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authorAntonio Ospite <ospite@studenti.unina.it>2009-06-19 07:55:42 -0400
committerRichard Purdie <rpurdie@linux.intel.com>2009-06-23 15:21:38 -0400
commit5054d39e327f76df022163a2ebd02e444c5d65f9 (patch)
tree915f4a5406a1147524ba8a2aa7ab42074127be84 /drivers/leds/leds-lp3944.c
parent07172d2bfa339d6c150d8cdd7c02128177feffbb (diff)
leds: LED driver for National Semiconductor LP3944 Funlight Chip
LEDs driver for National Semiconductor LP3944 Funlight Chip http://www.national.com/pf/LP/LP3944.html This helper chip can drive up to 8 leds, with two programmable DIM modes; it could even be used as a gpio expander but this driver assumes it is used as a led controller. The DIM modes are used to set _blink_ patterns for leds, the pattern is specified supplying two parameters: - period: from 0s to 1.6s - duty cycle: percentage of the period the led is on, from 0 to 100 LP3944 can be found on Motorola A910 smartphone, where it drives the rgb leds, the camera flash light and the displays backlights. Signed-off-by: Antonio Ospite <ospite@studenti.unina.it> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
Diffstat (limited to 'drivers/leds/leds-lp3944.c')
-rw-r--r--drivers/leds/leds-lp3944.c466
1 files changed, 466 insertions, 0 deletions
diff --git a/drivers/leds/leds-lp3944.c b/drivers/leds/leds-lp3944.c
new file mode 100644
index 000000000000..5946208ba26e
--- /dev/null
+++ b/drivers/leds/leds-lp3944.c
@@ -0,0 +1,466 @@
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 */
67struct 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
76struct lp3944_data {
77 struct mutex lock;
78 struct i2c_client *client;
79 struct lp3944_led_data leds[LP3944_LEDS_MAX];
80};
81
82static 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
95static 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 */
107static 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 */
138static 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 */
172static 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
226static 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
283static 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
295static 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
303static 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
357exit:
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
376static 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
409static 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 */
435static const struct i2c_device_id lp3944_id[] = {
436 {"lp3944", 0},
437 {}
438};
439
440MODULE_DEVICE_TABLE(i2c, lp3944_id);
441
442static 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
451static int __init lp3944_module_init(void)
452{
453 return i2c_add_driver(&lp3944_driver);
454}
455
456static void __exit lp3944_module_exit(void)
457{
458 i2c_del_driver(&lp3944_driver);
459}
460
461module_init(lp3944_module_init);
462module_exit(lp3944_module_exit);
463
464MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
465MODULE_DESCRIPTION("LP3944 Fun Light Chip");
466MODULE_LICENSE("GPL");