[hackers] [PATCH slstatus] Add basic backlight percentage support

From: David Demelier <markand_AT_malikania.fr>
Date: Sun, 20 May 2018 14:21:36 +0200

At the moment linux only, but will add support for FreeBSD and OpenBSD
as well.

---
 Makefile               |  1 +
 components/backlight.c | 33 +++++++++++++++++++++++++++++++++
 slstatus.h             |  3 +++
 3 files changed, 37 insertions(+)
 create mode 100644 components/backlight.c
diff --git a/Makefile b/Makefile
index 0e925cc..8e18969 100644
--- a/Makefile
+++ b/Makefile
_AT_@ -6,6 +6,7 @@ include config.mk
 
 REQ = util
 COM =\
+	components/backlight\
 	components/battery\
 	components/cpu\
 	components/datetime\
diff --git a/components/backlight.c b/components/backlight.c
new file mode 100644
index 0000000..05c12aa
--- /dev/null
+++ b/components/backlight.c
_AT_@ -0,0 +1,33 @@
+/* See LICENSE file for copyright and license details. */
+
+#include <stddef.h>
+
+#include "../util.h"
+
+#if defined(__linux__)
+
+#include <limits.h>
+
+#define BRIGHTNESS_MAX "/sys/class/backlight/%s/max_brightness"
+#define BRIGHTNESS_CUR "/sys/class/backlight/%s/brightness"
+
+const char *
+backlight_perc(const char *card)
+{
+	char path[PATH_MAX];
+	int max, cur;
+
+	if (esnprintf(path, sizeof (path), BRIGHTNESS_MAX, card) < 0 ||
+		pscanf(path, "%d", &max) < 0) {
+		return NULL;
+	}
+
+	if (esnprintf(path, sizeof (path), BRIGHTNESS_CUR, card) < 0 ||
+		pscanf(path, "%d", &cur) < 0) {
+		return NULL;
+	}
+
+	return bprintf("%d%%", cur * 100 / max);
+}
+
+#endif
diff --git a/slstatus.h b/slstatus.h
index 8bd8bb5..a18b881 100644
--- a/slstatus.h
+++ b/slstatus.h
_AT_@ -1,5 +1,8 @@
 /* See LICENSE file for copyright and license details. */
 
+/* backlight */
+const char *backlight_perc(const char *);
+
 /* battery */
 const char *battery_perc(const char *);
 const char *battery_state(const char *);
-- 
2.17.0

Received on Sun May 20 2018 - 14:21:36 CEST