2 * leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip
4 * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>
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.
13 * I2C driver for National Semiconductor LP3944 Funlight Chip
14 * http://www.national.com/pf/LP/LP3944.html
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.
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
25 * LP3944 can be found on Motorola A910 smartphone, where it drives the rgb
26 * leds, the camera flash light and the displays backlights.
29 #include <linux/module.h>
30 #include <linux/i2c.h>
31 #include <linux/slab.h>
32 #include <linux/leds.h>
33 #include <linux/mutex.h>
34 #include <linux/leds-lp3944.h>
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) */
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) */
47 /* These registers are not used to control leds in LP3944, they can store
48 * arbitrary values which the chip will ignore.
50 #define LP3944_REG_REGISTER8 0x08
51 #define LP3944_REG_REGISTER9 0x09
57 #define LP3944_PERIOD_MIN 0
58 #define LP3944_PERIOD_MAX 1600
60 /* duty cycle is a percentage */
61 #define LP3944_DUTY_CYCLE_MIN 0
62 #define LP3944_DUTY_CYCLE_MAX 100
64 #define ldev_to_led(c) container_of(c, struct lp3944_led_data, ldev)
67 struct lp3944_led_data
{
69 enum lp3944_type type
;
70 struct led_classdev ldev
;
71 struct i2c_client
*client
;
76 struct i2c_client
*client
;
77 struct lp3944_led_data leds
[LP3944_LEDS_MAX
];
80 static int lp3944_reg_read(struct i2c_client
*client
, u8 reg
, u8
*value
)
84 tmp
= i2c_smbus_read_byte_data(client
, reg
);
93 static int lp3944_reg_write(struct i2c_client
*client
, u8 reg
, u8 value
)
95 return i2c_smbus_write_byte_data(client
, reg
, value
);
99 * Set the period for DIM status
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.
105 static int lp3944_dim_set_period(struct i2c_client
*client
, u8 dim
, u16 period
)
111 if (dim
== LP3944_DIM0
)
112 psc_reg
= LP3944_REG_PSC0
;
113 else if (dim
== LP3944_DIM1
)
114 psc_reg
= LP3944_REG_PSC1
;
118 /* Convert period to Prescaler value */
119 if (period
> LP3944_PERIOD_MAX
)
122 psc_value
= (period
* 255) / LP3944_PERIOD_MAX
;
124 err
= lp3944_reg_write(client
, psc_reg
, psc_value
);
130 * Set the duty cycle for DIM status
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
136 static int lp3944_dim_set_dutycycle(struct i2c_client
*client
, u8 dim
,
143 if (dim
== LP3944_DIM0
)
144 pwm_reg
= LP3944_REG_PWM0
;
145 else if (dim
== LP3944_DIM1
)
146 pwm_reg
= LP3944_REG_PWM1
;
150 /* Convert duty cycle to PWM value */
151 if (duty_cycle
> LP3944_DUTY_CYCLE_MAX
)
154 pwm_value
= (duty_cycle
* 255) / LP3944_DUTY_CYCLE_MAX
;
156 err
= lp3944_reg_write(client
, pwm_reg
, pwm_value
);
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
170 static int lp3944_led_set(struct lp3944_led_data
*led
, u8 status
)
172 struct lp3944_data
*data
= i2c_get_clientdata(led
->client
);
178 dev_dbg(&led
->client
->dev
, "%s: %s, status before normalization:%d\n",
179 __func__
, led
->ldev
.name
, status
);
186 reg
= LP3944_REG_LS0
;
193 reg
= LP3944_REG_LS1
;
199 if (status
> LP3944_LED_STATUS_DIM1
)
202 /* invert only 0 and 1, leave unchanged the other values,
203 * remember we are abusing status to set blink patterns
205 if (led
->type
== LP3944_LED_TYPE_LED_INVERTED
&& status
< 2)
208 mutex_lock(&data
->lock
);
209 lp3944_reg_read(led
->client
, reg
, &val
);
211 val
&= ~(LP3944_LED_STATUS_MASK
<< (id
<< 1));
212 val
|= (status
<< (id
<< 1));
214 dev_dbg(&led
->client
->dev
, "%s: %s, reg:%d id:%d status:%d val:%#x\n",
215 __func__
, led
->ldev
.name
, reg
, id
, status
, val
);
218 err
= lp3944_reg_write(led
->client
, reg
, val
);
219 mutex_unlock(&data
->lock
);
224 static int lp3944_led_set_blink(struct led_classdev
*led_cdev
,
225 unsigned long *delay_on
,
226 unsigned long *delay_off
)
228 struct lp3944_led_data
*led
= ldev_to_led(led_cdev
);
233 /* units are in ms */
234 if (*delay_on
+ *delay_off
> LP3944_PERIOD_MAX
)
237 if (*delay_on
== 0 && *delay_off
== 0) {
238 /* Special case: the leds subsystem requires a default user
239 * friendly blink pattern for the LED. Let's blink the led
246 period
= (*delay_on
) + (*delay_off
);
248 /* duty_cycle is the percentage of period during which the led is ON */
249 duty_cycle
= 100 * (*delay_on
) / period
;
251 /* invert duty cycle for inverted leds, this has the same effect of
252 * swapping delay_on and delay_off
254 if (led
->type
== LP3944_LED_TYPE_LED_INVERTED
)
255 duty_cycle
= 100 - duty_cycle
;
257 /* NOTE: using always the first DIM mode, this means that all leds
258 * will have the same blinking pattern.
