LED subsystem supports POLLPRI on "brightness" sysfs file of LED
class devices. This tool demonstrates how to use the feature.
Signed-off-by: Jacek Anaszewski <[email protected]>
Cc: Hans de Goede <[email protected]>
---
Changes since v1:
- added lseek which fixes non-blocking poll() behaviour
tools/leds/Makefile | 4 +--
tools/leds/led_notify_mon.c | 83 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 85 insertions(+), 2 deletions(-)
create mode 100644 tools/leds/led_notify_mon.c
diff --git a/tools/leds/Makefile b/tools/leds/Makefile
index c03a79e..0fa948a 100644
--- a/tools/leds/Makefile
+++ b/tools/leds/Makefile
@@ -3,11 +3,11 @@
CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra -g -I../../include/uapi
-all: uledmon
+all: uledmon led_notify_mon
%: %.c
$(CC) $(CFLAGS) -o $@ $^
clean:
- $(RM) uledmon
+ $(RM) uledmon led_notify_mon
.PHONY: all clean
diff --git a/tools/leds/led_notify_mon.c b/tools/leds/led_notify_mon.c
new file mode 100644
index 0000000..8b6e6f9
--- /dev/null
+++ b/tools/leds/led_notify_mon.c
@@ -0,0 +1,83 @@
+/*
+ * led_notify_mon.c
+ *
+ * This program monitors LED brightness change notifications,
+ * either having its origin in the hardware or in the software.
+ * A timestamp and brightness value is printed each time the brightness changes.
+ *
+ * Usage: led_notify_mon <device-name>
+ *
+ * <device-name> is the name of the LED class device to be monitored. Pressing
+ * CTRL+C will exit.
+ */
+
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <linux/uleds.h>
+
+int main(int argc, char const *argv[])
+{
+ int fd, ret;
+ char brightness_file_path[LEDS_MAX_NAME_SIZE + 11];
+ struct pollfd pollfd;
+ struct timespec ts;
+ char buf[11];
+
+ if (argc != 2) {
+ fprintf(stderr, "Requires <device-name> argument\n");
+ return 1;
+ }
+
+ snprintf(brightness_file_path, LEDS_MAX_NAME_SIZE,
+ "/sys/class/leds/%s/brightness", argv[1]);
+
+ fd = open(brightness_file_path, O_RDONLY);
+ if (fd == -1) {
+ printf("Failed to open %s file\n", brightness_file_path);
+ return 1;
+ }
+
+ ret = read(fd, buf, sizeof(buf));
+ if (ret < 0) {
+ printf("Failed to read %s file\n", brightness_file_path);
+ goto err_read;
+ }
+
+ pollfd.fd = fd;
+ pollfd.events = POLLPRI;
+
+ while (1) {
+ ret = poll(&pollfd, 1, -1);
+ if (ret == -1) {
+ printf("Failed to poll %s file (%d)\n",
+ brightness_file_path, ret);
+ ret = 1;
+ break;
+ }
+
+ clock_gettime(CLOCK_MONOTONIC, &ts);
+
+ ret = read(fd, buf, sizeof(buf));
+ if (ret < 0)
+ break;
+
+ ret = lseek(pollfd.fd, 0, SEEK_SET);
+ if (ret < 0) {
+ printf("lseek failed (%d)\n", ret);
+ break;
+ }
+
+ printf("[%ld.%09ld] %d\n", ts.tv_sec, ts.tv_nsec, atoi(buf));
+ }
+
+err_read:
+ close(fd);
+
+ return ret;
+}
--
1.9.1
Hi,
On 08-11-16 12:36, Jacek Anaszewski wrote:
> LED subsystem supports POLLPRI on "brightness" sysfs file of LED
> class devices. This tool demonstrates how to use the feature.
>
> Signed-off-by: Jacek Anaszewski <[email protected]>
> Cc: Hans de Goede <[email protected]>
Thank you.
