150 lines
4.6 KiB
C
150 lines
4.6 KiB
C
/***************************************************************************
|
|
* __________ __ ___.
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
|
* \/ \/ \/ \/ \/
|
|
*
|
|
* Copyright (C) 2013 by Lorenzo Miori
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
*
|
|
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
* KIND, either express or implied.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#include "config.h"
|
|
#include "system.h"
|
|
#include "lcd.h"
|
|
#include "backlight.h"
|
|
#include "backlight-target.h"
|
|
#include "pinctrl-imx233.h"
|
|
|
|
/**
|
|
* AAT3151 Backlight Controller
|
|
*/
|
|
|
|
/* Timings */
|
|
#define TIME_OFF 500
|
|
#define TIME_LOW 50
|
|
#define TIME_HI 50
|
|
#define TIME_LAT 500
|
|
|
|
/* Number of raising edges to select the particular register */
|
|
#define D1_D4_CURRENT_E 17
|
|
#define D1_D3_CURRENT_E 18
|
|
#define D4_CURRENT_E 19
|
|
#define MAX_CURRENT_E 20
|
|
#define LOW_CURRENT_E 21
|
|
|
|
/* The actual register address / number */
|
|
#define D1_D4_CURRENT 1
|
|
#define D1_D3_CURRENT 2
|
|
#define D4_CURRENT 3
|
|
#define MAX_CURRENT 4
|
|
#define LOW_CURRENT 5
|
|
|
|
/* Valid values for LOW_CURRENT register */
|
|
#define MAX_CURRENT_20 1
|
|
#define MAX_CURRENT_30 2
|
|
#define MAX_CURRENT_15 3
|
|
#define MAX_CURRENT_LOW_CURRENT 4
|
|
|
|
static int current_level = -1;
|
|
|
|
static void create_raising_edges(int num)
|
|
{
|
|
while (num--)
|
|
{
|
|
/* Setting a register takes a sufficient small amount of time,
|
|
* in the order of 50 ns. Thus the necessary 2 delays TIME_LOW/TIME_HI
|
|
* are not strictly necessary */
|
|
imx233_pinctrl_set_gpio(3, 13, false);
|
|
imx233_pinctrl_set_gpio(3, 13, true);
|
|
}
|
|
}
|
|
|
|
static void aat3151_write(int addr, int data)
|
|
{
|
|
create_raising_edges(16 + addr);
|
|
udelay(TIME_LAT);
|
|
create_raising_edges(data);
|
|
udelay(TIME_LAT);
|
|
}
|
|
|
|
void backlight_hw_brightness(int level)
|
|
{
|
|
/* Don't try to reset backlight if not necessary
|
|
* Moreover this helps to avoid flickering when
|
|
* being in some screens like USB mode and
|
|
* pressing some keys / touchpad...
|
|
*/
|
|
if (current_level == level) return;
|
|
|
|
/* Check for limits and adjust in case */
|
|
level = MIN(MAX_BRIGHTNESS_SETTING, MAX(0, level));
|
|
|
|
if (level == 0)
|
|
{
|
|
/* Set pin low for a sufficient time, puts the device into low-power consumption state
|
|
* In other words backlight goes off
|
|
*/
|
|
imx233_pinctrl_set_gpio(3, 13, false);
|
|
udelay(TIME_OFF);
|
|
}
|
|
else
|
|
{
|
|
if (level > 3) {
|
|
/* This enables 16 levels of backlight */
|
|
aat3151_write(MAX_CURRENT, MAX_CURRENT_15);
|
|
/* Set the value according Table 1 in datasheet
|
|
* For MAX_CURRENT_15, the scale is from 0 mA to 15 mA in 16 steps
|
|
*/
|
|
aat3151_write(D1_D3_CURRENT, 19 - level);
|
|
}
|
|
else {
|
|
/* This enables other 4 levels of backlight */
|
|
aat3151_write(MAX_CURRENT, MAX_CURRENT_LOW_CURRENT);
|
|
/* Set the value according Table 1 in datasheet
|
|
* For LOW_CURRENT, there is no "real" scale. We have scattered values.
|
|
* We are interested in the last 3 -> 0.5 mA; 1 mA; 2 mA
|
|
*/
|
|
aat3151_write(LOW_CURRENT, 13 + level);
|
|
}
|
|
}
|
|
current_level = level;
|
|
}
|
|
|
|
bool backlight_hw_init(void)
|
|
{
|
|
imx233_pinctrl_acquire(3, 13, "backlight");
|
|
imx233_pinctrl_set_function(3, 13, PINCTRL_FUNCTION_GPIO);
|
|
imx233_pinctrl_set_drive(3, 13, PINCTRL_DRIVE_4mA);
|
|
imx233_pinctrl_enable_gpio(3, 13, true);
|
|
imx233_pinctrl_set_gpio(3, 13, false);
|
|
return true;
|
|
}
|
|
|
|
void backlight_hw_on(void)
|
|
{
|
|
#ifdef HAVE_LCD_ENABLE
|
|
lcd_enable(true); /* power on lcd + visible display */
|
|
#endif
|
|
/* restore the previous backlight level */
|
|
backlight_hw_brightness(backlight_brightness);
|
|
}
|
|
|
|
void backlight_hw_off(void)
|
|
{
|
|
/* there is no real on/off but we can set to 0 brightness */
|
|
backlight_hw_brightness(0);
|
|
#ifdef HAVE_LCD_ENABLE
|
|
lcd_enable(false); /* power off visible display */
|
|
#endif
|
|
}
|