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/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "chipset.h"
#include "common.h"
#include "console.h"
#include "gpio.h"
#include "hooks.h"
#include "host_command.h"
#include "i2c.h"
#include "lid_switch.h"
#define LP8555_REG_COMMAND 0x00
#define LP8555_REG_COMMAND_ON 0x01
#define LP8555_REG_CONFIG 0x10
#define LP8555_REG_CONFIG_MODE_MASK 0x03
#define LP8555_REG_CONFIG_MODE_PWM 0x00
/**
* Enable PWM mode in backlight controller and turn it on.
*/
static int lp8555_enable_pwm_mode(void)
{
int reg;
/* Enable PWM mode. */
i2c_read8(I2C_PORT_BACKLIGHT, I2C_ADDR_BACKLIGHT,
LP8555_REG_CONFIG, ®);
reg &= ~LP8555_REG_CONFIG_MODE_MASK;
reg |= LP8555_REG_CONFIG_MODE_PWM;
i2c_write8(I2C_PORT_BACKLIGHT, I2C_ADDR_BACKLIGHT,
LP8555_REG_CONFIG, reg);
/* Power on. */
i2c_read8(I2C_PORT_BACKLIGHT, I2C_ADDR_BACKLIGHT,
LP8555_REG_COMMAND, ®);
reg |= LP8555_REG_COMMAND_ON;
i2c_write8(I2C_PORT_BACKLIGHT, I2C_ADDR_BACKLIGHT,
LP8555_REG_COMMAND, reg);
return EC_SUCCESS;
}
/**
* Host command to toggle backlight.
*/
static int switch_command_enable_backlight(struct host_cmd_handler_args *args)
{
const struct ec_params_switch_enable_backlight *p = args->params;
gpio_set_level(GPIO_ENABLE_BACKLIGHT, p->enabled);
if (p->enabled)
lp8555_enable_pwm_mode();
return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_SWITCH_ENABLE_BKLIGHT,
switch_command_enable_backlight,
EC_VER_MASK(0));
/**
* Hook to turn backlight PWM mode on if it turns off.
*/
static void backlight_pwm_mode_hook(void)
{
int reg;
/* Only check if the system is powered. */
if (!chipset_in_state(CHIPSET_STATE_ON))
return;
/* Read current command reg to see if it is on. */
i2c_read8(I2C_PORT_BACKLIGHT, I2C_ADDR_BACKLIGHT,
LP8555_REG_COMMAND, ®);
/* Turn it on if needed. */
if (!(reg & LP8555_REG_COMMAND_ON))
lp8555_enable_pwm_mode();
}
DECLARE_HOOK(HOOK_SECOND, backlight_pwm_mode_hook, HOOK_PRIO_LAST);
/**
* Update backlight state.
*/
static void update_backlight(void)
{
/*
* Enable backlight if lid is open; this is AND'd with the request from
* the AP in hardware.
*/
gpio_set_level(GPIO_ENABLE_BACKLIGHT, lid_is_open());
}
DECLARE_HOOK(HOOK_LID_CHANGE, update_backlight, HOOK_PRIO_DEFAULT);
/**
* Initialize backlight module.
*/
static void backlight_init(void)
{
update_backlight();
}
DECLARE_HOOK(HOOK_INIT, backlight_init, HOOK_PRIO_DEFAULT);
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