Patch looks good to me:
Reviewed-by: Hans de Goede <[email protected]>
Regards,
Hans
> ---
> Changes since v1:
> - added lseek which fixes non-blocking poll() behaviour
>
> tools/leds/Makefile | 4 +--
> tools/leds/led_notify_mon.c | 83 +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 85 insertions(+), 2 deletions(-)
> create mode 100644 tools/leds/led_notify_mon.c
>
> diff --git a/tools/leds/Makefile b/tools/leds/Makefile
> index c03a79e..0fa948a 100644
> --- a/tools/leds/Makefile
> +++ b/tools/leds/Makefile
> @@ -3,11 +3,11 @@
> CC = $(CROSS_COMPILE)gcc
> CFLAGS = -Wall -Wextra -g -I../../include/uapi
>
> -all: uledmon
> +all: uledmon led_notify_mon
> %: %.c
> $(CC) $(CFLAGS) -o $@ $^
>
> clean:
> - $(RM) uledmon
> + $(RM) uledmon led_notify_mon
>
> .PHONY: all clean
> diff --git a/tools/leds/led_notify_mon.c b/tools/leds/led_notify_mon.c
> new file mode 100644
> index 0000000..8b6e6f9
> --- /dev/null
> +++ b/tools/leds/led_notify_mon.c
> @@ -0,0 +1,83 @@
> +/*
> + * led_notify_mon.c
> + *
> + * This program monitors LED brightness change notifications,
> + * either having its origin in the hardware or in the software.
> + * A timestamp and brightness value is printed each time the brightness changes.
> + *
> + * Usage: led_notify_mon <device-name>
> + *
> + * <device-name> is the name of the LED class device to be monitored. Pressing
> + * CTRL+C will exit.
> + */
> +
> +#include <fcntl.h>
> +#include <poll.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <time.h>
> +#include <unistd.h>
> +
> +#include <linux/uleds.h>
> +
> +int main(int argc, char const *argv[])
> +{
> + int fd, ret;
> + char brightness_file_path[LEDS_MAX_NAME_SIZE + 11];
> + struct pollfd pollfd;
> + struct timespec ts;
> + char buf[11];
> +
> + if (argc != 2) {
> + fprintf(stderr, "Requires <device-name> argument\n");
> + return 1;
> + }
> +
> + snprintf(brightness_file_path, LEDS_MAX_NAME_SIZE,
> + "/sys/class/leds/%s/brightness", argv[1]);
> +
> + fd = open(brightness_file_path, O_RDONLY);
> + if (fd == -1) {
> + printf("Failed to open %s file\n", brightness_file_path);
> + return 1;
> + }
> +
> + ret = read(fd, buf, sizeof(buf));
> + if (ret < 0) {
> + printf("Failed to read %s file\n", brightness_file_path);
> + goto err_read;
> + }
> +
> + pollfd.fd = fd;
> + pollfd.events = POLLPRI;
> +
> + while (1) {
> + ret = poll(&pollfd, 1, -1);
> + if (ret == -1) {
> + printf("Failed to poll %s file (%d)\n",
> + brightness_file_path, ret);
> + ret = 1;
> + break;
> + }
> +
> + clock_gettime(CLOCK_MONOTONIC, &ts);
> +
> + ret = read(fd, buf, sizeof(buf));
> + if (ret < 0)
> + break;
> +
> + ret = lseek(pollfd.fd, 0, SEEK_SET);
> + if (ret < 0) {
> + printf("lseek failed (%d)\n", ret);
> + break;
> + }
> +
> + printf("[%ld.%09ld] %d\n", ts.tv_sec, ts.tv_nsec, atoi(buf));
> + }
> +
> +err_read:
> + close(fd);
> +
> + return ret;
> +}
>
On 11/09/2016 12:50 PM, Hans de Goede wrote:
> Reviewed-by: Hans de Goede <[email protected]>
Applied, thanks.
--
Best regards,
Jacek Anaszewski