| /* |
| * This file is part of the coreboot project. |
| * |
| * Copyright 2014 Google Inc. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; version 2 of the License. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include <delay.h> |
| #include <gpiolib.h> |
| |
| int gpio_get_in_tristate_values(gpio_t gpio[], int num_gpio, int tertiary) |
| { |
| /* |
| * GPIOs which are tied to stronger external pull up or pull down |
| * will stay there regardless of the internal pull up or pull |
| * down setting. |
| * |
| * GPIOs which are floating will go to whatever level they're |
| * internally pulled to. |
| */ |
| |
| int temp; |
| int index; |
| int id = 0; |
| char value[num_gpio]; |
| |
| /* Enable internal pull up */ |
| for (index = 0; index < num_gpio; ++index) |
| gpio_input_pullup(gpio[index]); |
| |
| /* Wait until signals become stable */ |
| udelay(10); |
| |
| /* Get gpio values at internal pull up */ |
| for (index = 0; index < num_gpio; ++index) |
| value[index] = gpio_get_in_value(gpio[index]); |
| |
| /* Enable internal pull down */ |
| for (index = 0; index < num_gpio; ++index) |
| gpio_input_pulldown(gpio[index]); |
| |
| /* Wait until signals become stable */ |
| udelay(10); |
| |
| /* |
| * Get gpio values at internal pull down. |
| * Compare with gpio pull up value and then |
| * determine a gpio final value/state: |
| * 0: pull down |
| * 1: pull up |
| * 2: floating |
| */ |
| for (index = num_gpio - 1; index >= 0; --index) { |
| if (tertiary) |
| id *= 3; |
| else |
| id <<= 2; |
| temp = gpio_get_in_value(gpio[index]); |
| id += ((value[index] ^ temp) << 1) | temp; |
| } |
| |
| /* Disable pull up / pull down to conserve power */ |
| for (index = 0; index < num_gpio; ++index) |
| gpio_input(gpio[index]); |
| |
| return id; |
| } |