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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> | |
5054d39e AO |
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; | |
5054d39e AO |
70 | struct led_classdev ldev; |
71 | struct i2c_client *client; | |
5054d39e AO |
72 | }; |
73 | ||
74 | struct lp3944_data { | |
75 | struct mutex lock; | |
76 | struct i2c_client *client; | |
77 | struct lp3944_led_data leds[LP3944_LEDS_MAX]; | |
78 | }; | |
79 | ||
80 | static int lp3944_reg_read(struct i2c_client *client, u8 reg, u8 *value) | |
81 | { | |
82 | int tmp; | |
83 | ||
84 | tmp = i2c_smbus_read_byte_data(client, reg); | |
85 | if (tmp < 0) | |
4401e487 | 86 | return tmp; |
5054d39e AO |
87 | |
88 | *value = tmp; | |
89 | ||
90 | return 0; | |
91 | } | |
92 | ||
93 | static int lp3944_reg_write(struct i2c_client *client, u8 reg, u8 value) | |
94 | { | |
95 | return i2c_smbus_write_byte_data(client, reg, value); | |
96 | } | |
97 | ||
98 | /** | |
99 | * Set the period for DIM status | |
100 | * | |
101 | * @client: the i2c client | |
102 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
103 | * @period: period of a blink, that is a on/off cycle, expressed in ms. | |
104 | */ | |
105 | static int lp3944_dim_set_period(struct i2c_client *client, u8 dim, u16 period) | |
106 | { | |
107 | u8 psc_reg; | |
108 | u8 psc_value; | |
109 | int err; | |
110 | ||
111 | if (dim == LP3944_DIM0) | |
112 | psc_reg = LP3944_REG_PSC0; | |
113 | else if (dim == LP3944_DIM1) | |
114 | psc_reg = LP3944_REG_PSC1; | |
115 | else | |
116 | return -EINVAL; | |
117 | ||
118 | /* Convert period to Prescaler value */ | |
119 | if (period > LP3944_PERIOD_MAX) | |
120 | return -EINVAL; | |
121 | ||
122 | psc_value = (period * 255) / LP3944_PERIOD_MAX; | |
123 | ||
124 | err = lp3944_reg_write(client, psc_reg, psc_value); | |
125 | ||
126 | return err; | |
127 | } | |
128 | ||
129 | /** | |
130 | * Set the duty cycle for DIM status | |
131 | * | |
132 | * @client: the i2c client | |
133 | * @dim: either LP3944_DIM0 or LP3944_DIM1 | |
134 | * @duty_cycle: percentage of a period during which a led is ON | |
135 | */ | |
136 | static int lp3944_dim_set_dutycycle(struct i2c_client *client, u8 dim, | |
137 | u8 duty_cycle) | |
138 | { | |
139 | u8 pwm_reg; | |
140 | u8 pwm_value; | |
141 | int err; | |
142 | ||
143 | if (dim == LP3944_DIM0) | |
144 | pwm_reg = LP3944_REG_PWM0; | |
145 | else if (dim == LP3944_DIM1) | |
146 | pwm_reg = LP3944_REG_PWM1; | |
147 | else | |
148 | return -EINVAL; | |
149 | ||
150 | /* Convert duty cycle to PWM value */ | |
151 | if (duty_cycle > LP3944_DUTY_CYCLE_MAX) | |
152 | return -EINVAL; | |
153 | ||
154 | pwm_value = (duty_cycle * 255) / LP3944_DUTY_CYCLE_MAX; | |
155 | ||
156 | err = lp3944_reg_write(client, pwm_reg, pwm_value); | |
157 | ||
158 | return err; | |
159 | } | |
160 | ||
161 | /** | |
162 | * Set the led status | |
163 | * | |
164 | * @led: a lp3944_led_data structure | |
165 | * @status: one of LP3944_LED_STATUS_OFF | |
166 | * LP3944_LED_STATUS_ON | |
167 | * LP3944_LED_STATUS_DIM0 | |
168 | * LP3944_LED_STATUS_DIM1 | |
169 | */ | |
170 | static int lp3944_led_set(struct lp3944_led_data *led, u8 status) | |
171 | { | |
