170 lines
3.7 KiB
C
170 lines
3.7 KiB
C
/*
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* This file is part of the libsigrok project.
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*
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* Copyright (C) 2015 Bartosz Golaszewski <bgolaszewski@baylibre.com>
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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 3 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 <glib.h>
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#include <glib/gstdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include "libsigrok.h"
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#include "libsigrok-internal.h"
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#include "gpio.h"
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#define LOG_PREFIX "gpio"
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static int open_and_write(const gchar *path, const gchar *buf)
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{
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FILE *fd;
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ssize_t wr;
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fd = g_fopen(path, "w");
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if (!fd) {
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sr_err("Error opening %s: %s", path, strerror(errno));
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return -1;
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}
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wr = g_fprintf(fd, "%s", buf);
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fclose(fd);
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if (wr < 0) {
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sr_err("Error writing to %s: %s", path, strerror(errno));
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return -1;
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}
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return 0;
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}
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SR_PRIV int sr_gpio_export(unsigned gpio)
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{
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GString *path, *buf;
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gboolean exported;
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int status;
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path = g_string_sized_new(128);
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g_string_printf(path, "/sys/class/gpio/gpio%d", gpio);
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exported = g_file_test(path->str, G_FILE_TEST_IS_DIR);
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g_string_free(path, TRUE);
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if (exported)
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return 0; /* Already exported. */
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buf = g_string_sized_new(16);
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g_string_printf(buf, "%u\n", gpio);
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status = open_and_write("/sys/class/gpio/export", buf->str);
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g_string_free(buf, TRUE);
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return status;
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}
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SR_PRIV int sr_gpio_set_direction(unsigned gpio, unsigned direction)
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{
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GString *path, *buf;
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int status;
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path = g_string_sized_new(128);
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buf = g_string_sized_new(16);
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g_string_printf(path, "/sys/class/gpio/gpio%d/direction", gpio);
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g_string_printf(buf, "%s\n", direction == GPIO_DIR_IN ? "in" : "out");
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status = open_and_write(path->str, buf->str);
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g_string_free(path, TRUE);
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g_string_free(buf, TRUE);
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return status;
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}
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SR_PRIV int sr_gpio_set_value(unsigned gpio, unsigned value)
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{
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GString *path, *buf;
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int status;
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path = g_string_sized_new(128);
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buf = g_string_sized_new(16);
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g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio);
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g_string_printf(buf, "%d\n", value);
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status = open_and_write(path->str, buf->str);
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g_string_free(path, TRUE);
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g_string_free(buf, TRUE);
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return status;
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}
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SR_PRIV int sr_gpio_get_value(int gpio)
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{
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FILE *fd;
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GString *path;
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int ret, status;
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path = g_string_sized_new(128);
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g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio);
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fd = g_fopen(path->str, "r");
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if (!fd) {
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sr_err("Error opening %s: %s", path->str, strerror(errno));
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g_string_free(path, TRUE);
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return -1;
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}
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status = fscanf(fd, "%d", &ret);
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fclose(fd);
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if (status != 1) {
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sr_err("Error reading from %s: %s", path, strerror(errno));
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g_string_free(path, TRUE);
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return -1;
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}
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g_string_free(path, TRUE);
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return ret;
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}
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SR_PRIV int sr_gpio_setval_export(int gpio, int value)
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{
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int status;
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status = sr_gpio_export(gpio);
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if (status < 0)
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return status;
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status = sr_gpio_set_direction(gpio, GPIO_DIR_OUT);
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if (status < 0)
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return status;
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status = sr_gpio_set_value(gpio, value);
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if (status < 0)
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return status;
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return 0;
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}
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SR_PRIV int sr_gpio_getval_export(int gpio)
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{
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int status;
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status = sr_gpio_export(gpio);
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if (status < 0)
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return status;
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status = sr_gpio_set_direction(gpio, GPIO_DIR_IN);
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if (status < 0)
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return status;
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return sr_gpio_get_value(gpio);
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}
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