Naïve version of pin export #4

koodilehto · Mar 26, 2015 · b6962df · b6962df
1 parent b5b9b6f
commit b6962df
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Showing 3 changed files with 16 additions and 7 deletions.
diff --git a/src/gpio.c b/src/gpio.c
@@ -28,8 +28,6 @@
 #include <unistd.h>
 #include "gpio.h"
 
-#define GPIO_PATH "/sys/class/gpio/"
-
 static int gpio_open_one(char *fmt, gint value, int flags);
 
 static int gpio_open_one(char *fmt, gint value, int flags)
@@ -46,8 +44,14 @@ static int gpio_open_one(char *fmt, gint value, int flags)
 	err(2,"Unable to open GPIO %s", pathname);
 }
 
-void gpio_open(struct gpio *gpio, gint value)
+void gpio_open(FILE* export, struct gpio *gpio, gint value)
 {
+	// Try to export it first. Export creates the GPIO files
+	int exported = fprintf(export, "%d\n", value);
+	int flushed = fflush(export);
+	printf("Export of %d %s\n", value, exported < 0 || flushed != 0 ? "failed" : "ok");
+
+	// Open value, edge and direction for given GPIO pin
 	gpio->value = gpio_open_one(GPIO_PATH "gpio%d/value", value, O_RDWR);
 	gpio->edge = gpio_open_one(GPIO_PATH "gpio%d/edge", value, O_WRONLY);
 	gpio->direction = gpio_open_one(GPIO_PATH "gpio%d/direction", value, O_WRONLY);

diff --git a/src/gpio.h b/src/gpio.h
@@ -24,6 +24,8 @@
 #include <glib.h>
 #include <stdbool.h>
 
+#define GPIO_PATH "/sys/class/gpio/"
+
 struct gpio {
 	int value;
 	int edge;
@@ -33,7 +35,7 @@ struct gpio {
 /**
  * Open given GPIO pin and populate gpio structure. Dies if pin is not
  * accessible. */
-void gpio_open(struct gpio *gpio, gint value);
+void gpio_open(FILE* export, struct gpio *gpio, gint value);
 
 /**
  * Read value in given GPIO pin.

diff --git a/src/main.c b/src/main.c
@@ -148,20 +148,23 @@ int main(int argc, char *argv[])
 
 	// Open gpio pins
 
-	// FIXME export GPIO first!
+	FILE *export = fopen(GPIO_PATH "export", "w");
+	if (export == NULL) err(2,"Unable to open %s", GPIO_PATH "export");
 
 	dev->row = g_new(struct gpio, dev->rows);
 	for (gsize i=0; i<dev->rows; i++) {
-		gpio_open(dev->row+i, gpio_row_ix[i]);
+		gpio_open(export, dev->row+i, gpio_row_ix[i]);
 	}
 	g_free(gpio_row_ix);
 
 	dev->col = g_new(struct gpio, dev->cols);
 	for (gsize i=0; i<dev->cols; i++) {
-		gpio_open(dev->col+i, gpio_col_ix[i]);
+		gpio_open(export, dev->col+i, gpio_col_ix[i]);
 	}
 	g_free(gpio_col_ix);
 
+	fclose(export);
+
 	keypad_setup(dev);
 	keypad_loop(dev);