev.name, led->status); | |
345 | goto exit; | |
346 | } | |
347 | break; | |
348 | ||
349 | case LP3944_LED_TYPE_NONE: | |
350 | default: | |
351 | break; | |
352 | ||
353 | } | |
354 | } | |
355 | return 0; | |
356 | ||
357 | exit: | |
358 | if (i > 0) | |
359 | for (i = i - 1; i >= 0; i--) | |
360 | switch (pdata->leds[i].type) { | |
361 | ||
362 | case LP3944_LED_TYPE_LED: | |
363 | case LP3944_LED_TYPE_LED_INVERTED: | |
364 | led_classdev_unregister(&data->leds[i].ldev); | |
365 | cancel_work_sync(&data->leds[i].work); | |
366 | break; | |
367 | ||
368 | case LP3944_LED_TYPE_NONE: | |
369 | default: | |
370 | break; | |
371 | } | |
372 | ||
373 | return err; | |
374 | } | |
375 | ||
376 | static int __devinit lp3944_probe(struct i2c_client *client, | |
377 | const struct i2c_device_id *id) | |
378 | { | |
379 | struct lp3944_platform_data *lp3944_pdata = client->dev.platform_data; | |
380 | struct lp3944_data *data; | |
381 | ||
382 | if (lp3944_pdata == NULL) { | |
383 | dev_err(&client->dev, "no platform data\n"); | |
384 | return -EINVAL; | |
385 | } | |
386 | ||
387 | /* Let's see whether this adapter can support what we need. */ | |
388 | if (!i2c_check_functionality(client->adapter, | |
389 | I2C_FUNC_SMBUS_BYTE_DATA)) { | |
390 | dev_err(&client->dev, "insufficient functionality!\n"); | |
391 | return -ENODEV; | |
392 | } | |
393 | ||
394 | data = kzalloc(sizeof(struct lp3944_data), GFP_KERNEL); | |
395 | if (!data) | |
396 | return -ENOMEM; | |
397 | ||
398 | data->client = client; | |
399 | i2c_set_clientdata(client, data); | |
400 | ||
401 | mutex_init(&data->lock); | |
402 | ||
403 | dev_info(&client->dev, "lp3944 enabled\n"); | |
404 | ||
405 | lp3944_configure(client, data, lp3944_pdata); | |
406 | return 0; | |
407 | } | |
408 | ||
409 | static int __devexit lp3944_remove(struct i2c_client *client) | |
410 | { | |
411 | struct lp3944_platform_data *pdata = client->dev.platform_data; | |
412 | struct lp3944_data *data = i2c_get_clientdata(client); | |
413 | int i; | |
414 | ||
415 | for (i = 0; i < pdata->leds_size; i++) | |
416 | switch (data->leds[i].type) { | |
417 | case LP3944_LED_TYPE_LED: | |
418 | case LP3944_LED_TYPE_LED_INVERTED: | |
419 | led_classdev_unregister(&data->leds[i].ldev); | |
420 | cancel_work_sync(&data->leds[i].work); | |
421 | break; | |
422 | ||
423 | case LP3944_LED_TYPE_NONE: | |
424 | default: | |
425 | break; | |
426 | } | |
427 | ||
428 | kfree(data); | |
429 | i2c_set_clientdata(client, NULL); | |
430 | ||
431 | return 0; | |
432 | } | |
433 | ||
434 | /* lp3944 i2c driver struct */ | |
435 | static const struct i2c_device_id lp3944_id[] = { | |
436 | {"lp3944", 0}, | |
437 | {} | |
438 | }; | |
439 | ||
440 | MODULE_DEVICE_TABLE(i2c, lp3944_id); | |
441 | ||
442 | static struct i2c_driver lp3944_driver = { | |
443 | .driver = { | |
444 | .name = "lp3944", | |
445 | }, | |
446 | .probe = lp3944_probe, | |
447 | .remove = __devexit_p(lp3944_remove), | |
448 | .id_table = lp3944_id, | |
449 | }; | |
450 | ||
451 | static int __init lp3944_module_init(void) | |
452 | { | |
453 | return i2c_add_driver(&lp3944_driver); | |
454 | } | |
455 | ||
456 | static void __exit lp3944_module_exit(void) | |
457 | { | |
458 | i2c_del_driver(&lp3944_driver); | |
459 | } | |
460 | ||
461 | module_init(lp3944_module_init); | |
462 | module_exit(lp3944_module_exit); | |
463 | ||
464 | MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); | |
465 | MODULE_DESCRIPTION("LP3944 Fun Light Chip"); | |
466 | MODULE_LICENSE("GPL"); |