260 * We could find a way later to have two leds blinking in hardware
261 * with different patterns at the same time, falling back to software
262 * control for the other ones.
264 err
= lp3944_dim_set_period(led
->client
, LP3944_DIM0
, period
);
268 err
= lp3944_dim_set_dutycycle(led
->client
, LP3944_DIM0
, duty_cycle
);
272 dev_dbg(&led
->client
->dev
, "%s: OK hardware accelerated blink!\n",
275 lp3944_led_set(led
, LP3944_LED_STATUS_DIM0
);
280 static int lp3944_led_set_brightness(struct led_classdev
*led_cdev
,
281 enum led_brightness brightness
)
283 struct lp3944_led_data
*led
= ldev_to_led(led_cdev
);
285 dev_dbg(&led
->client
->dev
, "%s: %s, %d\n",
286 __func__
, led_cdev
->name
, brightness
);
288 return lp3944_led_set(led
, !!brightness
);
291 static int lp3944_configure(struct i2c_client
*client
,
292 struct lp3944_data
*data
,
293 struct lp3944_platform_data
*pdata
)
297 for (i
= 0; i
< pdata
->leds_size
; i
++) {
298 struct lp3944_led
*pled
= &pdata
->leds
[i
];
299 struct lp3944_led_data
*led
= &data
->leds
[i
];
300 led
->client
= client
;
303 switch (pled
->type
) {
305 case LP3944_LED_TYPE_LED
:
306 case LP3944_LED_TYPE_LED_INVERTED
:
307 led
->type
= pled
->type
;
308 led
->ldev
.name
= pled
->name
;
309 led
->ldev
.max_brightness
= 1;
310 led
->ldev
.brightness_set_blocking
=
311 lp3944_led_set_brightness
;
312 led
->ldev
.blink_set
= lp3944_led_set_blink
;
313 led
->ldev
.flags
= LED_CORE_SUSPENDRESUME
;
315 err
= led_classdev_register(&client
->dev
, &led
->ldev
);
317 dev_err(&client
->dev
,
318 "couldn't register LED %s\n",
323 /* to expose the default value to userspace */
324 led
->ldev
.brightness
=
325 (enum led_brightness
) pled
->status
;
327 /* Set the default led status */
328 err
= lp3944_led_set(led
, pled
->status
);
330 dev_err(&client
->dev
,
331 "%s couldn't set STATUS %d\n",
332 led
->ldev
.name
, pled
->status
);
337 case LP3944_LED_TYPE_NONE
:
347 for (i
= i
- 1; i
>= 0; i
--)
348 switch (pdata
->leds
[i
].type
) {
350 case LP3944_LED_TYPE_LED
:
351 case LP3944_LED_TYPE_LED_INVERTED
:
352 led_classdev_unregister(&data
->leds
[i
].ldev
);
355 case LP3944_LED_TYPE_NONE
:
363 static int lp3944_probe(struct i2c_client
*client
,
364 const struct i2c_device_id
*id
)
366 struct lp3944_platform_data
*lp3944_pdata
=
367 dev_get_platdata(&client
->dev
);
368 struct lp3944_data
*data
;
371 if (lp3944_pdata
== NULL
) {
372 dev_err(&client
->dev
, "no platform data\n");
376 /* Let's see whether this adapter can support what we need. */
377 if (!i2c_check_functionality(client
->adapter
,
378 I2C_FUNC_SMBUS_BYTE_DATA
)) {
379 dev_err(&client
->dev
, "insufficient functionality!\n");
383 data
= devm_kzalloc(&client
->dev
, sizeof(struct lp3944_data
),
388 data
->client
= client
;
389 i2c_set_clientdata(client
, data
);
391 mutex_init(&data
->lock
);
393 err
= lp3944_configure(client
, data
, lp3944_pdata
);
397 dev_info(&client
->dev
, "lp3944 enabled\n");
401 static int lp3944_remove(struct i2c_client
*client
)
403 struct lp3944_platform_data
*pdata
= dev_get_platdata(&client
->dev
);
404 struct lp3944_data
*data
= i2c_get_clientdata(client
);
407 for (i
= 0; i
< pdata
->leds_size
; i
++)
408 switch (data
->leds
[i
].type
) {
409 case LP3944_LED_TYPE_LED
:
410 case LP3944_LED_TYPE_LED_INVERTED
:
411 led_classdev_unregister(&data
->leds
[i
].ldev
);
414 case LP3944_LED_TYPE_NONE
:
422 /* lp3944 i2c driver struct */
423 static const struct i2c_device_id lp3944_id
[] = {
428 MODULE_DEVICE_TABLE(i2c
, lp3944_id
);
430 static struct i2c_driver lp3944_driver
= {
434 .probe
= lp3944_probe
,
435 .remove
= lp3944_remove
,
436 .id_table
= lp3944_id
,
439 module_i2c_driver(lp3944_driver
);
441 MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
442 MODULE_DESCRIPTION("LP3944 Fun Light Chip");
443 MODULE_LICENSE("GPL");