193 lines
5.6 KiB
C
193 lines
5.6 KiB
C
/* Copyright 2013 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "chipset.h"
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#include "common.h"
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#include "console.h"
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#include "gpio.h"
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#include "hooks.h"
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#include "host_command.h"
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#include "i2c.h"
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#include "lid_switch.h"
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#include "timer.h"
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#define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)
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#define I2C_ADDR_BACKLIGHT ((0x2C << 1) | I2C_FLAG_BIG_ENDIAN)
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#define I2C_RETRIES 3
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#define I2C_RETRY_DELAY (5*MSEC)
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#define LP8555_REG_COMMAND 0x00
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#define LP8555_REG_COMMAND_ON 0x01
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#define LP8555_REG_CONFIG 0x10
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#define LP8555_REG_CONFIG_MODE_MASK 0x03
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#define LP8555_REG_CONFIG_MODE_PWM 0x00
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#define LP8555_REG_CURRENT 0x11
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#define LP8555_REG_CURRENT_MAXCURR_5MA 0x00
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#define LP8555_REG_CURRENT_MAXCURR_10MA 0x01
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#define LP8555_REG_CURRENT_MAXCURR_15MA 0x02
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#define LP8555_REG_CURRENT_MAXCURR_20MA 0x03
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#define LP8555_REG_CURRENT_MAXCURR_23MA 0x04
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#define LP8555_REG_CURRENT_MAXCURR_25MA 0x05
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#define LP8555_REG_CURRENT_MAXCURR_30MA 0x06
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#define LP8555_REG_CURRENT_MAXCURR_50MA 0x07
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#define LP8555_REG_STEP 0x15
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#define LP8555_REG_STEP_STEP_0MS (0 << 0)
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#define LP8555_REG_STEP_STEP_8MS BIT(0)
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#define LP8555_REG_STEP_STEP_16MS (2 << 0)
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#define LP8555_REG_STEP_STEP_24MS (3 << 0)
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#define LP8555_REG_STEP_STEP_28MS (4 << 0)
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#define LP8555_REG_STEP_STEP_32MS (5 << 0)
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#define LP8555_REG_STEP_STEP_100MS (6 << 0)
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#define LP8555_REG_STEP_STEP_200MS (7 << 0)
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#define LP8555_REG_STEP_PWM_IN_HYST_NONE (0 << 3)
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#define LP8555_REG_STEP_PWM_IN_HYST_1LSB BIT(3)
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#define LP8555_REG_STEP_PWM_IN_HYST_2LSB (2 << 3)
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#define LP8555_REG_STEP_PWM_IN_HYST_4LSB (3 << 3)
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#define LP8555_REG_STEP_PWM_IN_HYST_8LSB (4 << 3)
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#define LP8555_REG_STEP_PWM_IN_HYST_16LSB (5 << 3)
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#define LP8555_REG_STEP_PWM_IN_HYST_32LSB (6 << 3)
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#define LP8555_REG_STEP_PWM_IN_HYST_64LSB (7 << 3)
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#define LP8555_REG_STEP_SMOOTH_NONE (0 << 6)
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#define LP8555_REG_STEP_SMOOTH_LIGHT BIT(6)
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#define LP8555_REG_STEP_SMOOTH_MEDIUM (2 << 6)
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#define LP8555_REG_STEP_SMOOTH_HEAVY (3 << 6)
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/* Read from lp8555 with automatic i2c retries */
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static int lp8555_read_with_retry(int reg, int *data)
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{
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int i, rv;
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for (i = 0; i < I2C_RETRIES; i++) {
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rv = i2c_read8(I2C_PORT_BACKLIGHT, I2C_ADDR_BACKLIGHT,
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reg, data);
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if (rv == EC_SUCCESS)
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return EC_SUCCESS;
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usleep(I2C_RETRY_DELAY);
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}
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CPRINTS("Backlight read fail: reg 0x%02x", reg);
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return rv;
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}
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/* Write to lp8555 with automatic i2c retries */
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static int lp8555_write_with_retry(int reg, int data)
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{
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int i, rv;
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for (i = 0; i < I2C_RETRIES; i++) {
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rv = i2c_write8(I2C_PORT_BACKLIGHT, I2C_ADDR_BACKLIGHT,
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reg, data);
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if (rv == EC_SUCCESS)
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return EC_SUCCESS;
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usleep(I2C_RETRY_DELAY);
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}
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CPRINTS("Backlight write fail: reg 0x%02x data %d", reg, data);
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return rv;
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}
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/**
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* Setup backlight controller and turn it on.
