mirror of
https://github.com/ipxe/ipxe
synced 2025-12-08 10:20:24 +03:00
[gpio] Add a framework for GPIO controllers
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
165
src/core/gpio.c
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165
src/core/gpio.c
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@@ -0,0 +1,165 @@
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/*
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* Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* 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 Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdlib.h>
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#include <errno.h>
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#include <ipxe/gpio.h>
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/** @file
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*
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* General purpose I/O
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*
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*/
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/** List of GPIO controllers */
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static LIST_HEAD ( all_gpios );
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/**
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* Allocate GPIO controller
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*
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* @v count Number of GPIO pins
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* @v priv_len Size of driver-private data
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* @ret gpios GPIO controller, or NULL
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*/
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struct gpios * alloc_gpios ( unsigned int count, size_t priv_len ) {
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struct gpios *gpios;
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struct gpio *gpio;
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size_t len;
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unsigned int i;
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/* Allocate and initialise structure */
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len = ( sizeof ( *gpios ) + ( count * sizeof ( *gpio ) ) + priv_len );
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gpios = zalloc ( len );
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if ( ! gpios )
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return NULL;
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gpios->count = count;
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gpios->gpio = ( ( ( void * ) gpios ) + sizeof ( *gpios ) );
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gpios->priv = ( ( ( void * ) gpios ) + sizeof ( *gpios ) +
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( count * sizeof ( *gpio ) ) );
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/* Initialise GPIO pins */
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for ( i = 0 ; i < count ; i++ ) {
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gpio = &gpios->gpio[i];
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gpio->gpios = gpios;
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gpio->index = i;
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}
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return gpios;
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}
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/**
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* Register GPIO controller
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*
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* @v gpios GPIO controller
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* @ret rc Return status code
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*/
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int gpios_register ( struct gpios *gpios ) {
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/* Add to list of GPIO controllers */
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gpios_get ( gpios );
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list_add_tail ( &gpios->list, &all_gpios );
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DBGC ( gpios, "GPIO %s registered with %d GPIOs\n",
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gpios->dev->name, gpios->count );
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return 0;
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}
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/**
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* Unregister GPIO controller
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*
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* @v gpios GPIO controller
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*/
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void gpios_unregister ( struct gpios *gpios ) {
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/* Remove from list of GPIO controllers */
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DBGC ( gpios, "GPIO %s unregistered\n", gpios->dev->name );
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list_del ( &gpios->list );
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gpios_put ( gpios );
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}
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/**
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* Find GPIO controller
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*
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* @v bus_type Bus type
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* @v location Bus location
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* @ret gpios GPIO controller, or NULL
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*/
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struct gpios * gpios_find ( unsigned int bus_type, unsigned int location ) {
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struct gpios *gpios;
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/* Scan through list of registered GPIO controllers */
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list_for_each_entry ( gpios, &all_gpios, list ) {
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if ( ( gpios->dev->desc.bus_type == bus_type ) &&
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( gpios->dev->desc.location == location ) )
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return gpios;
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}
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return NULL;
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}
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/**
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* Get null GPIO input value
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*
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* @v gpios GPIO controller
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* @v gpio GPIO pin
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* @ret active Pin is in the active state
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*/
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static int null_gpio_in ( struct gpios *gpios __unused,
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struct gpio *gpio __unused ) {
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return 0;
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}
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/**
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* Set null GPIO output value
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*
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* @v gpios GPIO controller
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* @v gpio GPIO pin
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* @v active Set pin to active state
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*/
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static void null_gpio_out ( struct gpios *gpios __unused,
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struct gpio *gpio __unused, int active __unused ) {
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/* Nothing to do */
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}
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/**
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* Configure null GPIO pin
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*
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* @v gpios GPIO controller
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* @v gpio GPIO pin
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* @v config Configuration
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* @ret rc Return status code
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*/
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static int null_gpio_config ( struct gpios *gpios __unused,
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struct gpio *gpio __unused,
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unsigned int config __unused ) {
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return -ENODEV;
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}
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/** Null GPIO operations */
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struct gpio_operations null_gpio_operations = {
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.in = null_gpio_in,
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.out = null_gpio_out,
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.config = null_gpio_config,
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};
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@@ -87,6 +87,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#define ERRFILE_efi_open ( ERRFILE_CORE | 0x002f0000 )
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#define ERRFILE_efi_table ( ERRFILE_CORE | 0x00300000 )
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#define ERRFILE_efi_connect ( ERRFILE_CORE | 0x00310000 )
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#define ERRFILE_gpio ( ERRFILE_CORE | 0x00320000 )
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#define ERRFILE_eisa ( ERRFILE_DRIVER | 0x00000000 )
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#define ERRFILE_isa ( ERRFILE_DRIVER | 0x00010000 )
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199
src/include/ipxe/gpio.h
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199
src/include/ipxe/gpio.h
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@@ -0,0 +1,199 @@
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#ifndef _IPXE_GPIO_H
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#define _IPXE_GPIO_H
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/** @file
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*
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* General purpose I/O
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*
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <ipxe/list.h>
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#include <ipxe/refcnt.h>
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#include <ipxe/device.h>
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/** A GPIO pin */
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struct gpio {
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/** GPIO controller */
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struct gpios *gpios;
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/** Pin index */
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unsigned int index;
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/** Configuration */
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unsigned int config;
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};
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/** GPIO is active low
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*
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* This bit is chosen to match the devicetree standard usage.
