21db62eb0e
This adds gpio_base2_value() which reads an array of 2-state GPIOs and returns a base-2 value, where gpio[0] represents the least significant bit. BUG=none BRANCH=none TEST=tested with follow-up patches for pinky Change-Id: I0d6bfac369da0d68079a38de0988c7b59d269a97 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: 27873b7a9ea237d13f0cbafd10033a8d0f821cbe Original-Change-Id: Ia7ffc16eb60e93413c0812573b9cf0999b92828e Original-Signed-off-by: David Hendricks <dhendrix@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/228323 Original-Reviewed-by: Julius Werner <jwerner@chromium.org> Reviewed-on: http://review.coreboot.org/9412 Tested-by: build bot (Jenkins) Reviewed-by: David Hendricks <dhendrix@chromium.org>
94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* Copyright 2014 Google Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <base3.h>
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#include <console/console.h>
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#include <delay.h>
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#include <gpio.h>
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int gpio_base2_value(gpio_t gpio[], int num_gpio)
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{
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int i, result = 0;
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for (i = 0; i < num_gpio; i++) {
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gpio_input(gpio[i]);
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result |= gpio_get(gpio[i]) << i;
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}
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return result;
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}
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int gpio_base3_value(gpio_t gpio[], int num_gpio)
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{
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/*
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* GPIOs which are tied to stronger external pull up or pull down
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* will stay there regardless of the internal pull up or pull
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* down setting.
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*
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* GPIOs which are floating will go to whatever level they're
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* internally pulled to.
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*/
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static const char tristate_char[] = {[0] = '0', [1] = '1', [Z] = 'Z'};
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int temp;
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int index;
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int result = 0;
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char value[num_gpio];
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/* Enable internal pull up */
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for (index = 0; index < num_gpio; ++index)
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gpio_input_pullup(gpio[index]);
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/* Wait until signals become stable */
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udelay(10);
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/* Get gpio values at internal pull up */
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for (index = 0; index < num_gpio; ++index)
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value[index] = gpio_get(gpio[index]);
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/* Enable internal pull down */
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for (index = 0; index < num_gpio; ++index)
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gpio_input_pulldown(gpio[index]);
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/* Wait until signals become stable */
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udelay(10);
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/*
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* Get gpio values at internal pull down.
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* Compare with gpio pull up value and then
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* determine a gpio final value/state:
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* 0: pull down
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* 1: pull up
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* 2: floating
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*/
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printk(BIOS_DEBUG, "Reading tristate GPIOs: ");
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for (index = num_gpio - 1; index >= 0; --index) {
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temp = gpio_get(gpio[index]);
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temp |= ((value[index] ^ temp) << 1);
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printk(BIOS_DEBUG, "%c ", tristate_char[temp]);
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result = (result * 3) + temp;
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}
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printk(BIOS_DEBUG, "= %d\n", result);
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/* Disable pull up / pull down to conserve power */
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for (index = 0; index < num_gpio; ++index)
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gpio_input(gpio[index]);
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return result;
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}
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