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*/
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static void lp8555_enable_pwm_mode(void)
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{
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int reg;
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int rv;
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/*
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* If not in S0, then PCH backlight enable will not be on, and if
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* lid is closed EC backlight enable will not be on. Since these
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* two signals are AND'ed together, no point in trying to talk to
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* the lp8555 if either one of them is not true.
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*/
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if (!chipset_in_state(CHIPSET_STATE_ON) || !lid_is_open())
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return;
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/* Enable PWM mode. */
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rv = lp8555_read_with_retry(LP8555_REG_CONFIG, ®);
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if (rv != EC_SUCCESS)
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return;
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reg &= ~LP8555_REG_CONFIG_MODE_MASK;
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reg |= LP8555_REG_CONFIG_MODE_PWM;
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rv = lp8555_write_with_retry(LP8555_REG_CONFIG, reg);
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if (rv != EC_SUCCESS)
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return;
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/* Set max LED current to 23mA. */
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rv = lp8555_write_with_retry(LP8555_REG_CURRENT,
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LP8555_REG_CURRENT_MAXCURR_23MA);
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if (rv != EC_SUCCESS)
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return;
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/* Set the rate of brightness change. */
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rv = lp8555_write_with_retry(LP8555_REG_STEP,
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LP8555_REG_STEP_STEP_200MS |
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LP8555_REG_STEP_PWM_IN_HYST_8LSB |
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LP8555_REG_STEP_SMOOTH_HEAVY);
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if (rv != EC_SUCCESS)
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return;
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/* Power on. */
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rv = lp8555_read_with_retry(LP8555_REG_COMMAND, ®);
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if (rv != EC_SUCCESS)
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return;
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reg |= LP8555_REG_COMMAND_ON;
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rv = lp8555_write_with_retry(LP8555_REG_COMMAND, reg);
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}
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DECLARE_DEFERRED(lp8555_enable_pwm_mode);
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/**
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* Host command to toggle backlight.
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*/
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static int switch_command_enable_backlight(struct host_cmd_handler_args *args)
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{
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const struct ec_params_switch_enable_backlight *p = args->params;
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gpio_set_level(GPIO_ENABLE_BACKLIGHT, p->enabled);
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if (p->enabled)
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lp8555_enable_pwm_mode();
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return EC_RES_SUCCESS;
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}
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DECLARE_HOST_COMMAND(EC_CMD_SWITCH_ENABLE_BKLIGHT,
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switch_command_enable_backlight,
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EC_VER_MASK(0));
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void backlight_interrupt(enum gpio_signal signal)
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{
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/*
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* PCH indicates it is turning on backlight so we should
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* attempt to put the backlight controller into PWM mode.
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*/
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hook_call_deferred(&lp8555_enable_pwm_mode_data, 0);
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}
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/**
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* Update backlight state.
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*/
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static void update_backlight(void)
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{
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/*
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* Enable backlight if lid is open; this is AND'd with the request from
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* the AP in hardware.
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*/
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gpio_set_level(GPIO_ENABLE_BACKLIGHT, lid_is_open());
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if (lid_is_open())
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hook_call_deferred(&lp8555_enable_pwm_mode_data, 0);
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}
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DECLARE_HOOK(HOOK_LID_CHANGE, update_backlight, HOOK_PRIO_DEFAULT);
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/**
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* Initialize backlight module.
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*/
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static void backlight_init(void)
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{
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gpio_enable_interrupt(GPIO_PCH_BL_EN);
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gpio_set_level(GPIO_ENABLE_BACKLIGHT, lid_is_open());
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}
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DECLARE_HOOK(HOOK_INIT, backlight_init, HOOK_PRIO_DEFAULT);
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