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a9f4794edb
BUG=chrome-os-partner:7498
TEST=powerled {off, red, yellow, green}
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Change-Id: I48beaad94d75c0ec30a969ea4b0e35f54e052085
101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
/* Copyright (c) 2012 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 "console.h"
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#include "onewire.h"
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#include "power_led.h"
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#include "timer.h"
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#include "uart.h"
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#include "util.h"
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#define POWERLED_RETRIES 10
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static const uint8_t led_masks[POWERLED_COLOR_COUNT] = {0xff, 0xfe, 0xfc, 0xfd};
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static const char * const color_names[POWERLED_COLOR_COUNT] = {
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"off", "red", "yellow", "green"};
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/* Set the power LED GPIO controller outputs to the specified mask. */
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static int powerled_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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int powerled_set(enum powerled_color color)
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{
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int rv = EC_SUCCESS;
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int i;
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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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for (i = 0; i < POWERLED_RETRIES; i++) {
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rv = powerled_set_mask(led_masks[color]);
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if (rv == EC_SUCCESS)
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break;
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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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usleep(100);
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}
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return rv;
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}
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/*****************************************************************************/
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/* Console commands */
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static int command_powerled(int argc, char **argv)
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{
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int i = POWERLED_COLOR_COUNT;
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/* Pick a color, any color... */
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if (argc >= 1) {
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for (i = 0; i < POWERLED_COLOR_COUNT; i++) {
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if (!strcasecmp(argv[1], color_names[i]))
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break;
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}
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}
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if (i >= POWERLED_COLOR_COUNT) {
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uart_puts("Please specify a color:");
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for (i = 0; i < POWERLED_COLOR_COUNT; i++)
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uart_printf(" %s", color_names[i]);
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uart_puts("\n");
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return EC_ERROR_INVAL;
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}
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uart_printf("Setting power LED to %s...\n", color_names[i]);
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return powerled_set(i);
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}
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DECLARE_CONSOLE_COMMAND(powerled, command_powerled);
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