From 9c9c3364643d9b8e138f503c391163475c9dfffc Mon Sep 17 00:00:00 2001 From: Vadim Bendebury Date: Wed, 23 Jul 2014 09:40:02 -0700 Subject: Generalize revision number calculation function Some platforms use tertiary interpretation of GPIO input state to increase number of distinct values represented by a limited number of GPIOs. The three states are - external pull down (interpreted as 0) - external pull up (1) - not connected (2) This has been required by Nvidia devices so far, but Exynos and Ipq8086 platforms need this too. This patch moves the function reading the tertiary state into the library and exposes the necessary GPIO API functions in a new include file. The functions are still supposed to be provided by platform specific modules. The function interpreting the GPIO states has been modified to allow to interpret the state either as a true tertiary number or as a set two bit fields. Since linker garbage collection is not happening when building x86 targets, a new configuration option is being added to include the new module only when needed. BUG=chrome-os-partner:30489 TEST=verified that nyan_big still reports proper revision ID. Change-Id: Ib55122c359629b58288c1022da83e6c63dc2264d Original-Change-Id: I243c9f43c82bd4a41de2154bbdbd07df0a241046 Original-Signed-off-by: Vadim Bendebury Original-Reviewed-on: https://chromium-review.googlesource.com/209673 Original-Reviewed-by: Aaron Durbin (cherry picked from commit c79ef1c545d073eaad69e6c8c629f9656b8c2f3e) Signed-off-by: Marc Jones Reviewed-on: http://review.coreboot.org/8717 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/include/gpiolib.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 src/include/gpiolib.h (limited to 'src/include') diff --git a/src/include/gpiolib.h b/src/include/gpiolib.h new file mode 100644 index 0000000000..daec3b66bd --- /dev/null +++ b/src/include/gpiolib.h @@ -0,0 +1,47 @@ +/* + * 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 + */ + +#ifndef __SRC_INCLUDE_GPIOLIB_H__ +#define __SRC_INCLUDE_GPIOLIB_H__ + +/* A generic type, use accessor macros to actually access the hardware. */ +typedef unsigned gpio_t; + +/* + * Read the value presented by the set of GPIOs, when each pin is interpreted + * as a number in 0..2 range depending on the external pullup situation. + * + * Depending on the third parameter, the return value is either a set of two + * bit fields, each representing one GPIO value, or a number where each GPIO is + * included multiplied by 3^gpio_num, resulting in a true tertiary value. + * + */ +int gpio_board_id(gpio_t gpio[], int num_gpio, int tertiary); + +/* + * The following functions are not provided by the common library, but must be + * implemented by the appropriate SOC/board instead. + */ +int gpio_get_in_value(gpio_t gpio); +void gpio_set_out_value(gpio_t gpio, int value); +void gpio_input_pulldown(gpio_t gpio); +void gpio_input_pullup(gpio_t gpio); +void gpio_input(gpio_t gpio); + +#endif -- cgit v1.2.3