144 lines
3.6 KiB
C
144 lines
3.6 KiB
C
/* GPIO handler routines */
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/* (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
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* All Rights Reserved
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*
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* Author: Philipp Maier
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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; either version 2 of the License, or
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* (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,
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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, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <errno.h>
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#include <string.h>
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#include <osmocom/core/talloc.h>
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#include <osmocom/core/utils.h>
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#include "gpio.h"
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#define SYSFS_EXPORT "/sys/class/gpio/export"
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#define SYSFS_UNEXPORT "/sys/class/gpio/unexport"
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#define SYSFS_DIRECTION "/sys/class/gpio/gpio%d/direction"
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#define SYSFS_VALUE "/sys/class/gpio/gpio%d/value"
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/* Open sysfs endpoints and initalize GPIOs */
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struct gpio_descr *gpio_open(void *ctx, unsigned int *gpios,
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unsigned int gpios_len)
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{
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int i;
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char buf[255];
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FILE *fd_export = NULL;
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FILE *fd_direction[MAX_GPIOS];
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FILE *fd_value[MAX_GPIOS];
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struct gpio_descr *gd;
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OSMO_ASSERT(gpios);
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OSMO_ASSERT(gpios_len <= MAX_GPIOS);
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/* Export requested GPIOs to userspace */
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fd_export = fopen(SYSFS_EXPORT, "w");
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if (!fd_export) {
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printf("Error: Could not open: %s\n", SYSFS_EXPORT);
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return NULL;
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} else {
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for (i = 0; i < gpios_len; i++) {
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sprintf(buf, "%d", gpios[i]);
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rewind(fd_export);
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fputs(buf, fd_export);
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}
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fclose(fd_export);
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fd_export = NULL;
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}
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/* Open GPIO file descriptors */
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for (i = 0; i < gpios_len; i++) {
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sprintf(buf, SYSFS_DIRECTION, gpios[i]);
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fd_direction[i] = fopen(buf, "w");
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if (!fd_direction[i]) {
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printf("Error: Could not open: %s\n", buf);
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return NULL;
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}
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sprintf(buf, SYSFS_VALUE, gpios[i]);
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fd_value[i] = fopen(buf, "w");
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if (!fd_value[i]) {
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printf("Error: Could not open: %s\n", buf);
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return NULL;
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}
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}
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/* Configure GPIOs as outputs */
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for (i = 0; i < gpios_len; i++) {
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rewind(fd_direction[i]);
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fputs("out", fd_direction[i]);
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fflush(fd_direction[i]);
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}
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/* Generate descriptor struct */
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gd = talloc_zero(ctx, struct gpio_descr);
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memcpy(gd->gpios, gpios, sizeof(gd->gpios));
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gd->gpios_len = gpios_len;
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memcpy(gd->fd_direction, fd_direction, sizeof(gd->fd_direction));
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memcpy(gd->fd_value, fd_value, sizeof(gd->fd_value));
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return gd;
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}
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/* Close sysfs endpoints and unintialize GPIOs */
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void gpio_close(struct gpio_descr *gd)
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{
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int i;
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char buf[255];
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FILE *fd_unexport = NULL;
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OSMO_ASSERT(gd);
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/* Close GPIOs file descriptors */
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for (i = 0; i < gd->gpios_len; i++) {
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if (gd->fd_direction[i])
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fclose(gd->fd_direction[i]);
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if (gd->fd_value[i])
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fclose(gd->fd_value[i]);
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}
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/* Remove requested GPIOs from userspace */
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fd_unexport = fopen(SYSFS_UNEXPORT, "w");
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if (fd_unexport) {
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for (i = 0; i < gd->gpios_len; i++) {
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sprintf(buf, "%d", gd->gpios[i]);
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rewind(fd_unexport);
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fputs(buf, fd_unexport);
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}
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fclose(fd_unexport);
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}
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/* Free descriptor struct */
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talloc_free(gd);
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}
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/* Set GPIO pin status */
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void gpio_set(struct gpio_descr *gd, unsigned int gpio, unsigned int state)
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{
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OSMO_ASSERT(gd);
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OSMO_ASSERT(gpio < gd->gpios_len);
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rewind(gd->fd_value[gpio]);
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if (state)
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fputs("1", gd->fd_value[gpio]);
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else
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fputs("0", gd->fd_value[gpio]);
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fflush(gd->fd_value[gpio]);
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}
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