172 | struct lp3944_data *data = i2c_get_clientdata(led->client); | |
173 | u8 id = led->id; | |
174 | u8 reg; | |
175 | u8 val = 0; | |
176 | int err; | |
177 | ||
178 | dev_dbg(&led->client->dev, "%s: %s, status before normalization:%d\n", | |
179 | __func__, led->ldev.name, status); | |
180 | ||
181 | switch (id) { | |
182 | case LP3944_LED0: | |
183 | case LP3944_LED1: | |
184 | case LP3944_LED2: | |
185 | case LP3944_LED3: | |
186 | reg = LP3944_REG_LS0; | |
187 | break; | |
188 | case LP3944_LED4: | |
189 | case LP3944_LED5: | |
190 | case LP3944_LED6: | |
191 | case LP3944_LED7: | |
192 | id -= LP3944_LED4; | |
193 | reg = LP3944_REG_LS1; | |
194 | break; | |
195 | default: | |
196 | return -EINVAL; | |
197 | } | |
198 | ||
199 | if (status > LP3944_LED_STATUS_DIM1) | |
200 | return -EINVAL; | |
201 | ||
c9eec908 AO |
202 | /* |
203 | * Invert status only when it's < 2 (i.e. 0 or 1) which means it's | |
204 | * controlling the on/off state directly. | |
205 | * When, instead, status is >= 2 don't invert it because it would mean | |
206 | * to mess with the hardware blinking mode. | |
5054d39e AO |
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 | ||
525d6a65 | 278 | lp3944_led_set(led, LP3944_LED_STATUS_DIM0); |
5054d39e AO |
279 | |
280 | return 0; | |
281 | } | |
282 | ||
525d6a65 | 283 | static int lp3944_led_set_brightness(struct led_classdev *led_cdev, |
5054d39e AO |
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 | ||
525d6a65 | 291 | return lp3944_led_set(led, !!brightness); |
5054d39e AO |
292 | } |
293 | ||
294 | static int lp3944_configure(struct i2c_client *client, | |
295 | struct lp3944_data *data, | |
296 | struct lp3944_platform_data *pdata) | |
297 | { | |
298 | int i, err = 0; | |
299 | ||
300 | for (i = 0; i < pdata->leds_size; i++) { | |
301 | struct lp3944_led *pled = &pdata->leds[i]; | |
302 | struct lp3944_led_data *led = &data->leds[i]; | |
303 | led->client = client; | |
304 | led->id = i; | |
305 | ||
306 | switch (pled->type) { | |
307 | ||
308 | case LP3944_LED_TYPE_LED: | |
309 | case LP3944_LED_TYPE_LED_INVERTED: | |
310 | led->type = pled->type; | |
5054d39e AO |
311 | led->ldev.name = pled->name; |
312 | led->ldev.max_brightness = 1; | |
525d6a65 AL |
313 | led->ldev.brightness_set_blocking = |
314 | lp3944_led_set_brightness; | |
5054d39e AO |
315 | led->ldev.blink_set = lp3944_led_set_blink; |
316 | led->ldev.flags = LED_CORE_SUSPENDRESUME; | |
317 | ||
5054d39e AO |
318 | err = led_classdev_register(&client->dev, &led->ldev); |
319 | if (err < 0) { | |
320 | dev_err(&client->dev, | |
321 | "couldn't register LED %s\n", | |
322 | led->ldev.name); | |
323 | goto exit; | |
324 | } | |
325 | ||
326 | /* to expose the default value to userspace */ | |
7f14e6b9 | 327 | led->ldev.brightness = |
525d6a65 | 328 | (enum led_brightness) pled->status; |
5054d39e AO |
329 | |
330 | /* Set the default led status */ | |
525d6a65 | 331 | err = lp3944_led_set(led, pled->status); |
5054d39e AO |
332 | if (err < 0) { |
333 | dev_err(&client->dev, | |
334 | "%s couldn't set STATUS %d\n", | |
525d6a65 | 335 | led->ldev.name, pled->status); |
5054d39e AO |
336 | goto exit; |
337 | } | |
338 | break; | |
339 | ||
340 | case LP3944_LED_TYPE_NONE: | |
341 | default: | |
342 | break; | |
