Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This file is part of the coreboot project. |
| 3 | * |
| 4 | * Copyright 2014 Google Inc. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; version 2 of the License. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 14 | */ |
| 15 | |
Julius Werner | 8d8799a | 2014-12-19 16:11:14 -0800 | [diff] [blame] | 16 | #include <assert.h> |
Julius Werner | 886d29b | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 17 | #include <base3.h> |
| 18 | #include <console/console.h> |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 19 | #include <delay.h> |
Julius Werner | eaa9c45 | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 20 | #include <gpio.h> |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 21 | |
David Hendricks | 21db62e | 2014-11-06 15:05:35 -0800 | [diff] [blame] | 22 | int gpio_base2_value(gpio_t gpio[], int num_gpio) |
| 23 | { |
| 24 | int i, result = 0; |
| 25 | |
David Hendricks | f9b49e8 | 2015-01-14 20:41:30 -0800 | [diff] [blame] | 26 | for (i = 0; i < num_gpio; i++) |
David Hendricks | 21db62e | 2014-11-06 15:05:35 -0800 | [diff] [blame] | 27 | gpio_input(gpio[i]); |
David Hendricks | f9b49e8 | 2015-01-14 20:41:30 -0800 | [diff] [blame] | 28 | |
| 29 | /* Wait until signals become stable */ |
| 30 | udelay(10); |
| 31 | |
| 32 | for (i = 0; i < num_gpio; i++) |
David Hendricks | 21db62e | 2014-11-06 15:05:35 -0800 | [diff] [blame] | 33 | result |= gpio_get(gpio[i]) << i; |
David Hendricks | 21db62e | 2014-11-06 15:05:35 -0800 | [diff] [blame] | 34 | |
| 35 | return result; |
| 36 | } |
| 37 | |
David Hendricks | 3fc6368 | 2014-11-06 15:09:27 -0800 | [diff] [blame] | 38 | int gpio_base3_value(gpio_t gpio[], int num_gpio) |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 39 | { |
| 40 | /* |
| 41 | * GPIOs which are tied to stronger external pull up or pull down |
| 42 | * will stay there regardless of the internal pull up or pull |
| 43 | * down setting. |
| 44 | * |
| 45 | * GPIOs which are floating will go to whatever level they're |
| 46 | * internally pulled to. |
| 47 | */ |
| 48 | |
Julius Werner | 886d29b | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 49 | static const char tristate_char[] = {[0] = '0', [1] = '1', [Z] = 'Z'}; |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 50 | int temp; |
| 51 | int index; |
David Hendricks | 3fc6368 | 2014-11-06 15:09:27 -0800 | [diff] [blame] | 52 | int result = 0; |
Julius Werner | 8d8799a | 2014-12-19 16:11:14 -0800 | [diff] [blame] | 53 | char value[32]; |
| 54 | assert(num_gpio <= 32); |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 55 | |
| 56 | /* Enable internal pull up */ |
| 57 | for (index = 0; index < num_gpio; ++index) |
| 58 | gpio_input_pullup(gpio[index]); |
| 59 | |
| 60 | /* Wait until signals become stable */ |
| 61 | udelay(10); |
| 62 | |
| 63 | /* Get gpio values at internal pull up */ |
| 64 | for (index = 0; index < num_gpio; ++index) |
Julius Werner | eaa9c45 | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 65 | value[index] = gpio_get(gpio[index]); |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 66 | |
| 67 | /* Enable internal pull down */ |
| 68 | for (index = 0; index < num_gpio; ++index) |
| 69 | gpio_input_pulldown(gpio[index]); |
| 70 | |
| 71 | /* Wait until signals become stable */ |
| 72 | udelay(10); |
| 73 | |
| 74 | /* |
| 75 | * Get gpio values at internal pull down. |
| 76 | * Compare with gpio pull up value and then |
| 77 | * determine a gpio final value/state: |
| 78 | * 0: pull down |
| 79 | * 1: pull up |
| 80 | * 2: floating |
| 81 | */ |
Julius Werner | 886d29b | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 82 | printk(BIOS_DEBUG, "Reading tristate GPIOs: "); |
Daisuke Nojiri | 573e211 | 2014-08-08 15:38:52 -0700 | [diff] [blame] | 83 | for (index = num_gpio - 1; index >= 0; --index) { |
Julius Werner | eaa9c45 | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 84 | temp = gpio_get(gpio[index]); |
Julius Werner | 886d29b | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 85 | temp |= ((value[index] ^ temp) << 1); |
| 86 | printk(BIOS_DEBUG, "%c ", tristate_char[temp]); |
David Hendricks | 3fc6368 | 2014-11-06 15:09:27 -0800 | [diff] [blame] | 87 | result = (result * 3) + temp; |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 88 | } |
David Hendricks | 3fc6368 | 2014-11-06 15:09:27 -0800 | [diff] [blame] | 89 | printk(BIOS_DEBUG, "= %d\n", result); |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 90 | |
| 91 | /* Disable pull up / pull down to conserve power */ |
| 92 | for (index = 0; index < num_gpio; ++index) |
| 93 | gpio_input(gpio[index]); |
| 94 | |
David Hendricks | 3fc6368 | 2014-11-06 15:09:27 -0800 | [diff] [blame] | 95 | return result; |
Vadim Bendebury | 9c9c336 | 2014-07-23 09:40:02 -0700 | [diff] [blame] | 96 | } |