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