baylibre-acme: Add Linux-specific GPIO helpers.

[libsigrok.git] / src / hardware / baylibre-acme / gpio.c

diff --git a/src/hardware/baylibre-acme/gpio.c b/src/hardware/baylibre-acme/gpio.c
new file mode 100644 (file)
index 0000000..f7348cd
--- /dev/null
+++ b/src/hardware/baylibre-acme/gpio.c
@@ -0,0 +1,169 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2015 Bartosz Golaszewski <bgolaszewski@baylibre.com>
+ *
+ * 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, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "libsigrok.h"
+#include "libsigrok-internal.h"
+#include "gpio.h"
+#include <glib.h>
+#include <glib/gstdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+
+#define LOG_PREFIX "gpio"
+
+static int open_and_write(const gchar *path, const gchar *buf)
+{
+       FILE *fd;
+       ssize_t wr;
+
+       fd = g_fopen(path, "w");
+       if (!fd) {
+               sr_err("error opening %s: %s", path, strerror(errno));
+               return -1;
+       }
+
+       wr = g_fprintf(fd, "%s", buf);
+       fclose(fd);
+       if (wr < 0) {
+               sr_err("error writing to %s: %s", path, strerror(errno));
+               return -1;
+       }
+
+       return 0;
+}
+
+SR_PRIV int sr_gpio_export(unsigned gpio)
+{
+       GString *path, *buf;
+       gboolean exported;
+       int status;
+
+       path = g_string_sized_new(128);
+       g_string_printf(path, "/sys/class/gpio/gpio%d", gpio);
+       exported = g_file_test(path->str, G_FILE_TEST_IS_DIR);
+       g_string_free(path, TRUE);
+       if (exported)
+               return 0; /* Already exported. */
+
+       buf = g_string_sized_new(16);
+       g_string_printf(buf, "%u\n", gpio);
+       status = open_and_write("/sys/class/gpio/export", buf->str);
+       g_string_free(buf, TRUE);
+
+       return status;
+}
+
+SR_PRIV int sr_gpio_set_direction(unsigned gpio, unsigned direction)
+{
+       GString *path, *buf;
+       int status;
+
+       path = g_string_sized_new(128);
+       buf = g_string_sized_new(16);
+       g_string_printf(path, "/sys/class/gpio/gpio%d/direction", gpio);
+       g_string_printf(buf, "%s\n", direction == GPIO_DIR_IN ? "in" : "out");
+
+       status = open_and_write(path->str, buf->str);
+
+       g_string_free(path, TRUE);
+       g_string_free(buf, TRUE);
+
+       return status;
+}
+
+SR_PRIV int sr_gpio_set_value(unsigned gpio, unsigned value)
+{
+       GString *path, *buf;
+       int status;
+
+       path = g_string_sized_new(128);
+       buf = g_string_sized_new(16);
+       g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio);
+       g_string_printf(buf, "%d\n", value);
+
+       status = open_and_write(path->str, buf->str);
+
+       g_string_free(path, TRUE);
+       g_string_free(buf, TRUE);
+
+       return status;
+}
+
+SR_PRIV int sr_gpio_get_value(int gpio)
+{
+       FILE *fd;
+       GString *path;
+       int ret, status;
+
+       path = g_string_sized_new(128);
+       g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio);
+       fd = g_fopen(path->str, "r");
+       if (!fd) {
+               sr_err("error opening %s: %s", path->str, strerror(errno));
+               g_string_free(path, TRUE);
+               return -1;
+       }
+
+       status = fscanf(fd, "%d", &ret);
+       fclose(fd);
+       if (status != 1) {
+               sr_err("error reading from %s: %s", path, strerror(errno));
+               g_string_free(path, TRUE);
+               return -1;
+       }
+
+       g_string_free(path, TRUE);
+       return ret;
+}
+
+SR_PRIV int sr_gpio_setval_export(int gpio, int value)
+{
+       int status;
+
+       status = sr_gpio_export(gpio);
+       if (status < 0)
+               return status;
+
+       status = sr_gpio_set_direction(gpio, GPIO_DIR_OUT);
+       if (status < 0)
+               return status;
+
+       status = sr_gpio_set_value(gpio, value);
+       if (status < 0)
+               return status;
+
+       return 0;
+}
+
+SR_PRIV int sr_gpio_getval_export(int gpio)
+{
+       int status;
+
+       status = sr_gpio_export(gpio);
+       if (status < 0)
+               return status;
+
+       status = sr_gpio_set_direction(gpio, GPIO_DIR_IN);
+       if (status < 0)
+               return status;
+
+       return sr_gpio_get_value(gpio);
+}