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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.
*/
/* Power LED control for Chrome EC */
#include "charge_state.h"
#include "console.h"
#include "hooks.h"
#include "onewire.h"
#include "timer.h"
#include "util.h"
#define ONEWIRE_RETRIES 10
enum led_color {
LED_OFF = 0,
LED_RED,
LED_YELLOW,
LED_GREEN,
LED_COLOR_COUNT /* Number of colors, not a color itself */
};
static const uint8_t led_masks[LED_COLOR_COUNT] = {0xff, 0xfe, 0xfc, 0xfd};
static const char * const color_names[LED_COLOR_COUNT] = {
"off", "red", "yellow", "green"};
/**
* Set the onewire LED GPIO controller outputs
*
* @param mask Mask of outputs to enable
*
* @return EC_SUCCESS, or non-zero if error.
*/
static int led_set_mask(int mask)
{
int rv;
/* Reset the 1-wire bus */
rv = onewire_reset();
if (rv)
return rv;
/* Skip ROM, since only one device */
onewire_write(0xcc);
/* Write and turn on the LEDs */
onewire_write(0x5a);
onewire_write(mask);
onewire_write(~mask); /* Repeat inverted */
rv = onewire_read(); /* Confirmation byte */
if (rv != 0xaa)
return EC_ERROR_UNKNOWN;
/* The next byte is a read-back of the chip status. Since we're only
* using lines as outputs, we can ignore it. */
return EC_SUCCESS;
}
static int led_set(enum led_color color)
{
int rv = EC_SUCCESS;
int i;
/*
* 1-wire communication can fail for timing reasons in the current
* system. We have a limited timing window to send/receive bits, but
* we can't disable interrupts for the rest of the system to guarantee
* we hit that window. Instead, simply retry the low-level command a
* few times.
*/
for (i = 0; i < ONEWIRE_RETRIES; i++) {
rv = led_set_mask(led_masks[color]);
if (rv == EC_SUCCESS)
break;
/*
* Sleep for a bit between tries. This gives the 1-wire GPIO
* chip time to recover from the failed attempt, and allows
* lower-priority tasks a chance to run.
*/
usleep(100);
}
return rv;
}
/*****************************************************************************/
/* Hooks */
static void onewire_led_tick(void)
{
static enum led_color current_color = LED_COLOR_COUNT;
static int tick_count;
enum led_color new_color = LED_OFF;
uint32_t chflags = charge_get_flags();
tick_count++;
if (!(chflags & CHARGE_FLAG_EXTERNAL_POWER)) {
/* AC isn't present, so the power LED on the AC plug is off */
current_color = LED_OFF;
return;
}
/* Translate charge state to LED color */
switch (charge_get_state()) {
case PWR_STATE_IDLE:
if (chflags & CHARGE_FLAG_FORCE_IDLE)
new_color = (tick_count & 1) ? LED_GREEN : LED_OFF;
else
new_color = LED_GREEN;
break;
case PWR_STATE_CHARGE:
new_color = LED_YELLOW;
break;
case PWR_STATE_CHARGE_NEAR_FULL:
new_color = LED_GREEN;
break;
case PWR_STATE_ERROR:
new_color = LED_RED;
break;
default:
/* Other states don't change LED color */
break;
}
/*
* The power adapter on link can partially unplug and lose its LED
* state. There's no way to detect this, so just assume it forgets its
* state every 10 seconds.
*/
if (!(tick_count % 10))
current_color = LED_COLOR_COUNT;
/* If current color is still correct, leave now */
if (new_color == current_color)
return;
/* Update LED */
if (!led_set(new_color))
current_color = new_color;
}
DECLARE_HOOK(HOOK_SECOND, onewire_led_tick, HOOK_PRIO_DEFAULT);
/*****************************************************************************/
/* Console commands */
#define CONFIG_CMD_POWERLED
static int command_powerled(int argc, char **argv)
{
int i;
/* Pick a color, any color... */
for (i = 0; i < LED_COLOR_COUNT; i++) {
if (!strcasecmp(argv[1], color_names[i]))
return led_set(i);
}
return EC_ERROR_PARAM1;
}
DECLARE_CONSOLE_COMMAND(powerled, command_powerled,
"<off | red | yellow | green>",
"Set power LED color");
#endif
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