linux-imx

// SPDX-License-Identifier: GPL-2.0-only

/*

 * leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip

 *

 * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>

 */

​

/*

 * I2C 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.

 */

​

#include <linux/module.h>

#include <linux/i2c.h>

#include <linux/slab.h>

#include <linux/leds.h>

#include <linux/mutex.h>

#include <linux/leds-lp3944.h>

​

/* Read Only Registers */

#define LP3944_REG_INPUT1     0x00 /* LEDs 0-7 InputRegister (Read Only) */

#define LP3944_REG_REGISTER1  0x01 /* None (Read Only) */

​

#define LP3944_REG_PSC0       0x02 /* Frequency Prescaler 0 (R/W) */

#define LP3944_REG_PWM0       0x03 /* PWM Register 0 (R/W) */

#define LP3944_REG_PSC1       0x04 /* Frequency Prescaler 1 (R/W) */

#define LP3944_REG_PWM1       0x05 /* PWM Register 1 (R/W) */

#define LP3944_REG_LS0        0x06 /* LEDs 0-3 Selector (R/W) */

#define LP3944_REG_LS1        0x07 /* LEDs 4-7 Selector (R/W) */

​

/* These registers are not used to control leds in LP3944, they can store

 * arbitrary values which the chip will ignore.

 */

#define LP3944_REG_REGISTER8  0x08

#define LP3944_REG_REGISTER9  0x09

​

#define LP3944_DIM0 0

#define LP3944_DIM1 1

​

/* period in ms */

#define LP3944_PERIOD_MIN 0

#define LP3944_PERIOD_MAX 1600

​

/* duty cycle is a percentage */

#define LP3944_DUTY_CYCLE_MIN 0

#define LP3944_DUTY_CYCLE_MAX 100

​

#define ldev_to_led(c)       container_of(c, struct lp3944_led_data, ldev)

​

/* Saved data */

struct lp3944_led_data {