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/* Copyright 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"
#include "timer.h"
#define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)
#define I2C_ADDR_BACKLIGHT_FLAGS (0x2C | I2C_FLAG_BIG_ENDIAN)
#define I2C_RETRIES 3
#define I2C_RETRY_DELAY (5*MSEC)
#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
#define LP8555_REG_CURRENT 0x11
#define LP8555_REG_CURRENT_MAXCURR_5MA 0x00
#define LP8555_REG_CURRENT_MAXCURR_10MA 0x01
#define LP8555_REG_CURRENT_MAXCURR_15MA 0x02
#define LP8555_REG_CURRENT_MAXCURR_20MA 0x03
#define LP8555_REG_CURRENT_MAXCURR_23MA 0x04
#define LP8555_REG_CURRENT_MAXCURR_25MA 0x05
#define LP8555_REG_CURRENT_MAXCURR_30MA 0x06
#define LP8555_REG_CURRENT_MAXCURR_50MA 0x07
#define LP8555_REG_STEP 0x15
#define LP8555_REG_STEP_STEP_0MS (0 << 0)
#define LP8555_REG_STEP_STEP_8MS BIT(0)
#define LP8555_REG_STEP_STEP_16MS (2 << 0)
#define LP8555_REG_STEP_STEP_24MS (3 << 0)
#define LP8555_REG_STEP_STEP_28MS (4 << 0)
#define LP8555_REG_STEP_STEP_32MS (5 << 0)
#define LP8555_REG_STEP_STEP_100MS (6 << 0)
#define LP8555_REG_STEP_STEP_200MS (7 << 0)
#define LP8555_REG_STEP_PWM_IN_HYST_NONE (0 << 3)
#define LP8555_REG_STEP_PWM_IN_HYST_1LSB BIT(3)
#define LP8555_REG_STEP_PWM_IN_HYST_2LSB (2 << 3)
#define LP8555_REG_STEP_PWM_IN_HYST_4LSB (3 << 3)
#define LP8555_REG_STEP_PWM_IN_HYST_8LSB (4 << 3)
#define LP8555_REG_STEP_PWM_IN_HYST_16LSB (5 << 3)
#define LP8555_REG_STEP_PWM_IN_HYST_32LSB (6 << 3)
#define LP8555_REG_STEP_PWM_IN_HYST_64LSB (7 << 3)
#define LP8555_REG_STEP_SMOOTH_NONE (0 << 6)
#define LP8555_REG_STEP_SMOOTH_LIGHT BIT(6)
#define LP8555_REG_STEP_SMOOTH_MEDIUM (2 << 6)
#define LP8555_REG_STEP_SMOOTH_HEAVY (3 << 6)
/* Read from lp8555 with automatic i2c retries */
static int lp8555_read_with_retry(int reg, int *data)
{
int i, rv;
for (i = 0; i < I2C_RETRIES; i++) {
rv = i2c_read8(I2C_PORT_BACKLIGHT,
I2C_ADDR_BACKLIGHT_FLAGS,
reg, data);
if (rv == EC_SUCCESS)
return EC_SUCCESS;
usleep(I2C_RETRY_DELAY);
}
CPRINTS("Backlight read fail: reg 0x%02x", reg);
return rv;
}
/* Write to lp8555 with automatic i2c retries */
static int lp8555_write_with_retry(int reg, int data)
{
int i, rv;
for (i = 0; i < I2C_RETRIES; i++) {
rv = i2c_write8(I2C_PORT_BACKLIGHT,
I2C_ADDR_BACKLIGHT_FLAGS,
reg, data);
if (rv == EC_SUCCESS)
return EC_SUCCESS;
usleep(I2C_RETRY_DELAY);
}
CPRINTS("Backlight write fail: reg 0x%02x data %d", reg, data);
return rv;
}
/**
* Setup backlight controller and turn it on.
*/
static void lp8555_enable_pwm_mode(void)
{
int reg;
int rv;
/*
* If not in S0, then PCH backlight enable will not be on, and if
* lid is closed EC backlight enable will not be on. Since these
* two signals are AND'ed together, no point in trying to talk to
* the lp8555 if either one of them is not true.
*/
if (!chipset_in_state(CHIPSET_STATE_ON) || !lid_is_open())
return;
/* Enable PWM mode. */
rv = lp8555_read_with_retry(LP8555_REG_CONFIG, ®);
if (rv != EC_SUCCESS)
return;
reg &= ~LP8555_REG_CONFIG_MODE_MASK;
reg |= LP8555_REG_CONFIG_MODE_PWM;
rv = lp8555_write_with_retry(LP8555_REG_CONFIG, reg);
if (rv != EC_SUCCESS)
return;
/* Set max LED current to 23mA. */
rv = lp8555_write_with_retry(LP8555_REG_CURRENT,
LP8555_REG_CURRENT_MAXCURR_23MA);
if (rv != EC_SUCCESS)
return;
/* Set the rate of brightness change. */
rv = lp8555_write_with_retry(LP8555_REG_STEP,
LP8555_REG_STEP_STEP_200MS |
LP8555_REG_STEP_PWM_IN_HYST_8LSB |
LP8555_REG_STEP_SMOOTH_HEAVY);
if (rv != EC_SUCCESS)
return;
/* Power on. */
rv = lp8555_read_with_retry(LP8555_REG_COMMAND, ®);
if (rv != EC_SUCCESS)
return;
reg |= LP8555_REG_COMMAND_ON;
rv = lp8555_write_with_retry(LP8555_REG_COMMAND, reg);
}
DECLARE_DEFERRED(lp8555_enable_pwm_mode);
/**
* Host command to toggle backlight.
*/
static enum ec_status
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));
void backlight_interrupt(enum gpio_signal signal)
{
/*
* PCH indicates it is turning on backlight so we should
* attempt to put the backlight controller into PWM mode.
*/
hook_call_deferred(&lp8555_enable_pwm_mode_data, 0);
}
/**
* 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());
if (lid_is_open())
hook_call_deferred(&lp8555_enable_pwm_mode_data, 0);
}
DECLARE_HOOK(HOOK_LID_CHANGE, update_backlight, HOOK_PRIO_DEFAULT);
/**
* Initialize backlight module.
*/
static void backlight_init(void)
{
gpio_enable_interrupt(GPIO_PCH_BL_EN);
gpio_set_level(GPIO_ENABLE_BACKLIGHT, lid_is_open());
}
DECLARE_HOOK(HOOK_INIT, backlight_init, HOOK_PRIO_DEFAULT);
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