examples/sensorbd_demo: use poll() to detect button actions

Rather than reading /dev/gpioX repeatedly with timeouts, using poll()
would be better to show GPIO functionality.

Change-Id: Id3318d821d4fcedd640161d3238a981f507109cf
Signed-off-by: Heesub Shin <heesub.shin@samsung.com>

diff --git a/apps/examples/sensorbd_demo/examples/gpio_buttons.c b/apps/examples/sensorbd_demo/examples/gpio_buttons.c
index f101224..597ff13 100644 (file)
--- a/apps/examples/sensorbd_demo/examples/gpio_buttons.c
+++ b/apps/examples/sensorbd_demo/examples/gpio_buttons.c
@@ -49,41 +49,70 @@
  * POSSIBILITY OF SUCH DAMAGE.
  *
  ****************************************************************************/
+#include <tinyara/config.h>
 
 #include <fcntl.h>
+#include <poll.h>
+#include <sys/types.h>
+#include <unistd.h>
+
 #include <tinyara/gpio.h>
 
-static int gpio_read(int port)
+void switch_main(int argc, char *argv[])
 {
-       char value[4];
-       static char buf[16];
-       snprintf(buf, 16, "/dev/gpio%d", port);
-       int fd = open(buf, O_RDWR);
+       int i, j, nbtns, prev;
+       struct pollfd *poll_list;
 
-       ioctl(fd, GPIOIOC_SET_DIRECTION, GPIO_DIRECTION_IN);
-       read(fd, &value, sizeof(value));
+       struct {
+               char *name;
+               char *devpath;
+               int fd;
+       } buttons[] = {
+               { "XEINT_0", "/dev/gpio57", },
+               { "XEINT_1", "/dev/gpio58", },
+               { "XEINT_2", "/dev/gpio59", },
+       };
 
-       close(fd);
-       return value[0] == '1';
-}
+       nbtns = sizeof(buttons) / sizeof(*buttons);
 
-void switch_main(int argc, char *argv[])
-{
-       // XEINT0 ~ XEINT2
-       // gpio57 ~ gpio59
+       poll_list = (struct pollfd *)malloc(sizeof(struct pollfd) * nbtns);
 
-       int i;
-       for (i = 0; i < 30; i++) {
-               if (gpio_read(57) == 0) {
-                       printf("XEINT0 pressed\n");
-               }
-               if (gpio_read(58) == 0) {
-                       printf("XEINT1 pressed\n");
-               }
-               if (gpio_read(59) == 0) {
-                       printf("XEINT2 pressed\n");
+       for (i = 0; i < nbtns; i++) {
+               printf("Opening %s(%s)...\n", buttons[i].devpath, buttons[i].name);
+               poll_list[i].fd = open(buttons[i].devpath, O_RDWR);
+               poll_list[i].events = POLLIN;
+       }
+
+       printf("Polling buttons...\n");
+       printf("(to terminate, press the same button twice in a row)\n");
+
+       prev = -1;
+       while (1) {
+               if (poll(poll_list, nbtns, 100)) {
+                       for (j = 0; j < nbtns; j++) {
+                               if (poll_list[j].revents & POLLIN) {
+                                       char buf[4];
+                                       lseek(poll_list[j].fd, 0, SEEK_SET);
+                                       read(poll_list[j].fd, buf, sizeof(buf));
+                                       printf("%s is %s\n", buttons[j].name,
+                                               buf[0] == '1' ? "rising" : "falling");
+
+                                       if (buf[0] == '1') {
+                                               if (prev == j) {
+                                                       goto out;
+                                               }
+                                               prev = j;
+                                       }
+                               }
+                       }
                }
+       }
 
-               up_mdelay(500);
+out:
+       for (i = 0; i < nbtns; i++) {
+               printf("Closing %s(%s)...\n", buttons[i].devpath, buttons[i].name);
+               close(poll_list[i].fd);
        }
+
+       free(poll_list);
 }