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*/
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#define GPIO_CFG_ACTIVE_LOW 0x01
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/** GPIO is an output */
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#define GPIO_CFG_OUTPUT 0x0100
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/** A GPIO controller */
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struct gpios {
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/** Reference count */
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struct refcnt refcnt;
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/** List of GPIO controllers */
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struct list_head list;
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/** Generic device */
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struct device *dev;
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/** Number of GPIOs */
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unsigned int count;
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/** Individual GPIOs */
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struct gpio *gpio;
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/** GPIO operations */
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struct gpio_operations *op;
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/** Driver-private data */
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void *priv;
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};
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/** GPIO operations */
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struct gpio_operations {
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/**
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* Get current GPIO input value
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*
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* @v gpios GPIO controller
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* @v gpio GPIO pin
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* @ret active Pin is in the active state
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*/
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int ( * in ) ( struct gpios *gpios, struct gpio *gpio );
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/**
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* Set current GPIO output value
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*
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* @v gpios GPIO controller
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* @v gpio GPIO pin
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* @v active Set pin to active state
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*/
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void ( * out ) ( struct gpios *gpios, struct gpio *gpio, int active );
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/**
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* Configure GPIO pin
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*
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* @v gpios GPIO controller
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* @v gpio GPIO pin
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* @v config Configuration
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* @ret rc Return status code
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*/
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int ( * config ) ( struct gpios *gpios, struct gpio *gpio,
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unsigned int config );
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};
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extern struct gpio_operations null_gpio_operations;
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/**
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* Get reference to GPIO controller
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*
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* @v gpios GPIO controller
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* @ret gpios GPIO controller
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*/
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static inline __attribute__ (( always_inline )) struct gpios *
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gpios_get ( struct gpios *gpios ) {
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ref_get ( &gpios->refcnt );
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return gpios;
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}
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/**
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* Drop reference to GPIO controller
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*
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* @v gpios GPIO controller
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*/
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static inline __attribute__ (( always_inline )) void
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gpios_put ( struct gpios *gpios ) {
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ref_put ( &gpios->refcnt );
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}
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/**
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* Get reference to GPIO pin
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*
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* @v gpio GPIO pin
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* @ret gpio GPIO pin
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*/
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static inline __attribute__ (( always_inline )) struct gpio *
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gpio_get ( struct gpio *gpio ) {
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gpios_get ( gpio->gpios );
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return gpio;
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}
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/**
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* Drop reference to GPIO ping
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*
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* @v gpio GPIO pin
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*/
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static inline __attribute__ (( always_inline )) void
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gpio_put ( struct gpio *gpio ) {
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gpios_put ( gpio->gpios );
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}
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/**
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* Initialise a GPIO controller
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*
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* @v gpios GPIO controller
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* @v op GPIO operations
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*/
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static inline __attribute__ (( always_inline )) void
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gpios_init ( struct gpios *gpios, struct gpio_operations *op ) {
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gpios->op = op;
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}
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/**
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* Stop using a GPIO controller
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*
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* @v gpios GPIO controller
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*
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* Drivers should call this method immediately before the final call
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* to gpios_put().
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*/
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static inline __attribute__ (( always_inline )) void
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gpios_nullify ( struct gpios *gpios ) {
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gpios->op = &null_gpio_operations;
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}
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/**
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* Get current GPIO input value
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*
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* @v gpio GPIO pin
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* @ret active Pin is in the active state
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*/
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static inline int gpio_in ( struct gpio *gpio ) {
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struct gpios *gpios = gpio->gpios;
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return gpios->op->in ( gpios, gpio );
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}
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/**
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* Set current GPIO output value
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*
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* @v gpio GPIO pin
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* @v active Set pin to active state
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*/
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static inline void gpio_out ( struct gpio *gpio, int active ) {
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struct gpios *gpios = gpio->gpios;
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gpios->op->out ( gpios, gpio, active );
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}
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/**
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* Configure GPIO pin
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*
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* @v gpio GPIO pin
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* @v config Configuration
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* @ret rc Return status code
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*/
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static inline int gpio_config ( struct gpio *gpio, unsigned int config ) {
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struct gpios *gpios = gpio->gpios;
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return gpios->op->config ( gpios, gpio, config );
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}
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extern struct gpios * alloc_gpios ( unsigned int count, size_t priv_len );
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extern int gpios_register ( struct gpios *gpios );
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extern void gpios_unregister ( struct gpios *gpios );
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extern struct gpios * gpios_find ( unsigned int bus_type,
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unsigned int location );
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#endif /* _IPXE_GPIO_H */
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