343 | ||
344 | } | |
345 | } | |
346 | return 0; | |
347 | ||
348 | exit: | |
349 | if (i > 0) | |
350 | for (i = i - 1; i >= 0; i--) | |
351 | switch (pdata->leds[i].type) { | |
352 | ||
353 | case LP3944_LED_TYPE_LED: | |
354 | case LP3944_LED_TYPE_LED_INVERTED: | |
355 | led_classdev_unregister(&data->leds[i].ldev); | |
5054d39e AO |
356 | break; |
357 | ||
358 | case LP3944_LED_TYPE_NONE: | |
359 | default: | |
360 | break; | |
361 | } | |
362 | ||
363 | return err; | |
364 | } | |
365 | ||
98ea1ea2 | 366 | static int lp3944_probe(struct i2c_client *client, |
5054d39e AO |
367 | const struct i2c_device_id *id) |
368 | { | |
87aae1ea JH |
369 | struct lp3944_platform_data *lp3944_pdata = |
370 | dev_get_platdata(&client->dev); | |
5054d39e | 371 | struct lp3944_data *data; |
7e1ce34f | 372 | int err; |
5054d39e AO |
373 | |
374 | if (lp3944_pdata == NULL) { | |
375 | dev_err(&client->dev, "no platform data\n"); | |
376 | return -EINVAL; | |
377 | } | |
378 | ||
379 | /* Let's see whether this adapter can support what we need. */ | |
380 | if (!i2c_check_functionality(client->adapter, | |
381 | I2C_FUNC_SMBUS_BYTE_DATA)) { | |
382 | dev_err(&client->dev, "insufficient functionality!\n"); | |
383 | return -ENODEV; | |
384 | } | |
385 | ||
9813d74f BW |
386 | data = devm_kzalloc(&client->dev, sizeof(struct lp3944_data), |
387 | GFP_KERNEL); | |
5054d39e AO |
388 | if (!data) |
389 | return -ENOMEM; | |
390 | ||
391 | data->client = client; | |
392 | i2c_set_clientdata(client, data); | |
393 | ||
394 | mutex_init(&data->lock); | |
395 | ||
7e1ce34f | 396 | err = lp3944_configure(client, data, lp3944_pdata); |
9813d74f | 397 | if (err < 0) |
7e1ce34f | 398 | return err; |
5054d39e | 399 | |
7e1ce34f | 400 | dev_info(&client->dev, "lp3944 enabled\n"); |
5054d39e AO |
401 | return 0; |
402 | } | |
403 | ||
678e8a6b | 404 | static int lp3944_remove(struct i2c_client *client) |
5054d39e | 405 | { |
87aae1ea | 406 | struct lp3944_platform_data *pdata = dev_get_platdata(&client->dev); |
5054d39e AO |
407 | struct lp3944_data *data = i2c_get_clientdata(client); |
408 | int i; | |
409 | ||
410 | for (i = 0; i < pdata->leds_size; i++) | |
411 | switch (data->leds[i].type) { | |
412 | case LP3944_LED_TYPE_LED: | |
413 | case LP3944_LED_TYPE_LED_INVERTED: | |
414 | led_classdev_unregister(&data->leds[i].ldev); | |
5054d39e AO |
415 | break; |
416 | ||
417 | case LP3944_LED_TYPE_NONE: | |
418 | default: | |
419 | break; | |
420 | } | |
421 | ||
5054d39e AO |
422 | return 0; |
423 | } | |
424 | ||
425 | /* lp3944 i2c driver struct */ | |
426 | static const struct i2c_device_id lp3944_id[] = { | |
427 | {"lp3944", 0}, | |
428 | {} | |
429 | }; | |
430 | ||
431 | MODULE_DEVICE_TABLE(i2c, lp3944_id); | |
432 | ||
433 | static struct i2c_driver lp3944_driver = { | |
434 | .driver = { | |
435 | .name = "lp3944", | |
436 | }, | |
437 | .probe = lp3944_probe, | |
df07cf81 | 438 | .remove = lp3944_remove, |
5054d39e AO |
439 | .id_table = lp3944_id, |
440 | }; | |
441 | ||
09a0d183 | 442 | module_i2c_driver(lp3944_driver); |
5054d39e AO |
443 | |
444 | MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); | |
445 | MODULE_DESCRIPTION("LP3944 Fun Light Chip"); | |
446 | MODULE_LICENSE("GPL"); |